ListView.java revision 2ea329290cb470cfd8a846c63bc333fdb4f9ff1d
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import android.annotation.Nullable; 20import android.os.Bundle; 21import android.os.Trace; 22import com.android.internal.R; 23import com.android.internal.util.Predicate; 24import com.google.android.collect.Lists; 25 26import android.annotation.IdRes; 27import android.annotation.NonNull; 28import android.content.Context; 29import android.content.Intent; 30import android.content.res.TypedArray; 31import android.graphics.Canvas; 32import android.graphics.Paint; 33import android.graphics.PixelFormat; 34import android.graphics.Rect; 35import android.graphics.drawable.Drawable; 36import android.util.AttributeSet; 37import android.util.MathUtils; 38import android.util.SparseBooleanArray; 39import android.view.FocusFinder; 40import android.view.KeyEvent; 41import android.view.SoundEffectConstants; 42import android.view.View; 43import android.view.ViewDebug; 44import android.view.ViewGroup; 45import android.view.ViewHierarchyEncoder; 46import android.view.ViewParent; 47import android.view.ViewRootImpl; 48import android.view.accessibility.AccessibilityNodeInfo; 49import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction; 50import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 51import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 52import android.view.accessibility.AccessibilityNodeProvider; 53import android.widget.RemoteViews.RemoteView; 54 55import java.util.ArrayList; 56 57/* 58 * Implementation Notes: 59 * 60 * Some terminology: 61 * 62 * index - index of the items that are currently visible 63 * position - index of the items in the cursor 64 */ 65 66 67/** 68 * A view that shows items in a vertically scrolling list. The items 69 * come from the {@link ListAdapter} associated with this view. 70 * 71 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 72 * guide.</p> 73 * 74 * @attr ref android.R.styleable#ListView_entries 75 * @attr ref android.R.styleable#ListView_divider 76 * @attr ref android.R.styleable#ListView_dividerHeight 77 * @attr ref android.R.styleable#ListView_headerDividersEnabled 78 * @attr ref android.R.styleable#ListView_footerDividersEnabled 79 */ 80@RemoteView 81public class ListView extends AbsListView { 82 /** 83 * Used to indicate a no preference for a position type. 84 */ 85 static final int NO_POSITION = -1; 86 87 /** 88 * When arrow scrolling, ListView will never scroll more than this factor 89 * times the height of the list. 90 */ 91 private static final float MAX_SCROLL_FACTOR = 0.33f; 92 93 /** 94 * When arrow scrolling, need a certain amount of pixels to preview next 95 * items. This is usually the fading edge, but if that is small enough, 96 * we want to make sure we preview at least this many pixels. 97 */ 98 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 99 100 /** 101 * A class that represents a fixed view in a list, for example a header at the top 102 * or a footer at the bottom. 103 */ 104 public class FixedViewInfo { 105 /** The view to add to the list */ 106 public View view; 107 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 108 public Object data; 109 /** <code>true</code> if the fixed view should be selectable in the list */ 110 public boolean isSelectable; 111 } 112 113 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 114 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 115 116 Drawable mDivider; 117 int mDividerHeight; 118 119 Drawable mOverScrollHeader; 120 Drawable mOverScrollFooter; 121 122 private boolean mIsCacheColorOpaque; 123 private boolean mDividerIsOpaque; 124 125 private boolean mHeaderDividersEnabled; 126 private boolean mFooterDividersEnabled; 127 128 private boolean mAreAllItemsSelectable = true; 129 130 private boolean mItemsCanFocus = false; 131 132 // used for temporary calculations. 133 private final Rect mTempRect = new Rect(); 134 private Paint mDividerPaint; 135 136 // the single allocated result per list view; kinda cheesey but avoids 137 // allocating these thingies too often. 138 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 139 140 // Keeps focused children visible through resizes 141 private FocusSelector mFocusSelector; 142 143 public ListView(Context context) { 144 this(context, null); 145 } 146 147 public ListView(Context context, AttributeSet attrs) { 148 this(context, attrs, R.attr.listViewStyle); 149 } 150 151 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 152 this(context, attrs, defStyleAttr, 0); 153 } 154 155 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 156 super(context, attrs, defStyleAttr, defStyleRes); 157 158 final TypedArray a = context.obtainStyledAttributes( 159 attrs, R.styleable.ListView, defStyleAttr, defStyleRes); 160 161 final CharSequence[] entries = a.getTextArray(R.styleable.ListView_entries); 162 if (entries != null) { 163 setAdapter(new ArrayAdapter<>(context, R.layout.simple_list_item_1, entries)); 164 } 165 166 final Drawable d = a.getDrawable(R.styleable.ListView_divider); 167 if (d != null) { 168 // Use an implicit divider height which may be explicitly 169 // overridden by android:dividerHeight further down. 170 setDivider(d); 171 } 172 173 final Drawable osHeader = a.getDrawable(R.styleable.ListView_overScrollHeader); 174 if (osHeader != null) { 175 setOverscrollHeader(osHeader); 176 } 177 178 final Drawable osFooter = a.getDrawable(R.styleable.ListView_overScrollFooter); 179 if (osFooter != null) { 180 setOverscrollFooter(osFooter); 181 } 182 183 // Use an explicit divider height, if specified. 184 if (a.hasValueOrEmpty(R.styleable.ListView_dividerHeight)) { 185 final int dividerHeight = a.getDimensionPixelSize( 186 R.styleable.ListView_dividerHeight, 0); 187 if (dividerHeight != 0) { 188 setDividerHeight(dividerHeight); 189 } 190 } 191 192 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 193 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 194 195 a.recycle(); 196 } 197 198 /** 199 * @return The maximum amount a list view will scroll in response to 200 * an arrow event. 201 */ 202 public int getMaxScrollAmount() { 203 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 204 } 205 206 /** 207 * Make sure views are touching the top or bottom edge, as appropriate for 208 * our gravity 209 */ 210 private void adjustViewsUpOrDown() { 211 final int childCount = getChildCount(); 212 int delta; 213 214 if (childCount > 0) { 215 View child; 216 217 if (!mStackFromBottom) { 218 // Uh-oh -- we came up short. Slide all views up to make them 219 // align with the top 220 child = getChildAt(0); 221 delta = child.getTop() - mListPadding.top; 222 if (mFirstPosition != 0) { 223 // It's OK to have some space above the first item if it is 224 // part of the vertical spacing 225 delta -= mDividerHeight; 226 } 227 if (delta < 0) { 228 // We only are looking to see if we are too low, not too high 229 delta = 0; 230 } 231 } else { 232 // we are too high, slide all views down to align with bottom 233 child = getChildAt(childCount - 1); 234 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 235 236 if (mFirstPosition + childCount < mItemCount) { 237 // It's OK to have some space below the last item if it is 238 // part of the vertical spacing 239 delta += mDividerHeight; 240 } 241 242 if (delta > 0) { 243 delta = 0; 244 } 245 } 246 247 if (delta != 0) { 248 offsetChildrenTopAndBottom(-delta); 249 } 250 } 251 } 252 253 /** 254 * Add a fixed view to appear at the top of the list. If this method is 255 * called more than once, the views will appear in the order they were 256 * added. Views added using this call can take focus if they want. 257 * <p> 258 * Note: When first introduced, this method could only be called before 259 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 260 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 261 * called at any time. If the ListView's adapter does not extend 262 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 263 * instance of {@link WrapperListAdapter}. 264 * 265 * @param v The view to add. 266 * @param data Data to associate with this view 267 * @param isSelectable whether the item is selectable 268 */ 269 public void addHeaderView(View v, Object data, boolean isSelectable) { 270 final FixedViewInfo info = new FixedViewInfo(); 271 info.view = v; 272 info.data = data; 273 info.isSelectable = isSelectable; 274 mHeaderViewInfos.add(info); 275 mAreAllItemsSelectable &= isSelectable; 276 277 // Wrap the adapter if it wasn't already wrapped. 278 if (mAdapter != null) { 279 if (!(mAdapter instanceof HeaderViewListAdapter)) { 280 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 281 } 282 283 // In the case of re-adding a header view, or adding one later on, 284 // we need to notify the observer. 285 if (mDataSetObserver != null) { 286 mDataSetObserver.onChanged(); 287 } 288 } 289 } 290 291 /** 292 * Add a fixed view to appear at the top of the list. If addHeaderView is 293 * called more than once, the views will appear in the order they were 294 * added. Views added using this call can take focus if they want. 295 * <p> 296 * Note: When first introduced, this method could only be called before 297 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 298 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 299 * called at any time. If the ListView's adapter does not extend 300 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 301 * instance of {@link WrapperListAdapter}. 302 * 303 * @param v The view to add. 304 */ 305 public void addHeaderView(View v) { 306 addHeaderView(v, null, true); 307 } 308 309 @Override 310 public int getHeaderViewsCount() { 311 return mHeaderViewInfos.size(); 312 } 313 314 /** 315 * Removes a previously-added header view. 316 * 317 * @param v The view to remove 318 * @return true if the view was removed, false if the view was not a header 319 * view 320 */ 321 public boolean removeHeaderView(View v) { 322 if (mHeaderViewInfos.size() > 0) { 323 boolean result = false; 324 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 325 if (mDataSetObserver != null) { 326 mDataSetObserver.onChanged(); 327 } 328 result = true; 329 } 330 removeFixedViewInfo(v, mHeaderViewInfos); 331 return result; 332 } 333 return false; 334 } 335 336 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 337 int len = where.size(); 338 for (int i = 0; i < len; ++i) { 339 FixedViewInfo info = where.get(i); 340 if (info.view == v) { 341 where.remove(i); 342 break; 343 } 344 } 345 } 346 347 /** 348 * Add a fixed view to appear at the bottom of the list. If addFooterView is 349 * called more than once, the views will appear in the order they were 350 * added. Views added using this call can take focus if they want. 351 * <p> 352 * Note: When first introduced, this method could only be called before 353 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 354 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 355 * called at any time. If the ListView's adapter does not extend 356 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 357 * instance of {@link WrapperListAdapter}. 358 * 359 * @param v The view to add. 360 * @param data Data to associate with this view 361 * @param isSelectable true if the footer view can be selected 362 */ 363 public void addFooterView(View v, Object data, boolean isSelectable) { 364 final FixedViewInfo info = new FixedViewInfo(); 365 info.view = v; 366 info.data = data; 367 info.isSelectable = isSelectable; 368 mFooterViewInfos.add(info); 369 mAreAllItemsSelectable &= isSelectable; 370 371 // Wrap the adapter if it wasn't already wrapped. 372 if (mAdapter != null) { 373 if (!(mAdapter instanceof HeaderViewListAdapter)) { 374 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 375 } 376 377 // In the case of re-adding a footer view, or adding one later on, 378 // we need to notify the observer. 379 if (mDataSetObserver != null) { 380 mDataSetObserver.onChanged(); 381 } 382 } 383 } 384 385 /** 386 * Add a fixed view to appear at the bottom of the list. If addFooterView is 387 * called more than once, the views will appear in the order they were 388 * added. Views added using this call can take focus if they want. 389 * <p> 390 * Note: When first introduced, this method could only be called before 391 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 392 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 393 * called at any time. If the ListView's adapter does not extend 394 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 395 * instance of {@link WrapperListAdapter}. 396 * 397 * @param v The view to add. 398 */ 399 public void addFooterView(View v) { 400 addFooterView(v, null, true); 401 } 402 403 @Override 404 public int getFooterViewsCount() { 405 return mFooterViewInfos.size(); 406 } 407 408 /** 409 * Removes a previously-added footer view. 410 * 411 * @param v The view to remove 412 * @return 413 * true if the view was removed, false if the view was not a footer view 414 */ 415 public boolean removeFooterView(View v) { 416 if (mFooterViewInfos.size() > 0) { 417 boolean result = false; 418 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 419 if (mDataSetObserver != null) { 420 mDataSetObserver.onChanged(); 421 } 422 result = true; 423 } 424 removeFixedViewInfo(v, mFooterViewInfos); 425 return result; 426 } 427 return false; 428 } 429 430 /** 431 * Returns the adapter currently in use in this ListView. The returned adapter 432 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 433 * might be a {@link WrapperListAdapter}. 434 * 435 * @return The adapter currently used to display data in this ListView. 436 * 437 * @see #setAdapter(ListAdapter) 438 */ 439 @Override 440 public ListAdapter getAdapter() { 441 return mAdapter; 442 } 443 444 /** 445 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 446 * through the specified intent. 447 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 448 */ 449 @android.view.RemotableViewMethod 450 public void setRemoteViewsAdapter(Intent intent) { 451 super.setRemoteViewsAdapter(intent); 452 } 453 454 /** 455 * Sets the data behind this ListView. 456 * 457 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 458 * depending on the ListView features currently in use. For instance, adding 459 * headers and/or footers will cause the adapter to be wrapped. 460 * 461 * @param adapter The ListAdapter which is responsible for maintaining the 462 * data backing this list and for producing a view to represent an 463 * item in that data set. 464 * 465 * @see #getAdapter() 466 */ 467 @Override 468 public void setAdapter(ListAdapter adapter) { 469 if (mAdapter != null && mDataSetObserver != null) { 470 mAdapter.unregisterDataSetObserver(mDataSetObserver); 471 } 472 473 resetList(); 474 mRecycler.clear(); 475 476 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 477 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 478 } else { 479 mAdapter = adapter; 480 } 481 482 mOldSelectedPosition = INVALID_POSITION; 483 mOldSelectedRowId = INVALID_ROW_ID; 484 485 // AbsListView#setAdapter will update choice mode states. 