ListView.java revision d5dbf4b2a09c9cf2d17fa6af3fdf75d1fb774056
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 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1147 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 measureScrapChild(child, 0, widthMeasureSpec, heightSize); 1161 1162 childWidth = child.getMeasuredWidth(); 1163 childHeight = child.getMeasuredHeight(); 1164 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1165 1166 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1167 ((LayoutParams) child.getLayoutParams()).viewType)) { 1168 mRecycler.addScrapView(child, 0); 1169 } 1170 } 1171 1172 if (widthMode == MeasureSpec.UNSPECIFIED) { 1173 widthSize = mListPadding.left + mListPadding.right + childWidth + 1174 getVerticalScrollbarWidth(); 1175 } else { 1176 widthSize |= (childState&MEASURED_STATE_MASK); 1177 } 1178 1179 if (heightMode == MeasureSpec.UNSPECIFIED) { 1180 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1181 getVerticalFadingEdgeLength() * 2; 1182 } 1183 1184 if (heightMode == MeasureSpec.AT_MOST) { 1185 // TODO: after first layout we should maybe start at the first visible position, not 0 1186 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1187 } 1188 1189 setMeasuredDimension(widthSize , heightSize); 1190 mWidthMeasureSpec = widthMeasureSpec; 1191 } 1192 1193 private void measureScrapChild(View child, int position, int widthMeasureSpec, int heightHint) { 1194 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1195 if (p == null) { 1196 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1197 child.setLayoutParams(p); 1198 } 1199 p.viewType = mAdapter.getItemViewType(position); 1200 p.forceAdd = true; 1201 1202 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1203 mListPadding.left + mListPadding.right, p.width); 1204 int lpHeight = p.height; 1205 int childHeightSpec; 1206 if (lpHeight > 0) { 1207 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1208 } else { 1209 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(heightHint, MeasureSpec.UNSPECIFIED); 1210 } 1211 child.measure(childWidthSpec, childHeightSpec); 1212 } 1213 1214 /** 1215 * @return True to recycle the views used to measure this ListView in 1216 * UNSPECIFIED/AT_MOST modes, false otherwise. 1217 * @hide 1218 */ 1219 @ViewDebug.ExportedProperty(category = "list") 1220 protected boolean recycleOnMeasure() { 1221 return true; 1222 } 1223 1224 /** 1225 * Measures the height of the given range of children (inclusive) and 1226 * returns the height with this ListView's padding and divider heights 1227 * included. If maxHeight is provided, the measuring will stop when the 1228 * current height reaches maxHeight. 1229 * 1230 * @param widthMeasureSpec The width measure spec to be given to a child's 1231 * {@link View#measure(int, int)}. 1232 * @param startPosition The position of the first child to be shown. 1233 * @param endPosition The (inclusive) position of the last child to be 1234 * shown. Specify {@link #NO_POSITION} if the last child should be 1235 * the last available child from the adapter. 1236 * @param maxHeight The maximum height that will be returned (if all the 1237 * children don't fit in this value, this value will be 1238 * returned). 1239 * @param disallowPartialChildPosition In general, whether the returned 1240 * height should only contain entire children. This is more 1241 * powerful--it is the first inclusive position at which partial 1242 * children will not be allowed. Example: it looks nice to have 1243 * at least 3 completely visible children, and in portrait this 1244 * will most likely fit; but in landscape there could be times 1245 * when even 2 children can not be completely shown, so a value 1246 * of 2 (remember, inclusive) would be good (assuming 1247 * startPosition is 0). 1248 * @return The height of this ListView with the given children. 1249 */ 1250 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1251 final int maxHeight, int disallowPartialChildPosition) { 1252 1253 final ListAdapter adapter = mAdapter; 1254 if (adapter == null) { 1255 return mListPadding.top + mListPadding.bottom; 1256 } 1257 1258 // Include the padding of the list 1259 int returnedHeight = mListPadding.top + mListPadding.bottom; 1260 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1261 // The previous height value that was less than maxHeight and contained 1262 // no partial children 1263 int prevHeightWithoutPartialChild = 0; 1264 int i; 1265 View child; 1266 1267 // mItemCount - 1 since endPosition parameter is inclusive 1268 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1269 final AbsListView.RecycleBin recycleBin = mRecycler; 1270 final boolean recyle = recycleOnMeasure(); 1271 final boolean[] isScrap = mIsScrap; 1272 1273 for (i = startPosition; i <= endPosition; ++i) { 1274 child = obtainView(i, isScrap); 1275 1276 measureScrapChild(child, i, widthMeasureSpec, maxHeight); 1277 1278 if (i > 0) { 1279 // Count the divider for all but one child 1280 returnedHeight += dividerHeight; 1281 } 1282 1283 // Recycle the view before we possibly return from the method 1284 if (recyle && recycleBin.shouldRecycleViewType( 1285 ((LayoutParams) child.getLayoutParams()).viewType)) { 1286 recycleBin.addScrapView(child, -1); 1287 } 1288 1289 returnedHeight += child.getMeasuredHeight(); 1290 1291 if (returnedHeight >= maxHeight) { 1292 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1293 // then the i'th position did not fit completely. 1294 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1295 && (i > disallowPartialChildPosition) // We've past the min pos 1296 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1297 && (returnedHeight != maxHeight) // i'th child did not fit completely 1298 ? prevHeightWithoutPartialChild 1299 : maxHeight; 1300 } 1301 1302 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1303 prevHeightWithoutPartialChild = returnedHeight; 1304 } 1305 } 1306 1307 // At this point, we went through the range of children, and they each 1308 // completely fit, so return the returnedHeight 1309 return returnedHeight; 1310 } 1311 1312 @Override 1313 int findMotionRow(int y) { 1314 int childCount = getChildCount(); 1315 if (childCount > 0) { 1316 if (!mStackFromBottom) { 1317 for (int i = 0; i < childCount; i++) { 1318 View v = getChildAt(i); 1319 if (y <= v.getBottom()) { 1320 return mFirstPosition + i; 1321 } 1322 } 1323 } else { 1324 for (int i = childCount - 1; i >= 0; i--) { 1325 View v = getChildAt(i); 1326 if (y >= v.getTop()) { 1327 return mFirstPosition + i; 1328 } 1329 } 1330 } 1331 } 1332 return INVALID_POSITION; 1333 } 1334 1335 /** 1336 * Put a specific item at a specific location on the screen and then build 1337 * up and down from there. 1338 * 1339 * @param position The reference view to use as the starting point 1340 * @param top Pixel offset from the top of this view to the top of the 1341 * reference view. 1342 * 1343 * @return The selected view, or null if the selected view is outside the 1344 * visible area. 1345 */ 1346 private View fillSpecific(int position, int top) { 1347 boolean tempIsSelected = position == mSelectedPosition; 1348 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1349 // Possibly changed again in fillUp if we add rows above this one. 1350 mFirstPosition = position; 1351 1352 View above; 1353 View below; 1354 1355 final int dividerHeight = mDividerHeight; 1356 if (!mStackFromBottom) { 1357 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1358 // This will correct for the top of the first view not touching the top of the list 1359 adjustViewsUpOrDown(); 1360 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1361 int childCount = getChildCount(); 1362 if (childCount > 0) { 1363 correctTooHigh(childCount); 1364 } 1365 } else { 1366 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1367 // This will correct for the bottom of the last view not touching the bottom of the list 1368 adjustViewsUpOrDown(); 1369 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1370 int childCount = getChildCount(); 1371 if (childCount > 0) { 1372 correctTooLow(childCount); 1373 } 1374 } 1375 1376 if (tempIsSelected) { 1377 return temp; 1378 } else if (above != null) { 1379 return above; 1380 } else { 1381 return below; 1382 } 1383 } 1384 1385 /** 1386 * Check if we have dragged the bottom of the list too high (we have pushed the 1387 * top element off the top of the screen when we did not need to). Correct by sliding 1388 * everything back down. 1389 * 1390 * @param childCount Number of children 1391 */ 1392 private void correctTooHigh(int childCount) { 1393 // First see if the last item is visible. If it is not, it is OK for the 1394 // top of the list to be pushed up. 1395 int lastPosition = mFirstPosition + childCount - 1; 1396 if (lastPosition == mItemCount - 1 && childCount > 0) { 1397 1398 // Get the last child ... 1399 final View lastChild = getChildAt(childCount - 1); 1400 1401 // ... and its bottom edge 1402 final int lastBottom = lastChild.getBottom(); 1403 1404 // This is bottom of our drawable area 1405 final int end = (mBottom - mTop) - mListPadding.bottom; 1406 1407 // This is how far the bottom edge of the last view is from the bottom of the 1408 // drawable area 1409 int bottomOffset = end - lastBottom; 1410 View firstChild = getChildAt(0); 1411 final int firstTop = firstChild.getTop(); 1412 1413 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1414 // first row or the first row is scrolled off the top of the drawable area 1415 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1416 if (mFirstPosition == 0) { 1417 // Don't pull the top too far down 1418 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1419 } 1420 // Move everything down 1421 offsetChildrenTopAndBottom(bottomOffset); 1422 if (mFirstPosition > 0) { 1423 // Fill the gap that was opened above mFirstPosition with more rows, if 1424 // possible 1425 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1426 // Close up the remaining gap 1427 adjustViewsUpOrDown(); 1428 } 1429 1430 } 1431 } 1432 } 1433 1434 /** 1435 * Check if we have dragged the bottom of the list too low (we have pushed the 1436 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1437 * everything back up. 1438 * 1439 * @param childCount Number of children 1440 */ 1441 private void correctTooLow(int childCount) { 1442 // First see if the first item is visible. If it is not, it is OK for the 1443 // bottom of the list to be pushed down. 1444 if (mFirstPosition == 0 && childCount > 0) { 1445 1446 // Get the first child ... 