ListView.java revision b6824bf58a0cd34395993fa204217e8e246de6fb
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.os.Bundle; 20import android.os.Trace; 21import com.android.internal.R; 22import com.android.internal.util.Predicate; 23import com.google.android.collect.Lists; 24 25import android.annotation.IdRes; 26import android.content.Context; 27import android.content.Intent; 28import android.content.res.TypedArray; 29import android.graphics.Canvas; 30import android.graphics.Paint; 31import android.graphics.PixelFormat; 32import android.graphics.Rect; 33import android.graphics.drawable.Drawable; 34import android.util.AttributeSet; 35import android.util.MathUtils; 36import android.util.SparseBooleanArray; 37import android.view.FocusFinder; 38import android.view.KeyEvent; 39import android.view.SoundEffectConstants; 40import android.view.View; 41import android.view.ViewDebug; 42import android.view.ViewGroup; 43import android.view.ViewParent; 44import android.view.ViewRootImpl; 45import android.view.accessibility.AccessibilityNodeInfo; 46import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction; 47import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 48import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 49import android.view.accessibility.AccessibilityNodeProvider; 50import android.widget.RemoteViews.RemoteView; 51 52import java.util.ArrayList; 53 54/* 55 * Implementation Notes: 56 * 57 * Some terminology: 58 * 59 * index - index of the items that are currently visible 60 * position - index of the items in the cursor 61 */ 62 63 64/** 65 * A view that shows items in a vertically scrolling list. The items 66 * come from the {@link ListAdapter} associated with this view. 67 * 68 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 69 * guide.</p> 70 * 71 * @attr ref android.R.styleable#ListView_entries 72 * @attr ref android.R.styleable#ListView_divider 73 * @attr ref android.R.styleable#ListView_dividerHeight 74 * @attr ref android.R.styleable#ListView_headerDividersEnabled 75 * @attr ref android.R.styleable#ListView_footerDividersEnabled 76 */ 77@RemoteView 78public class ListView extends AbsListView { 79 /** 80 * Used to indicate a no preference for a position type. 81 */ 82 static final int NO_POSITION = -1; 83 84 /** 85 * When arrow scrolling, ListView will never scroll more than this factor 86 * times the height of the list. 87 */ 88 private static final float MAX_SCROLL_FACTOR = 0.33f; 89 90 /** 91 * When arrow scrolling, need a certain amount of pixels to preview next 92 * items. This is usually the fading edge, but if that is small enough, 93 * we want to make sure we preview at least this many pixels. 94 */ 95 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 96 97 /** 98 * A class that represents a fixed view in a list, for example a header at the top 99 * or a footer at the bottom. 100 */ 101 public class FixedViewInfo { 102 /** The view to add to the list */ 103 public View view; 104 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 105 public Object data; 106 /** <code>true</code> if the fixed view should be selectable in the list */ 107 public boolean isSelectable; 108 } 109 110 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 111 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 112 113 Drawable mDivider; 114 int mDividerHeight; 115 116 Drawable mOverScrollHeader; 117 Drawable mOverScrollFooter; 118 119 private boolean mIsCacheColorOpaque; 120 private boolean mDividerIsOpaque; 121 122 private boolean mHeaderDividersEnabled; 123 private boolean mFooterDividersEnabled; 124 125 private boolean mAreAllItemsSelectable = true; 126 127 private boolean mItemsCanFocus = false; 128 129 // used for temporary calculations. 130 private final Rect mTempRect = new Rect(); 131 private Paint mDividerPaint; 132 133 // the single allocated result per list view; kinda cheesey but avoids 134 // allocating these thingies too often. 135 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 136 137 // Keeps focused children visible through resizes 138 private FocusSelector mFocusSelector; 139 140 public ListView(Context context) { 141 this(context, null); 142 } 143 144 public ListView(Context context, AttributeSet attrs) { 145 this(context, attrs, com.android.internal.R.attr.listViewStyle); 146 } 147 148 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 149 this(context, attrs, defStyleAttr, 0); 150 } 151 152 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 153 super(context, attrs, defStyleAttr, defStyleRes); 154 155 final TypedArray a = context.obtainStyledAttributes( 156 attrs, com.android.internal.R.styleable.ListView, defStyleAttr, defStyleRes); 157 158 CharSequence[] entries = a.getTextArray( 159 com.android.internal.R.styleable.ListView_entries); 160 if (entries != null) { 161 setAdapter(new ArrayAdapter<CharSequence>(context, 162 com.android.internal.R.layout.simple_list_item_1, entries)); 163 } 164 165 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 166 if (d != null) { 167 // If a divider is specified use its intrinsic height for divider height 168 setDivider(d); 169 } 170 171 final Drawable osHeader = a.getDrawable( 172 com.android.internal.R.styleable.ListView_overScrollHeader); 173 if (osHeader != null) { 174 setOverscrollHeader(osHeader); 175 } 176 177 final Drawable osFooter = a.getDrawable( 178 com.android.internal.R.styleable.ListView_overScrollFooter); 179 if (osFooter != null) { 180 setOverscrollFooter(osFooter); 181 } 182 183 // Use the height specified, zero being the default 184 final int dividerHeight = a.getDimensionPixelSize( 185 com.android.internal.R.styleable.ListView_dividerHeight, 0); 186 if (dividerHeight != 0) { 187 setDividerHeight(dividerHeight); 188 } 189 190 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 191 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 192 193 a.recycle(); 194 } 195 196 /** 197 * @return The maximum amount a list view will scroll in response to 198 * an arrow event. 199 */ 200 public int getMaxScrollAmount() { 201 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 202 } 203 204 /** 205 * Make sure views are touching the top or bottom edge, as appropriate for 206 * our gravity 207 */ 208 private void adjustViewsUpOrDown() { 209 final int childCount = getChildCount(); 210 int delta; 211 212 if (childCount > 0) { 213 View child; 214 215 if (!mStackFromBottom) { 216 // Uh-oh -- we came up short. Slide all views up to make them 217 // align with the top 218 child = getChildAt(0); 219 delta = child.getTop() - mListPadding.top; 220 if (mFirstPosition != 0) { 221 // It's OK to have some space above the first item if it is 222 // part of the vertical spacing 223 delta -= mDividerHeight; 224 } 225 if (delta < 0) { 226 // We only are looking to see if we are too low, not too high 227 delta = 0; 228 } 229 } else { 230 // we are too high, slide all views down to align with bottom 231 child = getChildAt(childCount - 1); 232 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 233 234 if (mFirstPosition + childCount < mItemCount) { 235 // It's OK to have some space below the last item if it is 236 // part of the vertical spacing 237 delta += mDividerHeight; 238 } 239 240 if (delta > 0) { 241 delta = 0; 242 } 243 } 244 245 if (delta != 0) { 246 offsetChildrenTopAndBottom(-delta); 247 } 248 } 249 } 250 251 /** 252 * Add a fixed view to appear at the top of the list. If this method is 253 * called more than once, the views will appear in the order they were 254 * added. Views added using this call can take focus if they want. 255 * <p> 256 * Note: When first introduced, this method could only be called before 257 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 258 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 259 * called at any time. If the ListView's adapter does not extend 260 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 261 * instance of {@link WrapperListAdapter}. 262 * 263 * @param v The view to add. 264 * @param data Data to associate with this view 265 * @param isSelectable whether the item is selectable 266 */ 267 public void addHeaderView(View v, Object data, boolean isSelectable) { 268 final FixedViewInfo info = new FixedViewInfo(); 269 info.view = v; 270 info.data = data; 271 info.isSelectable = isSelectable; 272 mHeaderViewInfos.add(info); 273 mAreAllItemsSelectable &= isSelectable; 274 275 // Wrap the adapter if it wasn't already wrapped. 276 if (mAdapter != null) { 277 if (!(mAdapter instanceof HeaderViewListAdapter)) { 278 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 279 } 280 281 // In the case of re-adding a header view, or adding one later on, 282 // we need to notify the observer. 283 if (mDataSetObserver != null) { 284 mDataSetObserver.onChanged(); 285 } 286 } 287 } 288 289 /** 290 * Add a fixed view to appear at the top of the list. If addHeaderView is 291 * called more than once, the views will appear in the order they were 292 * added. Views added using this call can take focus if they want. 293 * <p> 294 * Note: When first introduced, this method could only be called before 295 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 296 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 297 * called at any time. If the ListView's adapter does not extend 298 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 299 * instance of {@link WrapperListAdapter}. 300 * 301 * @param v The view to add. 302 */ 303 public void addHeaderView(View v) { 304 addHeaderView(v, null, true); 305 } 306 307 @Override 308 public int getHeaderViewsCount() { 309 return mHeaderViewInfos.size(); 310 } 311 312 /** 313 * Removes a previously-added header view. 314 * 315 * @param v The view to remove 316 * @return true if the view was removed, false if the view was not a header 317 * view 318 */ 319 public boolean removeHeaderView(View v) { 320 if (mHeaderViewInfos.size() > 0) { 321 boolean result = false; 322 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 323 if (mDataSetObserver != null) { 324 mDataSetObserver.onChanged(); 325 } 326 result = true; 327 } 328 removeFixedViewInfo(v, mHeaderViewInfos); 329 return result; 330 } 331 return false; 332 } 333 334 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 335 int len = where.size(); 336 for (int i = 0; i < len; ++i) { 337 FixedViewInfo info = where.get(i); 338 if (info.view == v) { 339 where.remove(i); 340 break; 341 } 342 } 343 } 344 345 /** 346 * Add a fixed view to appear at the bottom of the list. If addFooterView is 347 * called more than once, the views will appear in the order they were 348 * added. Views added using this call can take focus if they want. 349 * <p> 350 * Note: When first introduced, this method could only be called before 351 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 352 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 353 * called at any time. If the ListView's adapter does not extend 354 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 355 * instance of {@link WrapperListAdapter}. 356 * 357 * @param v The view to add. 358 * @param data Data to associate with this view 359 * @param isSelectable true if the footer view can be selected 360 */ 361 public void addFooterView(View v, Object data, boolean isSelectable) { 362 final FixedViewInfo info = new FixedViewInfo(); 363 info.view = v; 364 info.data = data; 365 info.isSelectable = isSelectable; 366 mFooterViewInfos.add(info); 367 mAreAllItemsSelectable &= isSelectable; 368 369 // Wrap the adapter if it wasn't already wrapped. 370 if (mAdapter != null) { 371 if (!(mAdapter instanceof HeaderViewListAdapter)) { 372 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 373 } 374 375 // In the case of re-adding a footer view, or adding one later on, 376 // we need to notify the observer. 377 if (mDataSetObserver != null) { 378 mDataSetObserver.onChanged(); 379 } 380 } 381 } 382 383 /** 384 * Add a fixed view to appear at the bottom of the list. If addFooterView is 385 * called more than once, the views will appear in the order they were 386 * added. Views added using this call can take focus if they want. 387 * <p> 388 * Note: When first introduced, this method could only be called before 389 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 390 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 391 * called at any time. If the ListView's adapter does not extend 392 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 393 * instance of {@link WrapperListAdapter}. 394 * 395 * @param v The view to add. 396 */ 397 public void addFooterView(View v) { 398 addFooterView(v, null, true); 399 } 400 401 @Override 402 public int getFooterViewsCount() { 403 return mFooterViewInfos.size(); 404 } 405 406 /** 407 * Removes a previously-added footer view. 408 * 409 * @param v The view to remove 410 * @return 411 * true if the view was removed, false if the view was not a footer view 412 */ 413 public boolean removeFooterView(View v) { 414 if (mFooterViewInfos.size() > 0) { 415 boolean result = false; 416 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 417 if (mDataSetObserver != null) { 418 mDataSetObserver.onChanged(); 419 } 420 result = true; 421 } 422 removeFixedViewInfo(v, mFooterViewInfos); 423 return result; 424 } 425 return false; 426 } 427 428 /** 429 * Returns the adapter currently in use in this ListView. The returned adapter 430 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 431 * might be a {@link WrapperListAdapter}. 432 * 433 * @return The adapter currently used to display data in this ListView. 434 * 435 * @see #setAdapter(ListAdapter) 436 */ 437 @Override 438 public ListAdapter getAdapter() { 439 return mAdapter; 440 } 441 442 /** 443 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 444 * through the specified intent. 445 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 446 */ 447 @android.view.RemotableViewMethod 448 public void setRemoteViewsAdapter(Intent intent) { 449 super.setRemoteViewsAdapter(intent); 450 } 451 452 /** 453 * Sets the data behind this ListView. 454 * 455 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 456 * depending on the ListView features currently in use. For instance, adding 457 * headers and/or footers will cause the adapter to be wrapped. 458 * 459 * @param adapter The ListAdapter which is responsible for maintaining the 460 * data backing this list and for producing a view to represent an 461 * item in that data set. 462 * 463 * @see #getAdapter() 464 */ 465 @Override 466 public void setAdapter(ListAdapter adapter) { 467 if (mAdapter != null && mDataSetObserver != null) { 468 mAdapter.unregisterDataSetObserver(mDataSetObserver); 469 } 470 471 resetList(); 472 mRecycler.clear(); 473 474 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 475 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 476 } else { 477 mAdapter = adapter; 478 } 479 480 mOldSelectedPosition = INVALID_POSITION; 481 mOldSelectedRowId = INVALID_ROW_ID; 482 483 // AbsListView#setAdapter will update choice mode states. 