486 super.setAdapter(adapter); 487 488 if (mAdapter != null) { 489 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 490 mOldItemCount = mItemCount; 491 mItemCount = mAdapter.getCount(); 492 checkFocus(); 493 494 mDataSetObserver = new AdapterDataSetObserver(); 495 mAdapter.registerDataSetObserver(mDataSetObserver); 496 497 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 498 499 int position; 500 if (mStackFromBottom) { 501 position = lookForSelectablePosition(mItemCount - 1, false); 502 } else { 503 position = lookForSelectablePosition(0, true); 504 } 505 setSelectedPositionInt(position); 506 setNextSelectedPositionInt(position); 507 508 if (mItemCount == 0) { 509 // Nothing selected 510 checkSelectionChanged(); 511 } 512 } else { 513 mAreAllItemsSelectable = true; 514 checkFocus(); 515 // Nothing selected 516 checkSelectionChanged(); 517 } 518 519 requestLayout(); 520 } 521 522 /** 523 * The list is empty. Clear everything out. 524 */ 525 @Override 526 void resetList() { 527 // The parent's resetList() will remove all views from the layout so we need to 528 // cleanup the state of our footers and headers 529 clearRecycledState(mHeaderViewInfos); 530 clearRecycledState(mFooterViewInfos); 531 532 super.resetList(); 533 534 mLayoutMode = LAYOUT_NORMAL; 535 } 536 537 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 538 if (infos != null) { 539 final int count = infos.size(); 540 541 for (int i = 0; i < count; i++) { 542 final View child = infos.get(i).view; 543 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 544 if (p != null) { 545 p.recycledHeaderFooter = false; 546 } 547 } 548 } 549 } 550 551 /** 552 * @return Whether the list needs to show the top fading edge 553 */ 554 private boolean showingTopFadingEdge() { 555 final int listTop = mScrollY + mListPadding.top; 556 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 557 } 558 559 /** 560 * @return Whether the list needs to show the bottom fading edge 561 */ 562 private boolean showingBottomFadingEdge() { 563 final int childCount = getChildCount(); 564 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 565 final int lastVisiblePosition = mFirstPosition + childCount - 1; 566 567 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 568 569 return (lastVisiblePosition < mItemCount - 1) 570 || (bottomOfBottomChild < listBottom); 571 } 572 573 574 @Override 575 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 576 577 int rectTopWithinChild = rect.top; 578 579 // offset so rect is in coordinates of the this view 580 rect.offset(child.getLeft(), child.getTop()); 581 rect.offset(-child.getScrollX(), -child.getScrollY()); 582 583 final int height = getHeight(); 584 int listUnfadedTop = getScrollY(); 585 int listUnfadedBottom = listUnfadedTop + height; 586 final int fadingEdge = getVerticalFadingEdgeLength(); 587 588 if (showingTopFadingEdge()) { 589 // leave room for top fading edge as long as rect isn't at very top 590 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 591 listUnfadedTop += fadingEdge; 592 } 593 } 594 595 int childCount = getChildCount(); 596 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 597 598 if (showingBottomFadingEdge()) { 599 // leave room for bottom fading edge as long as rect isn't at very bottom 600 if ((mSelectedPosition < mItemCount - 1) 601 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 602 listUnfadedBottom -= fadingEdge; 603 } 604 } 605 606 int scrollYDelta = 0; 607 608 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 609 // need to MOVE DOWN to get it in view: move down just enough so 610 // that the entire rectangle is in view (or at least the first 611 // screen size chunk). 612 613 if (rect.height() > height) { 614 // just enough to get screen size chunk on 615 scrollYDelta += (rect.top - listUnfadedTop); 616 } else { 617 // get entire rect at bottom of screen 618 scrollYDelta += (rect.bottom - listUnfadedBottom); 619 } 620 621 // make sure we aren't scrolling beyond the end of our children 622 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 623 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 624 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 625 // need to MOVE UP to get it in view: move up just enough so that 626 // entire rectangle is in view (or at least the first screen 627 // size chunk of it). 628 629 if (rect.height() > height) { 630 // screen size chunk 631 scrollYDelta -= (listUnfadedBottom - rect.bottom); 632 } else { 633 // entire rect at top 634 scrollYDelta -= (listUnfadedTop - rect.top); 635 } 636 637 // make sure we aren't scrolling any further than the top our children 638 int top = getChildAt(0).getTop(); 639 int deltaToTop = top - listUnfadedTop; 640 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 641 } 642 643 final boolean scroll = scrollYDelta != 0; 644 if (scroll) { 645 scrollListItemsBy(-scrollYDelta); 646 positionSelector(INVALID_POSITION, child); 647 mSelectedTop = child.getTop(); 648 invalidate(); 649 } 650 return scroll; 651 } 652 653 /** 654 * {@inheritDoc} 655 */ 656 @Override 657 void fillGap(boolean down) { 658 final int count = getChildCount(); 659 if (down) { 660 int paddingTop = 0; 661 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 662 paddingTop = getListPaddingTop(); 663 } 664 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 665 paddingTop; 666 fillDown(mFirstPosition + count, startOffset); 667 correctTooHigh(getChildCount()); 668 } else { 669 int paddingBottom = 0; 670 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 671 paddingBottom = getListPaddingBottom(); 672 } 673 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 674 getHeight() - paddingBottom; 675 fillUp(mFirstPosition - 1, startOffset); 676 correctTooLow(getChildCount()); 677 } 678 } 679 680 /** 681 * Fills the list from pos down to the end of the list view. 682 * 683 * @param pos The first position to put in the list 684 * 685 * @param nextTop The location where the top of the item associated with pos 686 * should be drawn 687 * 688 * @return The view that is currently selected, if it happens to be in the 689 * range that we draw. 690 */ 691 private View fillDown(int pos, int nextTop) { 692 View selectedView = null; 693 694 int end = (mBottom - mTop); 695 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 696 end -= mListPadding.bottom; 697 } 698 699 while (nextTop < end && pos < mItemCount) { 700 // is this the selected item? 701 boolean selected = pos == mSelectedPosition; 702 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 703 704 nextTop = child.getBottom() + mDividerHeight; 705 if (selected) { 706 selectedView = child; 707 } 708 pos++; 709 } 710 711 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 712 return selectedView; 713 } 714 715 /** 716 * Fills the list from pos up to the top of the list view. 717 * 718 * @param pos The first position to put in the list 719 * 720 * @param nextBottom The location where the bottom of the item associated 721 * with pos should be drawn 722 * 723 * @return The view that is currently selected 724 */ 725 private View fillUp(int pos, int nextBottom) { 726 View selectedView = null; 727 728 int end = 0; 729 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 730 end = mListPadding.top; 731 } 732 733 while (nextBottom > end && pos >= 0) { 734 // is this the selected item? 735 boolean selected = pos == mSelectedPosition; 736 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 737 nextBottom = child.getTop() - mDividerHeight; 738 if (selected) { 739 selectedView = child; 740 } 741 pos--; 742 } 743 744 mFirstPosition = pos + 1; 745 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 746 return selectedView; 747 } 748 749 /** 750 * Fills the list from top to bottom, starting with mFirstPosition 751 * 752 * @param nextTop The location where the top of the first item should be 753 * drawn 754 * 755 * @return The view that is currently selected 756 */ 757 private View fillFromTop(int nextTop) { 758 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 759 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 760 if (mFirstPosition < 0) { 761 mFirstPosition = 0; 762 } 763 return fillDown(mFirstPosition, nextTop); 764 } 765 766 767 /** 768 * Put mSelectedPosition in the middle of the screen and then build up and 769 * down from there. This method forces mSelectedPosition to the center. 770 * 771 * @param childrenTop Top of the area in which children can be drawn, as 772 * measured in pixels 773 * @param childrenBottom Bottom of the area in which children can be drawn, 774 * as measured in pixels 775 * @return Currently selected view 776 */ 777 private View fillFromMiddle(int childrenTop, int childrenBottom) { 778 int height = childrenBottom - childrenTop; 779 780 int position = reconcileSelectedPosition(); 781 782 View sel = makeAndAddView(position, childrenTop, true, 783 mListPadding.left, true); 784 mFirstPosition = position; 785 786 int selHeight = sel.getMeasuredHeight(); 787 if (selHeight <= height) { 788 sel.offsetTopAndBottom((height - selHeight) / 2); 789 } 790 791 fillAboveAndBelow(sel, position); 792 793 if (!mStackFromBottom) { 794 correctTooHigh(getChildCount()); 795 } else { 796 correctTooLow(getChildCount()); 797 } 798 799 return sel; 800 } 801 802 /** 803 * Once the selected view as been placed, fill up the visible area above and 804 * below it. 805 * 806 * @param sel The selected view 807 * @param position The position corresponding to sel 808 */ 809 private void fillAboveAndBelow(View sel, int position) { 810 final int dividerHeight = mDividerHeight; 811 if (!mStackFromBottom) { 812 fillUp(position - 1, sel.getTop() - dividerHeight); 813 adjustViewsUpOrDown(); 814 fillDown(position + 1, sel.getBottom() + dividerHeight); 815 } else { 816 fillDown(position + 1, sel.getBottom() + dividerHeight); 817 adjustViewsUpOrDown(); 818 fillUp(position - 1, sel.getTop() - dividerHeight); 819 } 820 } 821 822 823 /** 824 * Fills the grid based on positioning the new selection at a specific 825 * location. The selection may be moved so that it does not intersect the 826 * faded edges. The grid is then filled upwards and downwards from there. 827 * 828 * @param selectedTop Where the selected item should be 829 * @param childrenTop Where to start drawing children 830 * @param childrenBottom Last pixel where children can be drawn 831 * @return The view that currently has selection 832 */ 833 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 834 int fadingEdgeLength = getVerticalFadingEdgeLength(); 835 final int selectedPosition = mSelectedPosition; 836 837 View sel; 838 839 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 840 selectedPosition); 841 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 842 selectedPosition); 843 844 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 845 846 847 // Some of the newly selected item extends below the bottom of the list 848 if (sel.getBottom() > bottomSelectionPixel) { 849 // Find space available above the selection into which we can scroll 850 // upwards 851 final int spaceAbove = sel.getTop() - topSelectionPixel; 852 853 // Find space required to bring the bottom of the selected item 854 // fully into view 855 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 856 final int offset = Math.min(spaceAbove, spaceBelow); 857 858 // Now offset the selected item to get it into view 859 sel.offsetTopAndBottom(-offset); 860 } else if (sel.getTop() < topSelectionPixel) { 861 // Find space required to bring the top of the selected item fully 862 // into view 863 final int spaceAbove = topSelectionPixel - sel.getTop(); 864 865 // Find space available below the selection into which we can scroll 866 // downwards 867 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 868 final int offset = Math.min(spaceAbove, spaceBelow); 869 870 // Offset the selected item to get it into view 871 sel.offsetTopAndBottom(offset); 872 } 873 874 // Fill in views above and below 875 fillAboveAndBelow(sel, selectedPosition); 876 877 if (!mStackFromBottom) { 878 correctTooHigh(getChildCount()); 879 } else { 880 correctTooLow(getChildCount()); 881 } 882 883 return sel; 884 } 885 886 /** 887 * Calculate the bottom-most pixel we can draw the selection into 888 * 889 * @param childrenBottom Bottom pixel were children can be drawn 890 * @param fadingEdgeLength Length of the fading edge in pixels, if present 891 * @param selectedPosition The position that will be selected 892 * @return The bottom-most pixel we can draw the selection into 893 */ 894 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 895 int selectedPosition) { 896 int bottomSelectionPixel = childrenBottom; 897 if (selectedPosition != mItemCount - 1) { 898 bottomSelectionPixel -= fadingEdgeLength; 899 } 900 return bottomSelectionPixel; 901 } 902 903 /** 904 * Calculate the top-most pixel we can draw the selection into 905 * 906 * @param childrenTop Top pixel were children can be drawn 907 * @param fadingEdgeLength Length of the fading edge in pixels, if present 908 * @param selectedPosition The position that will be selected 909 * @return The top-most pixel we can draw the selection into 910 */ 911 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 912 // first pixel we can draw the selection into 913 int topSelectionPixel = childrenTop; 914 if (selectedPosition > 0) { 915 topSelectionPixel += fadingEdgeLength; 916 } 917 return topSelectionPixel; 918 } 919 920 /** 921 * Smoothly scroll to the specified adapter position. The view will 922 * scroll such that the indicated position is displayed. 923 * @param position Scroll to this adapter position. 924 */ 925 @android.view.RemotableViewMethod 926 public void smoothScrollToPosition(int position) { 927 super.smoothScrollToPosition(position); 928 } 929 930 /** 931 * Smoothly scroll to the specified adapter position offset. The view will 932 * scroll such that the indicated position is displayed. 933 * @param offset The amount to offset from the adapter position to scroll to. 934 */ 935 @android.view.RemotableViewMethod 936 public void smoothScrollByOffset(int offset) { 937 super.smoothScrollByOffset(offset); 938 } 939 940 /** 941 * Fills the list based on positioning the new selection relative to the old 942 * selection. The new selection will be placed at, above, or below the 943 * location of the new selection depending on how the selection is moving. 944 * The selection will then be pinned to the visible part of the screen, 945 * excluding the edges that are faded. The list is then filled upwards and 946 * downwards from there. 947 * 948 * @param oldSel The old selected view. Useful for trying to put the new 949 * selection in the same place 950 * @param newSel The view that is to become selected. Useful for trying to 951 * put the new selection in the same place 952 * @param delta Which way we are moving 953 * @param childrenTop Where to start drawing children 954 * @param childrenBottom Last pixel where children can be drawn 955 * @return The view that currently has selection 956 */ 957 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 958 int childrenBottom) { 959 int fadingEdgeLength = getVerticalFadingEdgeLength(); 960 final int selectedPosition = mSelectedPosition; 961 962 View sel; 963 964 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 965 selectedPosition); 966 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 967 selectedPosition); 968 969 if (delta > 0) { 970 /* 971 * Case 1: Scrolling down. 972 */ 973 974 /* 975 * Before After 976 * | | | | 977 * +-------+ +-------+ 978 * | A | | A | 979 * | 1 | => +-------+ 980 * +-------+ | B | 981 * | B | | 2 | 982 * +-------+ +-------+ 983 * | | | | 984 * 985 * Try to keep the top of the previously selected item where it was. 986 * oldSel = A 987 * sel = B 988 */ 989 990 // Put oldSel (A) where it belongs 991 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 992 mListPadding.left, false); 993 994 final int dividerHeight = mDividerHeight; 995 996 // Now put the new selection (B) below that 997 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 998 mListPadding.left, true); 999 1000 // Some of the newly selected item extends below the bottom of the list 1001 if (sel.getBottom() > bottomSelectionPixel) { 1002 1003 // Find space available above the selection into which we can scroll upwards 1004 int spaceAbove = sel.getTop() - topSelectionPixel; 1005 1006 // Find space required to bring the bottom of the selected item fully into view 1007 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1008 1009 // Don't scroll more than half the height of the list 1010 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1011 int offset = Math.min(spaceAbove, spaceBelow); 1012 offset = Math.min(offset, halfVerticalSpace); 1013 1014 // We placed oldSel, so offset that item 1015 oldSel.offsetTopAndBottom(-offset); 1016 // Now offset the selected item to get it into view 1017 sel.offsetTopAndBottom(-offset); 1018 } 1019 1020 // Fill in views above and below 1021 if (!mStackFromBottom) { 1022 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1023 adjustViewsUpOrDown(); 1024 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1025 } else { 1026 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1027 adjustViewsUpOrDown(); 1028 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1029 } 1030 } else if (delta < 0) { 1031 /* 1032 * Case 2: Scrolling up. 1033 */ 1034 1035 /* 1036 * Before After 1037 * | | | | 1038 * +-------+ +-------+ 1039 * | A | | A | 1040 * +-------+ => | 1 | 1041 * | B | +-------+ 1042 * | 2 | | B | 1043 * +-------+ +-------+ 1044 * | | | | 1045 * 1046 * Try to keep the top of the item about to become selected where it was. 1047 * newSel = A 1048 * olSel = B 1049 */ 1050 1051 if (newSel != null) { 1052 // Try to position the top of newSel (A) where it was before it was selected 1053 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1054 true); 1055 } else { 1056 // If (A) was not on screen and so did not have a view, position 1057 // it above the oldSel (B) 1058 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1059 true); 1060 } 1061 1062 // Some of the newly selected item extends above the top of the list 1063 if (sel.getTop() < topSelectionPixel) { 1064 // Find space required to bring the top of the selected item fully into view 1065 int spaceAbove = topSelectionPixel - sel.getTop(); 1066 1067 // Find space available below the selection into which we can scroll downwards 1068 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1069 1070 // Don't scroll more than half the height of the list 1071 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1072 int offset = Math.min(spaceAbove, spaceBelow); 1073 offset = Math.min(offset, halfVerticalSpace); 1074 1075 // Offset the selected item to get it into view 1076 sel.offsetTopAndBottom(offset); 1077 } 1078 1079 // Fill in views above and below 1080 fillAboveAndBelow(sel, selectedPosition); 1081 } else { 1082 1083 int oldTop = oldSel.getTop(); 1084 1085 /* 1086 * Case 3: Staying still 1087 */ 1088 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1089 1090 // We're staying still... 