ListView.java revision 20cc605b69a017316112929666255226c184a376
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.Trace; 20import com.android.internal.R; 21import com.android.internal.util.Predicate; 22import com.google.android.collect.Lists; 23 24import android.content.Context; 25import android.content.Intent; 26import android.content.res.TypedArray; 27import android.graphics.Canvas; 28import android.graphics.Paint; 29import android.graphics.PixelFormat; 30import android.graphics.Rect; 31import android.graphics.drawable.Drawable; 32import android.util.AttributeSet; 33import android.util.MathUtils; 34import android.util.SparseBooleanArray; 35import android.view.FocusFinder; 36import android.view.KeyEvent; 37import android.view.SoundEffectConstants; 38import android.view.View; 39import android.view.ViewDebug; 40import android.view.ViewGroup; 41import android.view.ViewParent; 42import android.view.ViewRootImpl; 43import android.view.accessibility.AccessibilityEvent; 44import android.view.accessibility.AccessibilityNodeInfo; 45import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 46import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 47import android.widget.RemoteViews.RemoteView; 48 49import java.util.ArrayList; 50 51/* 52 * Implementation Notes: 53 * 54 * Some terminology: 55 * 56 * index - index of the items that are currently visible 57 * position - index of the items in the cursor 58 */ 59 60 61/** 62 * A view that shows items in a vertically scrolling list. The items 63 * come from the {@link ListAdapter} associated with this view. 64 * 65 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 66 * guide.</p> 67 * 68 * @attr ref android.R.styleable#ListView_entries 69 * @attr ref android.R.styleable#ListView_divider 70 * @attr ref android.R.styleable#ListView_dividerHeight 71 * @attr ref android.R.styleable#ListView_headerDividersEnabled 72 * @attr ref android.R.styleable#ListView_footerDividersEnabled 73 */ 74@RemoteView 75public class ListView extends AbsListView { 76 /** 77 * Used to indicate a no preference for a position type. 78 */ 79 static final int NO_POSITION = -1; 80 81 /** 82 * When arrow scrolling, ListView will never scroll more than this factor 83 * times the height of the list. 84 */ 85 private static final float MAX_SCROLL_FACTOR = 0.33f; 86 87 /** 88 * When arrow scrolling, need a certain amount of pixels to preview next 89 * items. This is usually the fading edge, but if that is small enough, 90 * we want to make sure we preview at least this many pixels. 91 */ 92 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 93 94 /** 95 * A class that represents a fixed view in a list, for example a header at the top 96 * or a footer at the bottom. 97 */ 98 public class FixedViewInfo { 99 /** The view to add to the list */ 100 public View view; 101 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 102 public Object data; 103 /** <code>true</code> if the fixed view should be selectable in the list */ 104 public boolean isSelectable; 105 } 106 107 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 108 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 109 110 Drawable mDivider; 111 int mDividerHeight; 112 113 Drawable mOverScrollHeader; 114 Drawable mOverScrollFooter; 115 116 private boolean mIsCacheColorOpaque; 117 private boolean mDividerIsOpaque; 118 119 private boolean mHeaderDividersEnabled; 120 private boolean mFooterDividersEnabled; 121 122 private boolean mAreAllItemsSelectable = true; 123 124 private boolean mItemsCanFocus = false; 125 126 // used for temporary calculations. 127 private final Rect mTempRect = new Rect(); 128 private Paint mDividerPaint; 129 130 // the single allocated result per list view; kinda cheesey but avoids 131 // allocating these thingies too often. 132 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 133 134 // Keeps focused children visible through resizes 135 private FocusSelector mFocusSelector; 136 137 public ListView(Context context) { 138 this(context, null); 139 } 140 141 public ListView(Context context, AttributeSet attrs) { 142 this(context, attrs, com.android.internal.R.attr.listViewStyle); 143 } 144 145 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 146 this(context, attrs, defStyleAttr, 0); 147 } 148 149 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 150 super(context, attrs, defStyleAttr, defStyleRes); 151 152 final TypedArray a = context.obtainStyledAttributes( 153 attrs, com.android.internal.R.styleable.ListView, defStyleAttr, defStyleRes); 154 155 CharSequence[] entries = a.getTextArray( 156 com.android.internal.R.styleable.ListView_entries); 157 if (entries != null) { 158 setAdapter(new ArrayAdapter<CharSequence>(context, 159 com.android.internal.R.layout.simple_list_item_1, entries)); 160 } 161 162 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 163 if (d != null) { 164 // If a divider is specified use its intrinsic height for divider height 165 setDivider(d); 166 } 167 168 final Drawable osHeader = a.getDrawable( 169 com.android.internal.R.styleable.ListView_overScrollHeader); 170 if (osHeader != null) { 171 setOverscrollHeader(osHeader); 172 } 173 174 final Drawable osFooter = a.getDrawable( 175 com.android.internal.R.styleable.ListView_overScrollFooter); 176 if (osFooter != null) { 177 setOverscrollFooter(osFooter); 178 } 179 180 // Use the height specified, zero being the default 181 final int dividerHeight = a.getDimensionPixelSize( 182 com.android.internal.R.styleable.ListView_dividerHeight, 0); 183 if (dividerHeight != 0) { 184 setDividerHeight(dividerHeight); 185 } 186 187 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 188 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 189 190 a.recycle(); 191 } 192 193 /** 194 * @return The maximum amount a list view will scroll in response to 195 * an arrow event. 196 */ 197 public int getMaxScrollAmount() { 198 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 199 } 200 201 /** 202 * Make sure views are touching the top or bottom edge, as appropriate for 203 * our gravity 204 */ 205 private void adjustViewsUpOrDown() { 206 final int childCount = getChildCount(); 207 int delta; 208 209 if (childCount > 0) { 210 View child; 211 212 if (!mStackFromBottom) { 213 // Uh-oh -- we came up short. Slide all views up to make them 214 // align with the top 215 child = getChildAt(0); 216 delta = child.getTop() - mListPadding.top; 217 if (mFirstPosition != 0) { 218 // It's OK to have some space above the first item if it is 219 // part of the vertical spacing 220 delta -= mDividerHeight; 221 } 222 if (delta < 0) { 223 // We only are looking to see if we are too low, not too high 224 delta = 0; 225 } 226 } else { 227 // we are too high, slide all views down to align with bottom 228 child = getChildAt(childCount - 1); 229 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 230 231 if (mFirstPosition + childCount < mItemCount) { 232 // It's OK to have some space below the last item if it is 233 // part of the vertical spacing 234 delta += mDividerHeight; 235 } 236 237 if (delta > 0) { 238 delta = 0; 239 } 240 } 241 242 if (delta != 0) { 243 offsetChildrenTopAndBottom(-delta); 244 } 245 } 246 } 247 248 /** 249 * Add a fixed view to appear at the top of the list. If this method is 250 * called more than once, the views will appear in the order they were 251 * added. Views added using this call can take focus if they want. 252 * <p> 253 * Note: When first introduced, this method could only be called before 254 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 255 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 256 * called at any time. If the ListView's adapter does not extend 257 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 258 * instance of {@link WrapperListAdapter}. 259 * 260 * @param v The view to add. 261 * @param data Data to associate with this view 262 * @param isSelectable whether the item is selectable 263 */ 264 public void addHeaderView(View v, Object data, boolean isSelectable) { 265 final FixedViewInfo info = new FixedViewInfo(); 266 info.view = v; 267 info.data = data; 268 info.isSelectable = isSelectable; 269 mHeaderViewInfos.add(info); 270 mAreAllItemsSelectable &= isSelectable; 271 272 // Wrap the adapter if it wasn't already wrapped. 273 if (mAdapter != null) { 274 if (!(mAdapter instanceof HeaderViewListAdapter)) { 275 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 276 } 277 278 // In the case of re-adding a header view, or adding one later on, 279 // we need to notify the observer. 280 if (mDataSetObserver != null) { 281 mDataSetObserver.onChanged(); 282 } 283 } 284 } 285 286 /** 287 * Add a fixed view to appear at the top of the list. If addHeaderView is 288 * called more than once, the views will appear in the order they were 289 * added. Views added using this call can take focus if they want. 290 * <p> 291 * Note: When first introduced, this method could only be called before 292 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 293 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 294 * called at any time. If the ListView's adapter does not extend 295 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 296 * instance of {@link WrapperListAdapter}. 297 * 298 * @param v The view to add. 299 */ 300 public void addHeaderView(View v) { 301 addHeaderView(v, null, true); 302 } 303 304 @Override 305 public int getHeaderViewsCount() { 306 return mHeaderViewInfos.size(); 307 } 308 309 /** 310 * Removes a previously-added header view. 311 * 312 * @param v The view to remove 313 * @return true if the view was removed, false if the view was not a header 314 * view 315 */ 316 public boolean removeHeaderView(View v) { 317 if (mHeaderViewInfos.size() > 0) { 318 boolean result = false; 319 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 320 if (mDataSetObserver != null) { 321 mDataSetObserver.onChanged(); 322 } 323 result = true; 324 } 325 removeFixedViewInfo(v, mHeaderViewInfos); 326 return result; 327 } 328 return false; 329 } 330 331 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 332 int len = where.size(); 333 for (int i = 0; i < len; ++i) { 334 FixedViewInfo info = where.get(i); 335 if (info.view == v) { 336 where.remove(i); 337 break; 338 } 339 } 340 } 341 342 /** 343 * Add a fixed view to appear at the bottom of the list. If addFooterView is 344 * called more than once, the views will appear in the order they were 345 * added. Views added using this call can take focus if they want. 346 * <p> 347 * Note: When first introduced, this method could only be called before 348 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 349 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 350 * called at any time. If the ListView's adapter does not extend 351 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 352 * instance of {@link WrapperListAdapter}. 353 * 354 * @param v The view to add. 355 * @param data Data to associate with this view 356 * @param isSelectable true if the footer view can be selected 357 */ 358 public void addFooterView(View v, Object data, boolean isSelectable) { 359 final FixedViewInfo info = new FixedViewInfo(); 360 info.view = v; 361 info.data = data; 362 info.isSelectable = isSelectable; 363 mFooterViewInfos.add(info); 364 mAreAllItemsSelectable &= isSelectable; 365 366 // Wrap the adapter if it wasn't already wrapped. 367 if (mAdapter != null) { 368 if (!(mAdapter instanceof HeaderViewListAdapter)) { 369 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 370 } 371 372 // In the case of re-adding a footer view, or adding one later on, 373 // we need to notify the observer. 374 if (mDataSetObserver != null) { 375 mDataSetObserver.onChanged(); 376 } 377 } 378 } 379 380 /** 381 * Add a fixed view to appear at the bottom of the list. If addFooterView is 382 * called more than once, the views will appear in the order they were 383 * added. Views added using this call can take focus if they want. 384 * <p> 385 * Note: When first introduced, this method could only be called before 386 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 387 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 388 * called at any time. If the ListView's adapter does not extend 389 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 390 * instance of {@link WrapperListAdapter}. 391 * 392 * @param v The view to add. 393 */ 394 public void addFooterView(View v) { 395 addFooterView(v, null, true); 396 } 397 398 @Override 399 public int getFooterViewsCount() { 400 return mFooterViewInfos.size(); 401 } 402 403 /** 404 * Removes a previously-added footer view. 405 * 406 * @param v The view to remove 407 * @return 408 * true if the view was removed, false if the view was not a footer view 409 */ 410 public boolean removeFooterView(View v) { 411 if (mFooterViewInfos.size() > 0) { 412 boolean result = false; 413 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 414 if (mDataSetObserver != null) { 415 mDataSetObserver.onChanged(); 416 } 417 result = true; 418 } 419 removeFixedViewInfo(v, mFooterViewInfos); 420 return result; 421 } 422 return false; 423 } 424 425 /** 426 * Returns the adapter currently in use in this ListView. The returned adapter 427 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 428 * might be a {@link WrapperListAdapter}. 429 * 430 * @return The adapter currently used to display data in this ListView. 431 * 432 * @see #setAdapter(ListAdapter) 433 */ 434 @Override 435 public ListAdapter getAdapter() { 436 return mAdapter; 437 } 438 439 /** 440 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 441 * through the specified intent. 442 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 443 */ 444 @android.view.RemotableViewMethod 445 public void setRemoteViewsAdapter(Intent intent) { 446 super.setRemoteViewsAdapter(intent); 447 } 448 449 /** 450 * Sets the data behind this ListView. 451 * 452 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 453 * depending on the ListView features currently in use. For instance, adding 454 * headers and/or footers will cause the adapter to be wrapped. 