484 super.setAdapter(adapter); 485 486 if (mAdapter != null) { 487 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 488 mOldItemCount = mItemCount; 489 mItemCount = mAdapter.getCount(); 490 checkFocus(); 491 492 mDataSetObserver = new AdapterDataSetObserver(); 493 mAdapter.registerDataSetObserver(mDataSetObserver); 494 495 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 496 497 int position; 498 if (mStackFromBottom) { 499 position = lookForSelectablePosition(mItemCount - 1, false); 500 } else { 501 position = lookForSelectablePosition(0, true); 502 } 503 setSelectedPositionInt(position); 504 setNextSelectedPositionInt(position); 505 506 if (mItemCount == 0) { 507 // Nothing selected 508 checkSelectionChanged(); 509 } 510 } else { 511 mAreAllItemsSelectable = true; 512 checkFocus(); 513 // Nothing selected 514 checkSelectionChanged(); 515 } 516 517 requestLayout(); 518 } 519 520 /** 521 * The list is empty. Clear everything out. 522 */ 523 @Override 524 void resetList() { 525 // The parent's resetList() will remove all views from the layout so we need to 526 // cleanup the state of our footers and headers 527 clearRecycledState(mHeaderViewInfos); 528 clearRecycledState(mFooterViewInfos); 529 530 super.resetList(); 531 532 mLayoutMode = LAYOUT_NORMAL; 533 } 534 535 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 536 if (infos != null) { 537 final int count = infos.size(); 538 539 for (int i = 0; i < count; i++) { 540 final View child = infos.get(i).view; 541 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 542 if (p != null) { 543 p.recycledHeaderFooter = false; 544 } 545 } 546 } 547 } 548 549 /** 550 * @return Whether the list needs to show the top fading edge 551 */ 552 private boolean showingTopFadingEdge() { 553 final int listTop = mScrollY + mListPadding.top; 554 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 555 } 556 557 /** 558 * @return Whether the list needs to show the bottom fading edge 559 */ 560 private boolean showingBottomFadingEdge() { 561 final int childCount = getChildCount(); 562 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 563 final int lastVisiblePosition = mFirstPosition + childCount - 1; 564 565 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 566 567 return (lastVisiblePosition < mItemCount - 1) 568 || (bottomOfBottomChild < listBottom); 569 } 570 571 572 @Override 573 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 574 575 int rectTopWithinChild = rect.top; 576 577 // offset so rect is in coordinates of the this view 578 rect.offset(child.getLeft(), child.getTop()); 579 rect.offset(-child.getScrollX(), -child.getScrollY()); 580 581 final int height = getHeight(); 582 int listUnfadedTop = getScrollY(); 583 int listUnfadedBottom = listUnfadedTop + height; 584 final int fadingEdge = getVerticalFadingEdgeLength(); 585 586 if (showingTopFadingEdge()) { 587 // leave room for top fading edge as long as rect isn't at very top 588 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 589 listUnfadedTop += fadingEdge; 590 } 591 } 592 593 int childCount = getChildCount(); 594 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 595 596 if (showingBottomFadingEdge()) { 597 // leave room for bottom fading edge as long as rect isn't at very bottom 598 if ((mSelectedPosition < mItemCount - 1) 599 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 600 listUnfadedBottom -= fadingEdge; 601 } 602 } 603 604 int scrollYDelta = 0; 605 606 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 607 // need to MOVE DOWN to get it in view: move down just enough so 608 // that the entire rectangle is in view (or at least the first 609 // screen size chunk). 610 611 if (rect.height() > height) { 612 // just enough to get screen size chunk on 613 scrollYDelta += (rect.top - listUnfadedTop); 614 } else { 615 // get entire rect at bottom of screen 616 scrollYDelta += (rect.bottom - listUnfadedBottom); 617 } 618 619 // make sure we aren't scrolling beyond the end of our children 620 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 621 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 622 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 623 // need to MOVE UP to get it in view: move up just enough so that 624 // entire rectangle is in view (or at least the first screen 625 // size chunk of it). 626 627 if (rect.height() > height) { 628 // screen size chunk 629 scrollYDelta -= (listUnfadedBottom - rect.bottom); 630 } else { 631 // entire rect at top 632 scrollYDelta -= (listUnfadedTop - rect.top); 633 } 634 635 // make sure we aren't scrolling any further than the top our children 636 int top = getChildAt(0).getTop(); 637 int deltaToTop = top - listUnfadedTop; 638 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 639 } 640 641 final boolean scroll = scrollYDelta != 0; 642 if (scroll) { 643 scrollListItemsBy(-scrollYDelta); 644 positionSelector(INVALID_POSITION, child); 645 mSelectedTop = child.getTop(); 646 invalidate(); 647 } 648 return scroll; 649 } 650 651 /** 652 * {@inheritDoc} 653 */ 654 @Override 655 void fillGap(boolean down) { 656 final int count = getChildCount(); 657 if (down) { 658 int paddingTop = 0; 659 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 660 paddingTop = getListPaddingTop(); 661 } 662 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 663 paddingTop; 664 fillDown(mFirstPosition + count, startOffset); 665 correctTooHigh(getChildCount()); 666 } else { 667 int paddingBottom = 0; 668 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 669 paddingBottom = getListPaddingBottom(); 670 } 671 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 672 getHeight() - paddingBottom; 673 fillUp(mFirstPosition - 1, startOffset); 674 correctTooLow(getChildCount()); 675 } 676 } 677 678 /** 679 * Fills the list from pos down to the end of the list view. 680 * 681 * @param pos The first position to put in the list 682 * 683 * @param nextTop The location where the top of the item associated with pos 684 * should be drawn 685 * 686 * @return The view that is currently selected, if it happens to be in the 687 * range that we draw. 688 */ 689 private View fillDown(int pos, int nextTop) { 690 View selectedView = null; 691 692 int end = (mBottom - mTop); 693 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 694 end -= mListPadding.bottom; 695 } 696 697 while (nextTop < end && pos < mItemCount) { 698 // is this the selected item? 699 boolean selected = pos == mSelectedPosition; 700 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 701 702 nextTop = child.getBottom() + mDividerHeight; 703 if (selected) { 704 selectedView = child; 705 } 706 pos++; 707 } 708 709 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 710 return selectedView; 711 } 712 713 /** 714 * Fills the list from pos up to the top of the list view. 715 * 716 * @param pos The first position to put in the list 717 * 718 * @param nextBottom The location where the bottom of the item associated 719 * with pos should be drawn 720 * 721 * @return The view that is currently selected 722 */ 723 private View fillUp(int pos, int nextBottom) { 724 View selectedView = null; 725 726 int end = 0; 727 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 728 end = mListPadding.top; 729 } 730 731 while (nextBottom > end && pos >= 0) { 732 // is this the selected item? 733 boolean selected = pos == mSelectedPosition; 734 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 735 nextBottom = child.getTop() - mDividerHeight; 736 if (selected) { 737 selectedView = child; 738 } 739 pos--; 740 } 741 742 mFirstPosition = pos + 1; 743 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 744 return selectedView; 745 } 746 747 /** 748 * Fills the list from top to bottom, starting with mFirstPosition 749 * 750 * @param nextTop The location where the top of the first item should be 751 * drawn 752 * 753 * @return The view that is currently selected 754 */ 755 private View fillFromTop(int nextTop) { 756 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 757 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 758 if (mFirstPosition < 0) { 759 mFirstPosition = 0; 760 } 761 return fillDown(mFirstPosition, nextTop); 762 } 763 764 765 /** 766 * Put mSelectedPosition in the middle of the screen and then build up and 767 * down from there. This method forces mSelectedPosition to the center. 768 * 769 * @param childrenTop Top of the area in which children can be drawn, as 770 * measured in pixels 771 * @param childrenBottom Bottom of the area in which children can be drawn, 772 * as measured in pixels 773 * @return Currently selected view 774 */ 775 private View fillFromMiddle(int childrenTop, int childrenBottom) { 776 int height = childrenBottom - childrenTop; 777 778 int position = reconcileSelectedPosition(); 779 780 View sel = makeAndAddView(position, childrenTop, true, 781 mListPadding.left, true); 782 mFirstPosition = position; 783 784 int selHeight = sel.getMeasuredHeight(); 785 if (selHeight <= height) { 786 sel.offsetTopAndBottom((height - selHeight) / 2); 787 } 788 789 fillAboveAndBelow(sel, position); 790 791 if (!mStackFromBottom) { 792 correctTooHigh(getChildCount()); 793 } else { 794 correctTooLow(getChildCount()); 795 } 796 797 return sel; 798 } 799 800 /** 801 * Once the selected view as been placed, fill up the visible area above and 802 * below it. 803 * 804 * @param sel The selected view 805 * @param position The position corresponding to sel 806 */ 807 private void fillAboveAndBelow(View sel, int position) { 808 final int dividerHeight = mDividerHeight; 809 if (!mStackFromBottom) { 810 fillUp(position - 1, sel.getTop() - dividerHeight); 811 adjustViewsUpOrDown(); 812 fillDown(position + 1, sel.getBottom() + dividerHeight); 813 } else { 814 fillDown(position + 1, sel.getBottom() + dividerHeight); 815 adjustViewsUpOrDown(); 816 fillUp(position - 1, sel.getTop() - dividerHeight); 817 } 818 } 819 820 821 /** 822 * Fills the grid based on positioning the new selection at a specific 823 * location. The selection may be moved so that it does not intersect the 824 * faded edges. The grid is then filled upwards and downwards from there. 825 * 826 * @param selectedTop Where the selected item should be 827 * @param childrenTop Where to start drawing children 828 * @param childrenBottom Last pixel where children can be drawn 829 * @return The view that currently has selection 830 */ 831 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 832 int fadingEdgeLength = getVerticalFadingEdgeLength(); 833 final int selectedPosition = mSelectedPosition; 834 835 View sel; 836 837 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 838 selectedPosition); 839 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 840 selectedPosition); 841 842 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 843 844 845 // Some of the newly selected item extends below the bottom of the list 846 if (sel.getBottom() > bottomSelectionPixel) { 847 // Find space available above the selection into which we can scroll 848 // upwards 849 final int spaceAbove = sel.getTop() - topSelectionPixel; 850 851 // Find space required to bring the bottom of the selected item 852 // fully into view 853 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 854 final int offset = Math.min(spaceAbove, spaceBelow); 855 856 // Now offset the selected item to get it into view 857 sel.offsetTopAndBottom(-offset); 858 } else if (sel.getTop() < topSelectionPixel) { 859 // Find space required to bring the top of the selected item fully 860 // into view 861 final int spaceAbove = topSelectionPixel - sel.getTop(); 862 863 // Find space available below the selection into which we can scroll 864 // downwards 865 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 866 final int offset = Math.min(spaceAbove, spaceBelow); 867 868 // Offset the selected item to get it into view 869 sel.offsetTopAndBottom(offset); 870 } 871 872 // Fill in views above and below 873 fillAboveAndBelow(sel, selectedPosition); 874 875 if (!mStackFromBottom) { 876 correctTooHigh(getChildCount()); 877 } else { 878 correctTooLow(getChildCount()); 879 } 880 881 return sel; 882 } 883 884 /** 885 * Calculate the bottom-most pixel we can draw the selection into 886 * 887 * @param childrenBottom Bottom pixel were children can be drawn 888 * @param fadingEdgeLength Length of the fading edge in pixels, if present 889 * @param selectedPosition The position that will be selected 890 * @return The bottom-most pixel we can draw the selection into 891 */ 892 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 893 int selectedPosition) { 894 int bottomSelectionPixel = childrenBottom; 895 if (selectedPosition != mItemCount - 1) { 896 bottomSelectionPixel -= fadingEdgeLength; 897 } 898 return bottomSelectionPixel; 899 } 900 901 /** 902 * Calculate the top-most pixel we can draw the selection into 903 * 904 * @param childrenTop Top pixel were children can be drawn 905 * @param fadingEdgeLength Length of the fading edge in pixels, if present 906 * @param selectedPosition The position that will be selected 907 * @return The top-most pixel we can draw the selection into 908 */ 909 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 910 // first pixel we can draw the selection into 911 int topSelectionPixel = childrenTop; 912 if (selectedPosition > 0) { 913 topSelectionPixel += fadingEdgeLength; 914 } 915 return topSelectionPixel; 916 } 917 918 /** 919 * Smoothly scroll to the specified adapter position. The view will 920 * scroll such that the indicated position is displayed. 921 * @param position Scroll to this adapter position. 922 */ 923 @android.view.RemotableViewMethod 924 public void smoothScrollToPosition(int position) { 925 super.smoothScrollToPosition(position); 926 } 927 928 /** 929 * Smoothly scroll to the specified adapter position offset. The view will 930 * scroll such that the indicated position is displayed. 931 * @param offset The amount to offset from the adapter position to scroll to. 932 */ 933 @android.view.RemotableViewMethod 934 public void smoothScrollByOffset(int offset) { 935 super.smoothScrollByOffset(offset); 936 } 937 938 /** 939 * Fills the list based on positioning the new selection relative to the old 940 * selection. The new selection will be placed at, above, or below the 941 * location of the new selection depending on how the selection is moving. 942 * The selection will then be pinned to the visible part of the screen, 943 * excluding the edges that are faded. The list is then filled upwards and 944 * downwards from there. 