1091 if (oldTop < childrenTop) { 1092 // ... but the top of the old selection was off screen. 1093 // (This can happen if the data changes size out from under us) 1094 int newBottom = sel.getBottom(); 1095 if (newBottom < childrenTop + 20) { 1096 // Not enough visible -- bring it onscreen 1097 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1098 } 1099 } 1100 1101 // Fill in views above and below 1102 fillAboveAndBelow(sel, selectedPosition); 1103 } 1104 1105 return sel; 1106 } 1107 1108 private class FocusSelector implements Runnable { 1109 private int mPosition; 1110 private int mPositionTop; 1111 1112 public FocusSelector setup(int position, int top) { 1113 mPosition = position; 1114 mPositionTop = top; 1115 return this; 1116 } 1117 1118 public void run() { 1119 setSelectionFromTop(mPosition, mPositionTop); 1120 } 1121 } 1122 1123 @Override 1124 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1125 if (getChildCount() > 0) { 1126 View focusedChild = getFocusedChild(); 1127 if (focusedChild != null) { 1128 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1129 final int childBottom = focusedChild.getBottom(); 1130 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1131 final int top = focusedChild.getTop() - offset; 1132 if (mFocusSelector == null) { 1133 mFocusSelector = new FocusSelector(); 1134 } 1135 post(mFocusSelector.setup(childPosition, top)); 1136 } 1137 } 1138 super.onSizeChanged(w, h, oldw, oldh); 1139 } 1140 1141 @Override 1142 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1143 // Sets up mListPadding 1144 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1145 1146 final int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1147 final int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1148 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1149 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1150 1151 int childWidth = 0; 1152 int childHeight = 0; 1153 int childState = 0; 1154 1155 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1156 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED 1157 || heightMode == MeasureSpec.UNSPECIFIED)) { 1158 final View child = obtainView(0, mIsScrap); 1159 1160 // Lay out child directly against the parent measure spec so that 1161 // we can obtain exected minimum width and height. 1162 measureScrapChild(child, 0, widthMeasureSpec, heightSize); 1163 1164 childWidth = child.getMeasuredWidth(); 1165 childHeight = child.getMeasuredHeight(); 1166 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1167 1168 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1169 ((LayoutParams) child.getLayoutParams()).viewType)) { 1170 mRecycler.addScrapView(child, 0); 1171 } 1172 } 1173 1174 if (widthMode == MeasureSpec.UNSPECIFIED) { 1175 widthSize = mListPadding.left + mListPadding.right + childWidth + 1176 getVerticalScrollbarWidth(); 1177 } else { 1178 widthSize |= (childState & MEASURED_STATE_MASK); 1179 } 1180 1181 if (heightMode == MeasureSpec.UNSPECIFIED) { 1182 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1183 getVerticalFadingEdgeLength() * 2; 1184 } 1185 1186 if (heightMode == MeasureSpec.AT_MOST) { 1187 // TODO: after first layout we should maybe start at the first visible position, not 0 1188 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1189 } 1190 1191 setMeasuredDimension(widthSize, heightSize); 1192 1193 mWidthMeasureSpec = widthMeasureSpec; 1194 } 1195 1196 private void measureScrapChild(View child, int position, int widthMeasureSpec, int heightHint) { 1197 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1198 if (p == null) { 1199 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1200 child.setLayoutParams(p); 1201 } 1202 p.viewType = mAdapter.getItemViewType(position); 1203 p.forceAdd = true; 1204 1205 final int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1206 mListPadding.left + mListPadding.right, p.width); 1207 final int lpHeight = p.height; 1208 final int childHeightSpec; 1209 if (lpHeight > 0) { 1210 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1211 } else { 1212 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(heightHint, MeasureSpec.UNSPECIFIED); 1213 } 1214 child.measure(childWidthSpec, childHeightSpec); 1215 1216 // Since this view was measured directly aginst the parent measure 1217 // spec, we must measure it again before reuse. 1218 child.forceLayout(); 1219 } 1220 1221 /** 1222 * @return True to recycle the views used to measure this ListView in 1223 * UNSPECIFIED/AT_MOST modes, false otherwise. 1224 * @hide 1225 */ 1226 @ViewDebug.ExportedProperty(category = "list") 1227 protected boolean recycleOnMeasure() { 1228 return true; 1229 } 1230 1231 /** 1232 * Measures the height of the given range of children (inclusive) and 1233 * returns the height with this ListView's padding and divider heights 1234 * included. If maxHeight is provided, the measuring will stop when the 1235 * current height reaches maxHeight. 1236 * 1237 * @param widthMeasureSpec The width measure spec to be given to a child's 1238 * {@link View#measure(int, int)}. 1239 * @param startPosition The position of the first child to be shown. 1240 * @param endPosition The (inclusive) position of the last child to be 1241 * shown. Specify {@link #NO_POSITION} if the last child should be 1242 * the last available child from the adapter. 1243 * @param maxHeight The maximum height that will be returned (if all the 1244 * children don't fit in this value, this value will be 1245 * returned). 1246 * @param disallowPartialChildPosition In general, whether the returned 1247 * height should only contain entire children. This is more 1248 * powerful--it is the first inclusive position at which partial 1249 * children will not be allowed. Example: it looks nice to have 1250 * at least 3 completely visible children, and in portrait this 1251 * will most likely fit; but in landscape there could be times 1252 * when even 2 children can not be completely shown, so a value 1253 * of 2 (remember, inclusive) would be good (assuming 1254 * startPosition is 0). 1255 * @return The height of this ListView with the given children. 1256 */ 1257 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1258 int maxHeight, int disallowPartialChildPosition) { 1259 final ListAdapter adapter = mAdapter; 1260 if (adapter == null) { 1261 return mListPadding.top + mListPadding.bottom; 1262 } 1263 1264 // Include the padding of the list 1265 int returnedHeight = mListPadding.top + mListPadding.bottom; 1266 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1267 // The previous height value that was less than maxHeight and contained 1268 // no partial children 1269 int prevHeightWithoutPartialChild = 0; 1270 int i; 1271 View child; 1272 1273 // mItemCount - 1 since endPosition parameter is inclusive 1274 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1275 final AbsListView.RecycleBin recycleBin = mRecycler; 1276 final boolean recyle = recycleOnMeasure(); 1277 final boolean[] isScrap = mIsScrap; 1278 1279 for (i = startPosition; i <= endPosition; ++i) { 1280 child = obtainView(i, isScrap); 1281 1282 measureScrapChild(child, i, widthMeasureSpec, maxHeight); 1283 1284 if (i > 0) { 1285 // Count the divider for all but one child 1286 returnedHeight += dividerHeight; 1287 } 1288 1289 // Recycle the view before we possibly return from the method 1290 if (recyle && recycleBin.shouldRecycleViewType( 1291 ((LayoutParams) child.getLayoutParams()).viewType)) { 1292 recycleBin.addScrapView(child, -1); 1293 } 1294 1295 returnedHeight += child.getMeasuredHeight(); 1296 1297 if (returnedHeight >= maxHeight) { 1298 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1299 // then the i'th position did not fit completely. 1300 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1301 && (i > disallowPartialChildPosition) // We've past the min pos 1302 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1303 && (returnedHeight != maxHeight) // i'th child did not fit completely 1304 ? prevHeightWithoutPartialChild 1305 : maxHeight; 1306 } 1307 1308 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1309 prevHeightWithoutPartialChild = returnedHeight; 1310 } 1311 } 1312 1313 // At this point, we went through the range of children, and they each 1314 // completely fit, so return the returnedHeight 1315 return returnedHeight; 1316 } 1317 1318 @Override 1319 int findMotionRow(int y) { 1320 int childCount = getChildCount(); 1321 if (childCount > 0) { 1322 if (!mStackFromBottom) { 1323 for (int i = 0; i < childCount; i++) { 1324 View v = getChildAt(i); 1325 if (y <= v.getBottom()) { 1326 return mFirstPosition + i; 1327 } 1328 } 1329 } else { 1330 for (int i = childCount - 1; i >= 0; i--) { 1331 View v = getChildAt(i); 1332 if (y >= v.getTop()) { 1333 return mFirstPosition + i; 1334 } 1335 } 1336 } 1337 } 1338 return INVALID_POSITION; 1339 } 1340 1341 /** 1342 * Put a specific item at a specific location on the screen and then build 1343 * up and down from there. 1344 * 1345 * @param position The reference view to use as the starting point 1346 * @param top Pixel offset from the top of this view to the top of the 1347 * reference view. 1348 * 1349 * @return The selected view, or null if the selected view is outside the 1350 * visible area. 1351 */ 1352 private View fillSpecific(int position, int top) { 1353 boolean tempIsSelected = position == mSelectedPosition; 1354 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1355 // Possibly changed again in fillUp if we add rows above this one. 1356 mFirstPosition = position; 1357 1358 View above; 1359 View below; 1360 1361 final int dividerHeight = mDividerHeight; 1362 if (!mStackFromBottom) { 1363 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1364 // This will correct for the top of the first view not touching the top of the list 1365 adjustViewsUpOrDown(); 1366 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1367 int childCount = getChildCount(); 1368 if (childCount > 0) { 1369 correctTooHigh(childCount); 1370 } 1371 } else { 1372 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1373 // This will correct for the bottom of the last view not touching the bottom of the list 1374 adjustViewsUpOrDown(); 1375 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1376 int childCount = getChildCount(); 1377 if (childCount > 0) { 1378 correctTooLow(childCount); 1379 } 1380 } 1381 1382 if (tempIsSelected) { 1383 return temp; 1384 } else if (above != null) { 1385 return above; 1386 } else { 1387 return below; 1388 } 1389 } 1390 1391 /** 1392 * Check if we have dragged the bottom of the list too high (we have pushed the 1393 * top element off the top of the screen when we did not need to). Correct by sliding 1394 * everything back down. 1395 * 1396 * @param childCount Number of children 1397 */ 1398 private void correctTooHigh(int childCount) { 1399 // First see if the last item is visible. If it is not, it is OK for the 1400 // top of the list to be pushed up. 1401 int lastPosition = mFirstPosition + childCount - 1; 1402 if (lastPosition == mItemCount - 1 && childCount > 0) { 1403 1404 // Get the last child ... 1405 final View lastChild = getChildAt(childCount - 1); 1406 1407 // ... and its bottom edge 1408 final int lastBottom = lastChild.getBottom(); 1409 1410 // This is bottom of our drawable area 1411 final int end = (mBottom - mTop) - mListPadding.bottom; 1412 1413 // This is how far the bottom edge of the last view is from the bottom of the 1414 // drawable area 1415 int bottomOffset = end - lastBottom; 1416 View firstChild = getChildAt(0); 1417 final int firstTop = firstChild.getTop(); 1418 1419 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1420 // first row or the first row is scrolled off the top of the drawable area 1421 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1422 if (mFirstPosition == 0) { 1423 // Don't pull the top too far down 1424 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1425 } 1426 // Move everything down 1427 offsetChildrenTopAndBottom(bottomOffset); 1428 if (mFirstPosition > 0) { 1429 // Fill the gap that was opened above mFirstPosition with more rows, if 1430 // possible 1431 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1432 // Close up the remaining gap 1433 adjustViewsUpOrDown(); 1434 } 1435 1436 } 1437 } 1438 } 1439 1440 /** 1441 * Check if we have dragged the bottom of the list too low (we have pushed the 1442 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1443 * everything back up. 1444 * 1445 * @param childCount Number of children 1446 */ 1447 private void correctTooLow(int childCount) { 1448 // First see if the first item is visible. If it is not, it is OK for the 1449 // bottom of the list to be pushed down. 1450 if (mFirstPosition == 0 && childCount > 0) { 1451 1452 // Get the first child ... 