455 * 456 * @param adapter The ListAdapter which is responsible for maintaining the 457 * data backing this list and for producing a view to represent an 458 * item in that data set. 459 * 460 * @see #getAdapter() 461 */ 462 @Override 463 public void setAdapter(ListAdapter adapter) { 464 if (mAdapter != null && mDataSetObserver != null) { 465 mAdapter.unregisterDataSetObserver(mDataSetObserver); 466 } 467 468 resetList(); 469 mRecycler.clear(); 470 471 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 472 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 473 } else { 474 mAdapter = adapter; 475 } 476 477 mOldSelectedPosition = INVALID_POSITION; 478 mOldSelectedRowId = INVALID_ROW_ID; 479 480 // AbsListView#setAdapter will update choice mode states. 481 super.setAdapter(adapter); 482 483 if (mAdapter != null) { 484 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 485 mOldItemCount = mItemCount; 486 mItemCount = mAdapter.getCount(); 487 checkFocus(); 488 489 mDataSetObserver = new AdapterDataSetObserver(); 490 mAdapter.registerDataSetObserver(mDataSetObserver); 491 492 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 493 494 int position; 495 if (mStackFromBottom) { 496 position = lookForSelectablePosition(mItemCount - 1, false); 497 } else { 498 position = lookForSelectablePosition(0, true); 499 } 500 setSelectedPositionInt(position); 501 setNextSelectedPositionInt(position); 502 503 if (mItemCount == 0) { 504 // Nothing selected 505 checkSelectionChanged(); 506 } 507 } else { 508 mAreAllItemsSelectable = true; 509 checkFocus(); 510 // Nothing selected 511 checkSelectionChanged(); 512 } 513 514 requestLayout(); 515 } 516 517 /** 518 * The list is empty. Clear everything out. 519 */ 520 @Override 521 void resetList() { 522 // The parent's resetList() will remove all views from the layout so we need to 523 // cleanup the state of our footers and headers 524 clearRecycledState(mHeaderViewInfos); 525 clearRecycledState(mFooterViewInfos); 526 527 super.resetList(); 528 529 mLayoutMode = LAYOUT_NORMAL; 530 } 531 532 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 533 if (infos != null) { 534 final int count = infos.size(); 535 536 for (int i = 0; i < count; i++) { 537 final View child = infos.get(i).view; 538 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 539 if (p != null) { 540 p.recycledHeaderFooter = false; 541 } 542 } 543 } 544 } 545 546 /** 547 * @return Whether the list needs to show the top fading edge 548 */ 549 private boolean showingTopFadingEdge() { 550 final int listTop = mScrollY + mListPadding.top; 551 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 552 } 553 554 /** 555 * @return Whether the list needs to show the bottom fading edge 556 */ 557 private boolean showingBottomFadingEdge() { 558 final int childCount = getChildCount(); 559 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 560 final int lastVisiblePosition = mFirstPosition + childCount - 1; 561 562 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 563 564 return (lastVisiblePosition < mItemCount - 1) 565 || (bottomOfBottomChild < listBottom); 566 } 567 568 569 @Override 570 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 571 572 int rectTopWithinChild = rect.top; 573 574 // offset so rect is in coordinates of the this view 575 rect.offset(child.getLeft(), child.getTop()); 576 rect.offset(-child.getScrollX(), -child.getScrollY()); 577 578 final int height = getHeight(); 579 int listUnfadedTop = getScrollY(); 580 int listUnfadedBottom = listUnfadedTop + height; 581 final int fadingEdge = getVerticalFadingEdgeLength(); 582 583 if (showingTopFadingEdge()) { 584 // leave room for top fading edge as long as rect isn't at very top 585 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 586 listUnfadedTop += fadingEdge; 587 } 588 } 589 590 int childCount = getChildCount(); 591 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 592 593 if (showingBottomFadingEdge()) { 594 // leave room for bottom fading edge as long as rect isn't at very bottom 595 if ((mSelectedPosition < mItemCount - 1) 596 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 597 listUnfadedBottom -= fadingEdge; 598 } 599 } 600 601 int scrollYDelta = 0; 602 603 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 604 // need to MOVE DOWN to get it in view: move down just enough so 605 // that the entire rectangle is in view (or at least the first 606 // screen size chunk). 607 608 if (rect.height() > height) { 609 // just enough to get screen size chunk on 610 scrollYDelta += (rect.top - listUnfadedTop); 611 } else { 612 // get entire rect at bottom of screen 613 scrollYDelta += (rect.bottom - listUnfadedBottom); 614 } 615 616 // make sure we aren't scrolling beyond the end of our children 617 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 618 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 619 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 620 // need to MOVE UP to get it in view: move up just enough so that 621 // entire rectangle is in view (or at least the first screen 622 // size chunk of it). 623 624 if (rect.height() > height) { 625 // screen size chunk 626 scrollYDelta -= (listUnfadedBottom - rect.bottom); 627 } else { 628 // entire rect at top 629 scrollYDelta -= (listUnfadedTop - rect.top); 630 } 631 632 // make sure we aren't scrolling any further than the top our children 633 int top = getChildAt(0).getTop(); 634 int deltaToTop = top - listUnfadedTop; 635 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 636 } 637 638 final boolean scroll = scrollYDelta != 0; 639 if (scroll) { 640 scrollListItemsBy(-scrollYDelta); 641 positionSelector(INVALID_POSITION, child); 642 mSelectedTop = child.getTop(); 643 invalidate(); 644 } 645 return scroll; 646 } 647 648 /** 649 * {@inheritDoc} 650 */ 651 @Override 652 void fillGap(boolean down) { 653 final int count = getChildCount(); 654 if (down) { 655 int paddingTop = 0; 656 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 657 paddingTop = getListPaddingTop(); 658 } 659 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 660 paddingTop; 661 fillDown(mFirstPosition + count, startOffset); 662 correctTooHigh(getChildCount()); 663 } else { 664 int paddingBottom = 0; 665 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 666 paddingBottom = getListPaddingBottom(); 667 } 668 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 669 getHeight() - paddingBottom; 670 fillUp(mFirstPosition - 1, startOffset); 671 correctTooLow(getChildCount()); 672 } 673 } 674 675 /** 676 * Fills the list from pos down to the end of the list view. 677 * 678 * @param pos The first position to put in the list 679 * 680 * @param nextTop The location where the top of the item associated with pos 681 * should be drawn 682 * 683 * @return The view that is currently selected, if it happens to be in the 684 * range that we draw. 685 */ 686 private View fillDown(int pos, int nextTop) { 687 View selectedView = null; 688 689 int end = (mBottom - mTop); 690 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 691 end -= mListPadding.bottom; 692 } 693 694 while (nextTop < end && pos < mItemCount) { 695 // is this the selected item? 696 boolean selected = pos == mSelectedPosition; 697 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 698 699 nextTop = child.getBottom() + mDividerHeight; 700 if (selected) { 701 selectedView = child; 702 } 703 pos++; 704 } 705 706 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 707 return selectedView; 708 } 709 710 /** 711 * Fills the list from pos up to the top of the list view. 712 * 713 * @param pos The first position to put in the list 714 * 715 * @param nextBottom The location where the bottom of the item associated 716 * with pos should be drawn 717 * 718 * @return The view that is currently selected 719 */ 720 private View fillUp(int pos, int nextBottom) { 721 View selectedView = null; 722 723 int end = 0; 724 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 725 end = mListPadding.top; 726 } 727 728 while (nextBottom > end && pos >= 0) { 729 // is this the selected item? 730 boolean selected = pos == mSelectedPosition; 731 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 732 nextBottom = child.getTop() - mDividerHeight; 733 if (selected) { 734 selectedView = child; 735 } 736 pos--; 737 } 738 739 mFirstPosition = pos + 1; 740 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 741 return selectedView; 742 } 743 744 /** 745 * Fills the list from top to bottom, starting with mFirstPosition 746 * 747 * @param nextTop The location where the top of the first item should be 748 * drawn 749 * 750 * @return The view that is currently selected 751 */ 752 private View fillFromTop(int nextTop) { 753 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 754 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 755 if (mFirstPosition < 0) { 756 mFirstPosition = 0; 757 } 758 return fillDown(mFirstPosition, nextTop); 759 } 760 761 762 /** 763 * Put mSelectedPosition in the middle of the screen and then build up and 764 * down from there. This method forces mSelectedPosition to the center. 765 * 766 * @param childrenTop Top of the area in which children can be drawn, as 767 * measured in pixels 768 * @param childrenBottom Bottom of the area in which children can be drawn, 769 * as measured in pixels 770 * @return Currently selected view 771 */ 772 private View fillFromMiddle(int childrenTop, int childrenBottom) { 773 int height = childrenBottom - childrenTop; 774 775 int position = reconcileSelectedPosition(); 776 777 View sel = makeAndAddView(position, childrenTop, true, 778 mListPadding.left, true); 779 mFirstPosition = position; 780 781 int selHeight = sel.getMeasuredHeight(); 782 if (selHeight <= height) { 783 sel.offsetTopAndBottom((height - selHeight) / 2); 784 } 785 786 fillAboveAndBelow(sel, position); 787 788 if (!mStackFromBottom) { 789 correctTooHigh(getChildCount()); 790 } else { 791 correctTooLow(getChildCount()); 792 } 793 794 return sel; 795 } 796 797 /** 798 * Once the selected view as been placed, fill up the visible area above and 799 * below it. 800 * 801 * @param sel The selected view 802 * @param position The position corresponding to sel 803 */ 804 private void fillAboveAndBelow(View sel, int position) { 805 final int dividerHeight = mDividerHeight; 806 if (!mStackFromBottom) { 807 fillUp(position - 1, sel.getTop() - dividerHeight); 808 adjustViewsUpOrDown(); 809 fillDown(position + 1, sel.getBottom() + dividerHeight); 810 } else { 811 fillDown(position + 1, sel.getBottom() + dividerHeight); 812 adjustViewsUpOrDown(); 813 fillUp(position - 1, sel.getTop() - dividerHeight); 814 } 815 } 816 817 818 /** 819 * Fills the grid based on positioning the new selection at a specific 820 * location. The selection may be moved so that it does not intersect the 821 * faded edges. The grid is then filled upwards and downwards from there. 822 * 823 * @param selectedTop Where the selected item should be 824 * @param childrenTop Where to start drawing children 825 * @param childrenBottom Last pixel where children can be drawn 826 * @return The view that currently has selection 827 */ 828 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 829 int fadingEdgeLength = getVerticalFadingEdgeLength(); 830 final int selectedPosition = mSelectedPosition; 831 832 View sel; 833 834 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 835 selectedPosition); 836 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 837 selectedPosition); 838 839 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 840 841 842 // Some of the newly selected item extends below the bottom of the list 843 if (sel.getBottom() > bottomSelectionPixel) { 844 // Find space available above the selection into which we can scroll 845 // upwards 846 final int spaceAbove = sel.getTop() - topSelectionPixel; 847 848 // Find space required to bring the bottom of the selected item 849 // fully into view 850 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 851 final int offset = Math.min(spaceAbove, spaceBelow); 852 853 // Now offset the selected item to get it into view 854 sel.offsetTopAndBottom(-offset); 855 } else if (sel.getTop() < topSelectionPixel) { 856 // Find space required to bring the top of the selected item fully 857 // into view 858 final int spaceAbove = topSelectionPixel - sel.getTop(); 859 860 // Find space available below the selection into which we can scroll 861 // downwards 862 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 863 final int offset = Math.min(spaceAbove, spaceBelow); 864 865 // Offset the selected item to get it into view 866 sel.offsetTopAndBottom(offset); 867 } 868 869 // Fill in views above and below 870 fillAboveAndBelow(sel, selectedPosition); 871 872 if (!mStackFromBottom) { 873 correctTooHigh(getChildCount()); 874 } else { 875 correctTooLow(getChildCount()); 876 } 877 878 return sel; 879 } 880 881 /** 882 * Calculate the bottom-most pixel we can draw the selection into 883 * 884 * @param childrenBottom Bottom pixel were children can be drawn 885 * @param fadingEdgeLength Length of the fading edge in pixels, if present 886 * @param selectedPosition The position that will be selected 887 * @return The bottom-most pixel we can draw the selection into 888 */ 889 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 890 int selectedPosition) { 891 int bottomSelectionPixel = childrenBottom; 892 if (selectedPosition != mItemCount - 1) { 893 bottomSelectionPixel -= fadingEdgeLength; 894 } 895 return bottomSelectionPixel; 896 } 897 898 /** 899 * Calculate the top-most pixel we can draw the selection into 900 * 901 * @param childrenTop Top pixel were children can be drawn 902 * @param fadingEdgeLength Length of the fading edge in pixels, if present 903 * @param selectedPosition The position that will be selected 904 * @return The top-most pixel we can draw the selection into 905 */ 906 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 907 // first pixel we can draw the selection into 908 int topSelectionPixel = childrenTop; 909 if (selectedPosition > 0) { 910 topSelectionPixel += fadingEdgeLength; 911 } 912 return topSelectionPixel; 913 } 914 915 /** 916 * Smoothly scroll to the specified adapter position. The view will 917 * scroll such that the indicated position is displayed. 918 * @param position Scroll to this adapter position. 919 */ 920 @android.view.RemotableViewMethod 921 public void smoothScrollToPosition(int position) { 922 super.smoothScrollToPosition(position); 923 } 924 925 /** 926 * Smoothly scroll to the specified adapter position offset. The view will 927 * scroll such that the indicated position is displayed. 