945 * 946 * @param oldSel The old selected view. Useful for trying to put the new 947 * selection in the same place 948 * @param newSel The view that is to become selected. Useful for trying to 949 * put the new selection in the same place 950 * @param delta Which way we are moving 951 * @param childrenTop Where to start drawing children 952 * @param childrenBottom Last pixel where children can be drawn 953 * @return The view that currently has selection 954 */ 955 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 956 int childrenBottom) { 957 int fadingEdgeLength = getVerticalFadingEdgeLength(); 958 final int selectedPosition = mSelectedPosition; 959 960 View sel; 961 962 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 963 selectedPosition); 964 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 965 selectedPosition); 966 967 if (delta > 0) { 968 /* 969 * Case 1: Scrolling down. 970 */ 971 972 /* 973 * Before After 974 * | | | | 975 * +-------+ +-------+ 976 * | A | | A | 977 * | 1 | => +-------+ 978 * +-------+ | B | 979 * | B | | 2 | 980 * +-------+ +-------+ 981 * | | | | 982 * 983 * Try to keep the top of the previously selected item where it was. 984 * oldSel = A 985 * sel = B 986 */ 987 988 // Put oldSel (A) where it belongs 989 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 990 mListPadding.left, false); 991 992 final int dividerHeight = mDividerHeight; 993 994 // Now put the new selection (B) below that 995 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 996 mListPadding.left, true); 997 998 // Some of the newly selected item extends below the bottom of the list 999 if (sel.getBottom() > bottomSelectionPixel) { 1000 1001 // Find space available above the selection into which we can scroll upwards 1002 int spaceAbove = sel.getTop() - topSelectionPixel; 1003 1004 // Find space required to bring the bottom of the selected item fully into view 1005 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1006 1007 // Don't scroll more than half the height of the list 1008 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1009 int offset = Math.min(spaceAbove, spaceBelow); 1010 offset = Math.min(offset, halfVerticalSpace); 1011 1012 // We placed oldSel, so offset that item 1013 oldSel.offsetTopAndBottom(-offset); 1014 // Now offset the selected item to get it into view 1015 sel.offsetTopAndBottom(-offset); 1016 } 1017 1018 // Fill in views above and below 1019 if (!mStackFromBottom) { 1020 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1021 adjustViewsUpOrDown(); 1022 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1023 } else { 1024 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1025 adjustViewsUpOrDown(); 1026 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1027 } 1028 } else if (delta < 0) { 1029 /* 1030 * Case 2: Scrolling up. 1031 */ 1032 1033 /* 1034 * Before After 1035 * | | | | 1036 * +-------+ +-------+ 1037 * | A | | A | 1038 * +-------+ => | 1 | 1039 * | B | +-------+ 1040 * | 2 | | B | 1041 * +-------+ +-------+ 1042 * | | | | 1043 * 1044 * Try to keep the top of the item about to become selected where it was. 1045 * newSel = A 1046 * olSel = B 1047 */ 1048 1049 if (newSel != null) { 1050 // Try to position the top of newSel (A) where it was before it was selected 1051 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1052 true); 1053 } else { 1054 // If (A) was not on screen and so did not have a view, position 1055 // it above the oldSel (B) 1056 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1057 true); 1058 } 1059 1060 // Some of the newly selected item extends above the top of the list 1061 if (sel.getTop() < topSelectionPixel) { 1062 // Find space required to bring the top of the selected item fully into view 1063 int spaceAbove = topSelectionPixel - sel.getTop(); 1064 1065 // Find space available below the selection into which we can scroll downwards 1066 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1067 1068 // Don't scroll more than half the height of the list 1069 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1070 int offset = Math.min(spaceAbove, spaceBelow); 1071 offset = Math.min(offset, halfVerticalSpace); 1072 1073 // Offset the selected item to get it into view 1074 sel.offsetTopAndBottom(offset); 1075 } 1076 1077 // Fill in views above and below 1078 fillAboveAndBelow(sel, selectedPosition); 1079 } else { 1080 1081 int oldTop = oldSel.getTop(); 1082 1083 /* 1084 * Case 3: Staying still 1085 */ 1086 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1087 1088 // We're staying still... 1089 if (oldTop < childrenTop) { 1090 // ... but the top of the old selection was off screen. 1091 // (This can happen if the data changes size out from under us) 1092 int newBottom = sel.getBottom(); 1093 if (newBottom < childrenTop + 20) { 1094 // Not enough visible -- bring it onscreen 1095 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1096 } 1097 } 1098 1099 // Fill in views above and below 1100 fillAboveAndBelow(sel, selectedPosition); 1101 } 1102 1103 return sel; 1104 } 1105 1106 private class FocusSelector implements Runnable { 1107 private int mPosition; 1108 private int mPositionTop; 1109 1110 public FocusSelector setup(int position, int top) { 1111 mPosition = position; 1112 mPositionTop = top; 1113 return this; 1114 } 1115 1116 public void run() { 1117 setSelectionFromTop(mPosition, mPositionTop); 1118 } 1119 } 1120 1121 @Override 1122 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1123 if (getChildCount() > 0) { 1124 View focusedChild = getFocusedChild(); 1125 if (focusedChild != null) { 1126 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1127 final int childBottom = focusedChild.getBottom(); 1128 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1129 final int top = focusedChild.getTop() - offset; 1130 if (mFocusSelector == null) { 1131 mFocusSelector = new FocusSelector(); 1132 } 1133 post(mFocusSelector.setup(childPosition, top)); 1134 } 1135 } 1136 super.onSizeChanged(w, h, oldw, oldh); 1137 } 1138 1139 @Override 1140 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1141 // Sets up mListPadding 1142 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1143 1144 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1145 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1146 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1147 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1148 1149 int childWidth = 0; 1150 int childHeight = 0; 1151 int childState = 0; 1152 1153 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1154 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1155 heightMode == MeasureSpec.UNSPECIFIED)) { 1156 final View child = obtainView(0, mIsScrap); 1157 1158 measureScrapChild(child, 0, widthMeasureSpec, heightSize); 1159 1160 childWidth = child.getMeasuredWidth(); 1161 childHeight = child.getMeasuredHeight(); 1162 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1163 1164 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1165 ((LayoutParams) child.getLayoutParams()).viewType)) { 1166 mRecycler.addScrapView(child, 0); 1167 } 1168 } 1169 1170 if (widthMode == MeasureSpec.UNSPECIFIED) { 1171 widthSize = mListPadding.left + mListPadding.right + childWidth + 1172 getVerticalScrollbarWidth(); 1173 } else { 1174 widthSize |= (childState&MEASURED_STATE_MASK); 1175 } 1176 1177 if (heightMode == MeasureSpec.UNSPECIFIED) { 1178 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1179 getVerticalFadingEdgeLength() * 2; 1180 } 1181 1182 if (heightMode == MeasureSpec.AT_MOST) { 1183 // TODO: after first layout we should maybe start at the first visible position, not 0 1184 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1185 } 1186 1187 setMeasuredDimension(widthSize , heightSize); 1188 mWidthMeasureSpec = widthMeasureSpec; 1189 } 1190 1191 private void measureScrapChild(View child, int position, int widthMeasureSpec, int heightHint) { 1192 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1193 if (p == null) { 1194 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1195 child.setLayoutParams(p); 1196 } 1197 p.viewType = mAdapter.getItemViewType(position); 1198 p.forceAdd = true; 1199 1200 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1201 mListPadding.left + mListPadding.right, p.width); 1202 int lpHeight = p.height; 1203 int childHeightSpec; 1204 if (lpHeight > 0) { 1205 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1206 } else { 1207 childHeightSpec = MeasureSpec.makeMeasureSpec(heightHint, MeasureSpec.UNSPECIFIED); 1208 } 1209 child.measure(childWidthSpec, childHeightSpec); 1210 } 1211 1212 /** 1213 * @return True to recycle the views used to measure this ListView in 1214 * UNSPECIFIED/AT_MOST modes, false otherwise. 1215 * @hide 1216 */ 1217 @ViewDebug.ExportedProperty(category = "list") 1218 protected boolean recycleOnMeasure() { 1219 return true; 1220 } 1221 1222 /** 1223 * Measures the height of the given range of children (inclusive) and 1224 * returns the height with this ListView's padding and divider heights 1225 * included. If maxHeight is provided, the measuring will stop when the 1226 * current height reaches maxHeight. 1227 * 1228 * @param widthMeasureSpec The width measure spec to be given to a child's 1229 * {@link View#measure(int, int)}. 1230 * @param startPosition The position of the first child to be shown. 1231 * @param endPosition The (inclusive) position of the last child to be 1232 * shown. Specify {@link #NO_POSITION} if the last child should be 1233 * the last available child from the adapter. 1234 * @param maxHeight The maximum height that will be returned (if all the 1235 * children don't fit in this value, this value will be 1236 * returned). 1237 * @param disallowPartialChildPosition In general, whether the returned 1238 * height should only contain entire children. This is more 1239 * powerful--it is the first inclusive position at which partial 1240 * children will not be allowed. Example: it looks nice to have 1241 * at least 3 completely visible children, and in portrait this 1242 * will most likely fit; but in landscape there could be times 1243 * when even 2 children can not be completely shown, so a value 1244 * of 2 (remember, inclusive) would be good (assuming 1245 * startPosition is 0). 1246 * @return The height of this ListView with the given children. 1247 */ 1248 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1249 final int maxHeight, int disallowPartialChildPosition) { 1250 1251 final ListAdapter adapter = mAdapter; 1252 if (adapter == null) { 1253 return mListPadding.top + mListPadding.bottom; 1254 } 1255 1256 // Include the padding of the list 1257 int returnedHeight = mListPadding.top + mListPadding.bottom; 1258 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1259 // The previous height value that was less than maxHeight and contained 1260 // no partial children 1261 int prevHeightWithoutPartialChild = 0; 1262 int i; 1263 View child; 1264 1265 // mItemCount - 1 since endPosition parameter is inclusive 1266 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1267 final AbsListView.RecycleBin recycleBin = mRecycler; 1268 final boolean recyle = recycleOnMeasure(); 1269 final boolean[] isScrap = mIsScrap; 1270 1271 for (i = startPosition; i <= endPosition; ++i) { 1272 child = obtainView(i, isScrap); 1273 1274 measureScrapChild(child, i, widthMeasureSpec, maxHeight); 1275 1276 if (i > 0) { 1277 // Count the divider for all but one child 1278 returnedHeight += dividerHeight; 1279 } 1280 1281 // Recycle the view before we possibly return from the method 1282 if (recyle && recycleBin.shouldRecycleViewType( 1283 ((LayoutParams) child.getLayoutParams()).viewType)) { 1284 recycleBin.addScrapView(child, -1); 1285 } 1286 1287 returnedHeight += child.getMeasuredHeight(); 1288 1289 if (returnedHeight >= maxHeight) { 1290 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1291 // then the i'th position did not fit completely. 1292 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1293 && (i > disallowPartialChildPosition) // We've past the min pos 1294 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1295 && (returnedHeight != maxHeight) // i'th child did not fit completely 1296 ? prevHeightWithoutPartialChild 1297 : maxHeight; 1298 } 1299 1300 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1301 prevHeightWithoutPartialChild = returnedHeight; 1302 } 1303 } 1304 1305 // At this point, we went through the range of children, and they each 1306 // completely fit, so return the returnedHeight 1307 return returnedHeight; 1308 } 1309 1310 @Override 1311 int findMotionRow(int y) { 1312 int childCount = getChildCount(); 1313 if (childCount > 0) { 1314 if (!mStackFromBottom) { 1315 for (int i = 0; i < childCount; i++) { 1316 View v = getChildAt(i); 1317 if (y <= v.getBottom()) { 1318 return mFirstPosition + i; 1319 } 1320 } 1321 } else { 1322 for (int i = childCount - 1; i >= 0; i--) { 1323 View v = getChildAt(i); 1324 if (y >= v.getTop()) { 1325 return mFirstPosition + i; 1326 } 1327 } 1328 } 1329 } 1330 return INVALID_POSITION; 1331 } 1332 1333 /** 1334 * Put a specific item at a specific location on the screen and then build 1335 * up and down from there. 1336 * 1337 * @param position The reference view to use as the starting point 1338 * @param top Pixel offset from the top of this view to the top of the 1339 * reference view. 1340 * 1341 * @return The selected view, or null if the selected view is outside the 1342 * visible area. 1343 */ 1344 private View fillSpecific(int position, int top) { 1345 boolean tempIsSelected = position == mSelectedPosition; 1346 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1347 // Possibly changed again in fillUp if we add rows above this one. 1348 mFirstPosition = position; 1349 1350 View above; 1351 View below; 1352 1353 final int dividerHeight = mDividerHeight; 1354 if (!mStackFromBottom) { 1355 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1356 // This will correct for the top of the first view not touching the top of the list 1357 adjustViewsUpOrDown(); 1358 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1359 int childCount = getChildCount(); 1360 if (childCount > 0) { 1361 correctTooHigh(childCount); 1362 } 1363 } else { 1364 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1365 // This will correct for the bottom of the last view not touching the bottom of the list 1366 adjustViewsUpOrDown(); 1367 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1368 int childCount = getChildCount(); 1369 if (childCount > 0) { 1370 correctTooLow(childCount); 1371 } 1372 } 1373 1374 if (tempIsSelected) { 1375 return temp; 1376 } else if (above != null) { 1377 return above; 1378 } else { 1379 return below; 1380 } 1381 } 1382 1383 /** 1384 * Check if we have dragged the bottom of the list too high (we have pushed the 1385 * top element off the top of the screen when we did not need to). Correct by sliding 1386 * everything back down. 1387 * 1388 * @param childCount Number of children 1389 */ 1390 private void correctTooHigh(int childCount) { 1391 // First see if the last item is visible. If it is not, it is OK for the 1392 // top of the list to be pushed up. 1393 int lastPosition = mFirstPosition + childCount - 1; 1394 if (lastPosition == mItemCount - 1 && childCount > 0) { 1395 1396 // Get the last child ... 1397 final View lastChild = getChildAt(childCount - 1); 1398 1399 // ... and its bottom edge 1400 final int lastBottom = lastChild.getBottom(); 1401 1402 // This is bottom of our drawable area 1403 final int end = (mBottom - mTop) - mListPadding.bottom; 1404 1405 // This is how far the bottom edge of the last view is from the bottom of the 1406 // drawable area 1407 int bottomOffset = end - lastBottom; 1408 View firstChild = getChildAt(0); 1409 final int firstTop = firstChild.getTop(); 1410 1411 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1412 // first row or the first row is scrolled off the top of the drawable area 1413 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1414 if (mFirstPosition == 0) { 1415 // Don't pull the top too far down 1416 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1417 } 1418 // Move everything down 1419 offsetChildrenTopAndBottom(bottomOffset); 1420 if (mFirstPosition > 0) { 1421 // Fill the gap that was opened above mFirstPosition with more rows, if 1422 // possible 1423 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1424 // Close up the remaining gap 1425 adjustViewsUpOrDown(); 1426 } 1427 1428 } 1429 } 1430 } 1431 1432 /** 1433 * Check if we have dragged the bottom of the list too low (we have pushed the 1434 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1435 * everything back up. 1436 * 1437 * @param childCount Number of children 1438 */ 1439 private void correctTooLow(int childCount) { 1440 // First see if the first item is visible. If it is not, it is OK for the 1441 // bottom of the list to be pushed down. 1442 if (mFirstPosition == 0 && childCount > 0) { 1443 1444 // Get the first child ... 