1447 final View firstChild = getChildAt(0); 1448 1449 // ... and its top edge 1450 final int firstTop = firstChild.getTop(); 1451 1452 // This is top of our drawable area 1453 final int start = mListPadding.top; 1454 1455 // This is bottom of our drawable area 1456 final int end = (mBottom - mTop) - mListPadding.bottom; 1457 1458 // This is how far the top edge of the first view is from the top of the 1459 // drawable area 1460 int topOffset = firstTop - start; 1461 View lastChild = getChildAt(childCount - 1); 1462 final int lastBottom = lastChild.getBottom(); 1463 int lastPosition = mFirstPosition + childCount - 1; 1464 1465 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1466 // last row or the last row is scrolled off the bottom of the drawable area 1467 if (topOffset > 0) { 1468 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1469 if (lastPosition == mItemCount - 1) { 1470 // Don't pull the bottom too far up 1471 topOffset = Math.min(topOffset, lastBottom - end); 1472 } 1473 // Move everything up 1474 offsetChildrenTopAndBottom(-topOffset); 1475 if (lastPosition < mItemCount - 1) { 1476 // Fill the gap that was opened below the last position with more rows, if 1477 // possible 1478 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1479 // Close up the remaining gap 1480 adjustViewsUpOrDown(); 1481 } 1482 } else if (lastPosition == mItemCount - 1) { 1483 adjustViewsUpOrDown(); 1484 } 1485 } 1486 } 1487 } 1488 1489 @Override 1490 protected void layoutChildren() { 1491 final boolean blockLayoutRequests = mBlockLayoutRequests; 1492 if (blockLayoutRequests) { 1493 return; 1494 } 1495 1496 mBlockLayoutRequests = true; 1497 1498 try { 1499 super.layoutChildren(); 1500 1501 invalidate(); 1502 1503 if (mAdapter == null) { 1504 resetList(); 1505 invokeOnItemScrollListener(); 1506 return; 1507 } 1508 1509 final int childrenTop = mListPadding.top; 1510 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1511 final int childCount = getChildCount(); 1512 1513 int index = 0; 1514 int delta = 0; 1515 1516 View sel; 1517 View oldSel = null; 1518 View oldFirst = null; 1519 View newSel = null; 1520 1521 // Remember stuff we will need down below 1522 switch (mLayoutMode) { 1523 case LAYOUT_SET_SELECTION: 1524 index = mNextSelectedPosition - mFirstPosition; 1525 if (index >= 0 && index < childCount) { 1526 newSel = getChildAt(index); 1527 } 1528 break; 1529 case LAYOUT_FORCE_TOP: 1530 case LAYOUT_FORCE_BOTTOM: 1531 case LAYOUT_SPECIFIC: 1532 case LAYOUT_SYNC: 1533 break; 1534 case LAYOUT_MOVE_SELECTION: 1535 default: 1536 // Remember the previously selected view 1537 index = mSelectedPosition - mFirstPosition; 1538 if (index >= 0 && index < childCount) { 1539 oldSel = getChildAt(index); 1540 } 1541 1542 // Remember the previous first child 1543 oldFirst = getChildAt(0); 1544 1545 if (mNextSelectedPosition >= 0) { 1546 delta = mNextSelectedPosition - mSelectedPosition; 1547 } 1548 1549 // Caution: newSel might be null 1550 newSel = getChildAt(index + delta); 1551 } 1552 1553 1554 boolean dataChanged = mDataChanged; 1555 if (dataChanged) { 1556 handleDataChanged(); 1557 } 1558 1559 // Handle the empty set by removing all views that are visible 1560 // and calling it a day 1561 if (mItemCount == 0) { 1562 resetList(); 1563 invokeOnItemScrollListener(); 1564 return; 1565 } else if (mItemCount != mAdapter.getCount()) { 1566 throw new IllegalStateException("The content of the adapter has changed but " 1567 + "ListView did not receive a notification. Make sure the content of " 1568 + "your adapter is not modified from a background thread, but only from " 1569 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1570 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1571 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1572 } 1573 1574 setSelectedPositionInt(mNextSelectedPosition); 1575 1576 AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; 1577 View accessibilityFocusLayoutRestoreView = null; 1578 int accessibilityFocusPosition = INVALID_POSITION; 1579 1580 // Remember which child, if any, had accessibility focus. This must 1581 // occur before recycling any views, since that will clear 1582 // accessibility focus. 1583 final ViewRootImpl viewRootImpl = getViewRootImpl(); 1584 if (viewRootImpl != null) { 1585 final View focusHost = viewRootImpl.getAccessibilityFocusedHost(); 1586 if (focusHost != null) { 1587 final View focusChild = getAccessibilityFocusedChild(focusHost); 1588 if (focusChild != null) { 1589 if (!dataChanged || isDirectChildHeaderOrFooter(focusChild) 1590 || focusChild.hasTransientState() || mAdapterHasStableIds) { 1591 // The views won't be changing, so try to maintain 1592 // focus on the current host and virtual view. 1593 accessibilityFocusLayoutRestoreView = focusHost; 1594 accessibilityFocusLayoutRestoreNode = viewRootImpl 1595 .getAccessibilityFocusedVirtualView(); 1596 } 1597 1598 // If all else fails, maintain focus at the same 1599 // position. 1600 accessibilityFocusPosition = getPositionForView(focusChild); 1601 } 1602 } 1603 } 1604 1605 View focusLayoutRestoreDirectChild = null; 1606 View focusLayoutRestoreView = null; 1607 1608 // Take focus back to us temporarily to avoid the eventual call to 1609 // clear focus when removing the focused child below from messing 1610 // things up when ViewAncestor assigns focus back to someone else. 1611 final View focusedChild = getFocusedChild(); 1612 if (focusedChild != null) { 1613 // TODO: in some cases focusedChild.getParent() == null 1614 1615 // We can remember the focused view to restore after re-layout 1616 // if the data hasn't changed, or if the focused position is a 1617 // header or footer. 1618 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1619 focusLayoutRestoreDirectChild = focusedChild; 1620 // Remember the specific view that had focus. 1621 focusLayoutRestoreView = findFocus(); 1622 if (focusLayoutRestoreView != null) { 1623 // Tell it we are going to mess with it. 1624 focusLayoutRestoreView.onStartTemporaryDetach(); 1625 } 1626 } 1627 requestFocus(); 1628 } 1629 1630 // Pull all children into the RecycleBin. 1631 // These views will be reused if possible 1632 final int firstPosition = mFirstPosition; 1633 final RecycleBin recycleBin = mRecycler; 1634 if (dataChanged) { 1635 for (int i = 0; i < childCount; i++) { 1636 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1637 } 1638 } else { 1639 recycleBin.fillActiveViews(childCount, firstPosition); 1640 } 1641 1642 // Clear out old views 1643 detachAllViewsFromParent(); 1644 recycleBin.removeSkippedScrap(); 1645 1646 switch (mLayoutMode) { 1647 case LAYOUT_SET_SELECTION: 1648 if (newSel != null) { 1649 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1650 } else { 1651 sel = fillFromMiddle(childrenTop, childrenBottom); 1652 } 1653 break; 1654 case LAYOUT_SYNC: 1655 sel = fillSpecific(mSyncPosition, mSpecificTop); 1656 break; 1657 case LAYOUT_FORCE_BOTTOM: 1658 sel = fillUp(mItemCount - 1, childrenBottom); 1659 adjustViewsUpOrDown(); 1660 break; 1661 case LAYOUT_FORCE_TOP: 1662 mFirstPosition = 0; 1663 sel = fillFromTop(childrenTop); 1664 adjustViewsUpOrDown(); 1665 break; 1666 case LAYOUT_SPECIFIC: 1667 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1668 break; 1669 case LAYOUT_MOVE_SELECTION: 1670 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1671 break; 1672 default: 1673 if (childCount == 0) { 1674 if (!mStackFromBottom) { 1675 final int position = lookForSelectablePosition(0, true); 1676 setSelectedPositionInt(position); 1677 sel = fillFromTop(childrenTop); 1678 } else { 1679 final int position = lookForSelectablePosition(mItemCount - 1, false); 1680 setSelectedPositionInt(position); 1681 sel = fillUp(mItemCount - 1, childrenBottom); 1682 } 1683 } else { 1684 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1685 sel = fillSpecific(mSelectedPosition, 1686 oldSel == null ? childrenTop : oldSel.getTop()); 1687 } else if (mFirstPosition < mItemCount) { 1688 sel = fillSpecific(mFirstPosition, 1689 oldFirst == null ? childrenTop : oldFirst.getTop()); 1690 } else { 1691 sel = fillSpecific(0, childrenTop); 1692 } 1693 } 1694 break; 1695 } 1696 1697 // Flush any cached views that did not get reused above 1698 recycleBin.scrapActiveViews(); 1699 1700 if (sel != null) { 1701 // The current selected item should get focus if items are 1702 // focusable. 1703 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1704 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1705 focusLayoutRestoreView != null && 1706 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1707 if (!focusWasTaken) { 1708 // Selected item didn't take focus, but we still want to 1709 // make sure something else outside of the selected view 1710 // has focus. 1711 final View focused = getFocusedChild(); 1712 if (focused != null) { 1713 focused.clearFocus(); 1714 } 1715 positionSelector(INVALID_POSITION, sel); 1716 } else { 1717 sel.setSelected(false); 1718 mSelectorRect.setEmpty(); 1719 } 1720 } else { 1721 positionSelector(INVALID_POSITION, sel); 1722 } 1723 mSelectedTop = sel.getTop(); 1724 } else { 1725 final boolean inTouchMode = mTouchMode == TOUCH_MODE_TAP 1726 || mTouchMode == TOUCH_MODE_DONE_WAITING; 1727 if (inTouchMode) { 1728 // If the user's finger is down, select the motion position. 1729 final View child = getChildAt(mMotionPosition - mFirstPosition); 1730 if (child != null) { 1731 positionSelector(mMotionPosition, child); 1732 } 1733 } else if (mSelectorPosition != INVALID_POSITION) { 1734 // If we had previously positioned the selector somewhere, 1735 // put it back there. It might not match up with the data, 1736 // but it's transitioning out so it's not a big deal. 1737 final View child = getChildAt(mSelectorPosition - mFirstPosition); 1738 if (child != null) { 1739 positionSelector(mSelectorPosition, child); 1740 } 1741 } else { 1742 // Otherwise, clear selection. 1743 mSelectedTop = 0; 1744 mSelectorRect.setEmpty(); 1745 } 1746 1747 // Even if there is not selected position, we may need to 1748 // restore focus (i.e. something focusable in touch mode). 1749 if (hasFocus() && focusLayoutRestoreView != null) { 1750 focusLayoutRestoreView.requestFocus(); 1751 } 1752 } 1753 1754 // Attempt to restore accessibility focus, if necessary. 1755 if (viewRootImpl != null) { 1756 final View newAccessibilityFocusedView = viewRootImpl.getAccessibilityFocusedHost(); 1757 if (newAccessibilityFocusedView == null) { 1758 if (accessibilityFocusLayoutRestoreView != null 1759 && accessibilityFocusLayoutRestoreView.isAttachedToWindow()) { 1760 final AccessibilityNodeProvider provider = 1761 accessibilityFocusLayoutRestoreView.getAccessibilityNodeProvider(); 1762 if (accessibilityFocusLayoutRestoreNode != null && provider != null) { 1763 final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId( 1764 accessibilityFocusLayoutRestoreNode.getSourceNodeId()); 1765 provider.performAction(virtualViewId, 1766 AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null); 1767 } else { 1768 accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); 1769 } 1770 } else if (accessibilityFocusPosition != INVALID_POSITION) { 1771 // Bound the position within the visible children. 1772 final int position = MathUtils.constrain( 1773 accessibilityFocusPosition - mFirstPosition, 0, 1774 getChildCount() - 1); 1775 final View restoreView = getChildAt(position); 1776 if (restoreView != null) { 1777 restoreView.requestAccessibilityFocus(); 1778 } 1779 } 1780 } 1781 } 1782 1783 // Tell focus view we are done mucking with it, if it is still in 1784 // our view hierarchy. 