1453 final View firstChild = getChildAt(0); 1454 1455 // ... and its top edge 1456 final int firstTop = firstChild.getTop(); 1457 1458 // This is top of our drawable area 1459 final int start = mListPadding.top; 1460 1461 // This is bottom of our drawable area 1462 final int end = (mBottom - mTop) - mListPadding.bottom; 1463 1464 // This is how far the top edge of the first view is from the top of the 1465 // drawable area 1466 int topOffset = firstTop - start; 1467 View lastChild = getChildAt(childCount - 1); 1468 final int lastBottom = lastChild.getBottom(); 1469 int lastPosition = mFirstPosition + childCount - 1; 1470 1471 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1472 // last row or the last row is scrolled off the bottom of the drawable area 1473 if (topOffset > 0) { 1474 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1475 if (lastPosition == mItemCount - 1) { 1476 // Don't pull the bottom too far up 1477 topOffset = Math.min(topOffset, lastBottom - end); 1478 } 1479 // Move everything up 1480 offsetChildrenTopAndBottom(-topOffset); 1481 if (lastPosition < mItemCount - 1) { 1482 // Fill the gap that was opened below the last position with more rows, if 1483 // possible 1484 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1485 // Close up the remaining gap 1486 adjustViewsUpOrDown(); 1487 } 1488 } else if (lastPosition == mItemCount - 1) { 1489 adjustViewsUpOrDown(); 1490 } 1491 } 1492 } 1493 } 1494 1495 @Override 1496 protected void layoutChildren() { 1497 final boolean blockLayoutRequests = mBlockLayoutRequests; 1498 if (blockLayoutRequests) { 1499 return; 1500 } 1501 1502 mBlockLayoutRequests = true; 1503 1504 try { 1505 super.layoutChildren(); 1506 1507 invalidate(); 1508 1509 if (mAdapter == null) { 1510 resetList(); 1511 invokeOnItemScrollListener(); 1512 return; 1513 } 1514 1515 final int childrenTop = mListPadding.top; 1516 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1517 final int childCount = getChildCount(); 1518 1519 int index = 0; 1520 int delta = 0; 1521 1522 View sel; 1523 View oldSel = null; 1524 View oldFirst = null; 1525 View newSel = null; 1526 1527 // Remember stuff we will need down below 1528 switch (mLayoutMode) { 1529 case LAYOUT_SET_SELECTION: 1530 index = mNextSelectedPosition - mFirstPosition; 1531 if (index >= 0 && index < childCount) { 1532 newSel = getChildAt(index); 1533 } 1534 break; 1535 case LAYOUT_FORCE_TOP: 1536 case LAYOUT_FORCE_BOTTOM: 1537 case LAYOUT_SPECIFIC: 1538 case LAYOUT_SYNC: 1539 break; 1540 case LAYOUT_MOVE_SELECTION: 1541 default: 1542 // Remember the previously selected view 1543 index = mSelectedPosition - mFirstPosition; 1544 if (index >= 0 && index < childCount) { 1545 oldSel = getChildAt(index); 1546 } 1547 1548 // Remember the previous first child 1549 oldFirst = getChildAt(0); 1550 1551 if (mNextSelectedPosition >= 0) { 1552 delta = mNextSelectedPosition - mSelectedPosition; 1553 } 1554 1555 // Caution: newSel might be null 1556 newSel = getChildAt(index + delta); 1557 } 1558 1559 1560 boolean dataChanged = mDataChanged; 1561 if (dataChanged) { 1562 handleDataChanged(); 1563 } 1564 1565 // Handle the empty set by removing all views that are visible 1566 // and calling it a day 1567 if (mItemCount == 0) { 1568 resetList(); 1569 invokeOnItemScrollListener(); 1570 return; 1571 } else if (mItemCount != mAdapter.getCount()) { 1572 throw new IllegalStateException("The content of the adapter has changed but " 1573 + "ListView did not receive a notification. Make sure the content of " 1574 + "your adapter is not modified from a background thread, but only from " 1575 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1576 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1577 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1578 } 1579 1580 setSelectedPositionInt(mNextSelectedPosition); 1581 1582 AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; 1583 View accessibilityFocusLayoutRestoreView = null; 1584 int accessibilityFocusPosition = INVALID_POSITION; 1585 1586 // Remember which child, if any, had accessibility focus. This must 1587 // occur before recycling any views, since that will clear 1588 // accessibility focus. 1589 final ViewRootImpl viewRootImpl = getViewRootImpl(); 1590 if (viewRootImpl != null) { 1591 final View focusHost = viewRootImpl.getAccessibilityFocusedHost(); 1592 if (focusHost != null) { 1593 final View focusChild = getAccessibilityFocusedChild(focusHost); 1594 if (focusChild != null) { 1595 if (!dataChanged || isDirectChildHeaderOrFooter(focusChild) 1596 || focusChild.hasTransientState() || mAdapterHasStableIds) { 1597 // The views won't be changing, so try to maintain 1598 // focus on the current host and virtual view. 1599 accessibilityFocusLayoutRestoreView = focusHost; 1600 accessibilityFocusLayoutRestoreNode = viewRootImpl 1601 .getAccessibilityFocusedVirtualView(); 1602 } 1603 1604 // If all else fails, maintain focus at the same 1605 // position. 1606 accessibilityFocusPosition = getPositionForView(focusChild); 1607 } 1608 } 1609 } 1610 1611 View focusLayoutRestoreDirectChild = null; 1612 View focusLayoutRestoreView = null; 1613 1614 // Take focus back to us temporarily to avoid the eventual call to 1615 // clear focus when removing the focused child below from messing 1616 // things up when ViewAncestor assigns focus back to someone else. 1617 final View focusedChild = getFocusedChild(); 1618 if (focusedChild != null) { 1619 // TODO: in some cases focusedChild.getParent() == null 1620 1621 // We can remember the focused view to restore after re-layout 1622 // if the data hasn't changed, or if the focused position is a 1623 // header or footer. 1624 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1625 focusLayoutRestoreDirectChild = focusedChild; 1626 // Remember the specific view that had focus. 1627 focusLayoutRestoreView = findFocus(); 1628 if (focusLayoutRestoreView != null) { 1629 // Tell it we are going to mess with it. 1630 focusLayoutRestoreView.onStartTemporaryDetach(); 1631 } 1632 } 1633 requestFocus(); 1634 } 1635 1636 // Pull all children into the RecycleBin. 1637 // These views will be reused if possible 1638 final int firstPosition = mFirstPosition; 1639 final RecycleBin recycleBin = mRecycler; 1640 if (dataChanged) { 1641 for (int i = 0; i < childCount; i++) { 1642 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1643 } 1644 } else { 1645 recycleBin.fillActiveViews(childCount, firstPosition); 1646 } 1647 1648 // Clear out old views 1649 detachAllViewsFromParent(); 1650 recycleBin.removeSkippedScrap(); 1651 1652 switch (mLayoutMode) { 1653 case LAYOUT_SET_SELECTION: 1654 if (newSel != null) { 1655 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1656 } else { 1657 sel = fillFromMiddle(childrenTop, childrenBottom); 1658 } 1659 break; 1660 case LAYOUT_SYNC: 1661 sel = fillSpecific(mSyncPosition, mSpecificTop); 1662 break; 1663 case LAYOUT_FORCE_BOTTOM: 1664 sel = fillUp(mItemCount - 1, childrenBottom); 1665 adjustViewsUpOrDown(); 1666 break; 1667 case LAYOUT_FORCE_TOP: 1668 mFirstPosition = 0; 1669 sel = fillFromTop(childrenTop); 1670 adjustViewsUpOrDown(); 1671 break; 1672 case LAYOUT_SPECIFIC: 1673 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1674 break; 1675 case LAYOUT_MOVE_SELECTION: 1676 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1677 break; 1678 default: 1679 if (childCount == 0) { 1680 if (!mStackFromBottom) { 1681 final int position = lookForSelectablePosition(0, true); 1682 setSelectedPositionInt(position); 1683 sel = fillFromTop(childrenTop); 1684 } else { 1685 final int position = lookForSelectablePosition(mItemCount - 1, false); 1686 setSelectedPositionInt(position); 1687 sel = fillUp(mItemCount - 1, childrenBottom); 1688 } 1689 } else { 1690 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1691 sel = fillSpecific(mSelectedPosition, 1692 oldSel == null ? childrenTop : oldSel.getTop()); 1693 } else if (mFirstPosition < mItemCount) { 1694 sel = fillSpecific(mFirstPosition, 1695 oldFirst == null ? childrenTop : oldFirst.getTop()); 1696 } else { 1697 sel = fillSpecific(0, childrenTop); 1698 } 1699 } 1700 break; 1701 } 1702 1703 // Flush any cached views that did not get reused above 1704 recycleBin.scrapActiveViews(); 1705 1706 if (sel != null) { 1707 // The current selected item should get focus if items are 1708 // focusable. 1709 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1710 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1711 focusLayoutRestoreView != null && 1712 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1713 if (!focusWasTaken) { 1714 // Selected item didn't take focus, but we still want to 1715 // make sure something else outside of the selected view 1716 // has focus. 1717 final View focused = getFocusedChild(); 1718 if (focused != null) { 1719 focused.clearFocus(); 1720 } 1721 positionSelector(INVALID_POSITION, sel); 1722 } else { 1723 sel.setSelected(false); 1724 mSelectorRect.setEmpty(); 1725 } 1726 } else { 1727 positionSelector(INVALID_POSITION, sel); 1728 } 1729 mSelectedTop = sel.getTop(); 1730 } else { 1731 final boolean inTouchMode = mTouchMode == TOUCH_MODE_TAP 1732 || mTouchMode == TOUCH_MODE_DONE_WAITING; 1733 if (inTouchMode) { 1734 // If the user's finger is down, select the motion position. 1735 final View child = getChildAt(mMotionPosition - mFirstPosition); 1736 if (child != null) { 1737 positionSelector(mMotionPosition, child); 1738 } 1739 } else if (mSelectorPosition != INVALID_POSITION) { 1740 // If we had previously positioned the selector somewhere, 1741 // put it back there. It might not match up with the data, 1742 // but it's transitioning out so it's not a big deal. 1743 final View child = getChildAt(mSelectorPosition - mFirstPosition); 1744 if (child != null) { 1745 positionSelector(mSelectorPosition, child); 1746 } 1747 } else { 1748 // Otherwise, clear selection. 1749 mSelectedTop = 0; 1750 mSelectorRect.setEmpty(); 1751 } 1752 1753 // Even if there is not selected position, we may need to 1754 // restore focus (i.e. something focusable in touch mode). 1755 if (hasFocus() && focusLayoutRestoreView != null) { 1756 focusLayoutRestoreView.requestFocus(); 1757 } 1758 } 1759 1760 // Attempt to restore accessibility focus, if necessary. 1761 if (viewRootImpl != null) { 1762 final View newAccessibilityFocusedView = viewRootImpl.getAccessibilityFocusedHost(); 1763 if (newAccessibilityFocusedView == null) { 1764 if (accessibilityFocusLayoutRestoreView != null 1765 && accessibilityFocusLayoutRestoreView.isAttachedToWindow()) { 1766 final AccessibilityNodeProvider provider = 1767 accessibilityFocusLayoutRestoreView.getAccessibilityNodeProvider(); 1768 if (accessibilityFocusLayoutRestoreNode != null && provider != null) { 1769 final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId( 1770 accessibilityFocusLayoutRestoreNode.getSourceNodeId()); 1771 provider.performAction(virtualViewId, 1772 AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null); 1773 } else { 1774 accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); 1775 } 1776 } else if (accessibilityFocusPosition != INVALID_POSITION) { 1777 // Bound the position within the visible children. 1778 final int position = MathUtils.constrain( 1779 accessibilityFocusPosition - mFirstPosition, 0, 1780 getChildCount() - 1); 1781 final View restoreView = getChildAt(position); 1782 if (restoreView != null) { 1783 restoreView.requestAccessibilityFocus(); 1784 } 1785 } 1786 } 1787 } 1788 1789 // Tell focus view we are done mucking with it, if it is still in 1790 // our view hierarchy. 1791 if (focusLayoutRestoreView != null 1792 && focusLayoutRestoreView.getWindowToken() != null) { 1793 focusLayoutRestoreView.onFinishTemporaryDetach(); 1794 } 1795 1796 mLayoutMode = LAYOUT_NORMAL; 1797 mDataChanged = false; 1798 if (mPositionScrollAfterLayout != null) { 1799 post(mPositionScrollAfterLayout); 1800 mPositionScrollAfterLayout = null; 1801 } 1802 mNeedSync = false; 1803 setNextSelectedPositionInt(mSelectedPosition); 1804 1805 updateScrollIndicators(); 1806 1807 if (mItemCount > 0) { 1808 checkSelectionChanged(); 1809 } 1810 1811 invokeOnItemScrollListener(); 1812 } finally { 1813 if (!blockLayoutRequests) { 1814 mBlockLayoutRequests = false; 1815 } 1816 } 1817 } 1818 1819 /** 1820 * @param child a direct child of this list. 1821 * @return Whether child is a header or footer view. 1822 */ 1823 private boolean isDirectChildHeaderOrFooter(View child) { 1824 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1825 final int numHeaders = headers.size(); 1826 for (int i = 0; i < numHeaders; i++) { 1827 if (child == headers.get(i).view) { 1828 return true; 1829 } 1830 } 1831 1832 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1833 final int numFooters = footers.size(); 1834 for (int i = 0; i < numFooters; i++) { 1835 if (child == footers.get(i).view) { 1836 return true; 1837 } 1838 } 1839 1840 return false; 1841 } 1842 1843 /** 1844 * Obtain the view and add it to our list of children. The view can be made 1845 * fresh, converted from an unused view, or used as is if it was in the 1846 * recycle bin. 1847 * 1848 * @param position Logical position in the list 1849 * @param y Top or bottom edge of the view to add 1850 * @param flow If flow is true, align top edge to y. If false, align bottom 1851 * edge to y. 1852 * @param childrenLeft Left edge where children should be positioned 1853 * @param selected Is this position selected? 1854 * @return View that was added 1855 */ 1856 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1857 boolean selected) { 1858 View child; 1859 1860 1861 if (!mDataChanged) { 1862 // Try to use an existing view for this position 1863 child = mRecycler.getActiveView(position); 1864 if (child != null) { 1865 // Found it -- we're using an existing child 1866 // This just needs to be positioned 1867 setupChild(child, position, y, flow, childrenLeft, selected, true); 1868 1869 return child; 1870 } 1871 } 1872 1873 // Make a new view for this position, or convert an unused view if possible 1874 child = obtainView(position, mIsScrap); 1875 1876 // This needs to be positioned and measured 1877 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1878 1879 return child; 1880 } 1881 1882 /** 1883 * Add a view as a child and make sure it is measured (if necessary) and 1884 * positioned properly. 1885 * 1886 * @param child The view to add 1887 * @param position The position of this child 1888 * @param y The y position relative to which this view will be positioned 1889 * @param flowDown If true, align top edge to y. If false, align bottom 1890 * edge to y. 1891 * @param childrenLeft Left edge where children should be positioned 1892 * @param selected Is this position selected? 1893 * @param recycled Has this view been pulled from the recycle bin? If so it 1894 * does not need to be remeasured. 1895 */ 1896 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1897 boolean selected, boolean recycled) { 1898 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1899 1900 final boolean isSelected = selected && shouldShowSelector(); 1901 final boolean updateChildSelected = isSelected != child.isSelected(); 1902 final int mode = mTouchMode; 1903 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1904 mMotionPosition == position; 1905 final boolean updateChildPressed = isPressed != child.isPressed(); 1906 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1907 1908 // Respect layout params that are already in the view. Otherwise make some up... 1909 // noinspection unchecked 1910 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1911 if (p == null) { 1912 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1913 } 1914 p.viewType = mAdapter.getItemViewType(position); 1915 1916 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter 1917 && p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1918 attachViewToParent(child, flowDown ? -1 : 0, p); 1919 } else { 1920 p.forceAdd = false; 1921 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1922 p.recycledHeaderFooter = true; 1923 } 1924 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1925 } 1926 1927 if (updateChildSelected) { 1928 child.setSelected(isSelected); 1929 } 1930 1931 if (updateChildPressed) { 1932 child.setPressed(isPressed); 1933 } 1934 1935 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1936 if (child instanceof Checkable) { 1937 ((Checkable) child).setChecked(mCheckStates.get(position)); 1938 } else if (getContext().getApplicationInfo().targetSdkVersion 1939 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1940 child.setActivated(mCheckStates.get(position)); 1941 } 1942 } 1943 1944 if (needToMeasure) { 1945 final int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1946 mListPadding.left + mListPadding.right, p.width); 1947 final int lpHeight = p.height; 1948 final int childHeightSpec; 1949 if (lpHeight > 0) { 1950 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1951 } else { 1952 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 1953 MeasureSpec.UNSPECIFIED); 1954 } 1955 child.measure(childWidthSpec, childHeightSpec); 1956 } else { 1957 cleanupLayoutState(child); 1958 } 1959 1960 final int w = child.getMeasuredWidth(); 1961 final int h = child.getMeasuredHeight(); 1962 final int childTop = flowDown ? y : y - h; 1963 1964 if (needToMeasure) { 1965 final int childRight = childrenLeft + w; 1966 final int childBottom = childTop + h; 1967 child.layout(childrenLeft, childTop, childRight, childBottom); 1968 } else { 1969 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1970 child.offsetTopAndBottom(childTop - child.getTop()); 1971 } 1972 1973 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1974 child.setDrawingCacheEnabled(true); 1975 } 1976 1977 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1978 != position) { 1979 child.jumpDrawablesToCurrentState(); 1980 } 1981 1982 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1983 } 1984 1985 @Override 1986 protected boolean canAnimate() { 1987 return super.canAnimate() && mItemCount > 0; 1988 } 1989 1990 /** 1991 * Sets the currently selected item. If in touch mode, the item will not be selected 1992 * but it will still be positioned appropriately. If the specified selection position 1993 * is less than 0, then the item at position 0 will be selected. 