1445 final View firstChild = getChildAt(0); 1446 1447 // ... and its top edge 1448 final int firstTop = firstChild.getTop(); 1449 1450 // This is top of our drawable area 1451 final int start = mListPadding.top; 1452 1453 // This is bottom of our drawable area 1454 final int end = (mBottom - mTop) - mListPadding.bottom; 1455 1456 // This is how far the top edge of the first view is from the top of the 1457 // drawable area 1458 int topOffset = firstTop - start; 1459 View lastChild = getChildAt(childCount - 1); 1460 final int lastBottom = lastChild.getBottom(); 1461 int lastPosition = mFirstPosition + childCount - 1; 1462 1463 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1464 // last row or the last row is scrolled off the bottom of the drawable area 1465 if (topOffset > 0) { 1466 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1467 if (lastPosition == mItemCount - 1) { 1468 // Don't pull the bottom too far up 1469 topOffset = Math.min(topOffset, lastBottom - end); 1470 } 1471 // Move everything up 1472 offsetChildrenTopAndBottom(-topOffset); 1473 if (lastPosition < mItemCount - 1) { 1474 // Fill the gap that was opened below the last position with more rows, if 1475 // possible 1476 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1477 // Close up the remaining gap 1478 adjustViewsUpOrDown(); 1479 } 1480 } else if (lastPosition == mItemCount - 1) { 1481 adjustViewsUpOrDown(); 1482 } 1483 } 1484 } 1485 } 1486 1487 @Override 1488 protected void layoutChildren() { 1489 final boolean blockLayoutRequests = mBlockLayoutRequests; 1490 if (blockLayoutRequests) { 1491 return; 1492 } 1493 1494 mBlockLayoutRequests = true; 1495 1496 try { 1497 super.layoutChildren(); 1498 1499 invalidate(); 1500 1501 if (mAdapter == null) { 1502 resetList(); 1503 invokeOnItemScrollListener(); 1504 return; 1505 } 1506 1507 final int childrenTop = mListPadding.top; 1508 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1509 final int childCount = getChildCount(); 1510 1511 int index = 0; 1512 int delta = 0; 1513 1514 View sel; 1515 View oldSel = null; 1516 View oldFirst = null; 1517 View newSel = null; 1518 1519 // Remember stuff we will need down below 1520 switch (mLayoutMode) { 1521 case LAYOUT_SET_SELECTION: 1522 index = mNextSelectedPosition - mFirstPosition; 1523 if (index >= 0 && index < childCount) { 1524 newSel = getChildAt(index); 1525 } 1526 break; 1527 case LAYOUT_FORCE_TOP: 1528 case LAYOUT_FORCE_BOTTOM: 1529 case LAYOUT_SPECIFIC: 1530 case LAYOUT_SYNC: 1531 break; 1532 case LAYOUT_MOVE_SELECTION: 1533 default: 1534 // Remember the previously selected view 1535 index = mSelectedPosition - mFirstPosition; 1536 if (index >= 0 && index < childCount) { 1537 oldSel = getChildAt(index); 1538 } 1539 1540 // Remember the previous first child 1541 oldFirst = getChildAt(0); 1542 1543 if (mNextSelectedPosition >= 0) { 1544 delta = mNextSelectedPosition - mSelectedPosition; 1545 } 1546 1547 // Caution: newSel might be null 1548 newSel = getChildAt(index + delta); 1549 } 1550 1551 1552 boolean dataChanged = mDataChanged; 1553 if (dataChanged) { 1554 handleDataChanged(); 1555 } 1556 1557 // Handle the empty set by removing all views that are visible 1558 // and calling it a day 1559 if (mItemCount == 0) { 1560 resetList(); 1561 invokeOnItemScrollListener(); 1562 return; 1563 } else if (mItemCount != mAdapter.getCount()) { 1564 throw new IllegalStateException("The content of the adapter has changed but " 1565 + "ListView did not receive a notification. Make sure the content of " 1566 + "your adapter is not modified from a background thread, but only from " 1567 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1568 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1569 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1570 } 1571 1572 setSelectedPositionInt(mNextSelectedPosition); 1573 1574 AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; 1575 View accessibilityFocusLayoutRestoreView = null; 1576 int accessibilityFocusPosition = INVALID_POSITION; 1577 1578 // Remember which child, if any, had accessibility focus. This must 1579 // occur before recycling any views, since that will clear 1580 // accessibility focus. 1581 final ViewRootImpl viewRootImpl = getViewRootImpl(); 1582 if (viewRootImpl != null) { 1583 final View focusHost = viewRootImpl.getAccessibilityFocusedHost(); 1584 if (focusHost != null) { 1585 final View focusChild = getAccessibilityFocusedChild(focusHost); 1586 if (focusChild != null) { 1587 if (!dataChanged || isDirectChildHeaderOrFooter(focusChild) 1588 || focusChild.hasTransientState() || mAdapterHasStableIds) { 1589 // The views won't be changing, so try to maintain 1590 // focus on the current host and virtual view. 1591 accessibilityFocusLayoutRestoreView = focusHost; 1592 accessibilityFocusLayoutRestoreNode = viewRootImpl 1593 .getAccessibilityFocusedVirtualView(); 1594 } 1595 1596 // If all else fails, maintain focus at the same 1597 // position. 1598 accessibilityFocusPosition = getPositionForView(focusChild); 1599 } 1600 } 1601 } 1602 1603 View focusLayoutRestoreDirectChild = null; 1604 View focusLayoutRestoreView = null; 1605 1606 // Take focus back to us temporarily to avoid the eventual call to 1607 // clear focus when removing the focused child below from messing 1608 // things up when ViewAncestor assigns focus back to someone else. 1609 final View focusedChild = getFocusedChild(); 1610 if (focusedChild != null) { 1611 // TODO: in some cases focusedChild.getParent() == null 1612 1613 // We can remember the focused view to restore after re-layout 1614 // if the data hasn't changed, or if the focused position is a 1615 // header or footer. 1616 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1617 focusLayoutRestoreDirectChild = focusedChild; 1618 // Remember the specific view that had focus. 1619 focusLayoutRestoreView = findFocus(); 1620 if (focusLayoutRestoreView != null) { 1621 // Tell it we are going to mess with it. 1622 focusLayoutRestoreView.onStartTemporaryDetach(); 1623 } 1624 } 1625 requestFocus(); 1626 } 1627 1628 // Pull all children into the RecycleBin. 1629 // These views will be reused if possible 1630 final int firstPosition = mFirstPosition; 1631 final RecycleBin recycleBin = mRecycler; 1632 if (dataChanged) { 1633 for (int i = 0; i < childCount; i++) { 1634 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1635 } 1636 } else { 1637 recycleBin.fillActiveViews(childCount, firstPosition); 1638 } 1639 1640 // Clear out old views 1641 detachAllViewsFromParent(); 1642 recycleBin.removeSkippedScrap(); 1643 1644 switch (mLayoutMode) { 1645 case LAYOUT_SET_SELECTION: 1646 if (newSel != null) { 1647 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1648 } else { 1649 sel = fillFromMiddle(childrenTop, childrenBottom); 1650 } 1651 break; 1652 case LAYOUT_SYNC: 1653 sel = fillSpecific(mSyncPosition, mSpecificTop); 1654 break; 1655 case LAYOUT_FORCE_BOTTOM: 1656 sel = fillUp(mItemCount - 1, childrenBottom); 1657 adjustViewsUpOrDown(); 1658 break; 1659 case LAYOUT_FORCE_TOP: 1660 mFirstPosition = 0; 1661 sel = fillFromTop(childrenTop); 1662 adjustViewsUpOrDown(); 1663 break; 1664 case LAYOUT_SPECIFIC: 1665 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1666 break; 1667 case LAYOUT_MOVE_SELECTION: 1668 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1669 break; 1670 default: 1671 if (childCount == 0) { 1672 if (!mStackFromBottom) { 1673 final int position = lookForSelectablePosition(0, true); 1674 setSelectedPositionInt(position); 1675 sel = fillFromTop(childrenTop); 1676 } else { 1677 final int position = lookForSelectablePosition(mItemCount - 1, false); 1678 setSelectedPositionInt(position); 1679 sel = fillUp(mItemCount - 1, childrenBottom); 1680 } 1681 } else { 1682 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1683 sel = fillSpecific(mSelectedPosition, 1684 oldSel == null ? childrenTop : oldSel.getTop()); 1685 } else if (mFirstPosition < mItemCount) { 1686 sel = fillSpecific(mFirstPosition, 1687 oldFirst == null ? childrenTop : oldFirst.getTop()); 1688 } else { 1689 sel = fillSpecific(0, childrenTop); 1690 } 1691 } 1692 break; 1693 } 1694 1695 // Flush any cached views that did not get reused above 1696 recycleBin.scrapActiveViews(); 1697 1698 if (sel != null) { 1699 // The current selected item should get focus if items are 1700 // focusable. 1701 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1702 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1703 focusLayoutRestoreView != null && 1704 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1705 if (!focusWasTaken) { 1706 // Selected item didn't take focus, but we still want to 1707 // make sure something else outside of the selected view 1708 // has focus. 1709 final View focused = getFocusedChild(); 1710 if (focused != null) { 1711 focused.clearFocus(); 1712 } 1713 positionSelector(INVALID_POSITION, sel); 1714 } else { 1715 sel.setSelected(false); 1716 mSelectorRect.setEmpty(); 1717 } 1718 } else { 1719 positionSelector(INVALID_POSITION, sel); 1720 } 1721 mSelectedTop = sel.getTop(); 1722 } else { 1723 final boolean inTouchMode = mTouchMode == TOUCH_MODE_TAP 1724 || mTouchMode == TOUCH_MODE_DONE_WAITING; 1725 if (inTouchMode) { 1726 // If the user's finger is down, select the motion position. 1727 final View child = getChildAt(mMotionPosition - mFirstPosition); 1728 if (child != null) { 1729 positionSelector(mMotionPosition, child); 1730 } 1731 } else if (mSelectorPosition != INVALID_POSITION) { 1732 // If we had previously positioned the selector somewhere, 1733 // put it back there. It might not match up with the data, 1734 // but it's transitioning out so it's not a big deal. 1735 final View child = getChildAt(mSelectorPosition - mFirstPosition); 1736 if (child != null) { 1737 positionSelector(mSelectorPosition, child); 1738 } 1739 } else { 1740 // Otherwise, clear selection. 1741 mSelectedTop = 0; 1742 mSelectorRect.setEmpty(); 1743 } 1744 1745 // Even if there is not selected position, we may need to 1746 // restore focus (i.e. something focusable in touch mode). 1747 if (hasFocus() && focusLayoutRestoreView != null) { 1748 focusLayoutRestoreView.requestFocus(); 1749 } 1750 } 1751 1752 // Attempt to restore accessibility focus, if necessary. 1753 if (viewRootImpl != null) { 1754 final View newAccessibilityFocusedView = viewRootImpl.getAccessibilityFocusedHost(); 1755 if (newAccessibilityFocusedView == null) { 1756 if (accessibilityFocusLayoutRestoreView != null 1757 && accessibilityFocusLayoutRestoreView.isAttachedToWindow()) { 1758 final AccessibilityNodeProvider provider = 1759 accessibilityFocusLayoutRestoreView.getAccessibilityNodeProvider(); 1760 if (accessibilityFocusLayoutRestoreNode != null && provider != null) { 1761 final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId( 1762 accessibilityFocusLayoutRestoreNode.getSourceNodeId()); 1763 provider.performAction(virtualViewId, 1764 AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null); 1765 } else { 1766 accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); 1767 } 1768 } else if (accessibilityFocusPosition != INVALID_POSITION) { 1769 // Bound the position within the visible children. 1770 final int position = MathUtils.constrain( 1771 accessibilityFocusPosition - mFirstPosition, 0, 1772 getChildCount() - 1); 1773 final View restoreView = getChildAt(position); 1774 if (restoreView != null) { 1775 restoreView.requestAccessibilityFocus(); 1776 } 1777 } 1778 } 1779 } 1780 1781 // Tell focus view we are done mucking with it, if it is still in 1782 // our view hierarchy. 1783 if (focusLayoutRestoreView != null 1784 && focusLayoutRestoreView.getWindowToken() != null) { 1785 focusLayoutRestoreView.onFinishTemporaryDetach(); 1786 } 1787 1788 mLayoutMode = LAYOUT_NORMAL; 1789 mDataChanged = false; 1790 if (mPositionScrollAfterLayout != null) { 1791 post(mPositionScrollAfterLayout); 1792 mPositionScrollAfterLayout = null; 1793 } 1794 mNeedSync = false; 1795 setNextSelectedPositionInt(mSelectedPosition); 1796 1797 updateScrollIndicators(); 1798 1799 if (mItemCount > 0) { 1800 checkSelectionChanged(); 1801 } 1802 1803 invokeOnItemScrollListener(); 1804 } finally { 1805 if (!blockLayoutRequests) { 1806 mBlockLayoutRequests = false; 1807 } 1808 } 1809 } 1810 1811 /** 1812 * @param child a direct child of this list. 1813 * @return Whether child is a header or footer view. 1814 */ 1815 private boolean isDirectChildHeaderOrFooter(View child) { 1816 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1817 final int numHeaders = headers.size(); 1818 for (int i = 0; i < numHeaders; i++) { 1819 if (child == headers.get(i).view) { 1820 return true; 1821 } 1822 } 1823 1824 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1825 final int numFooters = footers.size(); 1826 for (int i = 0; i < numFooters; i++) { 1827 if (child == footers.get(i).view) { 1828 return true; 1829 } 1830 } 1831 1832 return false; 1833 } 1834 1835 /** 1836 * Obtain the view and add it to our list of children. The view can be made 1837 * fresh, converted from an unused view, or used as is if it was in the 1838 * recycle bin. 1839 * 1840 * @param position Logical position in the list 1841 * @param y Top or bottom edge of the view to add 1842 * @param flow If flow is true, align top edge to y. If false, align bottom 1843 * edge to y. 1844 * @param childrenLeft Left edge where children should be positioned 1845 * @param selected Is this position selected? 1846 * @return View that was added 1847 */ 1848 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1849 boolean selected) { 1850 View child; 1851 1852 1853 if (!mDataChanged) { 1854 // Try to use an existing view for this position 1855 child = mRecycler.getActiveView(position); 1856 if (child != null) { 1857 // Found it -- we're using an existing child 1858 // This just needs to be positioned 1859 setupChild(child, position, y, flow, childrenLeft, selected, true); 1860 1861 return child; 1862 } 1863 } 1864 1865 // Make a new view for this position, or convert an unused view if possible 1866 child = obtainView(position, mIsScrap); 1867 1868 // This needs to be positioned and measured 1869 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1870 1871 return child; 1872 } 1873 1874 /** 1875 * Add a view as a child and make sure it is measured (if necessary) and 1876 * positioned properly. 1877 * 1878 * @param child The view to add 1879 * @param position The position of this child 1880 * @param y The y position relative to which this view will be positioned 1881 * @param flowDown If true, align top edge to y. If false, align bottom 1882 * edge to y. 1883 * @param childrenLeft Left edge where children should be positioned 1884 * @param selected Is this position selected? 1885 * @param recycled Has this view been pulled from the recycle bin? If so it 1886 * does not need to be remeasured. 1887 */ 1888 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1889 boolean selected, boolean recycled) { 1890 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1891 1892 final boolean isSelected = selected && shouldShowSelector(); 1893 final boolean updateChildSelected = isSelected != child.isSelected(); 1894 final int mode = mTouchMode; 1895 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1896 mMotionPosition == position; 1897 final boolean updateChildPressed = isPressed != child.isPressed(); 1898 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1899 1900 // Respect layout params that are already in the view. Otherwise make some up... 1901 // noinspection unchecked 1902 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1903 if (p == null) { 1904 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1905 } 1906 p.viewType = mAdapter.getItemViewType(position); 1907 1908 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1909 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1910 attachViewToParent(child, flowDown ? -1 : 0, p); 1911 } else { 1912 p.forceAdd = false; 1913 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1914 p.recycledHeaderFooter = true; 1915 } 1916 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1917 } 1918 1919 if (updateChildSelected) { 1920 child.setSelected(isSelected); 1921 } 1922 1923 if (updateChildPressed) { 1924 child.setPressed(isPressed); 1925 } 1926 1927 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1928 if (child instanceof Checkable) { 1929 ((Checkable) child).setChecked(mCheckStates.get(position)); 1930 } else if (getContext().getApplicationInfo().targetSdkVersion 1931 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1932 child.setActivated(mCheckStates.get(position)); 1933 } 1934 } 1935 1936 if (needToMeasure) { 1937 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1938 mListPadding.left + mListPadding.right, p.width); 1939 int lpHeight = p.height; 1940 int childHeightSpec; 1941 if (lpHeight > 0) { 1942 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1943 } else { 1944 childHeightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), 1945 MeasureSpec.UNSPECIFIED); 1946 } 1947 child.measure(childWidthSpec, childHeightSpec); 1948 } else { 1949 cleanupLayoutState(child); 1950 } 1951 1952 final int w = child.getMeasuredWidth(); 1953 final int h = child.getMeasuredHeight(); 1954 final int childTop = flowDown ? y : y - h; 1955 1956 if (needToMeasure) { 1957 final int childRight = childrenLeft + w; 1958 final int childBottom = childTop + h; 1959 child.layout(childrenLeft, childTop, childRight, childBottom); 1960 } else { 1961 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1962 child.offsetTopAndBottom(childTop - child.getTop()); 1963 } 1964 1965 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1966 child.setDrawingCacheEnabled(true); 1967 } 1968 1969 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1970 != position) { 1971 child.jumpDrawablesToCurrentState(); 1972 } 1973 1974 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1975 } 1976 1977 @Override 1978 protected boolean canAnimate() { 1979 return super.canAnimate() && mItemCount > 0; 1980 } 1981 1982 /** 1983 * Sets the currently selected item. If in touch mode, the item will not be selected 1984 * but it will still be positioned appropriately. If the specified selection position 1985 * is less than 0, then the item at position 0 will be selected. 