1785 if (focusLayoutRestoreView != null 1786 && focusLayoutRestoreView.getWindowToken() != null) { 1787 focusLayoutRestoreView.onFinishTemporaryDetach(); 1788 } 1789 1790 mLayoutMode = LAYOUT_NORMAL; 1791 mDataChanged = false; 1792 if (mPositionScrollAfterLayout != null) { 1793 post(mPositionScrollAfterLayout); 1794 mPositionScrollAfterLayout = null; 1795 } 1796 mNeedSync = false; 1797 setNextSelectedPositionInt(mSelectedPosition); 1798 1799 updateScrollIndicators(); 1800 1801 if (mItemCount > 0) { 1802 checkSelectionChanged(); 1803 } 1804 1805 invokeOnItemScrollListener(); 1806 } finally { 1807 if (!blockLayoutRequests) { 1808 mBlockLayoutRequests = false; 1809 } 1810 } 1811 } 1812 1813 /** 1814 * @param child a direct child of this list. 1815 * @return Whether child is a header or footer view. 1816 */ 1817 private boolean isDirectChildHeaderOrFooter(View child) { 1818 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1819 final int numHeaders = headers.size(); 1820 for (int i = 0; i < numHeaders; i++) { 1821 if (child == headers.get(i).view) { 1822 return true; 1823 } 1824 } 1825 1826 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1827 final int numFooters = footers.size(); 1828 for (int i = 0; i < numFooters; i++) { 1829 if (child == footers.get(i).view) { 1830 return true; 1831 } 1832 } 1833 1834 return false; 1835 } 1836 1837 /** 1838 * Obtain the view and add it to our list of children. The view can be made 1839 * fresh, converted from an unused view, or used as is if it was in the 1840 * recycle bin. 1841 * 1842 * @param position Logical position in the list 1843 * @param y Top or bottom edge of the view to add 1844 * @param flow If flow is true, align top edge to y. If false, align bottom 1845 * edge to y. 1846 * @param childrenLeft Left edge where children should be positioned 1847 * @param selected Is this position selected? 1848 * @return View that was added 1849 */ 1850 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1851 boolean selected) { 1852 View child; 1853 1854 1855 if (!mDataChanged) { 1856 // Try to use an existing view for this position 1857 child = mRecycler.getActiveView(position); 1858 if (child != null) { 1859 // Found it -- we're using an existing child 1860 // This just needs to be positioned 1861 setupChild(child, position, y, flow, childrenLeft, selected, true); 1862 1863 return child; 1864 } 1865 } 1866 1867 // Make a new view for this position, or convert an unused view if possible 1868 child = obtainView(position, mIsScrap); 1869 1870 // This needs to be positioned and measured 1871 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1872 1873 return child; 1874 } 1875 1876 /** 1877 * Add a view as a child and make sure it is measured (if necessary) and 1878 * positioned properly. 1879 * 1880 * @param child The view to add 1881 * @param position The position of this child 1882 * @param y The y position relative to which this view will be positioned 1883 * @param flowDown If true, align top edge to y. If false, align bottom 1884 * edge to y. 1885 * @param childrenLeft Left edge where children should be positioned 1886 * @param selected Is this position selected? 1887 * @param recycled Has this view been pulled from the recycle bin? If so it 1888 * does not need to be remeasured. 1889 */ 1890 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1891 boolean selected, boolean recycled) { 1892 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1893 1894 final boolean isSelected = selected && shouldShowSelector(); 1895 final boolean updateChildSelected = isSelected != child.isSelected(); 1896 final int mode = mTouchMode; 1897 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1898 mMotionPosition == position; 1899 final boolean updateChildPressed = isPressed != child.isPressed(); 1900 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1901 1902 // Respect layout params that are already in the view. Otherwise make some up... 1903 // noinspection unchecked 1904 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1905 if (p == null) { 1906 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1907 } 1908 p.viewType = mAdapter.getItemViewType(position); 1909 1910 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1911 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1912 attachViewToParent(child, flowDown ? -1 : 0, p); 1913 } else { 1914 p.forceAdd = false; 1915 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1916 p.recycledHeaderFooter = true; 1917 } 1918 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1919 } 1920 1921 if (updateChildSelected) { 1922 child.setSelected(isSelected); 1923 } 1924 1925 if (updateChildPressed) { 1926 child.setPressed(isPressed); 1927 } 1928 1929 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1930 if (child instanceof Checkable) { 1931 ((Checkable) child).setChecked(mCheckStates.get(position)); 1932 } else if (getContext().getApplicationInfo().targetSdkVersion 1933 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1934 child.setActivated(mCheckStates.get(position)); 1935 } 1936 } 1937 1938 if (needToMeasure) { 1939 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1940 mListPadding.left + mListPadding.right, p.width); 1941 int lpHeight = p.height; 1942 int childHeightSpec; 1943 if (lpHeight > 0) { 1944 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1945 } else { 1946 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 1947 MeasureSpec.UNSPECIFIED); 1948 } 1949 child.measure(childWidthSpec, childHeightSpec); 1950 } else { 1951 cleanupLayoutState(child); 1952 } 1953 1954 final int w = child.getMeasuredWidth(); 1955 final int h = child.getMeasuredHeight(); 1956 final int childTop = flowDown ? y : y - h; 1957 1958 if (needToMeasure) { 1959 final int childRight = childrenLeft + w; 1960 final int childBottom = childTop + h; 1961 child.layout(childrenLeft, childTop, childRight, childBottom); 1962 } else { 1963 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1964 child.offsetTopAndBottom(childTop - child.getTop()); 1965 } 1966 1967 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1968 child.setDrawingCacheEnabled(true); 1969 } 1970 1971 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1972 != position) { 1973 child.jumpDrawablesToCurrentState(); 1974 } 1975 1976 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1977 } 1978 1979 @Override 1980 protected boolean canAnimate() { 1981 return super.canAnimate() && mItemCount > 0; 1982 } 1983 1984 /** 1985 * Sets the currently selected item. If in touch mode, the item will not be selected 1986 * but it will still be positioned appropriately. If the specified selection position 1987 * is less than 0, then the item at position 0 will be selected. 1988 * 1989 * @param position Index (starting at 0) of the data item to be selected. 1990 */ 1991 @Override 1992 public void setSelection(int position) { 1993 setSelectionFromTop(position, 0); 1994 } 1995 1996 /** 1997 * Makes the item at the supplied position selected. 1998 * 1999 * @param position the position of the item to select 2000 */ 2001 @Override 2002 void setSelectionInt(int position) { 2003 setNextSelectedPositionInt(position); 2004 boolean awakeScrollbars = false; 2005 2006 final int selectedPosition = mSelectedPosition; 2007 2008 if (selectedPosition >= 0) { 2009 if (position == selectedPosition - 1) { 2010 awakeScrollbars = true; 2011 } else if (position == selectedPosition + 1) { 2012 awakeScrollbars = true; 2013 } 2014 } 2015 2016 if (mPositionScroller != null) { 2017 mPositionScroller.stop(); 2018 } 2019 2020 layoutChildren(); 2021 2022 if (awakeScrollbars) { 2023 awakenScrollBars(); 2024 } 2025 } 2026 2027 /** 2028 * Find a position that can be selected (i.e., is not a separator). 2029 * 2030 * @param position The starting position to look at. 2031 * @param lookDown Whether to look down for other positions. 2032 * @return The next selectable position starting at position and then searching either up or 2033 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 2034 */ 2035 @Override 2036 int lookForSelectablePosition(int position, boolean lookDown) { 2037 final ListAdapter adapter = mAdapter; 2038 if (adapter == null || isInTouchMode()) { 2039 return INVALID_POSITION; 2040 } 2041 2042 final int count = adapter.getCount(); 2043 if (!mAreAllItemsSelectable) { 2044 if (lookDown) { 2045 position = Math.max(0, position); 2046 while (position < count && !adapter.isEnabled(position)) { 2047 position++; 2048 } 2049 } else { 2050 position = Math.min(position, count - 1); 2051 while (position >= 0 && !adapter.isEnabled(position)) { 2052 position--; 2053 } 2054 } 2055 } 2056 2057 if (position < 0 || position >= count) { 2058 return INVALID_POSITION; 2059 } 2060 2061 return position; 2062 } 2063 2064 /** 2065 * Find a position that can be selected (i.e., is not a separator). If there 2066 * are no selectable positions in the specified direction from the starting 2067 * position, searches in the opposite direction from the starting position 2068 * to the current position. 2069 * 2070 * @param current the current position 2071 * @param position the starting position 2072 * @param lookDown whether to look down for other positions 2073 * @return the next selectable position, or {@link #INVALID_POSITION} if 2074 * nothing can be found 2075 */ 2076 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2077 final ListAdapter adapter = mAdapter; 2078 if (adapter == null || isInTouchMode()) { 2079 return INVALID_POSITION; 2080 } 2081 2082 // First check after the starting position in the specified direction. 2083 final int after = lookForSelectablePosition(position, lookDown); 2084 if (after != INVALID_POSITION) { 2085 return after; 2086 } 2087 2088 // Then check between the starting position and the current position. 2089 final int count = adapter.getCount(); 2090 current = MathUtils.constrain(current, -1, count - 1); 2091 if (lookDown) { 2092 position = Math.min(position - 1, count - 1); 2093 while ((position > current) && !adapter.isEnabled(position)) { 2094 position--; 2095 } 2096 if (position <= current) { 2097 return INVALID_POSITION; 2098 } 2099 } else { 2100 position = Math.max(0, position + 1); 2101 while ((position < current) && !adapter.isEnabled(position)) { 2102 position++; 2103 } 2104 if (position >= current) { 2105 return INVALID_POSITION; 2106 } 2107 } 2108 2109 return position; 2110 } 2111 2112 /** 2113 * setSelectionAfterHeaderView set the selection to be the first list item 2114 * after the header views. 2115 */ 2116 public void setSelectionAfterHeaderView() { 2117 final int count = mHeaderViewInfos.size(); 2118 if (count > 0) { 2119 mNextSelectedPosition = 0; 2120 return; 2121 } 2122 2123 if (mAdapter != null) { 2124 setSelection(count); 2125 } else { 2126 mNextSelectedPosition = count; 2127 mLayoutMode = LAYOUT_SET_SELECTION; 2128 } 2129 2130 } 2131 2132 @Override 2133 public boolean dispatchKeyEvent(KeyEvent event) { 2134 // Dispatch in the normal way 2135 boolean handled = super.dispatchKeyEvent(event); 2136 if (!handled) { 2137 // If we didn't handle it... 2138 View focused = getFocusedChild(); 2139 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2140 // ... and our focused child didn't handle it 2141 // ... give it to ourselves so we can scroll if necessary 2142 handled = onKeyDown(event.getKeyCode(), event); 2143 } 2144 } 2145 return handled; 2146 } 2147 2148 @Override 2149 public boolean onKeyDown(int keyCode, KeyEvent event) { 2150 return commonKey(keyCode, 1, event); 2151 } 2152 2153 @Override 2154 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2155 return commonKey(keyCode, repeatCount, event); 2156 } 2157 2158 @Override 2159 public boolean onKeyUp(int keyCode, KeyEvent event) { 2160 return commonKey(keyCode, 1, event); 2161 } 2162 2163 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2164 if (mAdapter == null || !isAttachedToWindow()) { 2165 return false; 2166 } 2167 2168 if (mDataChanged) { 2169 layoutChildren(); 2170 } 2171 2172 boolean handled = false; 2173 int action = event.getAction(); 2174 2175 if (action != KeyEvent.ACTION_UP) { 2176 switch (keyCode) { 2177 case KeyEvent.KEYCODE_DPAD_UP: 2178 if (event.hasNoModifiers()) { 2179 handled = resurrectSelectionIfNeeded(); 2180 if (!handled) { 2181 while (count-- > 0) { 2182 if (arrowScroll(FOCUS_UP)) { 2183 handled = true; 2184 } else { 2185 break; 2186 } 2187 } 2188 } 2189 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2190 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2191 } 2192 break; 2193 2194 case KeyEvent.KEYCODE_DPAD_DOWN: 2195 if (event.hasNoModifiers()) { 2196 handled = resurrectSelectionIfNeeded(); 2197 if (!handled) { 2198 while (count-- > 0) { 2199 if (arrowScroll(FOCUS_DOWN)) { 2200 handled = true; 2201 } else { 2202 break; 2203 } 2204 } 2205 } 2206 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2207 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2208 } 2209 break; 2210 2211 case KeyEvent.KEYCODE_DPAD_LEFT: 2212 if (event.hasNoModifiers()) { 2213 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2214 } 2215 break; 2216 2217 case KeyEvent.KEYCODE_DPAD_RIGHT: 2218 if (event.hasNoModifiers()) { 2219 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2220 } 2221 break; 2222 2223 case KeyEvent.KEYCODE_DPAD_CENTER: 2224 case KeyEvent.KEYCODE_ENTER: 2225 if (event.hasNoModifiers()) { 2226 handled = resurrectSelectionIfNeeded(); 2227 if (!handled 2228 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2229 keyPressed(); 2230 handled = true; 2231 } 2232 } 2233 break; 2234 2235 case KeyEvent.KEYCODE_SPACE: 2236 if (mPopup == null || !mPopup.isShowing()) { 2237 if (event.hasNoModifiers()) { 2238 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2239 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2240 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2241 } 2242 handled = true; 2243 } 2244 break; 2245 2246 case KeyEvent.KEYCODE_PAGE_UP: 2247 if (event.hasNoModifiers()) { 2248 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2249 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2250 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2251 } 2252 break; 2253 2254 case KeyEvent.KEYCODE_PAGE_DOWN: 2255 if (event.hasNoModifiers()) { 2256 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2257 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2258 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2259 } 2260 break; 2261 2262 case KeyEvent.KEYCODE_MOVE_HOME: 2263 if (event.hasNoModifiers()) { 2264 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2265 } 2266 break; 2267 2268 case KeyEvent.KEYCODE_MOVE_END: 2269 if (event.hasNoModifiers()) { 2270 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2271 } 2272 break; 2273 2274 case KeyEvent.KEYCODE_TAB: 2275 // XXX Sometimes it is useful to be able to TAB through the items in 2276 // a ListView sequentially. Unfortunately this can create an 2277 // asymmetry in TAB navigation order unless the list selection 2278 // always reverts to the top or bottom when receiving TAB focus from 2279 // another widget. Leaving this behavior disabled for now but 2280 // perhaps it should be configurable (and more comprehensive). 2281 if (false) { 2282 if (event.hasNoModifiers()) { 2283 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2284 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2285 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2286 } 2287 } 2288 break; 2289 } 2290 } 2291 2292 if (handled) { 2293 return true; 2294 } 2295 2296 if (sendToTextFilter(keyCode, count, event)) { 2297 return true; 2298 } 2299 2300 switch (action) { 2301 case KeyEvent.ACTION_DOWN: 2302 return super.onKeyDown(keyCode, event); 2303 2304 case KeyEvent.ACTION_UP: 2305 return super.onKeyUp(keyCode, event); 2306 2307 case KeyEvent.ACTION_MULTIPLE: 2308 return super.onKeyMultiple(keyCode, count, event); 2309 2310 default: // shouldn't happen 2311 return false; 2312 } 2313 } 2314 2315 /** 2316 * Scrolls up or down by the number of items currently present on screen. 2317 * 2318 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2319 * @return whether selection was moved 2320 */ 2321 boolean pageScroll(int direction) { 2322 final int nextPage; 2323 final boolean down; 2324 2325 if (direction == FOCUS_UP) { 2326 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2327 down = false; 2328 } else if (direction == FOCUS_DOWN) { 2329 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2330 down = true; 2331 } else { 2332 return false; 2333 } 2334 2335 if (nextPage >= 0) { 2336 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2337 if (position >= 0) { 2338 mLayoutMode = LAYOUT_SPECIFIC; 2339 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2340 2341 if (down && (position > (mItemCount - getChildCount()))) { 2342 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2343 } 2344 2345 if (!down && (position < getChildCount())) { 2346 mLayoutMode = LAYOUT_FORCE_TOP; 2347 } 2348 2349 setSelectionInt(position); 2350 invokeOnItemScrollListener(); 2351 if (!awakenScrollBars()) { 2352 invalidate(); 2353 } 2354 2355 return true; 2356 } 2357 } 2358 2359 return false; 2360 } 2361 2362 /** 2363 * Go to the last or first item if possible (not worrying about panning 2364 * across or navigating within the internal focus of the currently selected 2365 * item.) 2366 * 2367 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2368 * @return whether selection was moved 2369 */ 2370 boolean fullScroll(int direction) { 2371 boolean moved = false; 2372 if (direction == FOCUS_UP) { 2373 if (mSelectedPosition != 0) { 2374 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2375 if (position >= 0) { 2376 mLayoutMode = LAYOUT_FORCE_TOP; 2377 setSelectionInt(position); 2378 invokeOnItemScrollListener(); 2379 } 2380 moved = true; 2381 } 2382 } else if (direction == FOCUS_DOWN) { 2383 final int lastItem = (mItemCount - 1); 2384 if (mSelectedPosition < lastItem) { 2385 final int position = lookForSelectablePositionAfter( 2386 mSelectedPosition, lastItem, false); 2387 if (position >= 0) { 2388 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2389 setSelectionInt(position); 2390 invokeOnItemScrollListener(); 2391 } 2392 moved = true; 2393 } 2394 } 2395 2396 if (moved && !awakenScrollBars()) { 2397 awakenScrollBars(); 2398 invalidate(); 2399 } 2400 2401 return moved; 2402 } 2403 2404 /** 2405 * To avoid horizontal focus searches changing the selected item, we 2406 * manually focus search within the selected item (as applicable), and 2407 * prevent focus from jumping to something within another item. 2408 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2409 * @return Whether this consumes the key event. 2410 */ 2411 private boolean handleHorizontalFocusWithinListItem(int direction) { 2412 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2413 throw new IllegalArgumentException("direction must be one of" 2414 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2415 } 2416 2417 final int numChildren = getChildCount(); 2418 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2419 final View selectedView = getSelectedView(); 2420 if (selectedView != null && selectedView.hasFocus() && 2421 selectedView instanceof ViewGroup) { 2422 2423 final View currentFocus = selectedView.findFocus(); 2424 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2425 (ViewGroup) selectedView, currentFocus, direction); 2426 if (nextFocus != null) { 2427 // do the math to get interesting rect in next focus' coordinates 2428 Rect focusedRect = mTempRect; 2429 if (currentFocus != null) { 2430 currentFocus.getFocusedRect(focusedRect); 2431 offsetDescendantRectToMyCoords(currentFocus, focusedRect); 2432 offsetRectIntoDescendantCoords(nextFocus, focusedRect); 2433 } else { 2434 focusedRect = null; 2435 } 2436 if (nextFocus.requestFocus(direction, focusedRect)) { 2437 return true; 2438 } 2439 } 2440 // we are blocking the key from being handled (by returning true) 2441 // if the global result is going to be some other view within this 2442 // list. this is to acheive the overall goal of having 2443 // horizontal d-pad navigation remain in the current item. 2444 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2445 (ViewGroup) getRootView(), currentFocus, direction); 2446 if (globalNextFocus != null) { 2447 return isViewAncestorOf(globalNextFocus, this); 2448 } 2449 } 2450 } 2451 return false; 2452 } 2453 2454 /** 2455 * Scrolls to the next or previous item if possible. 2456 * 2457 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2458 * 2459 * @return whether selection was moved 2460 */ 2461 boolean arrowScroll(int direction) { 2462 try { 2463 mInLayout = true; 2464 final boolean handled = arrowScrollImpl(direction); 2465 if (handled) { 2466 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2467 } 2468 return handled; 2469 } finally { 2470 mInLayout = false; 2471 } 2472 } 2473 2474 /** 2475 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2476 * to move to. This return a position in the direction given if the selected item 2477 * is fully visible. 2478 * 2479 * @param selectedView Current selected view to move from 2480 * @param selectedPos Current selected position to move from 2481 * @param direction Direction to move in 2482 * @return Desired selected position after moving in the given direction 2483 */ 2484 private final int nextSelectedPositionForDirection( 2485 View selectedView, int selectedPos, int direction) { 2486 int nextSelected; 2487 2488 if (direction == View.FOCUS_DOWN) { 2489 final int listBottom = getHeight() - mListPadding.bottom; 2490 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2491 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2492 selectedPos + 1 : 2493 mFirstPosition; 2494 } else { 2495 return INVALID_POSITION; 2496 } 2497 } else { 2498 final int listTop = mListPadding.top; 2499 if (selectedView != null && selectedView.getTop() >= listTop) { 2500 final int lastPos = mFirstPosition + getChildCount() - 1; 2501 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2502 selectedPos - 1 : 2503 lastPos; 2504 } else { 2505 return INVALID_POSITION; 2506 } 2507 } 2508 2509 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2510 return INVALID_POSITION; 2511 } 2512 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2513 } 2514 2515 /** 2516 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2517 * whether there are focusable items etc. 2518 * 2519 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2520 * @return Whether any scrolling, selection or focus change occured. 2521 */ 2522 private boolean arrowScrollImpl(int direction) { 2523 if (getChildCount() <= 0) { 2524 return false; 2525 } 2526 2527 View selectedView = getSelectedView(); 2528 int selectedPos = mSelectedPosition; 2529 2530 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2531 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2532 2533 // if we are moving focus, we may OVERRIDE the default behavior 2534 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2535 if (focusResult != null) { 2536 nextSelectedPosition = focusResult.getSelectedPosition(); 2537 amountToScroll = focusResult.getAmountToScroll(); 2538 } 2539 2540 boolean needToRedraw = focusResult != null; 2541 if (nextSelectedPosition != INVALID_POSITION) { 2542 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2543 setSelectedPositionInt(nextSelectedPosition); 2544 setNextSelectedPositionInt(nextSelectedPosition); 2545 selectedView = getSelectedView(); 2546 selectedPos = nextSelectedPosition; 2547 if (mItemsCanFocus && focusResult == null) { 2548 // there was no new view found to take focus, make sure we 2549 // don't leave focus with the old selection 2550 final View focused = getFocusedChild(); 2551 if (focused != null) { 2552 focused.clearFocus(); 2553 } 2554 } 2555 needToRedraw = true; 2556 checkSelectionChanged(); 2557 } 2558 2559 if (amountToScroll > 0) { 2560 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2561 needToRedraw = true; 2562 } 2563 2564 // if we didn't find a new focusable, make sure any existing focused 2565 // item that was panned off screen gives up focus. 