1994 * 1995 * @param position Index (starting at 0) of the data item to be selected. 1996 */ 1997 @Override 1998 public void setSelection(int position) { 1999 setSelectionFromTop(position, 0); 2000 } 2001 2002 /** 2003 * Makes the item at the supplied position selected. 2004 * 2005 * @param position the position of the item to select 2006 */ 2007 @Override 2008 void setSelectionInt(int position) { 2009 setNextSelectedPositionInt(position); 2010 boolean awakeScrollbars = false; 2011 2012 final int selectedPosition = mSelectedPosition; 2013 2014 if (selectedPosition >= 0) { 2015 if (position == selectedPosition - 1) { 2016 awakeScrollbars = true; 2017 } else if (position == selectedPosition + 1) { 2018 awakeScrollbars = true; 2019 } 2020 } 2021 2022 if (mPositionScroller != null) { 2023 mPositionScroller.stop(); 2024 } 2025 2026 layoutChildren(); 2027 2028 if (awakeScrollbars) { 2029 awakenScrollBars(); 2030 } 2031 } 2032 2033 /** 2034 * Find a position that can be selected (i.e., is not a separator). 2035 * 2036 * @param position The starting position to look at. 2037 * @param lookDown Whether to look down for other positions. 2038 * @return The next selectable position starting at position and then searching either up or 2039 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 2040 */ 2041 @Override 2042 int lookForSelectablePosition(int position, boolean lookDown) { 2043 final ListAdapter adapter = mAdapter; 2044 if (adapter == null || isInTouchMode()) { 2045 return INVALID_POSITION; 2046 } 2047 2048 final int count = adapter.getCount(); 2049 if (!mAreAllItemsSelectable) { 2050 if (lookDown) { 2051 position = Math.max(0, position); 2052 while (position < count && !adapter.isEnabled(position)) { 2053 position++; 2054 } 2055 } else { 2056 position = Math.min(position, count - 1); 2057 while (position >= 0 && !adapter.isEnabled(position)) { 2058 position--; 2059 } 2060 } 2061 } 2062 2063 if (position < 0 || position >= count) { 2064 return INVALID_POSITION; 2065 } 2066 2067 return position; 2068 } 2069 2070 /** 2071 * Find a position that can be selected (i.e., is not a separator). If there 2072 * are no selectable positions in the specified direction from the starting 2073 * position, searches in the opposite direction from the starting position 2074 * to the current position. 2075 * 2076 * @param current the current position 2077 * @param position the starting position 2078 * @param lookDown whether to look down for other positions 2079 * @return the next selectable position, or {@link #INVALID_POSITION} if 2080 * nothing can be found 2081 */ 2082 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2083 final ListAdapter adapter = mAdapter; 2084 if (adapter == null || isInTouchMode()) { 2085 return INVALID_POSITION; 2086 } 2087 2088 // First check after the starting position in the specified direction. 2089 final int after = lookForSelectablePosition(position, lookDown); 2090 if (after != INVALID_POSITION) { 2091 return after; 2092 } 2093 2094 // Then check between the starting position and the current position. 2095 final int count = adapter.getCount(); 2096 current = MathUtils.constrain(current, -1, count - 1); 2097 if (lookDown) { 2098 position = Math.min(position - 1, count - 1); 2099 while ((position > current) && !adapter.isEnabled(position)) { 2100 position--; 2101 } 2102 if (position <= current) { 2103 return INVALID_POSITION; 2104 } 2105 } else { 2106 position = Math.max(0, position + 1); 2107 while ((position < current) && !adapter.isEnabled(position)) { 2108 position++; 2109 } 2110 if (position >= current) { 2111 return INVALID_POSITION; 2112 } 2113 } 2114 2115 return position; 2116 } 2117 2118 /** 2119 * setSelectionAfterHeaderView set the selection to be the first list item 2120 * after the header views. 2121 */ 2122 public void setSelectionAfterHeaderView() { 2123 final int count = mHeaderViewInfos.size(); 2124 if (count > 0) { 2125 mNextSelectedPosition = 0; 2126 return; 2127 } 2128 2129 if (mAdapter != null) { 2130 setSelection(count); 2131 } else { 2132 mNextSelectedPosition = count; 2133 mLayoutMode = LAYOUT_SET_SELECTION; 2134 } 2135 2136 } 2137 2138 @Override 2139 public boolean dispatchKeyEvent(KeyEvent event) { 2140 // Dispatch in the normal way 2141 boolean handled = super.dispatchKeyEvent(event); 2142 if (!handled) { 2143 // If we didn't handle it... 2144 View focused = getFocusedChild(); 2145 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2146 // ... and our focused child didn't handle it 2147 // ... give it to ourselves so we can scroll if necessary 2148 handled = onKeyDown(event.getKeyCode(), event); 2149 } 2150 } 2151 return handled; 2152 } 2153 2154 @Override 2155 public boolean onKeyDown(int keyCode, KeyEvent event) { 2156 return commonKey(keyCode, 1, event); 2157 } 2158 2159 @Override 2160 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2161 return commonKey(keyCode, repeatCount, event); 2162 } 2163 2164 @Override 2165 public boolean onKeyUp(int keyCode, KeyEvent event) { 2166 return commonKey(keyCode, 1, event); 2167 } 2168 2169 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2170 if (mAdapter == null || !isAttachedToWindow()) { 2171 return false; 2172 } 2173 2174 if (mDataChanged) { 2175 layoutChildren(); 2176 } 2177 2178 boolean handled = false; 2179 int action = event.getAction(); 2180 2181 if (action != KeyEvent.ACTION_UP) { 2182 switch (keyCode) { 2183 case KeyEvent.KEYCODE_DPAD_UP: 2184 if (event.hasNoModifiers()) { 2185 handled = resurrectSelectionIfNeeded(); 2186 if (!handled) { 2187 while (count-- > 0) { 2188 if (arrowScroll(FOCUS_UP)) { 2189 handled = true; 2190 } else { 2191 break; 2192 } 2193 } 2194 } 2195 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2196 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2197 } 2198 break; 2199 2200 case KeyEvent.KEYCODE_DPAD_DOWN: 2201 if (event.hasNoModifiers()) { 2202 handled = resurrectSelectionIfNeeded(); 2203 if (!handled) { 2204 while (count-- > 0) { 2205 if (arrowScroll(FOCUS_DOWN)) { 2206 handled = true; 2207 } else { 2208 break; 2209 } 2210 } 2211 } 2212 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2213 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2214 } 2215 break; 2216 2217 case KeyEvent.KEYCODE_DPAD_LEFT: 2218 if (event.hasNoModifiers()) { 2219 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2220 } 2221 break; 2222 2223 case KeyEvent.KEYCODE_DPAD_RIGHT: 2224 if (event.hasNoModifiers()) { 2225 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2226 } 2227 break; 2228 2229 case KeyEvent.KEYCODE_DPAD_CENTER: 2230 case KeyEvent.KEYCODE_ENTER: 2231 if (event.hasNoModifiers()) { 2232 handled = resurrectSelectionIfNeeded(); 2233 if (!handled 2234 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2235 keyPressed(); 2236 handled = true; 2237 } 2238 } 2239 break; 2240 2241 case KeyEvent.KEYCODE_SPACE: 2242 if (mPopup == null || !mPopup.isShowing()) { 2243 if (event.hasNoModifiers()) { 2244 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2245 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2246 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2247 } 2248 handled = true; 2249 } 2250 break; 2251 2252 case KeyEvent.KEYCODE_PAGE_UP: 2253 if (event.hasNoModifiers()) { 2254 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2255 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2256 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2257 } 2258 break; 2259 2260 case KeyEvent.KEYCODE_PAGE_DOWN: 2261 if (event.hasNoModifiers()) { 2262 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2263 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2264 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2265 } 2266 break; 2267 2268 case KeyEvent.KEYCODE_MOVE_HOME: 2269 if (event.hasNoModifiers()) { 2270 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2271 } 2272 break; 2273 2274 case KeyEvent.KEYCODE_MOVE_END: 2275 if (event.hasNoModifiers()) { 2276 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2277 } 2278 break; 2279 2280 case KeyEvent.KEYCODE_TAB: 2281 // XXX Sometimes it is useful to be able to TAB through the items in 2282 // a ListView sequentially. Unfortunately this can create an 2283 // asymmetry in TAB navigation order unless the list selection 2284 // always reverts to the top or bottom when receiving TAB focus from 2285 // another widget. Leaving this behavior disabled for now but 2286 // perhaps it should be configurable (and more comprehensive). 2287 if (false) { 2288 if (event.hasNoModifiers()) { 2289 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2290 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2291 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2292 } 2293 } 2294 break; 2295 } 2296 } 2297 2298 if (handled) { 2299 return true; 2300 } 2301 2302 if (sendToTextFilter(keyCode, count, event)) { 2303 return true; 2304 } 2305 2306 switch (action) { 2307 case KeyEvent.ACTION_DOWN: 2308 return super.onKeyDown(keyCode, event); 2309 2310 case KeyEvent.ACTION_UP: 2311 return super.onKeyUp(keyCode, event); 2312 2313 case KeyEvent.ACTION_MULTIPLE: 2314 return super.onKeyMultiple(keyCode, count, event); 2315 2316 default: // shouldn't happen 2317 return false; 2318 } 2319 } 2320 2321 /** 2322 * Scrolls up or down by the number of items currently present on screen. 2323 * 2324 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2325 * @return whether selection was moved 2326 */ 2327 boolean pageScroll(int direction) { 2328 final int nextPage; 2329 final boolean down; 2330 2331 if (direction == FOCUS_UP) { 2332 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2333 down = false; 2334 } else if (direction == FOCUS_DOWN) { 2335 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2336 down = true; 2337 } else { 2338 return false; 2339 } 2340 2341 if (nextPage >= 0) { 2342 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2343 if (position >= 0) { 2344 mLayoutMode = LAYOUT_SPECIFIC; 2345 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2346 2347 if (down && (position > (mItemCount - getChildCount()))) { 2348 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2349 } 2350 2351 if (!down && (position < getChildCount())) { 2352 mLayoutMode = LAYOUT_FORCE_TOP; 2353 } 2354 2355 setSelectionInt(position); 2356 invokeOnItemScrollListener(); 2357 if (!awakenScrollBars()) { 2358 invalidate(); 2359 } 2360 2361 return true; 2362 } 2363 } 2364 2365 return false; 2366 } 2367 2368 /** 2369 * Go to the last or first item if possible (not worrying about panning 2370 * across or navigating within the internal focus of the currently selected 2371 * item.) 2372 * 2373 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2374 * @return whether selection was moved 2375 */ 2376 boolean fullScroll(int direction) { 2377 boolean moved = false; 2378 if (direction == FOCUS_UP) { 2379 if (mSelectedPosition != 0) { 2380 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2381 if (position >= 0) { 2382 mLayoutMode = LAYOUT_FORCE_TOP; 2383 setSelectionInt(position); 2384 invokeOnItemScrollListener(); 2385 } 2386 moved = true; 2387 } 2388 } else if (direction == FOCUS_DOWN) { 2389 final int lastItem = (mItemCount - 1); 2390 if (mSelectedPosition < lastItem) { 2391 final int position = lookForSelectablePositionAfter( 2392 mSelectedPosition, lastItem, false); 2393 if (position >= 0) { 2394 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2395 setSelectionInt(position); 2396 invokeOnItemScrollListener(); 2397 } 2398 moved = true; 2399 } 2400 } 2401 2402 if (moved && !awakenScrollBars()) { 2403 awakenScrollBars(); 2404 invalidate(); 2405 } 2406 2407 return moved; 2408 } 2409 2410 /** 2411 * To avoid horizontal focus searches changing the selected item, we 2412 * manually focus search within the selected item (as applicable), and 2413 * prevent focus from jumping to something within another item. 2414 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2415 * @return Whether this consumes the key event. 2416 */ 2417 private boolean handleHorizontalFocusWithinListItem(int direction) { 2418 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2419 throw new IllegalArgumentException("direction must be one of" 2420 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2421 } 2422 2423 final int numChildren = getChildCount(); 2424 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2425 final View selectedView = getSelectedView(); 2426 if (selectedView != null && selectedView.hasFocus() && 2427 selectedView instanceof ViewGroup) { 2428 2429 final View currentFocus = selectedView.findFocus(); 2430 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2431 (ViewGroup) selectedView, currentFocus, direction); 2432 if (nextFocus != null) { 2433 // do the math to get interesting rect in next focus' coordinates 2434 Rect focusedRect = mTempRect; 2435 if (currentFocus != null) { 2436 currentFocus.getFocusedRect(focusedRect); 2437 offsetDescendantRectToMyCoords(currentFocus, focusedRect); 2438 offsetRectIntoDescendantCoords(nextFocus, focusedRect); 2439 } else { 2440 focusedRect = null; 2441 } 2442 if (nextFocus.requestFocus(direction, focusedRect)) { 2443 return true; 2444 } 2445 } 2446 // we are blocking the key from being handled (by returning true) 2447 // if the global result is going to be some other view within this 2448 // list. this is to acheive the overall goal of having 2449 // horizontal d-pad navigation remain in the current item. 2450 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2451 (ViewGroup) getRootView(), currentFocus, direction); 2452 if (globalNextFocus != null) { 2453 return isViewAncestorOf(globalNextFocus, this); 2454 } 2455 } 2456 } 2457 return false; 2458 } 2459 2460 /** 2461 * Scrolls to the next or previous item if possible. 2462 * 2463 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2464 * 2465 * @return whether selection was moved 2466 */ 2467 boolean arrowScroll(int direction) { 2468 try { 2469 mInLayout = true; 2470 final boolean handled = arrowScrollImpl(direction); 2471 if (handled) { 2472 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2473 } 2474 return handled; 2475 } finally { 2476 mInLayout = false; 2477 } 2478 } 2479 2480 /** 2481 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2482 * to move to. This return a position in the direction given if the selected item 2483 * is fully visible. 