1986 * 1987 * @param position Index (starting at 0) of the data item to be selected. 1988 */ 1989 @Override 1990 public void setSelection(int position) { 1991 setSelectionFromTop(position, 0); 1992 } 1993 1994 /** 1995 * Makes the item at the supplied position selected. 1996 * 1997 * @param position the position of the item to select 1998 */ 1999 @Override 2000 void setSelectionInt(int position) { 2001 setNextSelectedPositionInt(position); 2002 boolean awakeScrollbars = false; 2003 2004 final int selectedPosition = mSelectedPosition; 2005 2006 if (selectedPosition >= 0) { 2007 if (position == selectedPosition - 1) { 2008 awakeScrollbars = true; 2009 } else if (position == selectedPosition + 1) { 2010 awakeScrollbars = true; 2011 } 2012 } 2013 2014 if (mPositionScroller != null) { 2015 mPositionScroller.stop(); 2016 } 2017 2018 layoutChildren(); 2019 2020 if (awakeScrollbars) { 2021 awakenScrollBars(); 2022 } 2023 } 2024 2025 /** 2026 * Find a position that can be selected (i.e., is not a separator). 2027 * 2028 * @param position The starting position to look at. 2029 * @param lookDown Whether to look down for other positions. 2030 * @return The next selectable position starting at position and then searching either up or 2031 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 2032 */ 2033 @Override 2034 int lookForSelectablePosition(int position, boolean lookDown) { 2035 final ListAdapter adapter = mAdapter; 2036 if (adapter == null || isInTouchMode()) { 2037 return INVALID_POSITION; 2038 } 2039 2040 final int count = adapter.getCount(); 2041 if (!mAreAllItemsSelectable) { 2042 if (lookDown) { 2043 position = Math.max(0, position); 2044 while (position < count && !adapter.isEnabled(position)) { 2045 position++; 2046 } 2047 } else { 2048 position = Math.min(position, count - 1); 2049 while (position >= 0 && !adapter.isEnabled(position)) { 2050 position--; 2051 } 2052 } 2053 } 2054 2055 if (position < 0 || position >= count) { 2056 return INVALID_POSITION; 2057 } 2058 2059 return position; 2060 } 2061 2062 /** 2063 * Find a position that can be selected (i.e., is not a separator). If there 2064 * are no selectable positions in the specified direction from the starting 2065 * position, searches in the opposite direction from the starting position 2066 * to the current position. 2067 * 2068 * @param current the current position 2069 * @param position the starting position 2070 * @param lookDown whether to look down for other positions 2071 * @return the next selectable position, or {@link #INVALID_POSITION} if 2072 * nothing can be found 2073 */ 2074 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2075 final ListAdapter adapter = mAdapter; 2076 if (adapter == null || isInTouchMode()) { 2077 return INVALID_POSITION; 2078 } 2079 2080 // First check after the starting position in the specified direction. 2081 final int after = lookForSelectablePosition(position, lookDown); 2082 if (after != INVALID_POSITION) { 2083 return after; 2084 } 2085 2086 // Then check between the starting position and the current position. 2087 final int count = adapter.getCount(); 2088 current = MathUtils.constrain(current, -1, count - 1); 2089 if (lookDown) { 2090 position = Math.min(position - 1, count - 1); 2091 while ((position > current) && !adapter.isEnabled(position)) { 2092 position--; 2093 } 2094 if (position <= current) { 2095 return INVALID_POSITION; 2096 } 2097 } else { 2098 position = Math.max(0, position + 1); 2099 while ((position < current) && !adapter.isEnabled(position)) { 2100 position++; 2101 } 2102 if (position >= current) { 2103 return INVALID_POSITION; 2104 } 2105 } 2106 2107 return position; 2108 } 2109 2110 /** 2111 * setSelectionAfterHeaderView set the selection to be the first list item 2112 * after the header views. 2113 */ 2114 public void setSelectionAfterHeaderView() { 2115 final int count = mHeaderViewInfos.size(); 2116 if (count > 0) { 2117 mNextSelectedPosition = 0; 2118 return; 2119 } 2120 2121 if (mAdapter != null) { 2122 setSelection(count); 2123 } else { 2124 mNextSelectedPosition = count; 2125 mLayoutMode = LAYOUT_SET_SELECTION; 2126 } 2127 2128 } 2129 2130 @Override 2131 public boolean dispatchKeyEvent(KeyEvent event) { 2132 // Dispatch in the normal way 2133 boolean handled = super.dispatchKeyEvent(event); 2134 if (!handled) { 2135 // If we didn't handle it... 2136 View focused = getFocusedChild(); 2137 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2138 // ... and our focused child didn't handle it 2139 // ... give it to ourselves so we can scroll if necessary 2140 handled = onKeyDown(event.getKeyCode(), event); 2141 } 2142 } 2143 return handled; 2144 } 2145 2146 @Override 2147 public boolean onKeyDown(int keyCode, KeyEvent event) { 2148 return commonKey(keyCode, 1, event); 2149 } 2150 2151 @Override 2152 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2153 return commonKey(keyCode, repeatCount, event); 2154 } 2155 2156 @Override 2157 public boolean onKeyUp(int keyCode, KeyEvent event) { 2158 return commonKey(keyCode, 1, event); 2159 } 2160 2161 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2162 if (mAdapter == null || !isAttachedToWindow()) { 2163 return false; 2164 } 2165 2166 if (mDataChanged) { 2167 layoutChildren(); 2168 } 2169 2170 boolean handled = false; 2171 int action = event.getAction(); 2172 2173 if (action != KeyEvent.ACTION_UP) { 2174 switch (keyCode) { 2175 case KeyEvent.KEYCODE_DPAD_UP: 2176 if (event.hasNoModifiers()) { 2177 handled = resurrectSelectionIfNeeded(); 2178 if (!handled) { 2179 while (count-- > 0) { 2180 if (arrowScroll(FOCUS_UP)) { 2181 handled = true; 2182 } else { 2183 break; 2184 } 2185 } 2186 } 2187 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2188 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2189 } 2190 break; 2191 2192 case KeyEvent.KEYCODE_DPAD_DOWN: 2193 if (event.hasNoModifiers()) { 2194 handled = resurrectSelectionIfNeeded(); 2195 if (!handled) { 2196 while (count-- > 0) { 2197 if (arrowScroll(FOCUS_DOWN)) { 2198 handled = true; 2199 } else { 2200 break; 2201 } 2202 } 2203 } 2204 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2205 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2206 } 2207 break; 2208 2209 case KeyEvent.KEYCODE_DPAD_LEFT: 2210 if (event.hasNoModifiers()) { 2211 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2212 } 2213 break; 2214 2215 case KeyEvent.KEYCODE_DPAD_RIGHT: 2216 if (event.hasNoModifiers()) { 2217 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2218 } 2219 break; 2220 2221 case KeyEvent.KEYCODE_DPAD_CENTER: 2222 case KeyEvent.KEYCODE_ENTER: 2223 if (event.hasNoModifiers()) { 2224 handled = resurrectSelectionIfNeeded(); 2225 if (!handled 2226 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2227 keyPressed(); 2228 handled = true; 2229 } 2230 } 2231 break; 2232 2233 case KeyEvent.KEYCODE_SPACE: 2234 if (mPopup == null || !mPopup.isShowing()) { 2235 if (event.hasNoModifiers()) { 2236 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2237 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2238 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2239 } 2240 handled = true; 2241 } 2242 break; 2243 2244 case KeyEvent.KEYCODE_PAGE_UP: 2245 if (event.hasNoModifiers()) { 2246 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2247 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2248 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2249 } 2250 break; 2251 2252 case KeyEvent.KEYCODE_PAGE_DOWN: 2253 if (event.hasNoModifiers()) { 2254 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2255 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2256 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2257 } 2258 break; 2259 2260 case KeyEvent.KEYCODE_MOVE_HOME: 2261 if (event.hasNoModifiers()) { 2262 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2263 } 2264 break; 2265 2266 case KeyEvent.KEYCODE_MOVE_END: 2267 if (event.hasNoModifiers()) { 2268 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2269 } 2270 break; 2271 2272 case KeyEvent.KEYCODE_TAB: 2273 // XXX Sometimes it is useful to be able to TAB through the items in 2274 // a ListView sequentially. Unfortunately this can create an 2275 // asymmetry in TAB navigation order unless the list selection 2276 // always reverts to the top or bottom when receiving TAB focus from 2277 // another widget. Leaving this behavior disabled for now but 2278 // perhaps it should be configurable (and more comprehensive). 2279 if (false) { 2280 if (event.hasNoModifiers()) { 2281 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2282 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2283 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2284 } 2285 } 2286 break; 2287 } 2288 } 2289 2290 if (handled) { 2291 return true; 2292 } 2293 2294 if (sendToTextFilter(keyCode, count, event)) { 2295 return true; 2296 } 2297 2298 switch (action) { 2299 case KeyEvent.ACTION_DOWN: 2300 return super.onKeyDown(keyCode, event); 2301 2302 case KeyEvent.ACTION_UP: 2303 return super.onKeyUp(keyCode, event); 2304 2305 case KeyEvent.ACTION_MULTIPLE: 2306 return super.onKeyMultiple(keyCode, count, event); 2307 2308 default: // shouldn't happen 2309 return false; 2310 } 2311 } 2312 2313 /** 2314 * Scrolls up or down by the number of items currently present on screen. 2315 * 2316 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2317 * @return whether selection was moved 2318 */ 2319 boolean pageScroll(int direction) { 2320 final int nextPage; 2321 final boolean down; 2322 2323 if (direction == FOCUS_UP) { 2324 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2325 down = false; 2326 } else if (direction == FOCUS_DOWN) { 2327 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2328 down = true; 2329 } else { 2330 return false; 2331 } 2332 2333 if (nextPage >= 0) { 2334 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2335 if (position >= 0) { 2336 mLayoutMode = LAYOUT_SPECIFIC; 2337 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2338 2339 if (down && (position > (mItemCount - getChildCount()))) { 2340 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2341 } 2342 2343 if (!down && (position < getChildCount())) { 2344 mLayoutMode = LAYOUT_FORCE_TOP; 2345 } 2346 2347 setSelectionInt(position); 2348 invokeOnItemScrollListener(); 2349 if (!awakenScrollBars()) { 2350 invalidate(); 2351 } 2352 2353 return true; 2354 } 2355 } 2356 2357 return false; 2358 } 2359 2360 /** 2361 * Go to the last or first item if possible (not worrying about panning 2362 * across or navigating within the internal focus of the currently selected 2363 * item.) 2364 * 2365 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2366 * @return whether selection was moved 2367 */ 2368 boolean fullScroll(int direction) { 2369 boolean moved = false; 2370 if (direction == FOCUS_UP) { 2371 if (mSelectedPosition != 0) { 2372 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2373 if (position >= 0) { 2374 mLayoutMode = LAYOUT_FORCE_TOP; 2375 setSelectionInt(position); 2376 invokeOnItemScrollListener(); 2377 } 2378 moved = true; 2379 } 2380 } else if (direction == FOCUS_DOWN) { 2381 final int lastItem = (mItemCount - 1); 2382 if (mSelectedPosition < lastItem) { 2383 final int position = lookForSelectablePositionAfter( 2384 mSelectedPosition, lastItem, false); 2385 if (position >= 0) { 2386 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2387 setSelectionInt(position); 2388 invokeOnItemScrollListener(); 2389 } 2390 moved = true; 2391 } 2392 } 2393 2394 if (moved && !awakenScrollBars()) { 2395 awakenScrollBars(); 2396 invalidate(); 2397 } 2398 2399 return moved; 2400 } 2401 2402 /** 2403 * To avoid horizontal focus searches changing the selected item, we 2404 * manually focus search within the selected item (as applicable), and 2405 * prevent focus from jumping to something within another item. 2406 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2407 * @return Whether this consumes the key event. 2408 */ 2409 private boolean handleHorizontalFocusWithinListItem(int direction) { 2410 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2411 throw new IllegalArgumentException("direction must be one of" 2412 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2413 } 2414 2415 final int numChildren = getChildCount(); 2416 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2417 final View selectedView = getSelectedView(); 2418 if (selectedView != null && selectedView.hasFocus() && 2419 selectedView instanceof ViewGroup) { 2420 2421 final View currentFocus = selectedView.findFocus(); 2422 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2423 (ViewGroup) selectedView, currentFocus, direction); 2424 if (nextFocus != null) { 2425 // do the math to get interesting rect in next focus' coordinates 2426 Rect focusedRect = mTempRect; 2427 if (currentFocus != null) { 2428 currentFocus.getFocusedRect(focusedRect); 2429 offsetDescendantRectToMyCoords(currentFocus, focusedRect); 2430 offsetRectIntoDescendantCoords(nextFocus, focusedRect); 2431 } else { 2432 focusedRect = null; 2433 } 2434 if (nextFocus.requestFocus(direction, focusedRect)) { 2435 return true; 2436 } 2437 } 2438 // we are blocking the key from being handled (by returning true) 2439 // if the global result is going to be some other view within this 2440 // list. this is to acheive the overall goal of having 2441 // horizontal d-pad navigation remain in the current item. 2442 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2443 (ViewGroup) getRootView(), currentFocus, direction); 2444 if (globalNextFocus != null) { 2445 return isViewAncestorOf(globalNextFocus, this); 2446 } 2447 } 2448 } 2449 return false; 2450 } 2451 2452 /** 2453 * Scrolls to the next or previous item if possible. 2454 * 2455 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2456 * 2457 * @return whether selection was moved 2458 */ 2459 boolean arrowScroll(int direction) { 2460 try { 2461 mInLayout = true; 2462 final boolean handled = arrowScrollImpl(direction); 2463 if (handled) { 2464 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2465 } 2466 return handled; 2467 } finally { 2468 mInLayout = false; 2469 } 2470 } 2471 2472 /** 2473 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2474 * to move to. This return a position in the direction given if the selected item 2475 * is fully visible. 