928 * @param offset The amount to offset from the adapter position to scroll to. 929 */ 930 @android.view.RemotableViewMethod 931 public void smoothScrollByOffset(int offset) { 932 super.smoothScrollByOffset(offset); 933 } 934 935 /** 936 * Fills the list based on positioning the new selection relative to the old 937 * selection. The new selection will be placed at, above, or below the 938 * location of the new selection depending on how the selection is moving. 939 * The selection will then be pinned to the visible part of the screen, 940 * excluding the edges that are faded. The list is then filled upwards and 941 * downwards from there. 942 * 943 * @param oldSel The old selected view. Useful for trying to put the new 944 * selection in the same place 945 * @param newSel The view that is to become selected. Useful for trying to 946 * put the new selection in the same place 947 * @param delta Which way we are moving 948 * @param childrenTop Where to start drawing children 949 * @param childrenBottom Last pixel where children can be drawn 950 * @return The view that currently has selection 951 */ 952 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 953 int childrenBottom) { 954 int fadingEdgeLength = getVerticalFadingEdgeLength(); 955 final int selectedPosition = mSelectedPosition; 956 957 View sel; 958 959 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 960 selectedPosition); 961 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 962 selectedPosition); 963 964 if (delta > 0) { 965 /* 966 * Case 1: Scrolling down. 967 */ 968 969 /* 970 * Before After 971 * | | | | 972 * +-------+ +-------+ 973 * | A | | A | 974 * | 1 | => +-------+ 975 * +-------+ | B | 976 * | B | | 2 | 977 * +-------+ +-------+ 978 * | | | | 979 * 980 * Try to keep the top of the previously selected item where it was. 981 * oldSel = A 982 * sel = B 983 */ 984 985 // Put oldSel (A) where it belongs 986 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 987 mListPadding.left, false); 988 989 final int dividerHeight = mDividerHeight; 990 991 // Now put the new selection (B) below that 992 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 993 mListPadding.left, true); 994 995 // Some of the newly selected item extends below the bottom of the list 996 if (sel.getBottom() > bottomSelectionPixel) { 997 998 // Find space available above the selection into which we can scroll upwards 999 int spaceAbove = sel.getTop() - topSelectionPixel; 1000 1001 // Find space required to bring the bottom of the selected item fully into view 1002 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1003 1004 // Don't scroll more than half the height of the list 1005 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1006 int offset = Math.min(spaceAbove, spaceBelow); 1007 offset = Math.min(offset, halfVerticalSpace); 1008 1009 // We placed oldSel, so offset that item 1010 oldSel.offsetTopAndBottom(-offset); 1011 // Now offset the selected item to get it into view 1012 sel.offsetTopAndBottom(-offset); 1013 } 1014 1015 // Fill in views above and below 1016 if (!mStackFromBottom) { 1017 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1018 adjustViewsUpOrDown(); 1019 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1020 } else { 1021 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1022 adjustViewsUpOrDown(); 1023 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1024 } 1025 } else if (delta < 0) { 1026 /* 1027 * Case 2: Scrolling up. 1028 */ 1029 1030 /* 1031 * Before After 1032 * | | | | 1033 * +-------+ +-------+ 1034 * | A | | A | 1035 * +-------+ => | 1 | 1036 * | B | +-------+ 1037 * | 2 | | B | 1038 * +-------+ +-------+ 1039 * | | | | 1040 * 1041 * Try to keep the top of the item about to become selected where it was. 1042 * newSel = A 1043 * olSel = B 1044 */ 1045 1046 if (newSel != null) { 1047 // Try to position the top of newSel (A) where it was before it was selected 1048 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1049 true); 1050 } else { 1051 // If (A) was not on screen and so did not have a view, position 1052 // it above the oldSel (B) 1053 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1054 true); 1055 } 1056 1057 // Some of the newly selected item extends above the top of the list 1058 if (sel.getTop() < topSelectionPixel) { 1059 // Find space required to bring the top of the selected item fully into view 1060 int spaceAbove = topSelectionPixel - sel.getTop(); 1061 1062 // Find space available below the selection into which we can scroll downwards 1063 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1064 1065 // Don't scroll more than half the height of the list 1066 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1067 int offset = Math.min(spaceAbove, spaceBelow); 1068 offset = Math.min(offset, halfVerticalSpace); 1069 1070 // Offset the selected item to get it into view 1071 sel.offsetTopAndBottom(offset); 1072 } 1073 1074 // Fill in views above and below 1075 fillAboveAndBelow(sel, selectedPosition); 1076 } else { 1077 1078 int oldTop = oldSel.getTop(); 1079 1080 /* 1081 * Case 3: Staying still 1082 */ 1083 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1084 1085 // We're staying still... 1086 if (oldTop < childrenTop) { 1087 // ... but the top of the old selection was off screen. 1088 // (This can happen if the data changes size out from under us) 1089 int newBottom = sel.getBottom(); 1090 if (newBottom < childrenTop + 20) { 1091 // Not enough visible -- bring it onscreen 1092 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1093 } 1094 } 1095 1096 // Fill in views above and below 1097 fillAboveAndBelow(sel, selectedPosition); 1098 } 1099 1100 return sel; 1101 } 1102 1103 private class FocusSelector implements Runnable { 1104 private int mPosition; 1105 private int mPositionTop; 1106 1107 public FocusSelector setup(int position, int top) { 1108 mPosition = position; 1109 mPositionTop = top; 1110 return this; 1111 } 1112 1113 public void run() { 1114 setSelectionFromTop(mPosition, mPositionTop); 1115 } 1116 } 1117 1118 @Override 1119 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1120 if (getChildCount() > 0) { 1121 View focusedChild = getFocusedChild(); 1122 if (focusedChild != null) { 1123 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1124 final int childBottom = focusedChild.getBottom(); 1125 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1126 final int top = focusedChild.getTop() - offset; 1127 if (mFocusSelector == null) { 1128 mFocusSelector = new FocusSelector(); 1129 } 1130 post(mFocusSelector.setup(childPosition, top)); 1131 } 1132 } 1133 super.onSizeChanged(w, h, oldw, oldh); 1134 } 1135 1136 @Override 1137 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1138 // Sets up mListPadding 1139 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1140 1141 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1142 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1143 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1144 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1145 1146 int childWidth = 0; 1147 int childHeight = 0; 1148 int childState = 0; 1149 1150 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1151 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1152 heightMode == MeasureSpec.UNSPECIFIED)) { 1153 final View child = obtainView(0, mIsScrap); 1154 1155 measureScrapChild(child, 0, widthMeasureSpec); 1156 1157 childWidth = child.getMeasuredWidth(); 1158 childHeight = child.getMeasuredHeight(); 1159 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1160 1161 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1162 ((LayoutParams) child.getLayoutParams()).viewType)) { 1163 mRecycler.addScrapView(child, -1); 1164 } 1165 } 1166 1167 if (widthMode == MeasureSpec.UNSPECIFIED) { 1168 widthSize = mListPadding.left + mListPadding.right + childWidth + 1169 getVerticalScrollbarWidth(); 1170 } else { 1171 widthSize |= (childState&MEASURED_STATE_MASK); 1172 } 1173 1174 if (heightMode == MeasureSpec.UNSPECIFIED) { 1175 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1176 getVerticalFadingEdgeLength() * 2; 1177 } 1178 1179 if (heightMode == MeasureSpec.AT_MOST) { 1180 // TODO: after first layout we should maybe start at the first visible position, not 0 1181 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1182 } 1183 1184 setMeasuredDimension(widthSize , heightSize); 1185 mWidthMeasureSpec = widthMeasureSpec; 1186 } 1187 1188 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1189 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1190 if (p == null) { 1191 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1192 child.setLayoutParams(p); 1193 } 1194 p.viewType = mAdapter.getItemViewType(position); 1195 p.forceAdd = true; 1196 1197 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1198 mListPadding.left + mListPadding.right, p.width); 1199 int lpHeight = p.height; 1200 int childHeightSpec; 1201 if (lpHeight > 0) { 1202 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1203 } else { 1204 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1205 } 1206 child.measure(childWidthSpec, childHeightSpec); 1207 } 1208 1209 /** 1210 * @return True to recycle the views used to measure this ListView in 1211 * UNSPECIFIED/AT_MOST modes, false otherwise. 1212 * @hide 1213 */ 1214 @ViewDebug.ExportedProperty(category = "list") 1215 protected boolean recycleOnMeasure() { 1216 return true; 1217 } 1218 1219 /** 1220 * Measures the height of the given range of children (inclusive) and 1221 * returns the height with this ListView's padding and divider heights 1222 * included. If maxHeight is provided, the measuring will stop when the 1223 * current height reaches maxHeight. 1224 * 1225 * @param widthMeasureSpec The width measure spec to be given to a child's 1226 * {@link View#measure(int, int)}. 1227 * @param startPosition The position of the first child to be shown. 1228 * @param endPosition The (inclusive) position of the last child to be 1229 * shown. Specify {@link #NO_POSITION} if the last child should be 1230 * the last available child from the adapter. 1231 * @param maxHeight The maximum height that will be returned (if all the 1232 * children don't fit in this value, this value will be 1233 * returned). 1234 * @param disallowPartialChildPosition In general, whether the returned 1235 * height should only contain entire children. This is more 1236 * powerful--it is the first inclusive position at which partial 1237 * children will not be allowed. Example: it looks nice to have 1238 * at least 3 completely visible children, and in portrait this 1239 * will most likely fit; but in landscape there could be times 1240 * when even 2 children can not be completely shown, so a value 1241 * of 2 (remember, inclusive) would be good (assuming 1242 * startPosition is 0). 1243 * @return The height of this ListView with the given children. 1244 */ 1245 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1246 final int maxHeight, int disallowPartialChildPosition) { 1247 1248 final ListAdapter adapter = mAdapter; 1249 if (adapter == null) { 1250 return mListPadding.top + mListPadding.bottom; 1251 } 1252 1253 // Include the padding of the list 1254 int returnedHeight = mListPadding.top + mListPadding.bottom; 1255 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1256 // The previous height value that was less than maxHeight and contained 1257 // no partial children 1258 int prevHeightWithoutPartialChild = 0; 1259 int i; 1260 View child; 1261 1262 // mItemCount - 1 since endPosition parameter is inclusive 1263 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1264 final AbsListView.RecycleBin recycleBin = mRecycler; 1265 final boolean recyle = recycleOnMeasure(); 1266 final boolean[] isScrap = mIsScrap; 1267 1268 for (i = startPosition; i <= endPosition; ++i) { 1269 child = obtainView(i, isScrap); 1270 1271 measureScrapChild(child, i, widthMeasureSpec); 1272 1273 if (i > 0) { 1274 // Count the divider for all but one child 1275 returnedHeight += dividerHeight; 1276 } 1277 1278 // Recycle the view before we possibly return from the method 1279 if (recyle && recycleBin.shouldRecycleViewType( 1280 ((LayoutParams) child.getLayoutParams()).viewType)) { 1281 recycleBin.addScrapView(child, -1); 1282 } 1283 1284 returnedHeight += child.getMeasuredHeight(); 1285 1286 if (returnedHeight >= maxHeight) { 1287 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1288 // then the i'th position did not fit completely. 1289 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1290 && (i > disallowPartialChildPosition) // We've past the min pos 1291 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1292 && (returnedHeight != maxHeight) // i'th child did not fit completely 1293 ? prevHeightWithoutPartialChild 1294 : maxHeight; 1295 } 1296 1297 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1298 prevHeightWithoutPartialChild = returnedHeight; 1299 } 1300 } 1301 1302 // At this point, we went through the range of children, and they each 1303 // completely fit, so return the returnedHeight 1304 return returnedHeight; 1305 } 1306 1307 @Override 1308 int findMotionRow(int y) { 1309 int childCount = getChildCount(); 1310 if (childCount > 0) { 1311 if (!mStackFromBottom) { 1312 for (int i = 0; i < childCount; i++) { 1313 View v = getChildAt(i); 1314 if (y <= v.getBottom()) { 1315 return mFirstPosition + i; 1316 } 1317 } 1318 } else { 1319 for (int i = childCount - 1; i >= 0; i--) { 1320 View v = getChildAt(i); 1321 if (y >= v.getTop()) { 1322 return mFirstPosition + i; 1323 } 1324 } 1325 } 1326 } 1327 return INVALID_POSITION; 1328 } 1329 1330 /** 1331 * Put a specific item at a specific location on the screen and then build 1332 * up and down from there. 