2484 * 2485 * @param selectedView Current selected view to move from 2486 * @param selectedPos Current selected position to move from 2487 * @param direction Direction to move in 2488 * @return Desired selected position after moving in the given direction 2489 */ 2490 private final int nextSelectedPositionForDirection( 2491 View selectedView, int selectedPos, int direction) { 2492 int nextSelected; 2493 2494 if (direction == View.FOCUS_DOWN) { 2495 final int listBottom = getHeight() - mListPadding.bottom; 2496 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2497 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2498 selectedPos + 1 : 2499 mFirstPosition; 2500 } else { 2501 return INVALID_POSITION; 2502 } 2503 } else { 2504 final int listTop = mListPadding.top; 2505 if (selectedView != null && selectedView.getTop() >= listTop) { 2506 final int lastPos = mFirstPosition + getChildCount() - 1; 2507 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2508 selectedPos - 1 : 2509 lastPos; 2510 } else { 2511 return INVALID_POSITION; 2512 } 2513 } 2514 2515 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2516 return INVALID_POSITION; 2517 } 2518 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2519 } 2520 2521 /** 2522 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2523 * whether there are focusable items etc. 2524 * 2525 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2526 * @return Whether any scrolling, selection or focus change occured. 2527 */ 2528 private boolean arrowScrollImpl(int direction) { 2529 if (getChildCount() <= 0) { 2530 return false; 2531 } 2532 2533 View selectedView = getSelectedView(); 2534 int selectedPos = mSelectedPosition; 2535 2536 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2537 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2538 2539 // if we are moving focus, we may OVERRIDE the default behavior 2540 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2541 if (focusResult != null) { 2542 nextSelectedPosition = focusResult.getSelectedPosition(); 2543 amountToScroll = focusResult.getAmountToScroll(); 2544 } 2545 2546 boolean needToRedraw = focusResult != null; 2547 if (nextSelectedPosition != INVALID_POSITION) { 2548 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2549 setSelectedPositionInt(nextSelectedPosition); 2550 setNextSelectedPositionInt(nextSelectedPosition); 2551 selectedView = getSelectedView(); 2552 selectedPos = nextSelectedPosition; 2553 if (mItemsCanFocus && focusResult == null) { 2554 // there was no new view found to take focus, make sure we 2555 // don't leave focus with the old selection 2556 final View focused = getFocusedChild(); 2557 if (focused != null) { 2558 focused.clearFocus(); 2559 } 2560 } 2561 needToRedraw = true; 2562 checkSelectionChanged(); 2563 } 2564 2565 if (amountToScroll > 0) { 2566 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2567 needToRedraw = true; 2568 } 2569 2570 // if we didn't find a new focusable, make sure any existing focused 2571 // item that was panned off screen gives up focus. 2572 if (mItemsCanFocus && (focusResult == null) 2573 && selectedView != null && selectedView.hasFocus()) { 2574 final View focused = selectedView.findFocus(); 2575 if (focused != null) { 2576 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2577 focused.clearFocus(); 2578 } 2579 } 2580 } 2581 2582 // if the current selection is panned off, we need to remove the selection 2583 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2584 && !isViewAncestorOf(selectedView, this)) { 2585 selectedView = null; 2586 hideSelector(); 2587 2588 // but we don't want to set the ressurect position (that would make subsequent 2589 // unhandled key events bring back the item we just scrolled off!) 2590 mResurrectToPosition = INVALID_POSITION; 2591 } 2592 2593 if (needToRedraw) { 2594 if (selectedView != null) { 2595 positionSelectorLikeFocus(selectedPos, selectedView); 2596 mSelectedTop = selectedView.getTop(); 2597 } 2598 if (!awakenScrollBars()) { 2599 invalidate(); 2600 } 2601 invokeOnItemScrollListener(); 2602 return true; 2603 } 2604 2605 return false; 2606 } 2607 2608 /** 2609 * When selection changes, it is possible that the previously selected or the 2610 * next selected item will change its size. If so, we need to offset some folks, 2611 * and re-layout the items as appropriate. 2612 * 2613 * @param selectedView The currently selected view (before changing selection). 2614 * should be <code>null</code> if there was no previous selection. 2615 * @param direction Either {@link android.view.View#FOCUS_UP} or 2616 * {@link android.view.View#FOCUS_DOWN}. 2617 * @param newSelectedPosition The position of the next selection. 2618 * @param newFocusAssigned whether new focus was assigned. This matters because 2619 * when something has focus, we don't want to show selection (ugh). 2620 */ 2621 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2622 boolean newFocusAssigned) { 2623 if (newSelectedPosition == INVALID_POSITION) { 2624 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2625 } 2626 2627 // whether or not we are moving down or up, we want to preserve the 2628 // top of whatever view is on top: 2629 // - moving down: the view that had selection 2630 // - moving up: the view that is getting selection 2631 View topView; 2632 View bottomView; 2633 int topViewIndex, bottomViewIndex; 2634 boolean topSelected = false; 2635 final int selectedIndex = mSelectedPosition - mFirstPosition; 2636 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2637 if (direction == View.FOCUS_UP) { 2638 topViewIndex = nextSelectedIndex; 2639 bottomViewIndex = selectedIndex; 2640 topView = getChildAt(topViewIndex); 2641 bottomView = selectedView; 2642 topSelected = true; 2643 } else { 2644 topViewIndex = selectedIndex; 2645 bottomViewIndex = nextSelectedIndex; 2646 topView = selectedView; 2647 bottomView = getChildAt(bottomViewIndex); 2648 } 2649 2650 final int numChildren = getChildCount(); 2651 2652 // start with top view: is it changing size? 2653 if (topView != null) { 2654 topView.setSelected(!newFocusAssigned && topSelected); 2655 measureAndAdjustDown(topView, topViewIndex, numChildren); 2656 } 2657 2658 // is the bottom view changing size? 2659 if (bottomView != null) { 2660 bottomView.setSelected(!newFocusAssigned && !topSelected); 2661 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2662 } 2663 } 2664 2665 /** 2666 * Re-measure a child, and if its height changes, lay it out preserving its 2667 * top, and adjust the children below it appropriately. 2668 * @param child The child 2669 * @param childIndex The view group index of the child. 2670 * @param numChildren The number of children in the view group. 2671 */ 2672 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2673 int oldHeight = child.getHeight(); 2674 measureItem(child); 2675 if (child.getMeasuredHeight() != oldHeight) { 2676 // lay out the view, preserving its top 2677 relayoutMeasuredItem(child); 2678 2679 // adjust views below appropriately 2680 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2681 for (int i = childIndex + 1; i < numChildren; i++) { 2682 getChildAt(i).offsetTopAndBottom(heightDelta); 2683 } 2684 } 2685 } 2686 2687 /** 2688 * Measure a particular list child. 2689 * TODO: unify with setUpChild. 2690 * @param child The child. 2691 */ 2692 private void measureItem(View child) { 2693 ViewGroup.LayoutParams p = child.getLayoutParams(); 2694 if (p == null) { 2695 p = new ViewGroup.LayoutParams( 2696 ViewGroup.LayoutParams.MATCH_PARENT, 2697 ViewGroup.LayoutParams.WRAP_CONTENT); 2698 } 2699 2700 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2701 mListPadding.left + mListPadding.right, p.width); 2702 int lpHeight = p.height; 2703 int childHeightSpec; 2704 if (lpHeight > 0) { 2705 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2706 } else { 2707 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 2708 MeasureSpec.UNSPECIFIED); 2709 } 2710 child.measure(childWidthSpec, childHeightSpec); 2711 } 2712 2713 /** 2714 * Layout a child that has been measured, preserving its top position. 2715 * TODO: unify with setUpChild. 2716 * @param child The child. 2717 */ 2718 private void relayoutMeasuredItem(View child) { 2719 final int w = child.getMeasuredWidth(); 2720 final int h = child.getMeasuredHeight(); 2721 final int childLeft = mListPadding.left; 2722 final int childRight = childLeft + w; 2723 final int childTop = child.getTop(); 2724 final int childBottom = childTop + h; 2725 child.layout(childLeft, childTop, childRight, childBottom); 2726 } 2727 2728 /** 2729 * @return The amount to preview next items when arrow srolling. 2730 */ 2731 private int getArrowScrollPreviewLength() { 2732 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2733 } 2734 2735 /** 2736 * Determine how much we need to scroll in order to get the next selected view 2737 * visible, with a fading edge showing below as applicable. The amount is 2738 * capped at {@link #getMaxScrollAmount()} . 2739 * 2740 * @param direction either {@link android.view.View#FOCUS_UP} or 2741 * {@link android.view.View#FOCUS_DOWN}. 2742 * @param nextSelectedPosition The position of the next selection, or 2743 * {@link #INVALID_POSITION} if there is no next selectable position 2744 * @return The amount to scroll. Note: this is always positive! Direction 2745 * needs to be taken into account when actually scrolling. 2746 */ 2747 private int amountToScroll(int direction, int nextSelectedPosition) { 2748 final int listBottom = getHeight() - mListPadding.bottom; 2749 final int listTop = mListPadding.top; 2750 2751 int numChildren = getChildCount(); 2752 2753 if (direction == View.FOCUS_DOWN) { 2754 int indexToMakeVisible = numChildren - 1; 2755 if (nextSelectedPosition != INVALID_POSITION) { 2756 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2757 } 2758 while (numChildren <= indexToMakeVisible) { 2759 // Child to view is not attached yet. 2760 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2761 numChildren++; 2762 } 2763 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2764 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2765 2766 int goalBottom = listBottom; 2767 if (positionToMakeVisible < mItemCount - 1) { 2768 goalBottom -= getArrowScrollPreviewLength(); 2769 } 2770 2771 if (viewToMakeVisible.getBottom() <= goalBottom) { 2772 // item is fully visible. 2773 return 0; 2774 } 2775 2776 if (nextSelectedPosition != INVALID_POSITION 2777 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2778 // item already has enough of it visible, changing selection is good enough 2779 return 0; 2780 } 2781 2782 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2783 2784 if ((mFirstPosition + numChildren) == mItemCount) { 2785 // last is last in list -> make sure we don't scroll past it 2786 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2787 amountToScroll = Math.min(amountToScroll, max); 2788 } 2789 2790 return Math.min(amountToScroll, getMaxScrollAmount()); 2791 } else { 2792 int indexToMakeVisible = 0; 2793 if (nextSelectedPosition != INVALID_POSITION) { 2794 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2795 } 2796 while (indexToMakeVisible < 0) { 2797 // Child to view is not attached yet. 2798 addViewAbove(getChildAt(0), mFirstPosition); 2799 mFirstPosition--; 2800 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2801 } 2802 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2803 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2804 int goalTop = listTop; 2805 if (positionToMakeVisible > 0) { 2806 goalTop += getArrowScrollPreviewLength(); 2807 } 2808 if (viewToMakeVisible.getTop() >= goalTop) { 2809 // item is fully visible. 2810 return 0; 2811 } 2812 2813 if (nextSelectedPosition != INVALID_POSITION && 2814 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2815 // item already has enough of it visible, changing selection is good enough 2816 return 0; 2817 } 2818 2819 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2820 if (mFirstPosition == 0) { 2821 // first is first in list -> make sure we don't scroll past it 2822 final int max = listTop - getChildAt(0).getTop(); 2823 amountToScroll = Math.min(amountToScroll, max); 2824 } 2825 return Math.min(amountToScroll, getMaxScrollAmount()); 2826 } 2827 } 2828 2829 /** 2830 * Holds results of focus aware arrow scrolling. 2831 */ 2832 static private class ArrowScrollFocusResult { 2833 private int mSelectedPosition; 2834 private int mAmountToScroll; 2835 2836 /** 2837 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2838 */ 2839 void populate(int selectedPosition, int amountToScroll) { 2840 mSelectedPosition = selectedPosition; 2841 mAmountToScroll = amountToScroll; 2842 } 2843 2844 public int getSelectedPosition() { 2845 return mSelectedPosition; 2846 } 2847 2848 public int getAmountToScroll() { 2849 return mAmountToScroll; 2850 } 2851 } 2852 2853 /** 2854 * @param direction either {@link android.view.View#FOCUS_UP} or 2855 * {@link android.view.View#FOCUS_DOWN}. 2856 * @return The position of the next selectable position of the views that 2857 * are currently visible, taking into account the fact that there might 2858 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2859 * selectable view on screen in the given direction. 2860 */ 2861 private int lookForSelectablePositionOnScreen(int direction) { 2862 final int firstPosition = mFirstPosition; 2863 if (direction == View.FOCUS_DOWN) { 2864 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2865 mSelectedPosition + 1 : 2866 firstPosition; 2867 if (startPos >= mAdapter.getCount()) { 2868 return INVALID_POSITION; 2869 } 2870 if (startPos < firstPosition) { 2871 startPos = firstPosition; 2872 } 2873 2874 final int lastVisiblePos = getLastVisiblePosition(); 2875 final ListAdapter adapter = getAdapter(); 2876 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2877 if (adapter.isEnabled(pos) 2878 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2879 return pos; 2880 } 2881 } 2882 } else { 2883 int last = firstPosition + getChildCount() - 1; 2884 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2885 mSelectedPosition - 1 : 2886 firstPosition + getChildCount() - 1; 2887 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2888 return INVALID_POSITION; 2889 } 2890 if (startPos > last) { 2891 startPos = last; 2892 } 2893 2894 final ListAdapter adapter = getAdapter(); 2895 for (int pos = startPos; pos >= firstPosition; pos--) { 2896 if (adapter.isEnabled(pos) 2897 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2898 return pos; 2899 } 2900 } 2901 } 2902 return INVALID_POSITION; 2903 } 2904 2905 /** 2906 * Do an arrow scroll based on focus searching. If a new view is 2907 * given focus, return the selection delta and amount to scroll via 2908 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2909 * 2910 * @param direction either {@link android.view.View#FOCUS_UP} or 2911 * {@link android.view.View#FOCUS_DOWN}. 2912 * @return The result if focus has changed, or <code>null</code>. 2913 */ 2914 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2915 final View selectedView = getSelectedView(); 2916 View newFocus; 2917 if (selectedView != null && selectedView.hasFocus()) { 2918 View oldFocus = selectedView.findFocus(); 2919 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2920 } else { 2921 if (direction == View.FOCUS_DOWN) { 2922 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2923 final int listTop = mListPadding.top + 2924 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2925 final int ySearchPoint = 2926 (selectedView != null && selectedView.getTop() > listTop) ? 2927 selectedView.getTop() : 2928 listTop; 2929 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2930 } else { 2931 final boolean bottomFadingEdgeShowing = 2932 (mFirstPosition + getChildCount() - 1) < mItemCount; 2933 final int listBottom = getHeight() - mListPadding.bottom - 2934 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2935 final int ySearchPoint = 2936 (selectedView != null && selectedView.getBottom() < listBottom) ? 