2566 if (mItemsCanFocus && (focusResult == null) 2567 && selectedView != null && selectedView.hasFocus()) { 2568 final View focused = selectedView.findFocus(); 2569 if (focused != null) { 2570 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2571 focused.clearFocus(); 2572 } 2573 } 2574 } 2575 2576 // if the current selection is panned off, we need to remove the selection 2577 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2578 && !isViewAncestorOf(selectedView, this)) { 2579 selectedView = null; 2580 hideSelector(); 2581 2582 // but we don't want to set the ressurect position (that would make subsequent 2583 // unhandled key events bring back the item we just scrolled off!) 2584 mResurrectToPosition = INVALID_POSITION; 2585 } 2586 2587 if (needToRedraw) { 2588 if (selectedView != null) { 2589 positionSelectorLikeFocus(selectedPos, selectedView); 2590 mSelectedTop = selectedView.getTop(); 2591 } 2592 if (!awakenScrollBars()) { 2593 invalidate(); 2594 } 2595 invokeOnItemScrollListener(); 2596 return true; 2597 } 2598 2599 return false; 2600 } 2601 2602 /** 2603 * When selection changes, it is possible that the previously selected or the 2604 * next selected item will change its size. If so, we need to offset some folks, 2605 * and re-layout the items as appropriate. 2606 * 2607 * @param selectedView The currently selected view (before changing selection). 2608 * should be <code>null</code> if there was no previous selection. 2609 * @param direction Either {@link android.view.View#FOCUS_UP} or 2610 * {@link android.view.View#FOCUS_DOWN}. 2611 * @param newSelectedPosition The position of the next selection. 2612 * @param newFocusAssigned whether new focus was assigned. This matters because 2613 * when something has focus, we don't want to show selection (ugh). 2614 */ 2615 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2616 boolean newFocusAssigned) { 2617 if (newSelectedPosition == INVALID_POSITION) { 2618 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2619 } 2620 2621 // whether or not we are moving down or up, we want to preserve the 2622 // top of whatever view is on top: 2623 // - moving down: the view that had selection 2624 // - moving up: the view that is getting selection 2625 View topView; 2626 View bottomView; 2627 int topViewIndex, bottomViewIndex; 2628 boolean topSelected = false; 2629 final int selectedIndex = mSelectedPosition - mFirstPosition; 2630 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2631 if (direction == View.FOCUS_UP) { 2632 topViewIndex = nextSelectedIndex; 2633 bottomViewIndex = selectedIndex; 2634 topView = getChildAt(topViewIndex); 2635 bottomView = selectedView; 2636 topSelected = true; 2637 } else { 2638 topViewIndex = selectedIndex; 2639 bottomViewIndex = nextSelectedIndex; 2640 topView = selectedView; 2641 bottomView = getChildAt(bottomViewIndex); 2642 } 2643 2644 final int numChildren = getChildCount(); 2645 2646 // start with top view: is it changing size? 2647 if (topView != null) { 2648 topView.setSelected(!newFocusAssigned && topSelected); 2649 measureAndAdjustDown(topView, topViewIndex, numChildren); 2650 } 2651 2652 // is the bottom view changing size? 2653 if (bottomView != null) { 2654 bottomView.setSelected(!newFocusAssigned && !topSelected); 2655 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2656 } 2657 } 2658 2659 /** 2660 * Re-measure a child, and if its height changes, lay it out preserving its 2661 * top, and adjust the children below it appropriately. 2662 * @param child The child 2663 * @param childIndex The view group index of the child. 2664 * @param numChildren The number of children in the view group. 2665 */ 2666 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2667 int oldHeight = child.getHeight(); 2668 measureItem(child); 2669 if (child.getMeasuredHeight() != oldHeight) { 2670 // lay out the view, preserving its top 2671 relayoutMeasuredItem(child); 2672 2673 // adjust views below appropriately 2674 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2675 for (int i = childIndex + 1; i < numChildren; i++) { 2676 getChildAt(i).offsetTopAndBottom(heightDelta); 2677 } 2678 } 2679 } 2680 2681 /** 2682 * Measure a particular list child. 2683 * TODO: unify with setUpChild. 2684 * @param child The child. 2685 */ 2686 private void measureItem(View child) { 2687 ViewGroup.LayoutParams p = child.getLayoutParams(); 2688 if (p == null) { 2689 p = new ViewGroup.LayoutParams( 2690 ViewGroup.LayoutParams.MATCH_PARENT, 2691 ViewGroup.LayoutParams.WRAP_CONTENT); 2692 } 2693 2694 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2695 mListPadding.left + mListPadding.right, p.width); 2696 int lpHeight = p.height; 2697 int childHeightSpec; 2698 if (lpHeight > 0) { 2699 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2700 } else { 2701 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 2702 MeasureSpec.UNSPECIFIED); 2703 } 2704 child.measure(childWidthSpec, childHeightSpec); 2705 } 2706 2707 /** 2708 * Layout a child that has been measured, preserving its top position. 2709 * TODO: unify with setUpChild. 2710 * @param child The child. 2711 */ 2712 private void relayoutMeasuredItem(View child) { 2713 final int w = child.getMeasuredWidth(); 2714 final int h = child.getMeasuredHeight(); 2715 final int childLeft = mListPadding.left; 2716 final int childRight = childLeft + w; 2717 final int childTop = child.getTop(); 2718 final int childBottom = childTop + h; 2719 child.layout(childLeft, childTop, childRight, childBottom); 2720 } 2721 2722 /** 2723 * @return The amount to preview next items when arrow srolling. 2724 */ 2725 private int getArrowScrollPreviewLength() { 2726 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2727 } 2728 2729 /** 2730 * Determine how much we need to scroll in order to get the next selected view 2731 * visible, with a fading edge showing below as applicable. The amount is 2732 * capped at {@link #getMaxScrollAmount()} . 2733 * 2734 * @param direction either {@link android.view.View#FOCUS_UP} or 2735 * {@link android.view.View#FOCUS_DOWN}. 2736 * @param nextSelectedPosition The position of the next selection, or 2737 * {@link #INVALID_POSITION} if there is no next selectable position 2738 * @return The amount to scroll. Note: this is always positive! Direction 2739 * needs to be taken into account when actually scrolling. 2740 */ 2741 private int amountToScroll(int direction, int nextSelectedPosition) { 2742 final int listBottom = getHeight() - mListPadding.bottom; 2743 final int listTop = mListPadding.top; 2744 2745 int numChildren = getChildCount(); 2746 2747 if (direction == View.FOCUS_DOWN) { 2748 int indexToMakeVisible = numChildren - 1; 2749 if (nextSelectedPosition != INVALID_POSITION) { 2750 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2751 } 2752 while (numChildren <= indexToMakeVisible) { 2753 // Child to view is not attached yet. 2754 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2755 numChildren++; 2756 } 2757 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2758 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2759 2760 int goalBottom = listBottom; 2761 if (positionToMakeVisible < mItemCount - 1) { 2762 goalBottom -= getArrowScrollPreviewLength(); 2763 } 2764 2765 if (viewToMakeVisible.getBottom() <= goalBottom) { 2766 // item is fully visible. 2767 return 0; 2768 } 2769 2770 if (nextSelectedPosition != INVALID_POSITION 2771 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2772 // item already has enough of it visible, changing selection is good enough 2773 return 0; 2774 } 2775 2776 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2777 2778 if ((mFirstPosition + numChildren) == mItemCount) { 2779 // last is last in list -> make sure we don't scroll past it 2780 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2781 amountToScroll = Math.min(amountToScroll, max); 2782 } 2783 2784 return Math.min(amountToScroll, getMaxScrollAmount()); 2785 } else { 2786 int indexToMakeVisible = 0; 2787 if (nextSelectedPosition != INVALID_POSITION) { 2788 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2789 } 2790 while (indexToMakeVisible < 0) { 2791 // Child to view is not attached yet. 2792 addViewAbove(getChildAt(0), mFirstPosition); 2793 mFirstPosition--; 2794 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2795 } 2796 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2797 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2798 int goalTop = listTop; 2799 if (positionToMakeVisible > 0) { 2800 goalTop += getArrowScrollPreviewLength(); 2801 } 2802 if (viewToMakeVisible.getTop() >= goalTop) { 2803 // item is fully visible. 2804 return 0; 2805 } 2806 2807 if (nextSelectedPosition != INVALID_POSITION && 2808 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2809 // item already has enough of it visible, changing selection is good enough 2810 return 0; 2811 } 2812 2813 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2814 if (mFirstPosition == 0) { 2815 // first is first in list -> make sure we don't scroll past it 2816 final int max = listTop - getChildAt(0).getTop(); 2817 amountToScroll = Math.min(amountToScroll, max); 2818 } 2819 return Math.min(amountToScroll, getMaxScrollAmount()); 2820 } 2821 } 2822 2823 /** 2824 * Holds results of focus aware arrow scrolling. 2825 */ 2826 static private class ArrowScrollFocusResult { 2827 private int mSelectedPosition; 2828 private int mAmountToScroll; 2829 2830 /** 2831 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2832 */ 2833 void populate(int selectedPosition, int amountToScroll) { 2834 mSelectedPosition = selectedPosition; 2835 mAmountToScroll = amountToScroll; 2836 } 2837 2838 public int getSelectedPosition() { 2839 return mSelectedPosition; 2840 } 2841 2842 public int getAmountToScroll() { 2843 return mAmountToScroll; 2844 } 2845 } 2846 2847 /** 2848 * @param direction either {@link android.view.View#FOCUS_UP} or 2849 * {@link android.view.View#FOCUS_DOWN}. 2850 * @return The position of the next selectable position of the views that 2851 * are currently visible, taking into account the fact that there might 2852 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2853 * selectable view on screen in the given direction. 