1333 * 1334 * @param position The reference view to use as the starting point 1335 * @param top Pixel offset from the top of this view to the top of the 1336 * reference view. 1337 * 1338 * @return The selected view, or null if the selected view is outside the 1339 * visible area. 1340 */ 1341 private View fillSpecific(int position, int top) { 1342 boolean tempIsSelected = position == mSelectedPosition; 1343 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1344 // Possibly changed again in fillUp if we add rows above this one. 1345 mFirstPosition = position; 1346 1347 View above; 1348 View below; 1349 1350 final int dividerHeight = mDividerHeight; 1351 if (!mStackFromBottom) { 1352 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1353 // This will correct for the top of the first view not touching the top of the list 1354 adjustViewsUpOrDown(); 1355 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1356 int childCount = getChildCount(); 1357 if (childCount > 0) { 1358 correctTooHigh(childCount); 1359 } 1360 } else { 1361 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1362 // This will correct for the bottom of the last view not touching the bottom of the list 1363 adjustViewsUpOrDown(); 1364 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1365 int childCount = getChildCount(); 1366 if (childCount > 0) { 1367 correctTooLow(childCount); 1368 } 1369 } 1370 1371 if (tempIsSelected) { 1372 return temp; 1373 } else if (above != null) { 1374 return above; 1375 } else { 1376 return below; 1377 } 1378 } 1379 1380 /** 1381 * Check if we have dragged the bottom of the list too high (we have pushed the 1382 * top element off the top of the screen when we did not need to). Correct by sliding 1383 * everything back down. 1384 * 1385 * @param childCount Number of children 1386 */ 1387 private void correctTooHigh(int childCount) { 1388 // First see if the last item is visible. If it is not, it is OK for the 1389 // top of the list to be pushed up. 1390 int lastPosition = mFirstPosition + childCount - 1; 1391 if (lastPosition == mItemCount - 1 && childCount > 0) { 1392 1393 // Get the last child ... 1394 final View lastChild = getChildAt(childCount - 1); 1395 1396 // ... and its bottom edge 1397 final int lastBottom = lastChild.getBottom(); 1398 1399 // This is bottom of our drawable area 1400 final int end = (mBottom - mTop) - mListPadding.bottom; 1401 1402 // This is how far the bottom edge of the last view is from the bottom of the 1403 // drawable area 1404 int bottomOffset = end - lastBottom; 1405 View firstChild = getChildAt(0); 1406 final int firstTop = firstChild.getTop(); 1407 1408 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1409 // first row or the first row is scrolled off the top of the drawable area 1410 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1411 if (mFirstPosition == 0) { 1412 // Don't pull the top too far down 1413 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1414 } 1415 // Move everything down 1416 offsetChildrenTopAndBottom(bottomOffset); 1417 if (mFirstPosition > 0) { 1418 // Fill the gap that was opened above mFirstPosition with more rows, if 1419 // possible 1420 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1421 // Close up the remaining gap 1422 adjustViewsUpOrDown(); 1423 } 1424 1425 } 1426 } 1427 } 1428 1429 /** 1430 * Check if we have dragged the bottom of the list too low (we have pushed the 1431 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1432 * everything back up. 1433 * 1434 * @param childCount Number of children 1435 */ 1436 private void correctTooLow(int childCount) { 1437 // First see if the first item is visible. If it is not, it is OK for the 1438 // bottom of the list to be pushed down. 1439 if (mFirstPosition == 0 && childCount > 0) { 1440 1441 // Get the first child ... 1442 final View firstChild = getChildAt(0); 1443 1444 // ... and its top edge 1445 final int firstTop = firstChild.getTop(); 1446 1447 // This is top of our drawable area 1448 final int start = mListPadding.top; 1449 1450 // This is bottom of our drawable area 1451 final int end = (mBottom - mTop) - mListPadding.bottom; 1452 1453 // This is how far the top edge of the first view is from the top of the 1454 // drawable area 1455 int topOffset = firstTop - start; 1456 View lastChild = getChildAt(childCount - 1); 1457 final int lastBottom = lastChild.getBottom(); 1458 int lastPosition = mFirstPosition + childCount - 1; 1459 1460 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1461 // last row or the last row is scrolled off the bottom of the drawable area 1462 if (topOffset > 0) { 1463 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1464 if (lastPosition == mItemCount - 1) { 1465 // Don't pull the bottom too far up 1466 topOffset = Math.min(topOffset, lastBottom - end); 1467 } 1468 // Move everything up 1469 offsetChildrenTopAndBottom(-topOffset); 1470 if (lastPosition < mItemCount - 1) { 1471 // Fill the gap that was opened below the last position with more rows, if 1472 // possible 1473 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1474 // Close up the remaining gap 1475 adjustViewsUpOrDown(); 1476 } 1477 } else if (lastPosition == mItemCount - 1) { 1478 adjustViewsUpOrDown(); 1479 } 1480 } 1481 } 1482 } 1483 1484 @Override 1485 protected void layoutChildren() { 1486 final boolean blockLayoutRequests = mBlockLayoutRequests; 1487 if (blockLayoutRequests) { 1488 return; 1489 } 1490 1491 mBlockLayoutRequests = true; 1492 1493 try { 1494 super.layoutChildren(); 1495 1496 invalidate(); 1497 1498 if (mAdapter == null) { 1499 resetList(); 1500 invokeOnItemScrollListener(); 1501 return; 1502 } 1503 1504 final int childrenTop = mListPadding.top; 1505 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1506 final int childCount = getChildCount(); 1507 1508 int index = 0; 1509 int delta = 0; 1510 1511 View sel; 1512 View oldSel = null; 1513 View oldFirst = null; 1514 View newSel = null; 1515 1516 // Remember stuff we will need down below 1517 switch (mLayoutMode) { 1518 case LAYOUT_SET_SELECTION: 1519 index = mNextSelectedPosition - mFirstPosition; 1520 if (index >= 0 && index < childCount) { 1521 newSel = getChildAt(index); 1522 } 1523 break; 1524 case LAYOUT_FORCE_TOP: 1525 case LAYOUT_FORCE_BOTTOM: 1526 case LAYOUT_SPECIFIC: 1527 case LAYOUT_SYNC: 1528 break; 1529 case LAYOUT_MOVE_SELECTION: 1530 default: 1531 // Remember the previously selected view 1532 index = mSelectedPosition - mFirstPosition; 1533 if (index >= 0 && index < childCount) { 1534 oldSel = getChildAt(index); 1535 } 1536 1537 // Remember the previous first child 1538 oldFirst = getChildAt(0); 1539 1540 if (mNextSelectedPosition >= 0) { 1541 delta = mNextSelectedPosition - mSelectedPosition; 1542 } 1543 1544 // Caution: newSel might be null 1545 newSel = getChildAt(index + delta); 1546 } 1547 1548 1549 boolean dataChanged = mDataChanged; 1550 if (dataChanged) { 1551 handleDataChanged(); 1552 } 1553 1554 // Handle the empty set by removing all views that are visible 1555 // and calling it a day 1556 if (mItemCount == 0) { 1557 resetList(); 1558 invokeOnItemScrollListener(); 1559 return; 1560 } else if (mItemCount != mAdapter.getCount()) { 1561 throw new IllegalStateException("The content of the adapter has changed but " 1562 + "ListView did not receive a notification. Make sure the content of " 1563 + "your adapter is not modified from a background thread, but only from " 1564 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1565 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1566 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1567 } 1568 1569 setSelectedPositionInt(mNextSelectedPosition); 1570 1571 // Remember which child, if any, had accessibility focus. 1572 final int accessibilityFocusPosition; 1573 final View accessFocusedChild = getAccessibilityFocusedChild(); 1574 if (accessFocusedChild != null) { 1575 accessibilityFocusPosition = getPositionForView(accessFocusedChild); 1576 accessFocusedChild.setHasTransientState(true); 1577 } else { 1578 accessibilityFocusPosition = INVALID_POSITION; 1579 } 1580 1581 // Ensure the child containing focus, if any, has transient state. 1582 // If the list data hasn't changed, or if the adapter has stable 1583 // IDs, this will maintain focus. 1584 final View focusedChild = getFocusedChild(); 1585 if (focusedChild != null) { 1586 focusedChild.setHasTransientState(true); 1587 } 1588 1589 // Pull all children into the RecycleBin. 1590 // These views will be reused if possible 1591 final int firstPosition = mFirstPosition; 1592 final RecycleBin recycleBin = mRecycler; 1593 if (dataChanged) { 1594 for (int i = 0; i < childCount; i++) { 1595 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1596 } 1597 } else { 1598 recycleBin.fillActiveViews(childCount, firstPosition); 1599 } 1600 1601 // Clear out old views 1602 detachAllViewsFromParent(); 1603 recycleBin.removeSkippedScrap(); 1604 1605 switch (mLayoutMode) { 1606 case LAYOUT_SET_SELECTION: 1607 if (newSel != null) { 1608 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1609 } else { 1610 sel = fillFromMiddle(childrenTop, childrenBottom); 1611 } 1612 break; 1613 case LAYOUT_SYNC: 1614 sel = fillSpecific(mSyncPosition, mSpecificTop); 1615 break; 1616 case LAYOUT_FORCE_BOTTOM: 1617 sel = fillUp(mItemCount - 1, childrenBottom); 1618 adjustViewsUpOrDown(); 1619 break; 1620 case LAYOUT_FORCE_TOP: 1621 mFirstPosition = 0; 1622 sel = fillFromTop(childrenTop); 1623 adjustViewsUpOrDown(); 1624 break; 1625 case LAYOUT_SPECIFIC: 1626 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1627 break; 1628 case LAYOUT_MOVE_SELECTION: 1629 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1630 break; 1631 default: 1632 if (childCount == 0) { 1633 if (!mStackFromBottom) { 1634 final int position = lookForSelectablePosition(0, true); 1635 setSelectedPositionInt(position); 1636 sel = fillFromTop(childrenTop); 1637 } else { 1638 final int position = lookForSelectablePosition(mItemCount - 1, false); 1639 setSelectedPositionInt(position); 1640 sel = fillUp(mItemCount - 1, childrenBottom); 1641 } 1642 } else { 1643 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1644 sel = fillSpecific(mSelectedPosition, 1645 oldSel == null ? childrenTop : oldSel.getTop()); 1646 } else if (mFirstPosition < mItemCount) { 1647 sel = fillSpecific(mFirstPosition, 1648 oldFirst == null ? childrenTop : oldFirst.getTop()); 1649 } else { 1650 sel = fillSpecific(0, childrenTop); 1651 } 1652 } 1653 break; 1654 } 1655 1656 // Flush any cached views that did not get reused above 1657 recycleBin.scrapActiveViews(); 1658 1659 if (sel != null) { 1660 final boolean shouldPlaceFocus = mItemsCanFocus && hasFocus(); 1661 final boolean maintainedFocus = focusedChild != null && focusedChild.hasFocus(); 1662 if (shouldPlaceFocus && !maintainedFocus && !sel.hasFocus()) { 1663 if (sel.requestFocus()) { 1664 // Successfully placed focus, clear selection. 1665 sel.setSelected(false); 1666 mSelectorRect.setEmpty(); 1667 } else { 1668 // Failed to place focus, clear current (invalid) focus. 1669 final View focused = getFocusedChild(); 1670 if (focused != null) { 1671 focused.clearFocus(); 1672 } 1673 positionSelector(INVALID_POSITION, sel); 1674 } 1675 } else { 1676 positionSelector(INVALID_POSITION, sel); 1677 } 1678 mSelectedTop = sel.getTop(); 1679 } else { 1680 // If the user's finger is down, select the motion position. 1681 // Otherwise, clear selection. 1682 if (mTouchMode == TOUCH_MODE_TAP || mTouchMode == TOUCH_MODE_DONE_WAITING) { 1683 final View child = getChildAt(mMotionPosition - mFirstPosition); 1684 if (child != null) { 1685 positionSelector(mMotionPosition, child); 1686 } 1687 } else { 1688 mSelectedTop = 0; 1689 mSelectorRect.setEmpty(); 1690 } 1691 } 1692 1693 if (accessFocusedChild != null) { 1694 accessFocusedChild.setHasTransientState(false); 1695 1696 // If we failed to maintain accessibility focus on the previous 1697 // view, attempt to restore it to the previous position. 1698 if (!accessFocusedChild.isAccessibilityFocused() 1699 && accessibilityFocusPosition != INVALID_POSITION) { 1700 // Bound the position within the visible children. 1701 final int position = MathUtils.constrain( 1702 accessibilityFocusPosition - mFirstPosition, 0, getChildCount() - 1); 1703 final View restoreView = getChildAt(position); 1704 if (restoreView != null) { 1705 restoreView.requestAccessibilityFocus(); 1706 } 1707 } 1708 } 1709 1710 if (focusedChild != null) { 1711 focusedChild.setHasTransientState(false); 1712 } 1713 1714 mLayoutMode = LAYOUT_NORMAL; 1715 mDataChanged = false; 1716 if (mPositionScrollAfterLayout != null) { 1717 post(mPositionScrollAfterLayout); 1718 mPositionScrollAfterLayout = null; 1719 } 1720 mNeedSync = false; 1721 setNextSelectedPositionInt(mSelectedPosition); 1722 1723 updateScrollIndicators(); 1724 1725 if (mItemCount > 0) { 1726 checkSelectionChanged(); 1727 } 1728 1729 invokeOnItemScrollListener(); 1730 } finally { 1731 if (!blockLayoutRequests) { 1732 mBlockLayoutRequests = false; 1733 } 1734 } 1735 } 1736 1737 /** 1738 * Obtain the view and add it to our list of children. The view can be made 1739 * fresh, converted from an unused view, or used as is if it was in the 1740 * recycle bin. 1741 * 1742 * @param position Logical position in the list 1743 * @param y Top or bottom edge of the view to add 1744 * @param flow If flow is true, align top edge to y. If false, align bottom 1745 * edge to y. 1746 * @param childrenLeft Left edge where children should be positioned 1747 * @param selected Is this position selected? 1748 * @return View that was added 1749 */ 1750 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1751 boolean selected) { 1752 View child; 1753 1754 1755 if (!mDataChanged) { 1756 // Try to use an existing view for this position 1757 child = mRecycler.getActiveView(position); 1758 if (child != null) { 1759 // Found it -- we're using an existing child 1760 // This just needs to be positioned 1761 setupChild(child, position, y, flow, childrenLeft, selected, true); 1762 1763 return child; 1764 } 1765 } 1766 1767 // Make a new view for this position, or convert an unused view if possible 1768 child = obtainView(position, mIsScrap); 1769 1770 // This needs to be positioned and measured 1771 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1772 1773 return child; 1774 } 1775 1776 /** 1777 * Add a view as a child and make sure it is measured (if necessary) and 1778 * positioned properly. 1779 * 1780 * @param child The view to add 1781 * @param position The position of this child 1782 * @param y The y position relative to which this view will be positioned 1783 * @param flowDown If true, align top edge to y. If false, align bottom 1784 * edge to y. 1785 * @param childrenLeft Left edge where children should be positioned 1786 * @param selected Is this position selected? 1787 * @param recycled Has this view been pulled from the recycle bin? If so it 1788 * does not need to be remeasured. 