2937 selectedView.getBottom() : 2938 listBottom; 2939 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2940 } 2941 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2942 } 2943 2944 if (newFocus != null) { 2945 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2946 2947 // if the focus change is in a different new position, make sure 2948 // we aren't jumping over another selectable position 2949 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2950 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2951 if (selectablePosition != INVALID_POSITION && 2952 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2953 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2954 return null; 2955 } 2956 } 2957 2958 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2959 2960 final int maxScrollAmount = getMaxScrollAmount(); 2961 if (focusScroll < maxScrollAmount) { 2962 // not moving too far, safe to give next view focus 2963 newFocus.requestFocus(direction); 2964 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2965 return mArrowScrollFocusResult; 2966 } else if (distanceToView(newFocus) < maxScrollAmount){ 2967 // Case to consider: 2968 // too far to get entire next focusable on screen, but by going 2969 // max scroll amount, we are getting it at least partially in view, 2970 // so give it focus and scroll the max ammount. 2971 newFocus.requestFocus(direction); 2972 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2973 return mArrowScrollFocusResult; 2974 } 2975 } 2976 return null; 2977 } 2978 2979 /** 2980 * @param newFocus The view that would have focus. 2981 * @return the position that contains newFocus 2982 */ 2983 private int positionOfNewFocus(View newFocus) { 2984 final int numChildren = getChildCount(); 2985 for (int i = 0; i < numChildren; i++) { 2986 final View child = getChildAt(i); 2987 if (isViewAncestorOf(newFocus, child)) { 2988 return mFirstPosition + i; 2989 } 2990 } 2991 throw new IllegalArgumentException("newFocus is not a child of any of the" 2992 + " children of the list!"); 2993 } 2994 2995 /** 2996 * Return true if child is an ancestor of parent, (or equal to the parent). 2997 */ 2998 private boolean isViewAncestorOf(View child, View parent) { 2999 if (child == parent) { 3000 return true; 3001 } 3002 3003 final ViewParent theParent = child.getParent(); 3004 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 3005 } 3006 3007 /** 3008 * Determine how much we need to scroll in order to get newFocus in view. 3009 * @param direction either {@link android.view.View#FOCUS_UP} or 3010 * {@link android.view.View#FOCUS_DOWN}. 3011 * @param newFocus The view that would take focus. 3012 * @param positionOfNewFocus The position of the list item containing newFocus 3013 * @return The amount to scroll. Note: this is always positive! Direction 3014 * needs to be taken into account when actually scrolling. 3015 */ 3016 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 3017 int amountToScroll = 0; 3018 newFocus.getDrawingRect(mTempRect); 3019 offsetDescendantRectToMyCoords(newFocus, mTempRect); 3020 if (direction == View.FOCUS_UP) { 3021 if (mTempRect.top < mListPadding.top) { 3022 amountToScroll = mListPadding.top - mTempRect.top; 3023 if (positionOfNewFocus > 0) { 3024 amountToScroll += getArrowScrollPreviewLength(); 3025 } 3026 } 3027 } else { 3028 final int listBottom = getHeight() - mListPadding.bottom; 3029 if (mTempRect.bottom > listBottom) { 3030 amountToScroll = mTempRect.bottom - listBottom; 3031 if (positionOfNewFocus < mItemCount - 1) { 3032 amountToScroll += getArrowScrollPreviewLength(); 3033 } 3034 } 3035 } 3036 return amountToScroll; 3037 } 3038 3039 /** 3040 * Determine the distance to the nearest edge of a view in a particular 3041 * direction. 3042 * 3043 * @param descendant A descendant of this list. 3044 * @return The distance, or 0 if the nearest edge is already on screen. 3045 */ 3046 private int distanceToView(View descendant) { 3047 int distance = 0; 3048 descendant.getDrawingRect(mTempRect); 3049 offsetDescendantRectToMyCoords(descendant, mTempRect); 3050 final int listBottom = mBottom - mTop - mListPadding.bottom; 3051 if (mTempRect.bottom < mListPadding.top) { 3052 distance = mListPadding.top - mTempRect.bottom; 3053 } else if (mTempRect.top > listBottom) { 3054 distance = mTempRect.top - listBottom; 3055 } 3056 return distance; 3057 } 3058 3059 3060 /** 3061 * Scroll the children by amount, adding a view at the end and removing 3062 * views that fall off as necessary. 3063 * 3064 * @param amount The amount (positive or negative) to scroll. 3065 */ 3066 private void scrollListItemsBy(int amount) { 3067 offsetChildrenTopAndBottom(amount); 3068 3069 final int listBottom = getHeight() - mListPadding.bottom; 3070 final int listTop = mListPadding.top; 3071 final AbsListView.RecycleBin recycleBin = mRecycler; 3072 3073 if (amount < 0) { 3074 // shifted items up 3075 3076 // may need to pan views into the bottom space 3077 int numChildren = getChildCount(); 3078 View last = getChildAt(numChildren - 1); 3079 while (last.getBottom() < listBottom) { 3080 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3081 if (lastVisiblePosition < mItemCount - 1) { 3082 last = addViewBelow(last, lastVisiblePosition); 3083 numChildren++; 3084 } else { 3085 break; 3086 } 3087 } 3088 3089 // may have brought in the last child of the list that is skinnier 3090 // than the fading edge, thereby leaving space at the end. need 3091 // to shift back 3092 if (last.getBottom() < listBottom) { 3093 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3094 } 3095 3096 // top views may be panned off screen 3097 View first = getChildAt(0); 3098 while (first.getBottom() < listTop) { 3099 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3100 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3101 recycleBin.addScrapView(first, mFirstPosition); 3102 } 3103 detachViewFromParent(first); 3104 first = getChildAt(0); 3105 mFirstPosition++; 3106 } 3107 } else { 3108 // shifted items down 3109 View first = getChildAt(0); 3110 3111 // may need to pan views into top 3112 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3113 first = addViewAbove(first, mFirstPosition); 3114 mFirstPosition--; 3115 } 3116 3117 // may have brought the very first child of the list in too far and 3118 // need to shift it back 3119 if (first.getTop() > listTop) { 3120 offsetChildrenTopAndBottom(listTop - first.getTop()); 3121 } 3122 3123 int lastIndex = getChildCount() - 1; 3124 View last = getChildAt(lastIndex); 3125 3126 // bottom view may be panned off screen 3127 while (last.getTop() > listBottom) { 3128 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3129 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3130 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3131 } 3132 detachViewFromParent(last); 3133 last = getChildAt(--lastIndex); 3134 } 3135 } 3136 } 3137 3138 private View addViewAbove(View theView, int position) { 3139 int abovePosition = position - 1; 3140 View view = obtainView(abovePosition, mIsScrap); 3141 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3142 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3143 false, mIsScrap[0]); 3144 return view; 3145 } 3146 3147 private View addViewBelow(View theView, int position) { 3148 int belowPosition = position + 1; 3149 View view = obtainView(belowPosition, mIsScrap); 3150 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3151 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3152 false, mIsScrap[0]); 3153 return view; 3154 } 3155 3156 /** 3157 * Indicates that the views created by the ListAdapter can contain focusable 3158 * items. 3159 * 3160 * @param itemsCanFocus true if items can get focus, false otherwise 3161 */ 3162 public void setItemsCanFocus(boolean itemsCanFocus) { 3163 mItemsCanFocus = itemsCanFocus; 3164 if (!itemsCanFocus) { 3165 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3166 } 3167 } 3168 3169 /** 3170 * @return Whether the views created by the ListAdapter can contain focusable 3171 * items. 3172 */ 3173 public boolean getItemsCanFocus() { 3174 return mItemsCanFocus; 3175 } 3176 3177 @Override 3178 public boolean isOpaque() { 3179 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3180 hasOpaqueScrollbars()) || super.isOpaque(); 3181 if (retValue) { 3182 // only return true if the list items cover the entire area of the view 3183 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3184 View first = getChildAt(0); 3185 if (first == null || first.getTop() > listTop) { 3186 return false; 3187 } 3188 final int listBottom = getHeight() - 3189 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3190 View last = getChildAt(getChildCount() - 1); 3191 if (last == null || last.getBottom() < listBottom) { 3192 return false; 3193 } 3194 } 3195 return retValue; 3196 } 3197 3198 @Override 3199 public void setCacheColorHint(int color) { 3200 final boolean opaque = (color >>> 24) == 0xFF; 3201 mIsCacheColorOpaque = opaque; 3202 if (opaque) { 3203 if (mDividerPaint == null) { 3204 mDividerPaint = new Paint(); 3205 } 3206 mDividerPaint.setColor(color); 3207 } 3208 super.setCacheColorHint(color); 3209 } 3210 3211 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3212 final int height = drawable.getMinimumHeight(); 3213 3214 canvas.save(); 3215 canvas.clipRect(bounds); 3216 3217 final int span = bounds.bottom - bounds.top; 3218 if (span < height) { 3219 bounds.top = bounds.bottom - height; 3220 } 3221 3222 drawable.setBounds(bounds); 3223 drawable.draw(canvas); 3224 3225 canvas.restore(); 3226 } 3227 3228 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3229 final int height = drawable.getMinimumHeight(); 3230 3231 canvas.save(); 3232 canvas.clipRect(bounds); 3233 3234 final int span = bounds.bottom - bounds.top; 3235 if (span < height) { 3236 bounds.bottom = bounds.top + height; 3237 } 3238 3239 drawable.setBounds(bounds); 3240 drawable.draw(canvas); 3241 3242 canvas.restore(); 3243 } 3244 3245 @Override 3246 protected void dispatchDraw(Canvas canvas) { 3247 if (mCachingStarted) { 3248 mCachingActive = true; 3249 } 3250 3251 // Draw the dividers 3252 final int dividerHeight = mDividerHeight; 3253 final Drawable overscrollHeader = mOverScrollHeader; 3254 final Drawable overscrollFooter = mOverScrollFooter; 3255 final boolean drawOverscrollHeader = overscrollHeader != null; 3256 final boolean drawOverscrollFooter = overscrollFooter != null; 3257 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3258 3259 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3260 // Only modify the top and bottom in the loop, we set the left and right here 3261 final Rect bounds = mTempRect; 3262 bounds.left = mPaddingLeft; 3263 bounds.right = mRight - mLeft - mPaddingRight; 3264 3265 final int count = getChildCount(); 3266 final int headerCount = mHeaderViewInfos.size(); 3267 final int itemCount = mItemCount; 3268 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3269 final boolean headerDividers = mHeaderDividersEnabled; 3270 final boolean footerDividers = mFooterDividersEnabled; 3271 final int first = mFirstPosition; 3272 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3273 final ListAdapter adapter = mAdapter; 3274 // If the list is opaque *and* the background is not, we want to 3275 // fill a rect where the dividers would be for non-selectable items 3276 // If the list is opaque and the background is also opaque, we don't 3277 // need to draw anything since the background will do it for us 3278 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3279 3280 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3281 mDividerPaint = new Paint(); 3282 mDividerPaint.setColor(getCacheColorHint()); 3283 } 3284 final Paint paint = mDividerPaint; 3285 3286 int effectivePaddingTop = 0; 3287 int effectivePaddingBottom = 0; 3288 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3289 effectivePaddingTop = mListPadding.top; 3290 effectivePaddingBottom = mListPadding.bottom; 3291 } 3292 3293 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3294 if (!mStackFromBottom) { 3295 int bottom = 0; 3296 3297 // Draw top divider or header for overscroll 3298 final int scrollY = mScrollY; 3299 if (count > 0 && scrollY < 0) { 3300 if (drawOverscrollHeader) { 3301 bounds.bottom = 0; 3302 bounds.top = scrollY; 3303 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3304 } else if (drawDividers) { 3305 bounds.bottom = 0; 3306 bounds.top = -dividerHeight; 3307 drawDivider(canvas, bounds, -1); 3308 } 3309 } 3310 3311 for (int i = 0; i < count; i++) { 3312 final int itemIndex = (first + i); 3313 final boolean isHeader = (itemIndex < headerCount); 3314 final boolean isFooter = (itemIndex >= footerLimit); 3315 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3316 final View child = getChildAt(i); 3317 bottom = child.getBottom(); 3318 final boolean isLastItem = (i == (count - 1)); 3319 3320 if (drawDividers && (bottom < listBottom) 3321 && !(drawOverscrollFooter && isLastItem)) { 3322 final int nextIndex = (itemIndex + 1); 3323 // Draw dividers between enabled items, headers 3324 // and/or footers when enabled and requested, and 3325 // after the last enabled item. 3326 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3327 && (nextIndex >= headerCount)) && (isLastItem 3328 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3329 && (nextIndex < footerLimit)))) { 3330 bounds.top = bottom; 3331 bounds.bottom = bottom + dividerHeight; 3332 drawDivider(canvas, bounds, i); 3333 } else if (fillForMissingDividers) { 3334 bounds.top = bottom; 3335 bounds.bottom = bottom + dividerHeight; 3336 canvas.drawRect(bounds, paint); 3337 } 3338 } 3339 } 3340 } 3341 3342 final int overFooterBottom = mBottom + mScrollY; 3343 if (drawOverscrollFooter && first + count == itemCount && 3344 overFooterBottom > bottom) { 3345 bounds.top = bottom; 3346 bounds.bottom = overFooterBottom; 3347 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3348 } 3349 } else { 3350 int top; 3351 3352 final int scrollY = mScrollY; 3353 3354 if (count > 0 && drawOverscrollHeader) { 3355 bounds.top = scrollY; 3356 bounds.bottom = getChildAt(0).getTop(); 3357 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3358 } 3359 3360 final int start = drawOverscrollHeader ? 1 : 0; 3361 for (int i = start; i < count; i++) { 3362 final int itemIndex = (first + i); 3363 final boolean isHeader = (itemIndex < headerCount); 3364 final boolean isFooter = (itemIndex >= footerLimit); 3365 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3366 final View child = getChildAt(i); 3367 top = child.getTop(); 3368 if (drawDividers && (top > effectivePaddingTop)) { 3369 final boolean isFirstItem = (i == start); 3370 final int previousIndex = (itemIndex - 1); 3371 // Draw dividers between enabled items, headers 3372 // and/or footers when enabled and requested, and 3373 // before the first enabled item. 3374 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3375 && (previousIndex >= headerCount)) && (isFirstItem || 3376 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3377 && (previousIndex < footerLimit)))) { 3378 bounds.top = top - dividerHeight; 3379 bounds.bottom = top; 3380 // Give the method the child ABOVE the divider, 3381 // so we subtract one from our child position. 3382 // Give -1 when there is no child above the 3383 // divider. 3384 drawDivider(canvas, bounds, i - 1); 3385 } else if (fillForMissingDividers) { 3386 bounds.top = top - dividerHeight; 3387 bounds.bottom = top; 3388 canvas.drawRect(bounds, paint); 3389 } 3390 } 3391 } 3392 } 3393 3394 if (count > 0 && scrollY > 0) { 3395 if (drawOverscrollFooter) { 3396 final int absListBottom = mBottom; 3397 bounds.top = absListBottom; 3398 bounds.bottom = absListBottom + scrollY; 3399 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3400 } else if (drawDividers) { 3401 bounds.top = listBottom; 3402 bounds.bottom = listBottom + dividerHeight; 3403 drawDivider(canvas, bounds, -1); 3404 } 3405 } 3406 } 3407 } 3408 3409 // Draw the indicators (these should be drawn above the dividers) and children 3410 super.dispatchDraw(canvas); 3411 } 3412 3413 @Override 3414 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3415 boolean more = super.drawChild(canvas, child, drawingTime); 3416 if (mCachingActive && child.mCachingFailed) { 3417 mCachingActive = false; 3418 } 3419 return more; 3420 } 3421 3422 /** 3423 * Draws a divider for the given child in the given bounds. 