2476 * 2477 * @param selectedView Current selected view to move from 2478 * @param selectedPos Current selected position to move from 2479 * @param direction Direction to move in 2480 * @return Desired selected position after moving in the given direction 2481 */ 2482 private final int nextSelectedPositionForDirection( 2483 View selectedView, int selectedPos, int direction) { 2484 int nextSelected; 2485 2486 if (direction == View.FOCUS_DOWN) { 2487 final int listBottom = getHeight() - mListPadding.bottom; 2488 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2489 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2490 selectedPos + 1 : 2491 mFirstPosition; 2492 } else { 2493 return INVALID_POSITION; 2494 } 2495 } else { 2496 final int listTop = mListPadding.top; 2497 if (selectedView != null && selectedView.getTop() >= listTop) { 2498 final int lastPos = mFirstPosition + getChildCount() - 1; 2499 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2500 selectedPos - 1 : 2501 lastPos; 2502 } else { 2503 return INVALID_POSITION; 2504 } 2505 } 2506 2507 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2508 return INVALID_POSITION; 2509 } 2510 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2511 } 2512 2513 /** 2514 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2515 * whether there are focusable items etc. 2516 * 2517 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2518 * @return Whether any scrolling, selection or focus change occured. 2519 */ 2520 private boolean arrowScrollImpl(int direction) { 2521 if (getChildCount() <= 0) { 2522 return false; 2523 } 2524 2525 View selectedView = getSelectedView(); 2526 int selectedPos = mSelectedPosition; 2527 2528 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2529 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2530 2531 // if we are moving focus, we may OVERRIDE the default behavior 2532 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2533 if (focusResult != null) { 2534 nextSelectedPosition = focusResult.getSelectedPosition(); 2535 amountToScroll = focusResult.getAmountToScroll(); 2536 } 2537 2538 boolean needToRedraw = focusResult != null; 2539 if (nextSelectedPosition != INVALID_POSITION) { 2540 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2541 setSelectedPositionInt(nextSelectedPosition); 2542 setNextSelectedPositionInt(nextSelectedPosition); 2543 selectedView = getSelectedView(); 2544 selectedPos = nextSelectedPosition; 2545 if (mItemsCanFocus && focusResult == null) { 2546 // there was no new view found to take focus, make sure we 2547 // don't leave focus with the old selection 2548 final View focused = getFocusedChild(); 2549 if (focused != null) { 2550 focused.clearFocus(); 2551 } 2552 } 2553 needToRedraw = true; 2554 checkSelectionChanged(); 2555 } 2556 2557 if (amountToScroll > 0) { 2558 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2559 needToRedraw = true; 2560 } 2561 2562 // if we didn't find a new focusable, make sure any existing focused 2563 // item that was panned off screen gives up focus. 2564 if (mItemsCanFocus && (focusResult == null) 2565 && selectedView != null && selectedView.hasFocus()) { 2566 final View focused = selectedView.findFocus(); 2567 if (focused != null) { 2568 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2569 focused.clearFocus(); 2570 } 2571 } 2572 } 2573 2574 // if the current selection is panned off, we need to remove the selection 2575 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2576 && !isViewAncestorOf(selectedView, this)) { 2577 selectedView = null; 2578 hideSelector(); 2579 2580 // but we don't want to set the ressurect position (that would make subsequent 2581 // unhandled key events bring back the item we just scrolled off!) 2582 mResurrectToPosition = INVALID_POSITION; 2583 } 2584 2585 if (needToRedraw) { 2586 if (selectedView != null) { 2587 positionSelectorLikeFocus(selectedPos, selectedView); 2588 mSelectedTop = selectedView.getTop(); 2589 } 2590 if (!awakenScrollBars()) { 2591 invalidate(); 2592 } 2593 invokeOnItemScrollListener(); 2594 return true; 2595 } 2596 2597 return false; 2598 } 2599 2600 /** 2601 * When selection changes, it is possible that the previously selected or the 2602 * next selected item will change its size. If so, we need to offset some folks, 2603 * and re-layout the items as appropriate. 2604 * 2605 * @param selectedView The currently selected view (before changing selection). 2606 * should be <code>null</code> if there was no previous selection. 2607 * @param direction Either {@link android.view.View#FOCUS_UP} or 2608 * {@link android.view.View#FOCUS_DOWN}. 2609 * @param newSelectedPosition The position of the next selection. 2610 * @param newFocusAssigned whether new focus was assigned. This matters because 2611 * when something has focus, we don't want to show selection (ugh). 2612 */ 2613 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2614 boolean newFocusAssigned) { 2615 if (newSelectedPosition == INVALID_POSITION) { 2616 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2617 } 2618 2619 // whether or not we are moving down or up, we want to preserve the 2620 // top of whatever view is on top: 2621 // - moving down: the view that had selection 2622 // - moving up: the view that is getting selection 2623 View topView; 2624 View bottomView; 2625 int topViewIndex, bottomViewIndex; 2626 boolean topSelected = false; 2627 final int selectedIndex = mSelectedPosition - mFirstPosition; 2628 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2629 if (direction == View.FOCUS_UP) { 2630 topViewIndex = nextSelectedIndex; 2631 bottomViewIndex = selectedIndex; 2632 topView = getChildAt(topViewIndex); 2633 bottomView = selectedView; 2634 topSelected = true; 2635 } else { 2636 topViewIndex = selectedIndex; 2637 bottomViewIndex = nextSelectedIndex; 2638 topView = selectedView; 2639 bottomView = getChildAt(bottomViewIndex); 2640 } 2641 2642 final int numChildren = getChildCount(); 2643 2644 // start with top view: is it changing size? 2645 if (topView != null) { 2646 topView.setSelected(!newFocusAssigned && topSelected); 2647 measureAndAdjustDown(topView, topViewIndex, numChildren); 2648 } 2649 2650 // is the bottom view changing size? 2651 if (bottomView != null) { 2652 bottomView.setSelected(!newFocusAssigned && !topSelected); 2653 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2654 } 2655 } 2656 2657 /** 2658 * Re-measure a child, and if its height changes, lay it out preserving its 2659 * top, and adjust the children below it appropriately. 2660 * @param child The child 2661 * @param childIndex The view group index of the child. 2662 * @param numChildren The number of children in the view group. 2663 */ 2664 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2665 int oldHeight = child.getHeight(); 2666 measureItem(child); 2667 if (child.getMeasuredHeight() != oldHeight) { 2668 // lay out the view, preserving its top 2669 relayoutMeasuredItem(child); 2670 2671 // adjust views below appropriately 2672 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2673 for (int i = childIndex + 1; i < numChildren; i++) { 2674 getChildAt(i).offsetTopAndBottom(heightDelta); 2675 } 2676 } 2677 } 2678 2679 /** 2680 * Measure a particular list child. 2681 * TODO: unify with setUpChild. 2682 * @param child The child. 2683 */ 2684 private void measureItem(View child) { 2685 ViewGroup.LayoutParams p = child.getLayoutParams(); 2686 if (p == null) { 2687 p = new ViewGroup.LayoutParams( 2688 ViewGroup.LayoutParams.MATCH_PARENT, 2689 ViewGroup.LayoutParams.WRAP_CONTENT); 2690 } 2691 2692 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2693 mListPadding.left + mListPadding.right, p.width); 2694 int lpHeight = p.height; 2695 int childHeightSpec; 2696 if (lpHeight > 0) { 2697 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2698 } else { 2699 childHeightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), 2700 MeasureSpec.UNSPECIFIED); 2701 } 2702 child.measure(childWidthSpec, childHeightSpec); 2703 } 2704 2705 /** 2706 * Layout a child that has been measured, preserving its top position. 2707 * TODO: unify with setUpChild. 2708 * @param child The child. 2709 */ 2710 private void relayoutMeasuredItem(View child) { 2711 final int w = child.getMeasuredWidth(); 2712 final int h = child.getMeasuredHeight(); 2713 final int childLeft = mListPadding.left; 2714 final int childRight = childLeft + w; 2715 final int childTop = child.getTop(); 2716 final int childBottom = childTop + h; 2717 child.layout(childLeft, childTop, childRight, childBottom); 2718 } 2719 2720 /** 2721 * @return The amount to preview next items when arrow srolling. 2722 */ 2723 private int getArrowScrollPreviewLength() { 2724 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2725 } 2726 2727 /** 2728 * Determine how much we need to scroll in order to get the next selected view 2729 * visible, with a fading edge showing below as applicable. The amount is 2730 * capped at {@link #getMaxScrollAmount()} . 2731 * 2732 * @param direction either {@link android.view.View#FOCUS_UP} or 2733 * {@link android.view.View#FOCUS_DOWN}. 2734 * @param nextSelectedPosition The position of the next selection, or 2735 * {@link #INVALID_POSITION} if there is no next selectable position 2736 * @return The amount to scroll. Note: this is always positive! Direction 2737 * needs to be taken into account when actually scrolling. 2738 */ 2739 private int amountToScroll(int direction, int nextSelectedPosition) { 2740 final int listBottom = getHeight() - mListPadding.bottom; 2741 final int listTop = mListPadding.top; 2742 2743 int numChildren = getChildCount(); 2744 2745 if (direction == View.FOCUS_DOWN) { 2746 int indexToMakeVisible = numChildren - 1; 2747 if (nextSelectedPosition != INVALID_POSITION) { 2748 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2749 } 2750 while (numChildren <= indexToMakeVisible) { 2751 // Child to view is not attached yet. 2752 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2753 numChildren++; 2754 } 2755 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2756 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2757 2758 int goalBottom = listBottom; 2759 if (positionToMakeVisible < mItemCount - 1) { 2760 goalBottom -= getArrowScrollPreviewLength(); 2761 } 2762 2763 if (viewToMakeVisible.getBottom() <= goalBottom) { 2764 // item is fully visible. 2765 return 0; 2766 } 2767 2768 if (nextSelectedPosition != INVALID_POSITION 2769 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2770 // item already has enough of it visible, changing selection is good enough 2771 return 0; 2772 } 2773 2774 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2775 2776 if ((mFirstPosition + numChildren) == mItemCount) { 2777 // last is last in list -> make sure we don't scroll past it 2778 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2779 amountToScroll = Math.min(amountToScroll, max); 2780 } 2781 2782 return Math.min(amountToScroll, getMaxScrollAmount()); 2783 } else { 2784 int indexToMakeVisible = 0; 2785 if (nextSelectedPosition != INVALID_POSITION) { 2786 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2787 } 2788 while (indexToMakeVisible < 0) { 2789 // Child to view is not attached yet. 2790 addViewAbove(getChildAt(0), mFirstPosition); 2791 mFirstPosition--; 2792 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2793 } 2794 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2795 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2796 int goalTop = listTop; 2797 if (positionToMakeVisible > 0) { 2798 goalTop += getArrowScrollPreviewLength(); 2799 } 2800 if (viewToMakeVisible.getTop() >= goalTop) { 2801 // item is fully visible. 2802 return 0; 2803 } 2804 2805 if (nextSelectedPosition != INVALID_POSITION && 2806 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2807 // item already has enough of it visible, changing selection is good enough 2808 return 0; 2809 } 2810 2811 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2812 if (mFirstPosition == 0) { 2813 // first is first in list -> make sure we don't scroll past it 2814 final int max = listTop - getChildAt(0).getTop(); 2815 amountToScroll = Math.min(amountToScroll, max); 2816 } 2817 return Math.min(amountToScroll, getMaxScrollAmount()); 2818 } 2819 } 2820 2821 /** 2822 * Holds results of focus aware arrow scrolling. 2823 */ 2824 static private class ArrowScrollFocusResult { 2825 private int mSelectedPosition; 2826 private int mAmountToScroll; 2827 2828 /** 2829 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2830 */ 2831 void populate(int selectedPosition, int amountToScroll) { 2832 mSelectedPosition = selectedPosition; 2833 mAmountToScroll = amountToScroll; 2834 } 2835 2836 public int getSelectedPosition() { 2837 return mSelectedPosition; 2838 } 2839 2840 public int getAmountToScroll() { 2841 return mAmountToScroll; 2842 } 2843 } 2844 2845 /** 2846 * @param direction either {@link android.view.View#FOCUS_UP} or 2847 * {@link android.view.View#FOCUS_DOWN}. 2848 * @return The position of the next selectable position of the views that 2849 * are currently visible, taking into account the fact that there might 2850 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2851 * selectable view on screen in the given direction. 2852 */ 2853 private int lookForSelectablePositionOnScreen(int direction) { 2854 final int firstPosition = mFirstPosition; 2855 if (direction == View.FOCUS_DOWN) { 2856 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2857 mSelectedPosition + 1 : 2858 firstPosition; 2859 if (startPos >= mAdapter.getCount()) { 2860 return INVALID_POSITION; 2861 } 2862 if (startPos < firstPosition) { 2863 startPos = firstPosition; 2864 } 2865 2866 final int lastVisiblePos = getLastVisiblePosition(); 2867 final ListAdapter adapter = getAdapter(); 2868 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2869 if (adapter.isEnabled(pos) 2870 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2871 return pos; 2872 } 2873 } 2874 } else { 2875 int last = firstPosition + getChildCount() - 1; 2876 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2877 mSelectedPosition - 1 : 2878 firstPosition + getChildCount() - 1; 2879 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2880 return INVALID_POSITION; 2881 } 2882 if (startPos > last) { 2883 startPos = last; 2884 } 2885 2886 final ListAdapter adapter = getAdapter(); 2887 for (int pos = startPos; pos >= firstPosition; pos--) { 2888 if (adapter.isEnabled(pos) 2889 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2890 return pos; 2891 } 2892 } 2893 } 2894 return INVALID_POSITION; 2895 } 2896 2897 /** 2898 * Do an arrow scroll based on focus searching. If a new view is 2899 * given focus, return the selection delta and amount to scroll via 2900 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2901 * 2902 * @param direction either {@link android.view.View#FOCUS_UP} or 2903 * {@link android.view.View#FOCUS_DOWN}. 2904 * @return The result if focus has changed, or <code>null</code>. 2905 */ 2906 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2907 final View selectedView = getSelectedView(); 2908 View newFocus; 2909 if (selectedView != null && selectedView.hasFocus()) { 2910 View oldFocus = selectedView.findFocus(); 2911 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2912 } else { 2913 if (direction == View.FOCUS_DOWN) { 2914 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2915 final int listTop = mListPadding.top + 2916 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2917 final int ySearchPoint = 2918 (selectedView != null && selectedView.getTop() > listTop) ? 2919 selectedView.getTop() : 2920 listTop; 2921 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2922 } else { 2923 final boolean bottomFadingEdgeShowing = 2924 (mFirstPosition + getChildCount() - 1) < mItemCount; 2925 final int listBottom = getHeight() - mListPadding.bottom - 2926 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2927 final int ySearchPoint = 2928 (selectedView != null && selectedView.getBottom() < listBottom) ? 