1789 */ 1790 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1791 boolean selected, boolean recycled) { 1792 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1793 1794 final boolean isSelected = selected && shouldShowSelector(); 1795 final boolean updateChildSelected = isSelected != child.isSelected(); 1796 final int mode = mTouchMode; 1797 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1798 mMotionPosition == position; 1799 final boolean updateChildPressed = isPressed != child.isPressed(); 1800 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1801 1802 // Respect layout params that are already in the view. Otherwise make some up... 1803 // noinspection unchecked 1804 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1805 if (p == null) { 1806 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1807 } 1808 p.viewType = mAdapter.getItemViewType(position); 1809 1810 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1811 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1812 attachViewToParent(child, flowDown ? -1 : 0, p); 1813 } else { 1814 p.forceAdd = false; 1815 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1816 p.recycledHeaderFooter = true; 1817 } 1818 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1819 } 1820 1821 if (updateChildSelected) { 1822 child.setSelected(isSelected); 1823 } 1824 1825 if (updateChildPressed) { 1826 child.setPressed(isPressed); 1827 } 1828 1829 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1830 if (child instanceof Checkable) { 1831 ((Checkable) child).setChecked(mCheckStates.get(position)); 1832 } else if (getContext().getApplicationInfo().targetSdkVersion 1833 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1834 child.setActivated(mCheckStates.get(position)); 1835 } 1836 } 1837 1838 if (needToMeasure) { 1839 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1840 mListPadding.left + mListPadding.right, p.width); 1841 int lpHeight = p.height; 1842 int childHeightSpec; 1843 if (lpHeight > 0) { 1844 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1845 } else { 1846 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1847 } 1848 child.measure(childWidthSpec, childHeightSpec); 1849 } else { 1850 cleanupLayoutState(child); 1851 } 1852 1853 final int w = child.getMeasuredWidth(); 1854 final int h = child.getMeasuredHeight(); 1855 final int childTop = flowDown ? y : y - h; 1856 1857 if (needToMeasure) { 1858 final int childRight = childrenLeft + w; 1859 final int childBottom = childTop + h; 1860 child.layout(childrenLeft, childTop, childRight, childBottom); 1861 } else { 1862 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1863 child.offsetTopAndBottom(childTop - child.getTop()); 1864 } 1865 1866 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1867 child.setDrawingCacheEnabled(true); 1868 } 1869 1870 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1871 != position) { 1872 child.jumpDrawablesToCurrentState(); 1873 } 1874 1875 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1876 } 1877 1878 @Override 1879 protected boolean canAnimate() { 1880 return super.canAnimate() && mItemCount > 0; 1881 } 1882 1883 /** 1884 * Sets the currently selected item. If in touch mode, the item will not be selected 1885 * but it will still be positioned appropriately. If the specified selection position 1886 * is less than 0, then the item at position 0 will be selected. 1887 * 1888 * @param position Index (starting at 0) of the data item to be selected. 1889 */ 1890 @Override 1891 public void setSelection(int position) { 1892 setSelectionFromTop(position, 0); 1893 } 1894 1895 /** 1896 * Sets the selected item and positions the selection y pixels from the top edge 1897 * of the ListView. (If in touch mode, the item will not be selected but it will 1898 * still be positioned appropriately.) 1899 * 1900 * @param position Index (starting at 0) of the data item to be selected. 1901 * @param y The distance from the top edge of the ListView (plus padding) that the 1902 * item will be positioned. 1903 */ 1904 public void setSelectionFromTop(int position, int y) { 1905 if (mAdapter == null) { 1906 return; 1907 } 1908 1909 if (!isInTouchMode()) { 1910 position = lookForSelectablePosition(position, true); 1911 if (position >= 0) { 1912 setNextSelectedPositionInt(position); 1913 } 1914 } else { 1915 mResurrectToPosition = position; 1916 } 1917 1918 if (position >= 0) { 1919 mLayoutMode = LAYOUT_SPECIFIC; 1920 mSpecificTop = mListPadding.top + y; 1921 1922 if (mNeedSync) { 1923 mSyncPosition = position; 1924 mSyncRowId = mAdapter.getItemId(position); 1925 } 1926 1927 if (mPositionScroller != null) { 1928 mPositionScroller.stop(); 1929 } 1930 requestLayout(); 1931 } 1932 } 1933 1934 /** 1935 * Makes the item at the supplied position selected. 1936 * 1937 * @param position the position of the item to select 1938 */ 1939 @Override 1940 void setSelectionInt(int position) { 1941 setNextSelectedPositionInt(position); 1942 boolean awakeScrollbars = false; 1943 1944 final int selectedPosition = mSelectedPosition; 1945 1946 if (selectedPosition >= 0) { 1947 if (position == selectedPosition - 1) { 1948 awakeScrollbars = true; 1949 } else if (position == selectedPosition + 1) { 1950 awakeScrollbars = true; 1951 } 1952 } 1953 1954 if (mPositionScroller != null) { 1955 mPositionScroller.stop(); 1956 } 1957 1958 layoutChildren(); 1959 1960 if (awakeScrollbars) { 1961 awakenScrollBars(); 1962 } 1963 } 1964 1965 /** 1966 * Find a position that can be selected (i.e., is not a separator). 1967 * 1968 * @param position The starting position to look at. 1969 * @param lookDown Whether to look down for other positions. 1970 * @return The next selectable position starting at position and then searching either up or 1971 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1972 */ 1973 @Override 1974 int lookForSelectablePosition(int position, boolean lookDown) { 1975 final ListAdapter adapter = mAdapter; 1976 if (adapter == null || isInTouchMode()) { 1977 return INVALID_POSITION; 1978 } 1979 1980 final int count = adapter.getCount(); 1981 if (!mAreAllItemsSelectable) { 1982 if (lookDown) { 1983 position = Math.max(0, position); 1984 while (position < count && !adapter.isEnabled(position)) { 1985 position++; 1986 } 1987 } else { 1988 position = Math.min(position, count - 1); 1989 while (position >= 0 && !adapter.isEnabled(position)) { 1990 position--; 1991 } 1992 } 1993 } 1994 1995 if (position < 0 || position >= count) { 1996 return INVALID_POSITION; 1997 } 1998 1999 return position; 2000 } 2001 2002 /** 2003 * Find a position that can be selected (i.e., is not a separator). If there 2004 * are no selectable positions in the specified direction from the starting 2005 * position, searches in the opposite direction from the starting position 2006 * to the current position. 2007 * 2008 * @param current the current position 2009 * @param position the starting position 2010 * @param lookDown whether to look down for other positions 2011 * @return the next selectable position, or {@link #INVALID_POSITION} if 2012 * nothing can be found 2013 */ 2014 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2015 final ListAdapter adapter = mAdapter; 2016 if (adapter == null || isInTouchMode()) { 2017 return INVALID_POSITION; 2018 } 2019 2020 // First check after the starting position in the specified direction. 2021 final int after = lookForSelectablePosition(position, lookDown); 2022 if (after != INVALID_POSITION) { 2023 return after; 2024 } 2025 2026 // Then check between the starting position and the current position. 2027 final int count = adapter.getCount(); 2028 current = MathUtils.constrain(current, -1, count - 1); 2029 if (lookDown) { 2030 position = Math.min(position - 1, count - 1); 2031 while ((position > current) && !adapter.isEnabled(position)) { 2032 position--; 2033 } 2034 if (position <= current) { 2035 return INVALID_POSITION; 2036 } 2037 } else { 2038 position = Math.max(0, position + 1); 2039 while ((position < current) && !adapter.isEnabled(position)) { 2040 position++; 2041 } 2042 if (position >= current) { 2043 return INVALID_POSITION; 2044 } 2045 } 2046 2047 return position; 2048 } 2049 2050 /** 2051 * setSelectionAfterHeaderView set the selection to be the first list item 2052 * after the header views. 2053 */ 2054 public void setSelectionAfterHeaderView() { 2055 final int count = mHeaderViewInfos.size(); 2056 if (count > 0) { 2057 mNextSelectedPosition = 0; 2058 return; 2059 } 2060 2061 if (mAdapter != null) { 2062 setSelection(count); 2063 } else { 2064 mNextSelectedPosition = count; 2065 mLayoutMode = LAYOUT_SET_SELECTION; 2066 } 2067 2068 } 2069 2070 @Override 2071 public boolean dispatchKeyEvent(KeyEvent event) { 2072 // Dispatch in the normal way 2073 boolean handled = super.dispatchKeyEvent(event); 2074 if (!handled) { 2075 // If we didn't handle it... 2076 View focused = getFocusedChild(); 2077 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2078 // ... and our focused child didn't handle it 2079 // ... give it to ourselves so we can scroll if necessary 2080 handled = onKeyDown(event.getKeyCode(), event); 2081 } 2082 } 2083 return handled; 2084 } 2085 2086 @Override 2087 public boolean onKeyDown(int keyCode, KeyEvent event) { 2088 return commonKey(keyCode, 1, event); 2089 } 2090 2091 @Override 2092 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2093 return commonKey(keyCode, repeatCount, event); 2094 } 2095 2096 @Override 2097 public boolean onKeyUp(int keyCode, KeyEvent event) { 2098 return commonKey(keyCode, 1, event); 2099 } 2100 2101 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2102 if (mAdapter == null || !isAttachedToWindow()) { 2103 return false; 2104 } 2105 2106 if (mDataChanged) { 2107 layoutChildren(); 2108 } 2109 2110 boolean handled = false; 2111 int action = event.getAction(); 2112 2113 if (action != KeyEvent.ACTION_UP) { 2114 switch (keyCode) { 2115 case KeyEvent.KEYCODE_DPAD_UP: 2116 if (event.hasNoModifiers()) { 2117 handled = resurrectSelectionIfNeeded(); 2118 if (!handled) { 2119 while (count-- > 0) { 2120 if (arrowScroll(FOCUS_UP)) { 2121 handled = true; 2122 } else { 2123 break; 2124 } 2125 } 2126 } 2127 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2128 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2129 } 2130 break; 2131 2132 case KeyEvent.KEYCODE_DPAD_DOWN: 2133 if (event.hasNoModifiers()) { 2134 handled = resurrectSelectionIfNeeded(); 2135 if (!handled) { 2136 while (count-- > 0) { 2137 if (arrowScroll(FOCUS_DOWN)) { 2138 handled = true; 2139 } else { 2140 break; 2141 } 2142 } 2143 } 2144 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2145 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2146 } 2147 break; 2148 2149 case KeyEvent.KEYCODE_DPAD_LEFT: 2150 if (event.hasNoModifiers()) { 2151 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2152 } 2153 break; 2154 2155 case KeyEvent.KEYCODE_DPAD_RIGHT: 2156 if (event.hasNoModifiers()) { 2157 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2158 } 2159 break; 2160 2161 case KeyEvent.KEYCODE_DPAD_CENTER: 2162 case KeyEvent.KEYCODE_ENTER: 2163 if (event.hasNoModifiers()) { 2164 handled = resurrectSelectionIfNeeded(); 2165 if (!handled 2166 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2167 keyPressed(); 2168 handled = true; 2169 } 2170 } 2171 break; 2172 2173 case KeyEvent.KEYCODE_SPACE: 2174 if (mPopup == null || !mPopup.isShowing()) { 2175 if (event.hasNoModifiers()) { 2176 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2177 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2178 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2179 } 2180 handled = true; 2181 } 2182 break; 2183 2184 case KeyEvent.KEYCODE_PAGE_UP: 2185 if (event.hasNoModifiers()) { 2186 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2187 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2188 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2189 } 2190 break; 2191 2192 case KeyEvent.KEYCODE_PAGE_DOWN: 2193 if (event.hasNoModifiers()) { 2194 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2195 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2196 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2197 } 2198 break; 2199 2200 case KeyEvent.KEYCODE_MOVE_HOME: 2201 if (event.hasNoModifiers()) { 2202 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2203 } 2204 break; 2205 2206 case KeyEvent.KEYCODE_MOVE_END: 2207 if (event.hasNoModifiers()) { 2208 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2209 } 2210 break; 2211 2212 case KeyEvent.KEYCODE_TAB: 2213 // XXX Sometimes it is useful to be able to TAB through the items in 2214 // a ListView sequentially. Unfortunately this can create an 2215 // asymmetry in TAB navigation order unless the list selection 2216 // always reverts to the top or bottom when receiving TAB focus from 2217 // another widget. Leaving this behavior disabled for now but 2218 // perhaps it should be configurable (and more comprehensive). 2219 if (false) { 2220 if (event.hasNoModifiers()) { 2221 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2222 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2223 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2224 } 2225 } 2226 break; 2227 } 2228 } 2229 2230 if (handled) { 2231 return true; 2232 } 2233 2234 if (sendToTextFilter(keyCode, count, event)) { 2235 return true; 2236 } 2237 2238 switch (action) { 2239 case KeyEvent.ACTION_DOWN: 2240 return super.onKeyDown(keyCode, event); 2241 2242 case KeyEvent.ACTION_UP: 2243 return super.onKeyUp(keyCode, event); 2244 2245 case KeyEvent.ACTION_MULTIPLE: 2246 return super.onKeyMultiple(keyCode, count, event); 2247 2248 default: // shouldn't happen 2249 return false; 2250 } 2251 } 2252 2253 /** 2254 * Scrolls up or down by the number of items currently present on screen. 