2854 */ 2855 private int lookForSelectablePositionOnScreen(int direction) { 2856 final int firstPosition = mFirstPosition; 2857 if (direction == View.FOCUS_DOWN) { 2858 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2859 mSelectedPosition + 1 : 2860 firstPosition; 2861 if (startPos >= mAdapter.getCount()) { 2862 return INVALID_POSITION; 2863 } 2864 if (startPos < firstPosition) { 2865 startPos = firstPosition; 2866 } 2867 2868 final int lastVisiblePos = getLastVisiblePosition(); 2869 final ListAdapter adapter = getAdapter(); 2870 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2871 if (adapter.isEnabled(pos) 2872 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2873 return pos; 2874 } 2875 } 2876 } else { 2877 int last = firstPosition + getChildCount() - 1; 2878 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2879 mSelectedPosition - 1 : 2880 firstPosition + getChildCount() - 1; 2881 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2882 return INVALID_POSITION; 2883 } 2884 if (startPos > last) { 2885 startPos = last; 2886 } 2887 2888 final ListAdapter adapter = getAdapter(); 2889 for (int pos = startPos; pos >= firstPosition; pos--) { 2890 if (adapter.isEnabled(pos) 2891 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2892 return pos; 2893 } 2894 } 2895 } 2896 return INVALID_POSITION; 2897 } 2898 2899 /** 2900 * Do an arrow scroll based on focus searching. If a new view is 2901 * given focus, return the selection delta and amount to scroll via 2902 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2903 * 2904 * @param direction either {@link android.view.View#FOCUS_UP} or 2905 * {@link android.view.View#FOCUS_DOWN}. 2906 * @return The result if focus has changed, or <code>null</code>. 2907 */ 2908 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2909 final View selectedView = getSelectedView(); 2910 View newFocus; 2911 if (selectedView != null && selectedView.hasFocus()) { 2912 View oldFocus = selectedView.findFocus(); 2913 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2914 } else { 2915 if (direction == View.FOCUS_DOWN) { 2916 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2917 final int listTop = mListPadding.top + 2918 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2919 final int ySearchPoint = 2920 (selectedView != null && selectedView.getTop() > listTop) ? 2921 selectedView.getTop() : 2922 listTop; 2923 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2924 } else { 2925 final boolean bottomFadingEdgeShowing = 2926 (mFirstPosition + getChildCount() - 1) < mItemCount; 2927 final int listBottom = getHeight() - mListPadding.bottom - 2928 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2929 final int ySearchPoint = 2930 (selectedView != null && selectedView.getBottom() < listBottom) ? 2931 selectedView.getBottom() : 2932 listBottom; 2933 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2934 } 2935 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2936 } 2937 2938 if (newFocus != null) { 2939 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2940 2941 // if the focus change is in a different new position, make sure 2942 // we aren't jumping over another selectable position 2943 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2944 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2945 if (selectablePosition != INVALID_POSITION && 2946 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2947 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2948 return null; 2949 } 2950 } 2951 2952 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2953 2954 final int maxScrollAmount = getMaxScrollAmount(); 2955 if (focusScroll < maxScrollAmount) { 2956 // not moving too far, safe to give next view focus 2957 newFocus.requestFocus(direction); 2958 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2959 return mArrowScrollFocusResult; 2960 } else if (distanceToView(newFocus) < maxScrollAmount){ 2961 // Case to consider: 2962 // too far to get entire next focusable on screen, but by going 2963 // max scroll amount, we are getting it at least partially in view, 2964 // so give it focus and scroll the max ammount. 2965 newFocus.requestFocus(direction); 2966 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2967 return mArrowScrollFocusResult; 2968 } 2969 } 2970 return null; 2971 } 2972 2973 /** 2974 * @param newFocus The view that would have focus. 2975 * @return the position that contains newFocus 2976 */ 2977 private int positionOfNewFocus(View newFocus) { 2978 final int numChildren = getChildCount(); 2979 for (int i = 0; i < numChildren; i++) { 2980 final View child = getChildAt(i); 2981 if (isViewAncestorOf(newFocus, child)) { 2982 return mFirstPosition + i; 2983 } 2984 } 2985 throw new IllegalArgumentException("newFocus is not a child of any of the" 2986 + " children of the list!"); 2987 } 2988 2989 /** 2990 * Return true if child is an ancestor of parent, (or equal to the parent). 2991 */ 2992 private boolean isViewAncestorOf(View child, View parent) { 2993 if (child == parent) { 2994 return true; 2995 } 2996 2997 final ViewParent theParent = child.getParent(); 2998 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2999 } 3000 3001 /** 3002 * Determine how much we need to scroll in order to get newFocus in view. 3003 * @param direction either {@link android.view.View#FOCUS_UP} or 3004 * {@link android.view.View#FOCUS_DOWN}. 3005 * @param newFocus The view that would take focus. 3006 * @param positionOfNewFocus The position of the list item containing newFocus 3007 * @return The amount to scroll. Note: this is always positive! Direction 3008 * needs to be taken into account when actually scrolling. 3009 */ 3010 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 3011 int amountToScroll = 0; 3012 newFocus.getDrawingRect(mTempRect); 3013 offsetDescendantRectToMyCoords(newFocus, mTempRect); 3014 if (direction == View.FOCUS_UP) { 3015 if (mTempRect.top < mListPadding.top) { 3016 amountToScroll = mListPadding.top - mTempRect.top; 3017 if (positionOfNewFocus > 0) { 3018 amountToScroll += getArrowScrollPreviewLength(); 3019 } 3020 } 3021 } else { 3022 final int listBottom = getHeight() - mListPadding.bottom; 3023 if (mTempRect.bottom > listBottom) { 3024 amountToScroll = mTempRect.bottom - listBottom; 3025 if (positionOfNewFocus < mItemCount - 1) { 3026 amountToScroll += getArrowScrollPreviewLength(); 3027 } 3028 } 3029 } 3030 return amountToScroll; 3031 } 3032 3033 /** 3034 * Determine the distance to the nearest edge of a view in a particular 3035 * direction. 3036 * 3037 * @param descendant A descendant of this list. 3038 * @return The distance, or 0 if the nearest edge is already on screen. 3039 */ 3040 private int distanceToView(View descendant) { 3041 int distance = 0; 3042 descendant.getDrawingRect(mTempRect); 3043 offsetDescendantRectToMyCoords(descendant, mTempRect); 3044 final int listBottom = mBottom - mTop - mListPadding.bottom; 3045 if (mTempRect.bottom < mListPadding.top) { 3046 distance = mListPadding.top - mTempRect.bottom; 3047 } else if (mTempRect.top > listBottom) { 3048 distance = mTempRect.top - listBottom; 3049 } 3050 return distance; 3051 } 3052 3053 3054 /** 3055 * Scroll the children by amount, adding a view at the end and removing 3056 * views that fall off as necessary. 3057 * 3058 * @param amount The amount (positive or negative) to scroll. 3059 */ 3060 private void scrollListItemsBy(int amount) { 3061 offsetChildrenTopAndBottom(amount); 3062 3063 final int listBottom = getHeight() - mListPadding.bottom; 3064 final int listTop = mListPadding.top; 3065 final AbsListView.RecycleBin recycleBin = mRecycler; 3066 3067 if (amount < 0) { 3068 // shifted items up 3069 3070 // may need to pan views into the bottom space 3071 int numChildren = getChildCount(); 3072 View last = getChildAt(numChildren - 1); 3073 while (last.getBottom() < listBottom) { 3074 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3075 if (lastVisiblePosition < mItemCount - 1) { 3076 last = addViewBelow(last, lastVisiblePosition); 3077 numChildren++; 3078 } else { 3079 break; 3080 } 3081 } 3082 3083 // may have brought in the last child of the list that is skinnier 3084 // than the fading edge, thereby leaving space at the end. need 3085 // to shift back 3086 if (last.getBottom() < listBottom) { 3087 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3088 } 3089 3090 // top views may be panned off screen 3091 View first = getChildAt(0); 3092 while (first.getBottom() < listTop) { 3093 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3094 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3095 recycleBin.addScrapView(first, mFirstPosition); 3096 } 3097 detachViewFromParent(first); 3098 first = getChildAt(0); 3099 mFirstPosition++; 3100 } 3101 } else { 3102 // shifted items down 3103 View first = getChildAt(0); 3104 3105 // may need to pan views into top 3106 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3107 first = addViewAbove(first, mFirstPosition); 3108 mFirstPosition--; 3109 } 3110 3111 // may have brought the very first child of the list in too far and 3112 // need to shift it back 3113 if (first.getTop() > listTop) { 3114 offsetChildrenTopAndBottom(listTop - first.getTop()); 3115 } 3116 3117 int lastIndex = getChildCount() - 1; 3118 View last = getChildAt(lastIndex); 3119 3120 // bottom view may be panned off screen 3121 while (last.getTop() > listBottom) { 3122 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3123 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3124 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3125 } 3126 detachViewFromParent(last); 3127 last = getChildAt(--lastIndex); 3128 } 3129 } 3130 } 3131 3132 private View addViewAbove(View theView, int position) { 3133 int abovePosition = position - 1; 3134 View view = obtainView(abovePosition, mIsScrap); 3135 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3136 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3137 false, mIsScrap[0]); 3138 return view; 3139 } 3140 3141 private View addViewBelow(View theView, int position) { 3142 int belowPosition = position + 1; 3143 View view = obtainView(belowPosition, mIsScrap); 3144 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3145 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3146 false, mIsScrap[0]); 3147 return view; 3148 } 3149 3150 /** 3151 * Indicates that the views created by the ListAdapter can contain focusable 3152 * items. 3153 * 3154 * @param itemsCanFocus true if items can get focus, false otherwise 3155 */ 3156 public void setItemsCanFocus(boolean itemsCanFocus) { 3157 mItemsCanFocus = itemsCanFocus; 3158 if (!itemsCanFocus) { 3159 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3160 } 3161 } 3162 3163 /** 3164 * @return Whether the views created by the ListAdapter can contain focusable 3165 * items. 