2929 selectedView.getBottom() : 2930 listBottom; 2931 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2932 } 2933 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2934 } 2935 2936 if (newFocus != null) { 2937 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2938 2939 // if the focus change is in a different new position, make sure 2940 // we aren't jumping over another selectable position 2941 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2942 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2943 if (selectablePosition != INVALID_POSITION && 2944 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2945 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2946 return null; 2947 } 2948 } 2949 2950 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2951 2952 final int maxScrollAmount = getMaxScrollAmount(); 2953 if (focusScroll < maxScrollAmount) { 2954 // not moving too far, safe to give next view focus 2955 newFocus.requestFocus(direction); 2956 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2957 return mArrowScrollFocusResult; 2958 } else if (distanceToView(newFocus) < maxScrollAmount){ 2959 // Case to consider: 2960 // too far to get entire next focusable on screen, but by going 2961 // max scroll amount, we are getting it at least partially in view, 2962 // so give it focus and scroll the max ammount. 2963 newFocus.requestFocus(direction); 2964 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2965 return mArrowScrollFocusResult; 2966 } 2967 } 2968 return null; 2969 } 2970 2971 /** 2972 * @param newFocus The view that would have focus. 2973 * @return the position that contains newFocus 2974 */ 2975 private int positionOfNewFocus(View newFocus) { 2976 final int numChildren = getChildCount(); 2977 for (int i = 0; i < numChildren; i++) { 2978 final View child = getChildAt(i); 2979 if (isViewAncestorOf(newFocus, child)) { 2980 return mFirstPosition + i; 2981 } 2982 } 2983 throw new IllegalArgumentException("newFocus is not a child of any of the" 2984 + " children of the list!"); 2985 } 2986 2987 /** 2988 * Return true if child is an ancestor of parent, (or equal to the parent). 2989 */ 2990 private boolean isViewAncestorOf(View child, View parent) { 2991 if (child == parent) { 2992 return true; 2993 } 2994 2995 final ViewParent theParent = child.getParent(); 2996 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2997 } 2998 2999 /** 3000 * Determine how much we need to scroll in order to get newFocus in view. 3001 * @param direction either {@link android.view.View#FOCUS_UP} or 3002 * {@link android.view.View#FOCUS_DOWN}. 3003 * @param newFocus The view that would take focus. 3004 * @param positionOfNewFocus The position of the list item containing newFocus 3005 * @return The amount to scroll. Note: this is always positive! Direction 3006 * needs to be taken into account when actually scrolling. 3007 */ 3008 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 3009 int amountToScroll = 0; 3010 newFocus.getDrawingRect(mTempRect); 3011 offsetDescendantRectToMyCoords(newFocus, mTempRect); 3012 if (direction == View.FOCUS_UP) { 3013 if (mTempRect.top < mListPadding.top) { 3014 amountToScroll = mListPadding.top - mTempRect.top; 3015 if (positionOfNewFocus > 0) { 3016 amountToScroll += getArrowScrollPreviewLength(); 3017 } 3018 } 3019 } else { 3020 final int listBottom = getHeight() - mListPadding.bottom; 3021 if (mTempRect.bottom > listBottom) { 3022 amountToScroll = mTempRect.bottom - listBottom; 3023 if (positionOfNewFocus < mItemCount - 1) { 3024 amountToScroll += getArrowScrollPreviewLength(); 3025 } 3026 } 3027 } 3028 return amountToScroll; 3029 } 3030 3031 /** 3032 * Determine the distance to the nearest edge of a view in a particular 3033 * direction. 3034 * 3035 * @param descendant A descendant of this list. 3036 * @return The distance, or 0 if the nearest edge is already on screen. 3037 */ 3038 private int distanceToView(View descendant) { 3039 int distance = 0; 3040 descendant.getDrawingRect(mTempRect); 3041 offsetDescendantRectToMyCoords(descendant, mTempRect); 3042 final int listBottom = mBottom - mTop - mListPadding.bottom; 3043 if (mTempRect.bottom < mListPadding.top) { 3044 distance = mListPadding.top - mTempRect.bottom; 3045 } else if (mTempRect.top > listBottom) { 3046 distance = mTempRect.top - listBottom; 3047 } 3048 return distance; 3049 } 3050 3051 3052 /** 3053 * Scroll the children by amount, adding a view at the end and removing 3054 * views that fall off as necessary. 3055 * 3056 * @param amount The amount (positive or negative) to scroll. 3057 */ 3058 private void scrollListItemsBy(int amount) { 3059 offsetChildrenTopAndBottom(amount); 3060 3061 final int listBottom = getHeight() - mListPadding.bottom; 3062 final int listTop = mListPadding.top; 3063 final AbsListView.RecycleBin recycleBin = mRecycler; 3064 3065 if (amount < 0) { 3066 // shifted items up 3067 3068 // may need to pan views into the bottom space 3069 int numChildren = getChildCount(); 3070 View last = getChildAt(numChildren - 1); 3071 while (last.getBottom() < listBottom) { 3072 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3073 if (lastVisiblePosition < mItemCount - 1) { 3074 last = addViewBelow(last, lastVisiblePosition); 3075 numChildren++; 3076 } else { 3077 break; 3078 } 3079 } 3080 3081 // may have brought in the last child of the list that is skinnier 3082 // than the fading edge, thereby leaving space at the end. need 3083 // to shift back 3084 if (last.getBottom() < listBottom) { 3085 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3086 } 3087 3088 // top views may be panned off screen 3089 View first = getChildAt(0); 3090 while (first.getBottom() < listTop) { 3091 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3092 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3093 recycleBin.addScrapView(first, mFirstPosition); 3094 } 3095 detachViewFromParent(first); 3096 first = getChildAt(0); 3097 mFirstPosition++; 3098 } 3099 } else { 3100 // shifted items down 3101 View first = getChildAt(0); 3102 3103 // may need to pan views into top 3104 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3105 first = addViewAbove(first, mFirstPosition); 3106 mFirstPosition--; 3107 } 3108 3109 // may have brought the very first child of the list in too far and 3110 // need to shift it back 3111 if (first.getTop() > listTop) { 3112 offsetChildrenTopAndBottom(listTop - first.getTop()); 3113 } 3114 3115 int lastIndex = getChildCount() - 1; 3116 View last = getChildAt(lastIndex); 3117 3118 // bottom view may be panned off screen 3119 while (last.getTop() > listBottom) { 3120 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3121 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3122 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3123 } 3124 detachViewFromParent(last); 3125 last = getChildAt(--lastIndex); 3126 } 3127 } 3128 } 3129 3130 private View addViewAbove(View theView, int position) { 3131 int abovePosition = position - 1; 3132 View view = obtainView(abovePosition, mIsScrap); 3133 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3134 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3135 false, mIsScrap[0]); 3136 return view; 3137 } 3138 3139 private View addViewBelow(View theView, int position) { 3140 int belowPosition = position + 1; 3141 View view = obtainView(belowPosition, mIsScrap); 3142 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3143 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3144 false, mIsScrap[0]); 3145 return view; 3146 } 3147 3148 /** 3149 * Indicates that the views created by the ListAdapter can contain focusable 3150 * items. 3151 * 3152 * @param itemsCanFocus true if items can get focus, false otherwise 3153 */ 3154 public void setItemsCanFocus(boolean itemsCanFocus) { 3155 mItemsCanFocus = itemsCanFocus; 3156 if (!itemsCanFocus) { 3157 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3158 } 3159 } 3160 3161 /** 3162 * @return Whether the views created by the ListAdapter can contain focusable 3163 * items. 3164 */ 3165 public boolean getItemsCanFocus() { 3166 return mItemsCanFocus; 3167 } 3168 3169 @Override 3170 public boolean isOpaque() { 3171 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3172 hasOpaqueScrollbars()) || super.isOpaque(); 3173 if (retValue) { 3174 // only return true if the list items cover the entire area of the view 3175 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3176 View first = getChildAt(0); 3177 if (first == null || first.getTop() > listTop) { 3178 return false; 3179 } 3180 final int listBottom = getHeight() - 3181 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3182 View last = getChildAt(getChildCount() - 1); 3183 if (last == null || last.getBottom() < listBottom) { 3184 return false; 3185 } 3186 } 3187 return retValue; 3188 } 3189 3190 @Override 3191 public void setCacheColorHint(int color) { 3192 final boolean opaque = (color >>> 24) == 0xFF; 3193 mIsCacheColorOpaque = opaque; 3194 if (opaque) { 3195 if (mDividerPaint == null) { 3196 mDividerPaint = new Paint(); 3197 } 3198 mDividerPaint.setColor(color); 3199 } 3200 super.setCacheColorHint(color); 3201 } 3202 3203 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3204 final int height = drawable.getMinimumHeight(); 3205 3206 canvas.save(); 3207 canvas.clipRect(bounds); 3208 3209 final int span = bounds.bottom - bounds.top; 3210 if (span < height) { 3211 bounds.top = bounds.bottom - height; 3212 } 3213 3214 drawable.setBounds(bounds); 3215 drawable.draw(canvas); 3216 3217 canvas.restore(); 3218 } 3219 3220 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3221 final int height = drawable.getMinimumHeight(); 3222 3223 canvas.save(); 3224 canvas.clipRect(bounds); 3225 3226 final int span = bounds.bottom - bounds.top; 3227 if (span < height) { 3228 bounds.bottom = bounds.top + height; 3229 } 3230 3231 drawable.setBounds(bounds); 3232 drawable.draw(canvas); 3233 3234 canvas.restore(); 3235 } 3236 3237 @Override 3238 protected void dispatchDraw(Canvas canvas) { 3239 if (mCachingStarted) { 3240 mCachingActive = true; 3241 } 3242 3243 // Draw the dividers 3244 final int dividerHeight = mDividerHeight; 3245 final Drawable overscrollHeader = mOverScrollHeader; 3246 final Drawable overscrollFooter = mOverScrollFooter; 3247 final boolean drawOverscrollHeader = overscrollHeader != null; 3248 final boolean drawOverscrollFooter = overscrollFooter != null; 3249 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3250 3251 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3252 // Only modify the top and bottom in the loop, we set the left and right here 3253 final Rect bounds = mTempRect; 3254 bounds.left = mPaddingLeft; 3255 bounds.right = mRight - mLeft - mPaddingRight; 3256 3257 final int count = getChildCount(); 3258 final int headerCount = mHeaderViewInfos.size(); 3259 final int itemCount = mItemCount; 3260 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3261 final boolean headerDividers = mHeaderDividersEnabled; 3262 final boolean footerDividers = mFooterDividersEnabled; 3263 final int first = mFirstPosition; 3264 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3265 final ListAdapter adapter = mAdapter; 3266 // If the list is opaque *and* the background is not, we want to 3267 // fill a rect where the dividers would be for non-selectable items 3268 // If the list is opaque and the background is also opaque, we don't 3269 // need to draw anything since the background will do it for us 3270 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3271 3272 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3273 mDividerPaint = new Paint(); 3274 mDividerPaint.setColor(getCacheColorHint()); 3275 } 3276 final Paint paint = mDividerPaint; 3277 3278 int effectivePaddingTop = 0; 3279 int effectivePaddingBottom = 0; 3280 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3281 effectivePaddingTop = mListPadding.top; 3282 effectivePaddingBottom = mListPadding.bottom; 3283 } 3284 3285 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3286 if (!mStackFromBottom) { 3287 int bottom = 0; 3288 3289 // Draw top divider or header for overscroll 3290 final int scrollY = mScrollY; 3291 if (count > 0 && scrollY < 0) { 3292 if (drawOverscrollHeader) { 3293 bounds.bottom = 0; 3294 bounds.top = scrollY; 3295 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3296 } else if (drawDividers) { 3297 bounds.bottom = 0; 3298 bounds.top = -dividerHeight; 3299 drawDivider(canvas, bounds, -1); 3300 } 3301 } 3302 3303 for (int i = 0; i < count; i++) { 3304 final int itemIndex = (first + i); 3305 final boolean isHeader = (itemIndex < headerCount); 3306 final boolean isFooter = (itemIndex >= footerLimit); 3307 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3308 final View child = getChildAt(i); 3309 bottom = child.getBottom(); 3310 final boolean isLastItem = (i == (count - 1)); 3311 3312 if (drawDividers && (bottom < listBottom) 3313 && !(drawOverscrollFooter && isLastItem)) { 3314 final int nextIndex = (itemIndex + 1); 3315 // Draw dividers between enabled items, headers 3316 // and/or footers when enabled and requested, and 3317 // after the last enabled item. 3318 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3319 && (nextIndex >= headerCount)) && (isLastItem 3320 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3321 && (nextIndex < footerLimit)))) { 3322 bounds.top = bottom; 3323 bounds.bottom = bottom + dividerHeight; 3324 drawDivider(canvas, bounds, i); 3325 } else if (fillForMissingDividers) { 3326 bounds.top = bottom; 3327 bounds.bottom = bottom + dividerHeight; 3328 canvas.drawRect(bounds, paint); 3329 } 3330 } 3331 } 3332 } 3333 3334 final int overFooterBottom = mBottom + mScrollY; 3335 if (drawOverscrollFooter && first + count == itemCount && 3336 overFooterBottom > bottom) { 3337 bounds.top = bottom; 3338 bounds.bottom = overFooterBottom; 3339 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3340 } 3341 } else { 3342 int top; 3343 3344 final int scrollY = mScrollY; 3345 3346 if (count > 0 && drawOverscrollHeader) { 3347 bounds.top = scrollY; 3348 bounds.bottom = getChildAt(0).getTop(); 3349 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3350 } 3351 3352 final int start = drawOverscrollHeader ? 1 : 0; 3353 for (int i = start; i < count; i++) { 3354 final int itemIndex = (first + i); 3355 final boolean isHeader = (itemIndex < headerCount); 3356 final boolean isFooter = (itemIndex >= footerLimit); 3357 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3358 final View child = getChildAt(i); 3359 top = child.getTop(); 3360 if (drawDividers && (top > effectivePaddingTop)) { 3361 final boolean isFirstItem = (i == start); 3362 final int previousIndex = (itemIndex - 1); 3363 // Draw dividers between enabled items, headers 3364 // and/or footers when enabled and requested, and 3365 // before the first enabled item. 3366 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3367 && (previousIndex >= headerCount)) && (isFirstItem || 3368 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3369 && (previousIndex < footerLimit)))) { 3370 bounds.top = top - dividerHeight; 3371 bounds.bottom = top; 3372 // Give the method the child ABOVE the divider, 3373 // so we subtract one from our child position. 3374 // Give -1 when there is no child above the 3375 // divider. 3376 drawDivider(canvas, bounds, i - 1); 3377 } else if (fillForMissingDividers) { 3378 bounds.top = top - dividerHeight; 3379 bounds.bottom = top; 3380 canvas.drawRect(bounds, paint); 3381 } 3382 } 3383 } 3384 } 3385 3386 if (count > 0 && scrollY > 0) { 3387 if (drawOverscrollFooter) { 3388 final int absListBottom = mBottom; 3389 bounds.top = absListBottom; 3390 bounds.bottom = absListBottom + scrollY; 3391 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3392 } else if (drawDividers) { 3393 bounds.top = listBottom; 3394 bounds.bottom = listBottom + dividerHeight; 3395 drawDivider(canvas, bounds, -1); 3396 } 3397 } 3398 } 3399 } 3400 3401 // Draw the indicators (these should be drawn above the dividers) and children 3402 super.dispatchDraw(canvas); 3403 } 3404 3405 @Override 3406 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3407 boolean more = super.drawChild(canvas, child, drawingTime); 3408 if (mCachingActive && child.mCachingFailed) { 3409 mCachingActive = false; 3410 } 3411 return more; 3412 } 3413 3414 /** 3415 * Draws a divider for the given child in the given bounds. 