2255 * 2256 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2257 * @return whether selection was moved 2258 */ 2259 boolean pageScroll(int direction) { 2260 final int nextPage; 2261 final boolean down; 2262 2263 if (direction == FOCUS_UP) { 2264 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2265 down = false; 2266 } else if (direction == FOCUS_DOWN) { 2267 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2268 down = true; 2269 } else { 2270 return false; 2271 } 2272 2273 if (nextPage >= 0) { 2274 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2275 if (position >= 0) { 2276 mLayoutMode = LAYOUT_SPECIFIC; 2277 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2278 2279 if (down && (position > (mItemCount - getChildCount()))) { 2280 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2281 } 2282 2283 if (!down && (position < getChildCount())) { 2284 mLayoutMode = LAYOUT_FORCE_TOP; 2285 } 2286 2287 setSelectionInt(position); 2288 invokeOnItemScrollListener(); 2289 if (!awakenScrollBars()) { 2290 invalidate(); 2291 } 2292 2293 return true; 2294 } 2295 } 2296 2297 return false; 2298 } 2299 2300 /** 2301 * Go to the last or first item if possible (not worrying about panning 2302 * across or navigating within the internal focus of the currently selected 2303 * item.) 2304 * 2305 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2306 * @return whether selection was moved 2307 */ 2308 boolean fullScroll(int direction) { 2309 boolean moved = false; 2310 if (direction == FOCUS_UP) { 2311 if (mSelectedPosition != 0) { 2312 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2313 if (position >= 0) { 2314 mLayoutMode = LAYOUT_FORCE_TOP; 2315 setSelectionInt(position); 2316 invokeOnItemScrollListener(); 2317 } 2318 moved = true; 2319 } 2320 } else if (direction == FOCUS_DOWN) { 2321 final int lastItem = (mItemCount - 1); 2322 if (mSelectedPosition < lastItem) { 2323 final int position = lookForSelectablePositionAfter( 2324 mSelectedPosition, lastItem, false); 2325 if (position >= 0) { 2326 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2327 setSelectionInt(position); 2328 invokeOnItemScrollListener(); 2329 } 2330 moved = true; 2331 } 2332 } 2333 2334 if (moved && !awakenScrollBars()) { 2335 awakenScrollBars(); 2336 invalidate(); 2337 } 2338 2339 return moved; 2340 } 2341 2342 /** 2343 * To avoid horizontal focus searches changing the selected item, we 2344 * manually focus search within the selected item (as applicable), and 2345 * prevent focus from jumping to something within another item. 2346 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2347 * @return Whether this consumes the key event. 2348 */ 2349 private boolean handleHorizontalFocusWithinListItem(int direction) { 2350 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2351 throw new IllegalArgumentException("direction must be one of" 2352 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2353 } 2354 2355 final int numChildren = getChildCount(); 2356 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2357 final View selectedView = getSelectedView(); 2358 if (selectedView != null && selectedView.hasFocus() && 2359 selectedView instanceof ViewGroup) { 2360 2361 final View currentFocus = selectedView.findFocus(); 2362 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2363 (ViewGroup) selectedView, currentFocus, direction); 2364 if (nextFocus != null) { 2365 // do the math to get interesting rect in next focus' coordinates 2366 currentFocus.getFocusedRect(mTempRect); 2367 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2368 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2369 if (nextFocus.requestFocus(direction, mTempRect)) { 2370 return true; 2371 } 2372 } 2373 // we are blocking the key from being handled (by returning true) 2374 // if the global result is going to be some other view within this 2375 // list. this is to acheive the overall goal of having 2376 // horizontal d-pad navigation remain in the current item. 2377 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2378 (ViewGroup) getRootView(), currentFocus, direction); 2379 if (globalNextFocus != null) { 2380 return isViewAncestorOf(globalNextFocus, this); 2381 } 2382 } 2383 } 2384 return false; 2385 } 2386 2387 /** 2388 * Scrolls to the next or previous item if possible. 2389 * 2390 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2391 * 2392 * @return whether selection was moved 2393 */ 2394 boolean arrowScroll(int direction) { 2395 try { 2396 mInLayout = true; 2397 final boolean handled = arrowScrollImpl(direction); 2398 if (handled) { 2399 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2400 } 2401 return handled; 2402 } finally { 2403 mInLayout = false; 2404 } 2405 } 2406 2407 /** 2408 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2409 * to move to. This return a position in the direction given if the selected item 2410 * is fully visible. 2411 * 2412 * @param selectedView Current selected view to move from 2413 * @param selectedPos Current selected position to move from 2414 * @param direction Direction to move in 2415 * @return Desired selected position after moving in the given direction 2416 */ 2417 private final int nextSelectedPositionForDirection( 2418 View selectedView, int selectedPos, int direction) { 2419 int nextSelected; 2420 2421 if (direction == View.FOCUS_DOWN) { 2422 final int listBottom = getHeight() - mListPadding.bottom; 2423 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2424 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2425 selectedPos + 1 : 2426 mFirstPosition; 2427 } else { 2428 return INVALID_POSITION; 2429 } 2430 } else { 2431 final int listTop = mListPadding.top; 2432 if (selectedView != null && selectedView.getTop() >= listTop) { 2433 final int lastPos = mFirstPosition + getChildCount() - 1; 2434 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2435 selectedPos - 1 : 2436 lastPos; 2437 } else { 2438 return INVALID_POSITION; 2439 } 2440 } 2441 2442 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2443 return INVALID_POSITION; 2444 } 2445 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2446 } 2447 2448 /** 2449 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2450 * whether there are focusable items etc. 2451 * 2452 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2453 * @return Whether any scrolling, selection or focus change occured. 2454 */ 2455 private boolean arrowScrollImpl(int direction) { 2456 if (getChildCount() <= 0) { 2457 return false; 2458 } 2459 2460 View selectedView = getSelectedView(); 2461 int selectedPos = mSelectedPosition; 2462 2463 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2464 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2465 2466 // if we are moving focus, we may OVERRIDE the default behavior 2467 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2468 if (focusResult != null) { 2469 nextSelectedPosition = focusResult.getSelectedPosition(); 2470 amountToScroll = focusResult.getAmountToScroll(); 2471 } 2472 2473 boolean needToRedraw = focusResult != null; 2474 if (nextSelectedPosition != INVALID_POSITION) { 2475 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2476 setSelectedPositionInt(nextSelectedPosition); 2477 setNextSelectedPositionInt(nextSelectedPosition); 2478 selectedView = getSelectedView(); 2479 selectedPos = nextSelectedPosition; 2480 if (mItemsCanFocus && focusResult == null) { 2481 // there was no new view found to take focus, make sure we 2482 // don't leave focus with the old selection 2483 final View focused = getFocusedChild(); 2484 if (focused != null) { 2485 focused.clearFocus(); 2486 } 2487 } 2488 needToRedraw = true; 2489 checkSelectionChanged(); 2490 } 2491 2492 if (amountToScroll > 0) { 2493 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2494 needToRedraw = true; 2495 } 2496 2497 // if we didn't find a new focusable, make sure any existing focused 2498 // item that was panned off screen gives up focus. 2499 if (mItemsCanFocus && (focusResult == null) 2500 && selectedView != null && selectedView.hasFocus()) { 2501 final View focused = selectedView.findFocus(); 2502 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2503 focused.clearFocus(); 2504 } 2505 } 2506 2507 // if the current selection is panned off, we need to remove the selection 2508 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2509 && !isViewAncestorOf(selectedView, this)) { 2510 selectedView = null; 2511 hideSelector(); 2512 2513 // but we don't want to set the ressurect position (that would make subsequent 2514 // unhandled key events bring back the item we just scrolled off!) 2515 mResurrectToPosition = INVALID_POSITION; 2516 } 2517 2518 if (needToRedraw) { 2519 if (selectedView != null) { 2520 positionSelector(selectedPos, selectedView); 2521 mSelectedTop = selectedView.getTop(); 2522 } 2523 if (!awakenScrollBars()) { 2524 invalidate(); 2525 } 2526 invokeOnItemScrollListener(); 2527 return true; 2528 } 2529 2530 return false; 2531 } 2532 2533 /** 2534 * When selection changes, it is possible that the previously selected or the 2535 * next selected item will change its size. If so, we need to offset some folks, 2536 * and re-layout the items as appropriate. 2537 * 2538 * @param selectedView The currently selected view (before changing selection). 2539 * should be <code>null</code> if there was no previous selection. 2540 * @param direction Either {@link android.view.View#FOCUS_UP} or 2541 * {@link android.view.View#FOCUS_DOWN}. 2542 * @param newSelectedPosition The position of the next selection. 2543 * @param newFocusAssigned whether new focus was assigned. This matters because 2544 * when something has focus, we don't want to show selection (ugh). 2545 */ 2546 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2547 boolean newFocusAssigned) { 2548 if (newSelectedPosition == INVALID_POSITION) { 2549 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2550 } 2551 2552 // whether or not we are moving down or up, we want to preserve the 2553 // top of whatever view is on top: 2554 // - moving down: the view that had selection 2555 // - moving up: the view that is getting selection 2556 View topView; 2557 View bottomView; 2558 int topViewIndex, bottomViewIndex; 2559 boolean topSelected = false; 2560 final int selectedIndex = mSelectedPosition - mFirstPosition; 2561 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2562 if (direction == View.FOCUS_UP) { 2563 topViewIndex = nextSelectedIndex; 2564 bottomViewIndex = selectedIndex; 2565 topView = getChildAt(topViewIndex); 2566 bottomView = selectedView; 2567 topSelected = true; 2568 } else { 2569 topViewIndex = selectedIndex; 2570 bottomViewIndex = nextSelectedIndex; 2571 topView = selectedView; 2572 bottomView = getChildAt(bottomViewIndex); 2573 } 2574 2575 final int numChildren = getChildCount(); 2576 2577 // start with top view: is it changing size? 2578 if (topView != null) { 2579 topView.setSelected(!newFocusAssigned && topSelected); 2580 measureAndAdjustDown(topView, topViewIndex, numChildren); 2581 } 2582 2583 // is the bottom view changing size? 2584 if (bottomView != null) { 2585 bottomView.setSelected(!newFocusAssigned && !topSelected); 2586 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2587 } 2588 } 2589 2590 /** 2591 * Re-measure a child, and if its height changes, lay it out preserving its 2592 * top, and adjust the children below it appropriately. 2593 * @param child The child 2594 * @param childIndex The view group index of the child. 2595 * @param numChildren The number of children in the view group. 2596 */ 2597 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2598 int oldHeight = child.getHeight(); 2599 measureItem(child); 2600 if (child.getMeasuredHeight() != oldHeight) { 2601 // lay out the view, preserving its top 2602 relayoutMeasuredItem(child); 2603 2604 // adjust views below appropriately 2605 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2606 for (int i = childIndex + 1; i < numChildren; i++) { 2607 getChildAt(i).offsetTopAndBottom(heightDelta); 2608 } 2609 } 2610 } 2611 2612 /** 2613 * Measure a particular list child. 2614 * TODO: unify with setUpChild. 2615 * @param child The child. 2616 */ 2617 private void measureItem(View child) { 2618 ViewGroup.LayoutParams p = child.getLayoutParams(); 2619 if (p == null) { 2620 p = new ViewGroup.LayoutParams( 2621 ViewGroup.LayoutParams.MATCH_PARENT, 2622 ViewGroup.LayoutParams.WRAP_CONTENT); 2623 } 2624 2625 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2626 mListPadding.left + mListPadding.right, p.width); 2627 int lpHeight = p.height; 2628 int childHeightSpec; 2629 if (lpHeight > 0) { 2630 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2631 } else { 2632 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2633 } 2634 child.measure(childWidthSpec, childHeightSpec); 2635 } 2636 2637 /** 2638 * Layout a child that has been measured, preserving its top position. 2639 * TODO: unify with setUpChild. 2640 * @param child The child. 2641 */ 2642 private void relayoutMeasuredItem(View child) { 2643 final int w = child.getMeasuredWidth(); 2644 final int h = child.getMeasuredHeight(); 2645 final int childLeft = mListPadding.left; 2646 final int childRight = childLeft + w; 2647 final int childTop = child.getTop(); 2648 final int childBottom = childTop + h; 2649 child.layout(childLeft, childTop, childRight, childBottom); 2650 } 2651 2652 /** 2653 * @return The amount to preview next items when arrow srolling. 2654 */ 2655 private int getArrowScrollPreviewLength() { 2656 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2657 } 2658 2659 /** 2660 * Determine how much we need to scroll in order to get the next selected view 2661 * visible, with a fading edge showing below as applicable. The amount is 2662 * capped at {@link #getMaxScrollAmount()} . 2663 * 2664 * @param direction either {@link android.view.View#FOCUS_UP} or 2665 * {@link android.view.View#FOCUS_DOWN}. 2666 * @param nextSelectedPosition The position of the next selection, or 2667 * {@link #INVALID_POSITION} if there is no next selectable position 2668 * @return The amount to scroll. Note: this is always positive! Direction 2669 * needs to be taken into account when actually scrolling. 2670 */ 2671 private int amountToScroll(int direction, int nextSelectedPosition) { 2672 final int listBottom = getHeight() - mListPadding.bottom; 2673 final int listTop = mListPadding.top; 2674 2675 int numChildren = getChildCount(); 2676 2677 if (direction == View.FOCUS_DOWN) { 2678 int indexToMakeVisible = numChildren - 1; 2679 if (nextSelectedPosition != INVALID_POSITION) { 2680 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2681 } 2682 while (numChildren <= indexToMakeVisible) { 2683 // Child to view is not attached yet. 2684 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2685 numChildren++; 2686 } 2687 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2688 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2689 2690 int goalBottom = listBottom; 2691 if (positionToMakeVisible < mItemCount - 1) { 2692 goalBottom -= getArrowScrollPreviewLength(); 2693 } 2694 2695 if (viewToMakeVisible.getBottom() <= goalBottom) { 2696 // item is fully visible. 