3166 */ 3167 public boolean getItemsCanFocus() { 3168 return mItemsCanFocus; 3169 } 3170 3171 @Override 3172 public boolean isOpaque() { 3173 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3174 hasOpaqueScrollbars()) || super.isOpaque(); 3175 if (retValue) { 3176 // only return true if the list items cover the entire area of the view 3177 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3178 View first = getChildAt(0); 3179 if (first == null || first.getTop() > listTop) { 3180 return false; 3181 } 3182 final int listBottom = getHeight() - 3183 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3184 View last = getChildAt(getChildCount() - 1); 3185 if (last == null || last.getBottom() < listBottom) { 3186 return false; 3187 } 3188 } 3189 return retValue; 3190 } 3191 3192 @Override 3193 public void setCacheColorHint(int color) { 3194 final boolean opaque = (color >>> 24) == 0xFF; 3195 mIsCacheColorOpaque = opaque; 3196 if (opaque) { 3197 if (mDividerPaint == null) { 3198 mDividerPaint = new Paint(); 3199 } 3200 mDividerPaint.setColor(color); 3201 } 3202 super.setCacheColorHint(color); 3203 } 3204 3205 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3206 final int height = drawable.getMinimumHeight(); 3207 3208 canvas.save(); 3209 canvas.clipRect(bounds); 3210 3211 final int span = bounds.bottom - bounds.top; 3212 if (span < height) { 3213 bounds.top = bounds.bottom - height; 3214 } 3215 3216 drawable.setBounds(bounds); 3217 drawable.draw(canvas); 3218 3219 canvas.restore(); 3220 } 3221 3222 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3223 final int height = drawable.getMinimumHeight(); 3224 3225 canvas.save(); 3226 canvas.clipRect(bounds); 3227 3228 final int span = bounds.bottom - bounds.top; 3229 if (span < height) { 3230 bounds.bottom = bounds.top + height; 3231 } 3232 3233 drawable.setBounds(bounds); 3234 drawable.draw(canvas); 3235 3236 canvas.restore(); 3237 } 3238 3239 @Override 3240 protected void dispatchDraw(Canvas canvas) { 3241 if (mCachingStarted) { 3242 mCachingActive = true; 3243 } 3244 3245 // Draw the dividers 3246 final int dividerHeight = mDividerHeight; 3247 final Drawable overscrollHeader = mOverScrollHeader; 3248 final Drawable overscrollFooter = mOverScrollFooter; 3249 final boolean drawOverscrollHeader = overscrollHeader != null; 3250 final boolean drawOverscrollFooter = overscrollFooter != null; 3251 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3252 3253 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3254 // Only modify the top and bottom in the loop, we set the left and right here 3255 final Rect bounds = mTempRect; 3256 bounds.left = mPaddingLeft; 3257 bounds.right = mRight - mLeft - mPaddingRight; 3258 3259 final int count = getChildCount(); 3260 final int headerCount = mHeaderViewInfos.size(); 3261 final int itemCount = mItemCount; 3262 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3263 final boolean headerDividers = mHeaderDividersEnabled; 3264 final boolean footerDividers = mFooterDividersEnabled; 3265 final int first = mFirstPosition; 3266 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3267 final ListAdapter adapter = mAdapter; 3268 // If the list is opaque *and* the background is not, we want to 3269 // fill a rect where the dividers would be for non-selectable items 3270 // If the list is opaque and the background is also opaque, we don't 3271 // need to draw anything since the background will do it for us 3272 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3273 3274 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3275 mDividerPaint = new Paint(); 3276 mDividerPaint.setColor(getCacheColorHint()); 3277 } 3278 final Paint paint = mDividerPaint; 3279 3280 int effectivePaddingTop = 0; 3281 int effectivePaddingBottom = 0; 3282 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3283 effectivePaddingTop = mListPadding.top; 3284 effectivePaddingBottom = mListPadding.bottom; 3285 } 3286 3287 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3288 if (!mStackFromBottom) { 3289 int bottom = 0; 3290 3291 // Draw top divider or header for overscroll 3292 final int scrollY = mScrollY; 3293 if (count > 0 && scrollY < 0) { 3294 if (drawOverscrollHeader) { 3295 bounds.bottom = 0; 3296 bounds.top = scrollY; 3297 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3298 } else if (drawDividers) { 3299 bounds.bottom = 0; 3300 bounds.top = -dividerHeight; 3301 drawDivider(canvas, bounds, -1); 3302 } 3303 } 3304 3305 for (int i = 0; i < count; i++) { 3306 final int itemIndex = (first + i); 3307 final boolean isHeader = (itemIndex < headerCount); 3308 final boolean isFooter = (itemIndex >= footerLimit); 3309 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3310 final View child = getChildAt(i); 3311 bottom = child.getBottom(); 3312 final boolean isLastItem = (i == (count - 1)); 3313 3314 if (drawDividers && (bottom < listBottom) 3315 && !(drawOverscrollFooter && isLastItem)) { 3316 final int nextIndex = (itemIndex + 1); 3317 // Draw dividers between enabled items, headers 3318 // and/or footers when enabled and requested, and 3319 // after the last enabled item. 3320 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3321 && (nextIndex >= headerCount)) && (isLastItem 3322 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3323 && (nextIndex < footerLimit)))) { 3324 bounds.top = bottom; 3325 bounds.bottom = bottom + dividerHeight; 3326 drawDivider(canvas, bounds, i); 3327 } else if (fillForMissingDividers) { 3328 bounds.top = bottom; 3329 bounds.bottom = bottom + dividerHeight; 3330 canvas.drawRect(bounds, paint); 3331 } 3332 } 3333 } 3334 } 3335 3336 final int overFooterBottom = mBottom + mScrollY; 3337 if (drawOverscrollFooter && first + count == itemCount && 3338 overFooterBottom > bottom) { 3339 bounds.top = bottom; 3340 bounds.bottom = overFooterBottom; 3341 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3342 } 3343 } else { 3344 int top; 3345 3346 final int scrollY = mScrollY; 3347 3348 if (count > 0 && drawOverscrollHeader) { 3349 bounds.top = scrollY; 3350 bounds.bottom = getChildAt(0).getTop(); 3351 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3352 } 3353 3354 final int start = drawOverscrollHeader ? 1 : 0; 3355 for (int i = start; i < count; i++) { 3356 final int itemIndex = (first + i); 3357 final boolean isHeader = (itemIndex < headerCount); 3358 final boolean isFooter = (itemIndex >= footerLimit); 3359 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3360 final View child = getChildAt(i); 3361 top = child.getTop(); 3362 if (drawDividers && (top > effectivePaddingTop)) { 3363 final boolean isFirstItem = (i == start); 3364 final int previousIndex = (itemIndex - 1); 3365 // Draw dividers between enabled items, headers 3366 // and/or footers when enabled and requested, and 3367 // before the first enabled item. 3368 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3369 && (previousIndex >= headerCount)) && (isFirstItem || 3370 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3371 && (previousIndex < footerLimit)))) { 3372 bounds.top = top - dividerHeight; 3373 bounds.bottom = top; 3374 // Give the method the child ABOVE the divider, 3375 // so we subtract one from our child position. 3376 // Give -1 when there is no child above the 3377 // divider. 3378 drawDivider(canvas, bounds, i - 1); 3379 } else if (fillForMissingDividers) { 3380 bounds.top = top - dividerHeight; 3381 bounds.bottom = top; 3382 canvas.drawRect(bounds, paint); 3383 } 3384 } 3385 } 3386 } 3387 3388 if (count > 0 && scrollY > 0) { 3389 if (drawOverscrollFooter) { 3390 final int absListBottom = mBottom; 3391 bounds.top = absListBottom; 3392 bounds.bottom = absListBottom + scrollY; 3393 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3394 } else if (drawDividers) { 3395 bounds.top = listBottom; 3396 bounds.bottom = listBottom + dividerHeight; 3397 drawDivider(canvas, bounds, -1); 3398 } 3399 } 3400 } 3401 } 3402 3403 // Draw the indicators (these should be drawn above the dividers) and children 3404 super.dispatchDraw(canvas); 3405 } 3406 3407 @Override 3408 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3409 boolean more = super.drawChild(canvas, child, drawingTime); 3410 if (mCachingActive && child.mCachingFailed) { 3411 mCachingActive = false; 3412 } 3413 return more; 3414 } 3415 3416 /** 3417 * Draws a divider for the given child in the given bounds. 3418 * 3419 * @param canvas The canvas to draw to. 3420 * @param bounds The bounds of the divider. 3421 * @param childIndex The index of child (of the View) above the divider. 3422 * This will be -1 if there is no child above the divider to be 3423 * drawn. 3424 */ 3425 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3426 // This widget draws the same divider for all children 3427 final Drawable divider = mDivider; 3428 3429 divider.setBounds(bounds); 3430 divider.draw(canvas); 3431 } 3432 3433 /** 3434 * Returns the drawable that will be drawn between each item in the list. 3435 * 3436 * @return the current drawable drawn between list elements 3437 * @attr ref R.styleable#ListView_divider 3438 */ 3439 @Nullable 3440 public Drawable getDivider() { 3441 return mDivider; 3442 } 3443 3444 /** 3445 * Sets the drawable that will be drawn between each item in the list. 3446 * <p> 3447 * <strong>Note:</strong> If the drawable does not have an intrinsic 3448 * height, you should also call {@link #setDividerHeight(int)}. 3449 * 3450 * @param divider the drawable to use 3451 * @attr ref R.styleable#ListView_divider 3452 */ 3453 public void setDivider(@Nullable Drawable divider) { 3454 if (divider != null) { 3455 mDividerHeight = divider.getIntrinsicHeight(); 3456 } else { 3457 mDividerHeight = 0; 3458 } 3459 mDivider = divider; 3460 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3461 requestLayout(); 3462 invalidate(); 3463 } 3464 3465 /** 3466 * @return Returns the height of the divider that will be drawn between each item in the list. 3467 */ 3468 public int getDividerHeight() { 3469 return mDividerHeight; 3470 } 3471 3472 /** 3473 * Sets the height of the divider that will be drawn between each item in the list. Calling 3474 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3475 * 3476 * @param height The new height of the divider in pixels. 3477 */ 3478 public void setDividerHeight(int height) { 3479 mDividerHeight = height; 3480 requestLayout(); 3481 invalidate(); 3482 } 3483 3484 /** 3485 * Enables or disables the drawing of the divider for header views. 3486 * 3487 * @param headerDividersEnabled True to draw the headers, false otherwise. 3488 * 3489 * @see #setFooterDividersEnabled(boolean) 3490 * @see #areHeaderDividersEnabled() 3491 * @see #addHeaderView(android.view.View) 3492 */ 3493 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3494 mHeaderDividersEnabled = headerDividersEnabled; 3495 invalidate(); 3496 } 3497 3498 /** 3499 * @return Whether the drawing of the divider for header views is enabled 3500 * 3501 * @see #setHeaderDividersEnabled(boolean) 3502 */ 3503 public boolean areHeaderDividersEnabled() { 3504 return mHeaderDividersEnabled; 3505 } 3506 3507 /** 3508 * Enables or disables the drawing of the divider for footer views. 3509 * 3510 * @param footerDividersEnabled True to draw the footers, false otherwise. 3511 * 3512 * @see #setHeaderDividersEnabled(boolean) 3513 * @see #areFooterDividersEnabled() 3514 * @see #addFooterView(android.view.View) 3515 */ 3516 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3517 mFooterDividersEnabled = footerDividersEnabled; 3518 invalidate(); 3519 } 3520 3521 /** 3522 * @return Whether the drawing of the divider for footer views is enabled 3523 * 3524 * @see #setFooterDividersEnabled(boolean) 3525 */ 3526 public boolean areFooterDividersEnabled() { 3527 return mFooterDividersEnabled; 3528 } 3529 3530 /** 3531 * Sets the drawable that will be drawn above all other list content. 3532 * This area can become visible when the user overscrolls the list. 3533 * 3534 * @param header The drawable to use 3535 */ 3536 public void setOverscrollHeader(Drawable header) { 3537 mOverScrollHeader = header; 3538 if (mScrollY < 0) { 3539 invalidate(); 3540 } 3541 } 3542 3543 /** 3544 * @return The drawable that will be drawn above all other list content 3545 */ 3546 public Drawable getOverscrollHeader() { 3547 return mOverScrollHeader; 3548 } 3549 3550 /** 3551 * Sets the drawable that will be drawn below all other list content. 