3416 * 3417 * @param canvas The canvas to draw to. 3418 * @param bounds The bounds of the divider. 3419 * @param childIndex The index of child (of the View) above the divider. 3420 * This will be -1 if there is no child above the divider to be 3421 * drawn. 3422 */ 3423 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3424 // This widget draws the same divider for all children 3425 final Drawable divider = mDivider; 3426 3427 divider.setBounds(bounds); 3428 divider.draw(canvas); 3429 } 3430 3431 /** 3432 * Returns the drawable that will be drawn between each item in the list. 3433 * 3434 * @return the current drawable drawn between list elements 3435 */ 3436 public Drawable getDivider() { 3437 return mDivider; 3438 } 3439 3440 /** 3441 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3442 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3443 * 3444 * @param divider The drawable to use. 3445 */ 3446 public void setDivider(Drawable divider) { 3447 if (divider != null) { 3448 mDividerHeight = divider.getIntrinsicHeight(); 3449 } else { 3450 mDividerHeight = 0; 3451 } 3452 mDivider = divider; 3453 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3454 requestLayout(); 3455 invalidate(); 3456 } 3457 3458 /** 3459 * @return Returns the height of the divider that will be drawn between each item in the list. 3460 */ 3461 public int getDividerHeight() { 3462 return mDividerHeight; 3463 } 3464 3465 /** 3466 * Sets the height of the divider that will be drawn between each item in the list. Calling 3467 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3468 * 3469 * @param height The new height of the divider in pixels. 3470 */ 3471 public void setDividerHeight(int height) { 3472 mDividerHeight = height; 3473 requestLayout(); 3474 invalidate(); 3475 } 3476 3477 /** 3478 * Enables or disables the drawing of the divider for header views. 3479 * 3480 * @param headerDividersEnabled True to draw the headers, false otherwise. 3481 * 3482 * @see #setFooterDividersEnabled(boolean) 3483 * @see #areHeaderDividersEnabled() 3484 * @see #addHeaderView(android.view.View) 3485 */ 3486 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3487 mHeaderDividersEnabled = headerDividersEnabled; 3488 invalidate(); 3489 } 3490 3491 /** 3492 * @return Whether the drawing of the divider for header views is enabled 3493 * 3494 * @see #setHeaderDividersEnabled(boolean) 3495 */ 3496 public boolean areHeaderDividersEnabled() { 3497 return mHeaderDividersEnabled; 3498 } 3499 3500 /** 3501 * Enables or disables the drawing of the divider for footer views. 3502 * 3503 * @param footerDividersEnabled True to draw the footers, false otherwise. 3504 * 3505 * @see #setHeaderDividersEnabled(boolean) 3506 * @see #areFooterDividersEnabled() 3507 * @see #addFooterView(android.view.View) 3508 */ 3509 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3510 mFooterDividersEnabled = footerDividersEnabled; 3511 invalidate(); 3512 } 3513 3514 /** 3515 * @return Whether the drawing of the divider for footer views is enabled 3516 * 3517 * @see #setFooterDividersEnabled(boolean) 3518 */ 3519 public boolean areFooterDividersEnabled() { 3520 return mFooterDividersEnabled; 3521 } 3522 3523 /** 3524 * Sets the drawable that will be drawn above all other list content. 3525 * This area can become visible when the user overscrolls the list. 3526 * 3527 * @param header The drawable to use 3528 */ 3529 public void setOverscrollHeader(Drawable header) { 3530 mOverScrollHeader = header; 3531 if (mScrollY < 0) { 3532 invalidate(); 3533 } 3534 } 3535 3536 /** 3537 * @return The drawable that will be drawn above all other list content 3538 */ 3539 public Drawable getOverscrollHeader() { 3540 return mOverScrollHeader; 3541 } 3542 3543 /** 3544 * Sets the drawable that will be drawn below all other list content. 3545 * This area can become visible when the user overscrolls the list, 3546 * or when the list's content does not fully fill the container area. 3547 * 3548 * @param footer The drawable to use 3549 */ 3550 public void setOverscrollFooter(Drawable footer) { 3551 mOverScrollFooter = footer; 3552 invalidate(); 3553 } 3554 3555 /** 3556 * @return The drawable that will be drawn below all other list content 3557 */ 3558 public Drawable getOverscrollFooter() { 3559 return mOverScrollFooter; 3560 } 3561 3562 @Override 3563 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3564 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3565 3566 final ListAdapter adapter = mAdapter; 3567 int closetChildIndex = -1; 3568 int closestChildTop = 0; 3569 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3570 previouslyFocusedRect.offset(mScrollX, mScrollY); 3571 3572 // Don't cache the result of getChildCount or mFirstPosition here, 3573 // it could change in layoutChildren. 3574 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3575 mLayoutMode = LAYOUT_NORMAL; 3576 layoutChildren(); 3577 } 3578 3579 // figure out which item should be selected based on previously 3580 // focused rect 3581 Rect otherRect = mTempRect; 3582 int minDistance = Integer.MAX_VALUE; 3583 final int childCount = getChildCount(); 3584 final int firstPosition = mFirstPosition; 3585 3586 for (int i = 0; i < childCount; i++) { 3587 // only consider selectable views 3588 if (!adapter.isEnabled(firstPosition + i)) { 3589 continue; 3590 } 3591 3592 View other = getChildAt(i); 3593 other.getDrawingRect(otherRect); 3594 offsetDescendantRectToMyCoords(other, otherRect); 3595 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3596 3597 if (distance < minDistance) { 3598 minDistance = distance; 3599 closetChildIndex = i; 3600 closestChildTop = other.getTop(); 3601 } 3602 } 3603 } 3604 3605 if (closetChildIndex >= 0) { 3606 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3607 } else { 3608 requestLayout(); 3609 } 3610 } 3611 3612 3613 /* 3614 * (non-Javadoc) 3615 * 3616 * Children specified in XML are assumed to be header views. After we have 3617 * parsed them move them out of the children list and into mHeaderViews. 3618 */ 3619 @Override 3620 protected void onFinishInflate() { 3621 super.onFinishInflate(); 3622 3623 int count = getChildCount(); 3624 if (count > 0) { 3625 for (int i = 0; i < count; ++i) { 3626 addHeaderView(getChildAt(i)); 3627 } 3628 removeAllViews(); 3629 } 3630 } 3631 3632 /* (non-Javadoc) 3633 * @see android.view.View#findViewById(int) 3634 * First look in our children, then in any header and footer views that may be scrolled off. 3635 */ 3636 @Override 3637 protected View findViewTraversal(@IdRes int id) { 3638 View v; 3639 v = super.findViewTraversal(id); 3640 if (v == null) { 3641 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3642 if (v != null) { 3643 return v; 3644 } 3645 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3646 if (v != null) { 3647 return v; 3648 } 3649 } 3650 return v; 3651 } 3652 3653 /* (non-Javadoc) 3654 * 3655 * Look in the passed in list of headers or footers for the view. 3656 */ 3657 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3658 if (where != null) { 3659 int len = where.size(); 3660 View v; 3661 3662 for (int i = 0; i < len; i++) { 3663 v = where.get(i).view; 3664 3665 if (!v.isRootNamespace()) { 3666 v = v.findViewById(id); 3667 3668 if (v != null) { 3669 return v; 3670 } 3671 } 3672 } 3673 } 3674 return null; 3675 } 3676 3677 /* (non-Javadoc) 3678 * @see android.view.View#findViewWithTag(Object) 3679 * First look in our children, then in any header and footer views that may be scrolled off. 3680 */ 3681 @Override 3682 protected View findViewWithTagTraversal(Object tag) { 3683 View v; 3684 v = super.findViewWithTagTraversal(tag); 3685 if (v == null) { 3686 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3687 if (v != null) { 3688 return v; 3689 } 3690 3691 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3692 if (v != null) { 3693 return v; 3694 } 3695 } 3696 return v; 3697 } 3698 3699 /* (non-Javadoc) 3700 * 3701 * Look in the passed in list of headers or footers for the view with the tag. 3702 */ 3703 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3704 if (where != null) { 3705 int len = where.size(); 3706 View v; 3707 3708 for (int i = 0; i < len; i++) { 3709 v = where.get(i).view; 3710 3711 if (!v.isRootNamespace()) { 3712 v = v.findViewWithTag(tag); 3713 3714 if (v != null) { 3715 return v; 3716 } 3717 } 3718 } 3719 } 3720 return null; 3721 } 3722 3723 /** 3724 * @hide 3725 * @see android.view.View#findViewByPredicate(Predicate) 3726 * First look in our children, then in any header and footer views that may be scrolled off. 3727 */ 3728 @Override 3729 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3730 View v; 3731 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3732 if (v == null) { 3733 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3734 if (v != null) { 3735 return v; 3736 } 3737 3738 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3739 if (v != null) { 3740 return v; 3741 } 3742 } 3743 return v; 3744 } 3745 3746 /* (non-Javadoc) 3747 * 3748 * Look in the passed in list of headers or footers for the first view that matches 3749 * the predicate. 3750 */ 3751 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3752 Predicate<View> predicate, View childToSkip) { 3753 if (where != null) { 3754 int len = where.size(); 3755 View v; 3756 3757 for (int i = 0; i < len; i++) { 3758 v = where.get(i).view; 3759 3760 if (v != childToSkip && !v.isRootNamespace()) { 3761 v = v.findViewByPredicate(predicate); 3762 3763 if (v != null) { 3764 return v; 3765 } 3766 } 3767 } 3768 } 3769 return null; 3770 } 3771 3772 /** 3773 * Returns the set of checked items ids. The result is only valid if the 3774 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3775 * 3776 * @return A new array which contains the id of each checked item in the 3777 * list. 3778 * 3779 * @deprecated Use {@link #getCheckedItemIds()} instead. 3780 */ 3781 @Deprecated 3782 public long[] getCheckItemIds() { 3783 // Use new behavior that correctly handles stable ID mapping. 3784 if (mAdapter != null && mAdapter.hasStableIds()) { 3785 return getCheckedItemIds(); 3786 } 3787 3788 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3789 // Fall back to it to support legacy apps. 3790 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3791 final SparseBooleanArray states = mCheckStates; 3792 final int count = states.size(); 3793 final long[] ids = new long[count]; 3794 final ListAdapter adapter = mAdapter; 3795 3796 int checkedCount = 0; 3797 for (int i = 0; i < count; i++) { 3798 if (states.valueAt(i)) { 3799 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3800 } 3801 } 3802 3803 // Trim array if needed. mCheckStates may contain false values 3804 // resulting in checkedCount being smaller than count. 3805 if (checkedCount == count) { 3806 return ids; 3807 } else { 3808 final long[] result = new long[checkedCount]; 3809 System.arraycopy(ids, 0, result, 0, checkedCount); 3810 3811 return result; 3812 } 3813 } 3814 return new long[0]; 3815 } 3816 3817 @Override 3818 int getHeightForPosition(int position) { 3819 final int height = super.getHeightForPosition(position); 3820 if (shouldAdjustHeightForDivider(position)) { 3821 return height + mDividerHeight; 3822 } 3823 return height; 3824 } 3825 3826 private boolean shouldAdjustHeightForDivider(int itemIndex) { 3827 final int dividerHeight = mDividerHeight; 3828 final Drawable overscrollHeader = mOverScrollHeader; 3829 final Drawable overscrollFooter = mOverScrollFooter; 3830 final boolean drawOverscrollHeader = overscrollHeader != null; 3831 final boolean drawOverscrollFooter = overscrollFooter != null; 3832 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3833 3834 if (drawDividers) { 3835 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3836 final int itemCount = mItemCount; 3837 final int headerCount = mHeaderViewInfos.size(); 3838 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3839 final boolean isHeader = (itemIndex < headerCount); 3840 final boolean isFooter = (itemIndex >= footerLimit); 3841 final boolean headerDividers = mHeaderDividersEnabled; 3842 final boolean footerDividers = mFooterDividersEnabled; 3843 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3844 final ListAdapter adapter = mAdapter; 3845 if (!mStackFromBottom) { 3846 final boolean isLastItem = (itemIndex == (itemCount - 1)); 3847 if (!drawOverscrollFooter || !isLastItem) { 3848 final int nextIndex = itemIndex + 1; 3849 // Draw dividers between enabled items, headers 3850 // and/or footers when enabled and requested, and 3851 // after the last enabled item. 3852 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3853 && (nextIndex >= headerCount)) && (isLastItem 3854 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3855 && (nextIndex < footerLimit)))) { 3856 return true; 3857 } else if (fillForMissingDividers) { 3858 return true; 3859 } 3860 } 3861 } else { 3862 final int start = drawOverscrollHeader ? 1 : 0; 3863 final boolean isFirstItem = (itemIndex == start); 3864 if (!isFirstItem) { 3865 final int previousIndex = (itemIndex - 1); 3866 // Draw dividers between enabled items, headers 3867 // and/or footers when enabled and requested, and 3868 // before the first enabled item. 3869 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3870 && (previousIndex >= headerCount)) && (isFirstItem || 3871 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3872 && (previousIndex < footerLimit)))) { 3873 return true; 3874 } else if (fillForMissingDividers) { 3875 return true; 3876 } 3877 } 3878 } 3879 } 3880 } 3881 3882 return false; 3883 } 3884 3885 @Override 3886 public CharSequence getAccessibilityClassName() { 3887 return ListView.class.getName(); 3888 } 3889 3890 /** @hide */ 3891 @Override 3892 public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { 3893 super.onInitializeAccessibilityNodeInfoInternal(info); 3894 3895 final int rowsCount = getCount(); 3896 final int selectionMode = getSelectionModeForAccessibility(); 3897 final CollectionInfo collectionInfo = CollectionInfo.obtain( 3898 rowsCount, 1, false, selectionMode); 3899 info.setCollectionInfo(collectionInfo); 3900 3901 if (rowsCount > 0) { 3902 info.addAction(AccessibilityAction.ACTION_SCROLL_TO_POSITION); 3903 } 3904 } 3905 3906 /** @hide */ 3907 @Override 3908 public boolean performAccessibilityActionInternal(int action, Bundle arguments) { 3909 if (super.performAccessibilityActionInternal(action, arguments)) { 3910 return true; 3911 } 3912 3913 switch (action) { 3914 case R.id.accessibilityActionScrollToPosition: { 3915 final int row = arguments.getInt(AccessibilityNodeInfo.ACTION_ARGUMENT_ROW_INT, -1); 3916 final int position = Math.min(row, getCount() - 1); 3917 if (row >= 0) { 3918 // The accessibility service gets data asynchronously, so 3919 // we'll be a little lenient by clamping the last position. 3920 smoothScrollToPosition(position); 3921 return true; 3922 } 3923 } break; 3924 } 3925 3926 return false; 3927 } 3928 3929 @Override 3930 public void onInitializeAccessibilityNodeInfoForItem( 3931 View view, int position, AccessibilityNodeInfo info) { 3932 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3933 3934 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3935 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3936 final boolean isSelected = isItemChecked(position); 3937 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain( 3938 position, 1, 0, 1, isHeading, isSelected); 3939 info.setCollectionItemInfo(itemInfo); 3940 } 3941} 3942