2697 return 0; 2698 } 2699 2700 if (nextSelectedPosition != INVALID_POSITION 2701 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2702 // item already has enough of it visible, changing selection is good enough 2703 return 0; 2704 } 2705 2706 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2707 2708 if ((mFirstPosition + numChildren) == mItemCount) { 2709 // last is last in list -> make sure we don't scroll past it 2710 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2711 amountToScroll = Math.min(amountToScroll, max); 2712 } 2713 2714 return Math.min(amountToScroll, getMaxScrollAmount()); 2715 } else { 2716 int indexToMakeVisible = 0; 2717 if (nextSelectedPosition != INVALID_POSITION) { 2718 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2719 } 2720 while (indexToMakeVisible < 0) { 2721 // Child to view is not attached yet. 2722 addViewAbove(getChildAt(0), mFirstPosition); 2723 mFirstPosition--; 2724 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2725 } 2726 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2727 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2728 int goalTop = listTop; 2729 if (positionToMakeVisible > 0) { 2730 goalTop += getArrowScrollPreviewLength(); 2731 } 2732 if (viewToMakeVisible.getTop() >= goalTop) { 2733 // item is fully visible. 2734 return 0; 2735 } 2736 2737 if (nextSelectedPosition != INVALID_POSITION && 2738 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2739 // item already has enough of it visible, changing selection is good enough 2740 return 0; 2741 } 2742 2743 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2744 if (mFirstPosition == 0) { 2745 // first is first in list -> make sure we don't scroll past it 2746 final int max = listTop - getChildAt(0).getTop(); 2747 amountToScroll = Math.min(amountToScroll, max); 2748 } 2749 return Math.min(amountToScroll, getMaxScrollAmount()); 2750 } 2751 } 2752 2753 /** 2754 * Holds results of focus aware arrow scrolling. 2755 */ 2756 static private class ArrowScrollFocusResult { 2757 private int mSelectedPosition; 2758 private int mAmountToScroll; 2759 2760 /** 2761 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2762 */ 2763 void populate(int selectedPosition, int amountToScroll) { 2764 mSelectedPosition = selectedPosition; 2765 mAmountToScroll = amountToScroll; 2766 } 2767 2768 public int getSelectedPosition() { 2769 return mSelectedPosition; 2770 } 2771 2772 public int getAmountToScroll() { 2773 return mAmountToScroll; 2774 } 2775 } 2776 2777 /** 2778 * @param direction either {@link android.view.View#FOCUS_UP} or 2779 * {@link android.view.View#FOCUS_DOWN}. 2780 * @return The position of the next selectable position of the views that 2781 * are currently visible, taking into account the fact that there might 2782 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2783 * selectable view on screen in the given direction. 2784 */ 2785 private int lookForSelectablePositionOnScreen(int direction) { 2786 final int firstPosition = mFirstPosition; 2787 if (direction == View.FOCUS_DOWN) { 2788 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2789 mSelectedPosition + 1 : 2790 firstPosition; 2791 if (startPos >= mAdapter.getCount()) { 2792 return INVALID_POSITION; 2793 } 2794 if (startPos < firstPosition) { 2795 startPos = firstPosition; 2796 } 2797 2798 final int lastVisiblePos = getLastVisiblePosition(); 2799 final ListAdapter adapter = getAdapter(); 2800 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2801 if (adapter.isEnabled(pos) 2802 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2803 return pos; 2804 } 2805 } 2806 } else { 2807 int last = firstPosition + getChildCount() - 1; 2808 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2809 mSelectedPosition - 1 : 2810 firstPosition + getChildCount() - 1; 2811 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2812 return INVALID_POSITION; 2813 } 2814 if (startPos > last) { 2815 startPos = last; 2816 } 2817 2818 final ListAdapter adapter = getAdapter(); 2819 for (int pos = startPos; pos >= firstPosition; pos--) { 2820 if (adapter.isEnabled(pos) 2821 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2822 return pos; 2823 } 2824 } 2825 } 2826 return INVALID_POSITION; 2827 } 2828 2829 /** 2830 * Do an arrow scroll based on focus searching. If a new view is 2831 * given focus, return the selection delta and amount to scroll via 2832 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2833 * 2834 * @param direction either {@link android.view.View#FOCUS_UP} or 2835 * {@link android.view.View#FOCUS_DOWN}. 2836 * @return The result if focus has changed, or <code>null</code>. 2837 */ 2838 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2839 final View selectedView = getSelectedView(); 2840 View newFocus; 2841 if (selectedView != null && selectedView.hasFocus()) { 2842 View oldFocus = selectedView.findFocus(); 2843 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2844 } else { 2845 if (direction == View.FOCUS_DOWN) { 2846 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2847 final int listTop = mListPadding.top + 2848 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2849 final int ySearchPoint = 2850 (selectedView != null && selectedView.getTop() > listTop) ? 2851 selectedView.getTop() : 2852 listTop; 2853 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2854 } else { 2855 final boolean bottomFadingEdgeShowing = 2856 (mFirstPosition + getChildCount() - 1) < mItemCount; 2857 final int listBottom = getHeight() - mListPadding.bottom - 2858 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2859 final int ySearchPoint = 2860 (selectedView != null && selectedView.getBottom() < listBottom) ? 2861 selectedView.getBottom() : 2862 listBottom; 2863 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2864 } 2865 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2866 } 2867 2868 if (newFocus != null) { 2869 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2870 2871 // if the focus change is in a different new position, make sure 2872 // we aren't jumping over another selectable position 2873 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2874 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2875 if (selectablePosition != INVALID_POSITION && 2876 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2877 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2878 return null; 2879 } 2880 } 2881 2882 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2883 2884 final int maxScrollAmount = getMaxScrollAmount(); 2885 if (focusScroll < maxScrollAmount) { 2886 // not moving too far, safe to give next view focus 2887 newFocus.requestFocus(direction); 2888 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2889 return mArrowScrollFocusResult; 2890 } else if (distanceToView(newFocus) < maxScrollAmount){ 2891 // Case to consider: 2892 // too far to get entire next focusable on screen, but by going 2893 // max scroll amount, we are getting it at least partially in view, 2894 // so give it focus and scroll the max ammount. 2895 newFocus.requestFocus(direction); 2896 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2897 return mArrowScrollFocusResult; 2898 } 2899 } 2900 return null; 2901 } 2902 2903 /** 2904 * @param newFocus The view that would have focus. 2905 * @return the position that contains newFocus 2906 */ 2907 private int positionOfNewFocus(View newFocus) { 2908 final int numChildren = getChildCount(); 2909 for (int i = 0; i < numChildren; i++) { 2910 final View child = getChildAt(i); 2911 if (isViewAncestorOf(newFocus, child)) { 2912 return mFirstPosition + i; 2913 } 2914 } 2915 throw new IllegalArgumentException("newFocus is not a child of any of the" 2916 + " children of the list!"); 2917 } 2918 2919 /** 2920 * Return true if child is an ancestor of parent, (or equal to the parent). 2921 */ 2922 private boolean isViewAncestorOf(View child, View parent) { 2923 if (child == parent) { 2924 return true; 2925 } 2926 2927 final ViewParent theParent = child.getParent(); 2928 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2929 } 2930 2931 /** 2932 * Determine how much we need to scroll in order to get newFocus in view. 2933 * @param direction either {@link android.view.View#FOCUS_UP} or 2934 * {@link android.view.View#FOCUS_DOWN}. 2935 * @param newFocus The view that would take focus. 2936 * @param positionOfNewFocus The position of the list item containing newFocus 2937 * @return The amount to scroll. Note: this is always positive! Direction 2938 * needs to be taken into account when actually scrolling. 2939 */ 2940 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2941 int amountToScroll = 0; 2942 newFocus.getDrawingRect(mTempRect); 2943 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2944 if (direction == View.FOCUS_UP) { 2945 if (mTempRect.top < mListPadding.top) { 2946 amountToScroll = mListPadding.top - mTempRect.top; 2947 if (positionOfNewFocus > 0) { 2948 amountToScroll += getArrowScrollPreviewLength(); 2949 } 2950 } 2951 } else { 2952 final int listBottom = getHeight() - mListPadding.bottom; 2953 if (mTempRect.bottom > listBottom) { 2954 amountToScroll = mTempRect.bottom - listBottom; 2955 if (positionOfNewFocus < mItemCount - 1) { 2956 amountToScroll += getArrowScrollPreviewLength(); 2957 } 2958 } 2959 } 2960 return amountToScroll; 2961 } 2962 2963 /** 2964 * Determine the distance to the nearest edge of a view in a particular 2965 * direction. 2966 * 2967 * @param descendant A descendant of this list. 2968 * @return The distance, or 0 if the nearest edge is already on screen. 2969 */ 2970 private int distanceToView(View descendant) { 2971 int distance = 0; 2972 descendant.getDrawingRect(mTempRect); 2973 offsetDescendantRectToMyCoords(descendant, mTempRect); 2974 final int listBottom = mBottom - mTop - mListPadding.bottom; 2975 if (mTempRect.bottom < mListPadding.top) { 2976 distance = mListPadding.top - mTempRect.bottom; 2977 } else if (mTempRect.top > listBottom) { 2978 distance = mTempRect.top - listBottom; 2979 } 2980 return distance; 2981 } 2982 2983 2984 /** 2985 * Scroll the children by amount, adding a view at the end and removing 2986 * views that fall off as necessary. 2987 * 2988 * @param amount The amount (positive or negative) to scroll. 2989 */ 2990 private void scrollListItemsBy(int amount) { 2991 offsetChildrenTopAndBottom(amount); 2992 2993 final int listBottom = getHeight() - mListPadding.bottom; 2994 final int listTop = mListPadding.top; 2995 final AbsListView.RecycleBin recycleBin = mRecycler; 2996 2997 if (amount < 0) { 2998 // shifted items up 2999 3000 // may need to pan views into the bottom space 3001 int numChildren = getChildCount(); 3002 View last = getChildAt(numChildren - 1); 3003 while (last.getBottom() < listBottom) { 3004 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3005 if (lastVisiblePosition < mItemCount - 1) { 3006 last = addViewBelow(last, lastVisiblePosition); 3007 numChildren++; 3008 } else { 3009 break; 3010 } 3011 } 3012 3013 // may have brought in the last child of the list that is skinnier 3014 // than the fading edge, thereby leaving space at the end. need 3015 // to shift back 3016 if (last.getBottom() < listBottom) { 3017 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3018 } 3019 3020 // top views may be panned off screen 3021 View first = getChildAt(0); 3022 while (first.getBottom() < listTop) { 3023 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3024 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3025 recycleBin.addScrapView(first, mFirstPosition); 3026 } 3027 detachViewFromParent(first); 3028 first = getChildAt(0); 3029 mFirstPosition++; 3030 } 3031 } else { 3032 // shifted items down 3033 View first = getChildAt(0); 3034 3035 // may need to pan views into top 3036 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3037 first = addViewAbove(first, mFirstPosition); 3038 mFirstPosition--; 3039 } 3040 3041 // may have brought the very first child of the list in too far and 3042 // need to shift it back 3043 if (first.getTop() > listTop) { 3044 offsetChildrenTopAndBottom(listTop - first.getTop()); 3045 } 3046 3047 int lastIndex = getChildCount() - 1; 3048 View last = getChildAt(lastIndex); 3049 3050 // bottom view may be panned off screen 3051 while (last.getTop() > listBottom) { 3052 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3053 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3054 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3055 } 3056 detachViewFromParent(last); 3057 last = getChildAt(--lastIndex); 3058 } 3059 } 3060 } 3061 3062 private View addViewAbove(View theView, int position) { 3063 int abovePosition = position - 1; 3064 View view = obtainView(abovePosition, mIsScrap); 3065 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3066 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3067 false, mIsScrap[0]); 3068 return view; 3069 } 3070 3071 private View addViewBelow(View theView, int position) { 3072 int belowPosition = position + 1; 3073 View view = obtainView(belowPosition, mIsScrap); 3074 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3075 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3076 false, mIsScrap[0]); 3077 return view; 3078 } 3079 3080 /** 3081 * Indicates that the views created by the ListAdapter can contain focusable 3082 * items. 3083 * 3084 * @param itemsCanFocus true if items can get focus, false otherwise 3085 */ 3086 public void setItemsCanFocus(boolean itemsCanFocus) { 3087 mItemsCanFocus = itemsCanFocus; 3088 if (!itemsCanFocus) { 3089 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3090 } 3091 } 3092 3093 /** 3094 * @return Whether the views created by the ListAdapter can contain focusable 3095 * items. 