3424 * 3425 * @param canvas The canvas to draw to. 3426 * @param bounds The bounds of the divider. 3427 * @param childIndex The index of child (of the View) above the divider. 3428 * This will be -1 if there is no child above the divider to be 3429 * drawn. 3430 */ 3431 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3432 // This widget draws the same divider for all children 3433 final Drawable divider = mDivider; 3434 3435 divider.setBounds(bounds); 3436 divider.draw(canvas); 3437 } 3438 3439 /** 3440 * Returns the drawable that will be drawn between each item in the list. 3441 * 3442 * @return the current drawable drawn between list elements 3443 * @attr ref R.styleable#ListView_divider 3444 */ 3445 @Nullable 3446 public Drawable getDivider() { 3447 return mDivider; 3448 } 3449 3450 /** 3451 * Sets the drawable that will be drawn between each item in the list. 3452 * <p> 3453 * <strong>Note:</strong> If the drawable does not have an intrinsic 3454 * height, you should also call {@link #setDividerHeight(int)}. 3455 * 3456 * @param divider the drawable to use 3457 * @attr ref R.styleable#ListView_divider 3458 */ 3459 public void setDivider(@Nullable Drawable divider) { 3460 if (divider != null) { 3461 mDividerHeight = divider.getIntrinsicHeight(); 3462 } else { 3463 mDividerHeight = 0; 3464 } 3465 mDivider = divider; 3466 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3467 requestLayout(); 3468 invalidate(); 3469 } 3470 3471 /** 3472 * @return Returns the height of the divider that will be drawn between each item in the list. 3473 */ 3474 public int getDividerHeight() { 3475 return mDividerHeight; 3476 } 3477 3478 /** 3479 * Sets the height of the divider that will be drawn between each item in the list. Calling 3480 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3481 * 3482 * @param height The new height of the divider in pixels. 3483 */ 3484 public void setDividerHeight(int height) { 3485 mDividerHeight = height; 3486 requestLayout(); 3487 invalidate(); 3488 } 3489 3490 /** 3491 * Enables or disables the drawing of the divider for header views. 3492 * 3493 * @param headerDividersEnabled True to draw the headers, false otherwise. 3494 * 3495 * @see #setFooterDividersEnabled(boolean) 3496 * @see #areHeaderDividersEnabled() 3497 * @see #addHeaderView(android.view.View) 3498 */ 3499 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3500 mHeaderDividersEnabled = headerDividersEnabled; 3501 invalidate(); 3502 } 3503 3504 /** 3505 * @return Whether the drawing of the divider for header views is enabled 3506 * 3507 * @see #setHeaderDividersEnabled(boolean) 3508 */ 3509 public boolean areHeaderDividersEnabled() { 3510 return mHeaderDividersEnabled; 3511 } 3512 3513 /** 3514 * Enables or disables the drawing of the divider for footer views. 3515 * 3516 * @param footerDividersEnabled True to draw the footers, false otherwise. 3517 * 3518 * @see #setHeaderDividersEnabled(boolean) 3519 * @see #areFooterDividersEnabled() 3520 * @see #addFooterView(android.view.View) 3521 */ 3522 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3523 mFooterDividersEnabled = footerDividersEnabled; 3524 invalidate(); 3525 } 3526 3527 /** 3528 * @return Whether the drawing of the divider for footer views is enabled 3529 * 3530 * @see #setFooterDividersEnabled(boolean) 3531 */ 3532 public boolean areFooterDividersEnabled() { 3533 return mFooterDividersEnabled; 3534 } 3535 3536 /** 3537 * Sets the drawable that will be drawn above all other list content. 3538 * This area can become visible when the user overscrolls the list. 3539 * 3540 * @param header The drawable to use 3541 */ 3542 public void setOverscrollHeader(Drawable header) { 3543 mOverScrollHeader = header; 3544 if (mScrollY < 0) { 3545 invalidate(); 3546 } 3547 } 3548 3549 /** 3550 * @return The drawable that will be drawn above all other list content 3551 */ 3552 public Drawable getOverscrollHeader() { 3553 return mOverScrollHeader; 3554 } 3555 3556 /** 3557 * Sets the drawable that will be drawn below all other list content. 3558 * This area can become visible when the user overscrolls the list, 3559 * or when the list's content does not fully fill the container area. 3560 * 3561 * @param footer The drawable to use 3562 */ 3563 public void setOverscrollFooter(Drawable footer) { 3564 mOverScrollFooter = footer; 3565 invalidate(); 3566 } 3567 3568 /** 3569 * @return The drawable that will be drawn below all other list content 3570 */ 3571 public Drawable getOverscrollFooter() { 3572 return mOverScrollFooter; 3573 } 3574 3575 @Override 3576 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3577 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3578 3579 final ListAdapter adapter = mAdapter; 3580 int closetChildIndex = -1; 3581 int closestChildTop = 0; 3582 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3583 previouslyFocusedRect.offset(mScrollX, mScrollY); 3584 3585 // Don't cache the result of getChildCount or mFirstPosition here, 3586 // it could change in layoutChildren. 3587 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3588 mLayoutMode = LAYOUT_NORMAL; 3589 layoutChildren(); 3590 } 3591 3592 // figure out which item should be selected based on previously 3593 // focused rect 3594 Rect otherRect = mTempRect; 3595 int minDistance = Integer.MAX_VALUE; 3596 final int childCount = getChildCount(); 3597 final int firstPosition = mFirstPosition; 3598 3599 for (int i = 0; i < childCount; i++) { 3600 // only consider selectable views 3601 if (!adapter.isEnabled(firstPosition + i)) { 3602 continue; 3603 } 3604 3605 View other = getChildAt(i); 3606 other.getDrawingRect(otherRect); 3607 offsetDescendantRectToMyCoords(other, otherRect); 3608 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3609 3610 if (distance < minDistance) { 3611 minDistance = distance; 3612 closetChildIndex = i; 3613 closestChildTop = other.getTop(); 3614 } 3615 } 3616 } 3617 3618 if (closetChildIndex >= 0) { 3619 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3620 } else { 3621 requestLayout(); 3622 } 3623 } 3624 3625 3626 /* 3627 * (non-Javadoc) 3628 * 3629 * Children specified in XML are assumed to be header views. After we have 3630 * parsed them move them out of the children list and into mHeaderViews. 3631 */ 3632 @Override 3633 protected void onFinishInflate() { 3634 super.onFinishInflate(); 3635 3636 int count = getChildCount(); 3637 if (count > 0) { 3638 for (int i = 0; i < count; ++i) { 3639 addHeaderView(getChildAt(i)); 3640 } 3641 removeAllViews(); 3642 } 3643 } 3644 3645 /* (non-Javadoc) 3646 * @see android.view.View#findViewById(int) 3647 * First look in our children, then in any header and footer views that may be scrolled off. 3648 */ 3649 @Override 3650 protected View findViewTraversal(@IdRes int id) { 3651 View v; 3652 v = super.findViewTraversal(id); 3653 if (v == null) { 3654 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3655 if (v != null) { 3656 return v; 3657 } 3658 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3659 if (v != null) { 3660 return v; 3661 } 3662 } 3663 return v; 3664 } 3665 3666 /* (non-Javadoc) 3667 * 3668 * Look in the passed in list of headers or footers for the view. 3669 */ 3670 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3671 if (where != null) { 3672 int len = where.size(); 3673 View v; 3674 3675 for (int i = 0; i < len; i++) { 3676 v = where.get(i).view; 3677 3678 if (!v.isRootNamespace()) { 3679 v = v.findViewById(id); 3680 3681 if (v != null) { 3682 return v; 3683 } 3684 } 3685 } 3686 } 3687 return null; 3688 } 3689 3690 /* (non-Javadoc) 3691 * @see android.view.View#findViewWithTag(Object) 3692 * First look in our children, then in any header and footer views that may be scrolled off. 3693 */ 3694 @Override 3695 protected View findViewWithTagTraversal(Object tag) { 3696 View v; 3697 v = super.findViewWithTagTraversal(tag); 3698 if (v == null) { 3699 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3700 if (v != null) { 3701 return v; 3702 } 3703 3704 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3705 if (v != null) { 3706 return v; 3707 } 3708 } 3709 return v; 3710 } 3711 3712 /* (non-Javadoc) 3713 * 3714 * Look in the passed in list of headers or footers for the view with the tag. 3715 */ 3716 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3717 if (where != null) { 3718 int len = where.size(); 3719 View v; 3720 3721 for (int i = 0; i < len; i++) { 3722 v = where.get(i).view; 3723 3724 if (!v.isRootNamespace()) { 3725 v = v.findViewWithTag(tag); 3726 3727 if (v != null) { 3728 return v; 3729 } 3730 } 3731 } 3732 } 3733 return null; 3734 } 3735 3736 /** 3737 * @hide 3738 * @see android.view.View#findViewByPredicate(Predicate) 3739 * First look in our children, then in any header and footer views that may be scrolled off. 3740 */ 3741 @Override 3742 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3743 View v; 3744 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3745 if (v == null) { 3746 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3747 if (v != null) { 3748 return v; 3749 } 3750 3751 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3752 if (v != null) { 3753 return v; 3754 } 3755 } 3756 return v; 3757 } 3758 3759 /* (non-Javadoc) 3760 * 3761 * Look in the passed in list of headers or footers for the first view that matches 3762 * the predicate. 3763 */ 3764 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3765 Predicate<View> predicate, View childToSkip) { 3766 if (where != null) { 3767 int len = where.size(); 3768 View v; 3769 3770 for (int i = 0; i < len; i++) { 3771 v = where.get(i).view; 3772 3773 if (v != childToSkip && !v.isRootNamespace()) { 3774 v = v.findViewByPredicate(predicate); 3775 3776 if (v != null) { 3777 return v; 3778 } 3779 } 3780 } 3781 } 3782 return null; 3783 } 3784 3785 /** 3786 * Returns the set of checked items ids. The result is only valid if the 3787 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3788 * 3789 * @return A new array which contains the id of each checked item in the 3790 * list. 3791 * 3792 * @deprecated Use {@link #getCheckedItemIds()} instead. 3793 */ 3794 @Deprecated 3795 public long[] getCheckItemIds() { 3796 // Use new behavior that correctly handles stable ID mapping. 3797 if (mAdapter != null && mAdapter.hasStableIds()) { 3798 return getCheckedItemIds(); 3799 } 3800 3801 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3802 // Fall back to it to support legacy apps. 3803 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3804 final SparseBooleanArray states = mCheckStates; 3805 final int count = states.size(); 3806 final long[] ids = new long[count]; 3807 final ListAdapter adapter = mAdapter; 3808 3809 int checkedCount = 0; 3810 for (int i = 0; i < count; i++) { 3811 if (states.valueAt(i)) { 3812 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3813 } 3814 } 3815 3816 // Trim array if needed. mCheckStates may contain false values 3817 // resulting in checkedCount being smaller than count. 3818 if (checkedCount == count) { 3819 return ids; 3820 } else { 3821 final long[] result = new long[checkedCount]; 3822 System.arraycopy(ids, 0, result, 0, checkedCount); 3823 3824 return result; 3825 } 3826 } 3827 return new long[0]; 3828 } 3829 3830 @Override 3831 int getHeightForPosition(int position) { 3832 final int height = super.getHeightForPosition(position); 3833 if (shouldAdjustHeightForDivider(position)) { 3834 return height + mDividerHeight; 3835 } 3836 return height; 3837 } 3838 3839 private boolean shouldAdjustHeightForDivider(int itemIndex) { 3840 final int dividerHeight = mDividerHeight; 3841 final Drawable overscrollHeader = mOverScrollHeader; 3842 final Drawable overscrollFooter = mOverScrollFooter; 3843 final boolean drawOverscrollHeader = overscrollHeader != null; 3844 final boolean drawOverscrollFooter = overscrollFooter != null; 3845 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3846 3847 if (drawDividers) { 3848 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3849 final int itemCount = mItemCount; 3850 final int headerCount = mHeaderViewInfos.size(); 3851 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3852 final boolean isHeader = (itemIndex < headerCount); 3853 final boolean isFooter = (itemIndex >= footerLimit); 3854 final boolean headerDividers = mHeaderDividersEnabled; 3855 final boolean footerDividers = mFooterDividersEnabled; 3856 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3857 final ListAdapter adapter = mAdapter; 3858 if (!mStackFromBottom) { 3859 final boolean isLastItem = (itemIndex == (itemCount - 1)); 3860 if (!drawOverscrollFooter || !isLastItem) { 3861 final int nextIndex = itemIndex + 1; 3862 // Draw dividers between enabled items, headers 3863 // and/or footers when enabled and requested, and 3864 // after the last enabled item. 3865 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3866 && (nextIndex >= headerCount)) && (isLastItem 3867 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3868 && (nextIndex < footerLimit)))) { 3869 return true; 3870 } else if (fillForMissingDividers) { 3871 return true; 3872 } 3873 } 3874 } else { 3875 final int start = drawOverscrollHeader ? 1 : 0; 3876 final boolean isFirstItem = (itemIndex == start); 3877 if (!isFirstItem) { 3878 final int previousIndex = (itemIndex - 1); 3879 // Draw dividers between enabled items, headers 3880 // and/or footers when enabled and requested, and 3881 // before the first enabled item. 3882 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3883 && (previousIndex >= headerCount)) && (isFirstItem || 3884 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3885 && (previousIndex < footerLimit)))) { 3886 return true; 3887 } else if (fillForMissingDividers) { 3888 return true; 3889 } 3890 } 3891 } 3892 } 3893 } 3894 3895 return false; 3896 } 3897 3898 @Override 3899 public CharSequence getAccessibilityClassName() { 3900 return ListView.class.getName(); 3901 } 3902 3903 /** @hide */ 3904 @Override 3905 public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { 3906 super.onInitializeAccessibilityNodeInfoInternal(info); 3907 3908 final int rowsCount = getCount(); 3909 final int selectionMode = getSelectionModeForAccessibility(); 3910 final CollectionInfo collectionInfo = CollectionInfo.obtain( 3911 rowsCount, 1, false, selectionMode); 3912 info.setCollectionInfo(collectionInfo); 3913 3914 if (rowsCount > 0) { 3915 info.addAction(AccessibilityAction.ACTION_SCROLL_TO_POSITION); 3916 } 3917 } 3918 3919 /** @hide */ 3920 @Override 3921 public boolean performAccessibilityActionInternal(int action, Bundle arguments) { 3922 if (super.performAccessibilityActionInternal(action, arguments)) { 3923 return true; 3924 } 3925 3926 switch (action) { 3927 case R.id.accessibilityActionScrollToPosition: { 3928 final int row = arguments.getInt(AccessibilityNodeInfo.ACTION_ARGUMENT_ROW_INT, -1); 3929 final int position = Math.min(row, getCount() - 1); 3930 if (row >= 0) { 3931 // The accessibility service gets data asynchronously, so 3932 // we'll be a little lenient by clamping the last position. 3933 smoothScrollToPosition(position); 3934 return true; 3935 } 3936 } break; 3937 } 3938 3939 return false; 3940 } 3941 3942 @Override 3943 public void onInitializeAccessibilityNodeInfoForItem( 3944 View view, int position, AccessibilityNodeInfo info) { 3945 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3946 3947 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3948 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3949 final boolean isSelected = isItemChecked(position); 3950 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain( 3951 position, 1, 0, 1, isHeading, isSelected); 3952 info.setCollectionItemInfo(itemInfo); 3953 } 3954 3955 /** @hide */ 3956 @Override 3957 protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { 3958 super.encodeProperties(encoder); 3959 3960 encoder.addProperty("recycleOnMeasure", recycleOnMeasure()); 3961 } 3962} 3963