3552 * This area can become visible when the user overscrolls the list, 3553 * or when the list's content does not fully fill the container area. 3554 * 3555 * @param footer The drawable to use 3556 */ 3557 public void setOverscrollFooter(Drawable footer) { 3558 mOverScrollFooter = footer; 3559 invalidate(); 3560 } 3561 3562 /** 3563 * @return The drawable that will be drawn below all other list content 3564 */ 3565 public Drawable getOverscrollFooter() { 3566 return mOverScrollFooter; 3567 } 3568 3569 @Override 3570 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3571 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3572 3573 final ListAdapter adapter = mAdapter; 3574 int closetChildIndex = -1; 3575 int closestChildTop = 0; 3576 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3577 previouslyFocusedRect.offset(mScrollX, mScrollY); 3578 3579 // Don't cache the result of getChildCount or mFirstPosition here, 3580 // it could change in layoutChildren. 3581 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3582 mLayoutMode = LAYOUT_NORMAL; 3583 layoutChildren(); 3584 } 3585 3586 // figure out which item should be selected based on previously 3587 // focused rect 3588 Rect otherRect = mTempRect; 3589 int minDistance = Integer.MAX_VALUE; 3590 final int childCount = getChildCount(); 3591 final int firstPosition = mFirstPosition; 3592 3593 for (int i = 0; i < childCount; i++) { 3594 // only consider selectable views 3595 if (!adapter.isEnabled(firstPosition + i)) { 3596 continue; 3597 } 3598 3599 View other = getChildAt(i); 3600 other.getDrawingRect(otherRect); 3601 offsetDescendantRectToMyCoords(other, otherRect); 3602 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3603 3604 if (distance < minDistance) { 3605 minDistance = distance; 3606 closetChildIndex = i; 3607 closestChildTop = other.getTop(); 3608 } 3609 } 3610 } 3611 3612 if (closetChildIndex >= 0) { 3613 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3614 } else { 3615 requestLayout(); 3616 } 3617 } 3618 3619 3620 /* 3621 * (non-Javadoc) 3622 * 3623 * Children specified in XML are assumed to be header views. After we have 3624 * parsed them move them out of the children list and into mHeaderViews. 3625 */ 3626 @Override 3627 protected void onFinishInflate() { 3628 super.onFinishInflate(); 3629 3630 int count = getChildCount(); 3631 if (count > 0) { 3632 for (int i = 0; i < count; ++i) { 3633 addHeaderView(getChildAt(i)); 3634 } 3635 removeAllViews(); 3636 } 3637 } 3638 3639 /* (non-Javadoc) 3640 * @see android.view.View#findViewById(int) 3641 * First look in our children, then in any header and footer views that may be scrolled off. 3642 */ 3643 @Override 3644 protected View findViewTraversal(@IdRes int id) { 3645 View v; 3646 v = super.findViewTraversal(id); 3647 if (v == null) { 3648 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3649 if (v != null) { 3650 return v; 3651 } 3652 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3653 if (v != null) { 3654 return v; 3655 } 3656 } 3657 return v; 3658 } 3659 3660 /* (non-Javadoc) 3661 * 3662 * Look in the passed in list of headers or footers for the view. 3663 */ 3664 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3665 if (where != null) { 3666 int len = where.size(); 3667 View v; 3668 3669 for (int i = 0; i < len; i++) { 3670 v = where.get(i).view; 3671 3672 if (!v.isRootNamespace()) { 3673 v = v.findViewById(id); 3674 3675 if (v != null) { 3676 return v; 3677 } 3678 } 3679 } 3680 } 3681 return null; 3682 } 3683 3684 /* (non-Javadoc) 3685 * @see android.view.View#findViewWithTag(Object) 3686 * First look in our children, then in any header and footer views that may be scrolled off. 3687 */ 3688 @Override 3689 protected View findViewWithTagTraversal(Object tag) { 3690 View v; 3691 v = super.findViewWithTagTraversal(tag); 3692 if (v == null) { 3693 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3694 if (v != null) { 3695 return v; 3696 } 3697 3698 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3699 if (v != null) { 3700 return v; 3701 } 3702 } 3703 return v; 3704 } 3705 3706 /* (non-Javadoc) 3707 * 3708 * Look in the passed in list of headers or footers for the view with the tag. 3709 */ 3710 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3711 if (where != null) { 3712 int len = where.size(); 3713 View v; 3714 3715 for (int i = 0; i < len; i++) { 3716 v = where.get(i).view; 3717 3718 if (!v.isRootNamespace()) { 3719 v = v.findViewWithTag(tag); 3720 3721 if (v != null) { 3722 return v; 3723 } 3724 } 3725 } 3726 } 3727 return null; 3728 } 3729 3730 /** 3731 * @hide 3732 * @see android.view.View#findViewByPredicate(Predicate) 3733 * First look in our children, then in any header and footer views that may be scrolled off. 3734 */ 3735 @Override 3736 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3737 View v; 3738 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3739 if (v == null) { 3740 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3741 if (v != null) { 3742 return v; 3743 } 3744 3745 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3746 if (v != null) { 3747 return v; 3748 } 3749 } 3750 return v; 3751 } 3752 3753 /* (non-Javadoc) 3754 * 3755 * Look in the passed in list of headers or footers for the first view that matches 3756 * the predicate. 3757 */ 3758 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3759 Predicate<View> predicate, View childToSkip) { 3760 if (where != null) { 3761 int len = where.size(); 3762 View v; 3763 3764 for (int i = 0; i < len; i++) { 3765 v = where.get(i).view; 3766 3767 if (v != childToSkip && !v.isRootNamespace()) { 3768 v = v.findViewByPredicate(predicate); 3769 3770 if (v != null) { 3771 return v; 3772 } 3773 } 3774 } 3775 } 3776 return null; 3777 } 3778 3779 /** 3780 * Returns the set of checked items ids. The result is only valid if the 3781 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3782 * 3783 * @return A new array which contains the id of each checked item in the 3784 * list. 3785 * 3786 * @deprecated Use {@link #getCheckedItemIds()} instead. 3787 */ 3788 @Deprecated 3789 public long[] getCheckItemIds() { 3790 // Use new behavior that correctly handles stable ID mapping. 3791 if (mAdapter != null && mAdapter.hasStableIds()) { 3792 return getCheckedItemIds(); 3793 } 3794 3795 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3796 // Fall back to it to support legacy apps. 3797 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3798 final SparseBooleanArray states = mCheckStates; 3799 final int count = states.size(); 3800 final long[] ids = new long[count]; 3801 final ListAdapter adapter = mAdapter; 3802 3803 int checkedCount = 0; 3804 for (int i = 0; i < count; i++) { 3805 if (states.valueAt(i)) { 3806 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3807 } 3808 } 3809 3810 // Trim array if needed. mCheckStates may contain false values 3811 // resulting in checkedCount being smaller than count. 3812 if (checkedCount == count) { 3813 return ids; 3814 } else { 3815 final long[] result = new long[checkedCount]; 3816 System.arraycopy(ids, 0, result, 0, checkedCount); 3817 3818 return result; 3819 } 3820 } 3821 return new long[0]; 3822 } 3823 3824 @Override 3825 int getHeightForPosition(int position) { 3826 final int height = super.getHeightForPosition(position); 3827 if (shouldAdjustHeightForDivider(position)) { 3828 return height + mDividerHeight; 3829 } 3830 return height; 3831 } 3832 3833 private boolean shouldAdjustHeightForDivider(int itemIndex) { 3834 final int dividerHeight = mDividerHeight; 3835 final Drawable overscrollHeader = mOverScrollHeader; 3836 final Drawable overscrollFooter = mOverScrollFooter; 3837 final boolean drawOverscrollHeader = overscrollHeader != null; 3838 final boolean drawOverscrollFooter = overscrollFooter != null; 3839 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3840 3841 if (drawDividers) { 3842 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3843 final int itemCount = mItemCount; 3844 final int headerCount = mHeaderViewInfos.size(); 3845 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3846 final boolean isHeader = (itemIndex < headerCount); 3847 final boolean isFooter = (itemIndex >= footerLimit); 3848 final boolean headerDividers = mHeaderDividersEnabled; 3849 final boolean footerDividers = mFooterDividersEnabled; 3850 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3851 final ListAdapter adapter = mAdapter; 3852 if (!mStackFromBottom) { 3853 final boolean isLastItem = (itemIndex == (itemCount - 1)); 3854 if (!drawOverscrollFooter || !isLastItem) { 3855 final int nextIndex = itemIndex + 1; 3856 // Draw dividers between enabled items, headers 3857 // and/or footers when enabled and requested, and 3858 // after the last enabled item. 3859 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3860 && (nextIndex >= headerCount)) && (isLastItem 3861 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3862 && (nextIndex < footerLimit)))) { 3863 return true; 3864 } else if (fillForMissingDividers) { 3865 return true; 3866 } 3867 } 3868 } else { 3869 final int start = drawOverscrollHeader ? 1 : 0; 3870 final boolean isFirstItem = (itemIndex == start); 3871 if (!isFirstItem) { 3872 final int previousIndex = (itemIndex - 1); 3873 // Draw dividers between enabled items, headers 3874 // and/or footers when enabled and requested, and 3875 // before the first enabled item. 3876 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3877 && (previousIndex >= headerCount)) && (isFirstItem || 3878 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3879 && (previousIndex < footerLimit)))) { 3880 return true; 3881 } else if (fillForMissingDividers) { 3882 return true; 3883 } 3884 } 3885 } 3886 } 3887 } 3888 3889 return false; 3890 } 3891 3892 @Override 3893 public CharSequence getAccessibilityClassName() { 3894 return ListView.class.getName(); 3895 } 3896 3897 /** @hide */ 3898 @Override 3899 public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { 3900 super.onInitializeAccessibilityNodeInfoInternal(info); 3901 3902 final int rowsCount = getCount(); 3903 final int selectionMode = getSelectionModeForAccessibility(); 3904 final CollectionInfo collectionInfo = CollectionInfo.obtain( 3905 rowsCount, 1, false, selectionMode); 3906 info.setCollectionInfo(collectionInfo); 3907 3908 if (rowsCount > 0) { 3909 info.addAction(AccessibilityAction.ACTION_SCROLL_TO_POSITION); 3910 } 3911 } 3912 3913 /** @hide */ 3914 @Override 3915 public boolean performAccessibilityActionInternal(int action, Bundle arguments) { 3916 if (super.performAccessibilityActionInternal(action, arguments)) { 3917 return true; 3918 } 3919 3920 switch (action) { 3921 case R.id.accessibilityActionScrollToPosition: { 3922 final int row = arguments.getInt(AccessibilityNodeInfo.ACTION_ARGUMENT_ROW_INT, -1); 3923 final int position = Math.min(row, getCount() - 1); 3924 if (row >= 0) { 3925 // The accessibility service gets data asynchronously, so 3926 // we'll be a little lenient by clamping the last position. 3927 smoothScrollToPosition(position); 3928 return true; 3929 } 3930 } break; 3931 } 3932 3933 return false; 3934 } 3935 3936 @Override 3937 public void onInitializeAccessibilityNodeInfoForItem( 3938 View view, int position, AccessibilityNodeInfo info) { 3939 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3940 3941 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3942 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3943 final boolean isSelected = isItemChecked(position); 3944 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain( 3945 position, 1, 0, 1, isHeading, isSelected); 3946 info.setCollectionItemInfo(itemInfo); 3947 } 3948 3949 /** @hide */ 3950 @Override 3951 protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { 3952 super.encodeProperties(encoder); 3953 3954 encoder.addProperty("recycleOnMeasure", recycleOnMeasure()); 3955 } 3956} 3957