3096 */ 3097 public boolean getItemsCanFocus() { 3098 return mItemsCanFocus; 3099 } 3100 3101 @Override 3102 public boolean isOpaque() { 3103 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3104 hasOpaqueScrollbars()) || super.isOpaque(); 3105 if (retValue) { 3106 // only return true if the list items cover the entire area of the view 3107 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3108 View first = getChildAt(0); 3109 if (first == null || first.getTop() > listTop) { 3110 return false; 3111 } 3112 final int listBottom = getHeight() - 3113 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3114 View last = getChildAt(getChildCount() - 1); 3115 if (last == null || last.getBottom() < listBottom) { 3116 return false; 3117 } 3118 } 3119 return retValue; 3120 } 3121 3122 @Override 3123 public void setCacheColorHint(int color) { 3124 final boolean opaque = (color >>> 24) == 0xFF; 3125 mIsCacheColorOpaque = opaque; 3126 if (opaque) { 3127 if (mDividerPaint == null) { 3128 mDividerPaint = new Paint(); 3129 } 3130 mDividerPaint.setColor(color); 3131 } 3132 super.setCacheColorHint(color); 3133 } 3134 3135 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3136 final int height = drawable.getMinimumHeight(); 3137 3138 canvas.save(); 3139 canvas.clipRect(bounds); 3140 3141 final int span = bounds.bottom - bounds.top; 3142 if (span < height) { 3143 bounds.top = bounds.bottom - height; 3144 } 3145 3146 drawable.setBounds(bounds); 3147 drawable.draw(canvas); 3148 3149 canvas.restore(); 3150 } 3151 3152 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3153 final int height = drawable.getMinimumHeight(); 3154 3155 canvas.save(); 3156 canvas.clipRect(bounds); 3157 3158 final int span = bounds.bottom - bounds.top; 3159 if (span < height) { 3160 bounds.bottom = bounds.top + height; 3161 } 3162 3163 drawable.setBounds(bounds); 3164 drawable.draw(canvas); 3165 3166 canvas.restore(); 3167 } 3168 3169 @Override 3170 protected void dispatchDraw(Canvas canvas) { 3171 if (mCachingStarted) { 3172 mCachingActive = true; 3173 } 3174 3175 // Draw the dividers 3176 final int dividerHeight = mDividerHeight; 3177 final Drawable overscrollHeader = mOverScrollHeader; 3178 final Drawable overscrollFooter = mOverScrollFooter; 3179 final boolean drawOverscrollHeader = overscrollHeader != null; 3180 final boolean drawOverscrollFooter = overscrollFooter != null; 3181 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3182 3183 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3184 // Only modify the top and bottom in the loop, we set the left and right here 3185 final Rect bounds = mTempRect; 3186 bounds.left = mPaddingLeft; 3187 bounds.right = mRight - mLeft - mPaddingRight; 3188 3189 final int count = getChildCount(); 3190 final int headerCount = mHeaderViewInfos.size(); 3191 final int itemCount = mItemCount; 3192 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3193 final boolean headerDividers = mHeaderDividersEnabled; 3194 final boolean footerDividers = mFooterDividersEnabled; 3195 final int first = mFirstPosition; 3196 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3197 final ListAdapter adapter = mAdapter; 3198 // If the list is opaque *and* the background is not, we want to 3199 // fill a rect where the dividers would be for non-selectable items 3200 // If the list is opaque and the background is also opaque, we don't 3201 // need to draw anything since the background will do it for us 3202 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3203 3204 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3205 mDividerPaint = new Paint(); 3206 mDividerPaint.setColor(getCacheColorHint()); 3207 } 3208 final Paint paint = mDividerPaint; 3209 3210 int effectivePaddingTop = 0; 3211 int effectivePaddingBottom = 0; 3212 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3213 effectivePaddingTop = mListPadding.top; 3214 effectivePaddingBottom = mListPadding.bottom; 3215 } 3216 3217 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3218 if (!mStackFromBottom) { 3219 int bottom = 0; 3220 3221 // Draw top divider or header for overscroll 3222 final int scrollY = mScrollY; 3223 if (count > 0 && scrollY < 0) { 3224 if (drawOverscrollHeader) { 3225 bounds.bottom = 0; 3226 bounds.top = scrollY; 3227 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3228 } else if (drawDividers) { 3229 bounds.bottom = 0; 3230 bounds.top = -dividerHeight; 3231 drawDivider(canvas, bounds, -1); 3232 } 3233 } 3234 3235 for (int i = 0; i < count; i++) { 3236 final int itemIndex = (first + i); 3237 final boolean isHeader = (itemIndex < headerCount); 3238 final boolean isFooter = (itemIndex >= footerLimit); 3239 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3240 final View child = getChildAt(i); 3241 bottom = child.getBottom(); 3242 final boolean isLastItem = (i == (count - 1)); 3243 3244 if (drawDividers && (bottom < listBottom) 3245 && !(drawOverscrollFooter && isLastItem)) { 3246 final int nextIndex = (itemIndex + 1); 3247 // Draw dividers between enabled items, headers 3248 // and/or footers when enabled and requested, and 3249 // after the last enabled item. 3250 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3251 && (nextIndex >= headerCount)) && (isLastItem 3252 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3253 && (nextIndex < footerLimit)))) { 3254 bounds.top = bottom; 3255 bounds.bottom = bottom + dividerHeight; 3256 drawDivider(canvas, bounds, i); 3257 } else if (fillForMissingDividers) { 3258 bounds.top = bottom; 3259 bounds.bottom = bottom + dividerHeight; 3260 canvas.drawRect(bounds, paint); 3261 } 3262 } 3263 } 3264 } 3265 3266 final int overFooterBottom = mBottom + mScrollY; 3267 if (drawOverscrollFooter && first + count == itemCount && 3268 overFooterBottom > bottom) { 3269 bounds.top = bottom; 3270 bounds.bottom = overFooterBottom; 3271 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3272 } 3273 } else { 3274 int top; 3275 3276 final int scrollY = mScrollY; 3277 3278 if (count > 0 && drawOverscrollHeader) { 3279 bounds.top = scrollY; 3280 bounds.bottom = getChildAt(0).getTop(); 3281 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3282 } 3283 3284 final int start = drawOverscrollHeader ? 1 : 0; 3285 for (int i = start; i < count; i++) { 3286 final int itemIndex = (first + i); 3287 final boolean isHeader = (itemIndex < headerCount); 3288 final boolean isFooter = (itemIndex >= footerLimit); 3289 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3290 final View child = getChildAt(i); 3291 top = child.getTop(); 3292 if (drawDividers && (top > effectivePaddingTop)) { 3293 final boolean isFirstItem = (i == start); 3294 final int previousIndex = (itemIndex - 1); 3295 // Draw dividers between enabled items, headers 3296 // and/or footers when enabled and requested, and 3297 // before the first enabled item. 3298 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3299 && (previousIndex >= headerCount)) && (isFirstItem || 3300 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3301 && (previousIndex < footerLimit)))) { 3302 bounds.top = top - dividerHeight; 3303 bounds.bottom = top; 3304 // Give the method the child ABOVE the divider, 3305 // so we subtract one from our child position. 3306 // Give -1 when there is no child above the 3307 // divider. 3308 drawDivider(canvas, bounds, i - 1); 3309 } else if (fillForMissingDividers) { 3310 bounds.top = top - dividerHeight; 3311 bounds.bottom = top; 3312 canvas.drawRect(bounds, paint); 3313 } 3314 } 3315 } 3316 } 3317 3318 if (count > 0 && scrollY > 0) { 3319 if (drawOverscrollFooter) { 3320 final int absListBottom = mBottom; 3321 bounds.top = absListBottom; 3322 bounds.bottom = absListBottom + scrollY; 3323 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3324 } else if (drawDividers) { 3325 bounds.top = listBottom; 3326 bounds.bottom = listBottom + dividerHeight; 3327 drawDivider(canvas, bounds, -1); 3328 } 3329 } 3330 } 3331 } 3332 3333 // Draw the indicators (these should be drawn above the dividers) and children 3334 super.dispatchDraw(canvas); 3335 } 3336 3337 @Override 3338 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3339 boolean more = super.drawChild(canvas, child, drawingTime); 3340 if (mCachingActive && child.mCachingFailed) { 3341 mCachingActive = false; 3342 } 3343 return more; 3344 } 3345 3346 /** 3347 * Draws a divider for the given child in the given bounds. 3348 * 3349 * @param canvas The canvas to draw to. 3350 * @param bounds The bounds of the divider. 3351 * @param childIndex The index of child (of the View) above the divider. 3352 * This will be -1 if there is no child above the divider to be 3353 * drawn. 3354 */ 3355 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3356 // This widget draws the same divider for all children 3357 final Drawable divider = mDivider; 3358 3359 divider.setBounds(bounds); 3360 divider.draw(canvas); 3361 } 3362 3363 /** 3364 * Returns the drawable that will be drawn between each item in the list. 3365 * 3366 * @return the current drawable drawn between list elements 3367 */ 3368 public Drawable getDivider() { 3369 return mDivider; 3370 } 3371 3372 /** 3373 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3374 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3375 * 3376 * @param divider The drawable to use. 3377 */ 3378 public void setDivider(Drawable divider) { 3379 if (divider != null) { 3380 mDividerHeight = divider.getIntrinsicHeight(); 3381 } else { 3382 mDividerHeight = 0; 3383 } 3384 mDivider = divider; 3385 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3386 requestLayout(); 3387 invalidate(); 3388 } 3389 3390 /** 3391 * @return Returns the height of the divider that will be drawn between each item in the list. 3392 */ 3393 public int getDividerHeight() { 3394 return mDividerHeight; 3395 } 3396 3397 /** 3398 * Sets the height of the divider that will be drawn between each item in the list. Calling 3399 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3400 * 3401 * @param height The new height of the divider in pixels. 3402 */ 3403 public void setDividerHeight(int height) { 3404 mDividerHeight = height; 3405 requestLayout(); 3406 invalidate(); 3407 } 3408 3409 /** 3410 * Enables or disables the drawing of the divider for header views. 3411 * 3412 * @param headerDividersEnabled True to draw the headers, false otherwise. 3413 * 3414 * @see #setFooterDividersEnabled(boolean) 3415 * @see #areHeaderDividersEnabled() 3416 * @see #addHeaderView(android.view.View) 3417 */ 3418 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3419 mHeaderDividersEnabled = headerDividersEnabled; 3420 invalidate(); 3421 } 3422 3423 /** 3424 * @return Whether the drawing of the divider for header views is enabled 3425 * 3426 * @see #setHeaderDividersEnabled(boolean) 3427 */ 3428 public boolean areHeaderDividersEnabled() { 3429 return mHeaderDividersEnabled; 3430 } 3431 3432 /** 3433 * Enables or disables the drawing of the divider for footer views. 3434 * 3435 * @param footerDividersEnabled True to draw the footers, false otherwise. 3436 * 3437 * @see #setHeaderDividersEnabled(boolean) 3438 * @see #areFooterDividersEnabled() 3439 * @see #addFooterView(android.view.View) 3440 */ 3441 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3442 mFooterDividersEnabled = footerDividersEnabled; 3443 invalidate(); 3444 } 3445 3446 /** 3447 * @return Whether the drawing of the divider for footer views is enabled 3448 * 3449 * @see #setFooterDividersEnabled(boolean) 3450 */ 3451 public boolean areFooterDividersEnabled() { 3452 return mFooterDividersEnabled; 3453 } 3454 3455 /** 3456 * Sets the drawable that will be drawn above all other list content. 3457 * This area can become visible when the user overscrolls the list. 3458 * 3459 * @param header The drawable to use 3460 */ 3461 public void setOverscrollHeader(Drawable header) { 3462 mOverScrollHeader = header; 3463 if (mScrollY < 0) { 3464 invalidate(); 3465 } 3466 } 3467 3468 /** 3469 * @return The drawable that will be drawn above all other list content 3470 */ 3471 public Drawable getOverscrollHeader() { 3472 return mOverScrollHeader; 3473 } 3474 3475 /** 3476 * Sets the drawable that will be drawn below all other list content. 3477 * This area can become visible when the user overscrolls the list, 3478 * or when the list's content does not fully fill the container area. 3479 * 3480 * @param footer The drawable to use 3481 */ 3482 public void setOverscrollFooter(Drawable footer) { 3483 mOverScrollFooter = footer; 3484 invalidate(); 3485 } 3486 3487 /** 3488 * @return The drawable that will be drawn below all other list content 3489 */ 3490 public Drawable getOverscrollFooter() { 3491 return mOverScrollFooter; 3492 } 3493 3494 @Override 3495 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3496 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3497 3498 final ListAdapter adapter = mAdapter; 3499 int closetChildIndex = -1; 3500 int closestChildTop = 0; 3501 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3502 previouslyFocusedRect.offset(mScrollX, mScrollY); 3503 3504 // Don't cache the result of getChildCount or mFirstPosition here, 3505 // it could change in layoutChildren. 3506 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3507 mLayoutMode = LAYOUT_NORMAL; 3508 layoutChildren(); 3509 } 3510 3511 // figure out which item should be selected based on previously 3512 // focused rect 3513 Rect otherRect = mTempRect; 3514 int minDistance = Integer.MAX_VALUE; 3515 final int childCount = getChildCount(); 3516 final int firstPosition = mFirstPosition; 3517 3518 for (int i = 0; i < childCount; i++) { 3519 // only consider selectable views 3520 if (!adapter.isEnabled(firstPosition + i)) { 3521 continue; 3522 } 3523 3524 View other = getChildAt(i); 3525 other.getDrawingRect(otherRect); 3526 offsetDescendantRectToMyCoords(other, otherRect); 3527 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3528 3529 if (distance < minDistance) { 3530 minDistance = distance; 3531 closetChildIndex = i; 3532 closestChildTop = other.getTop(); 3533 } 3534 } 3535 } 3536 3537 if (closetChildIndex >= 0) { 3538 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3539 } else { 3540 requestLayout(); 3541 } 3542 } 3543 3544 3545 /* 3546 * (non-Javadoc) 3547 * 3548 * Children specified in XML are assumed to be header views. After we have 3549 * parsed them move them out of the children list and into mHeaderViews. 3550 */ 3551 @Override 3552 protected void onFinishInflate() { 3553 super.onFinishInflate(); 3554 3555 int count = getChildCount(); 3556 if (count > 0) { 3557 for (int i = 0; i < count; ++i) { 3558 addHeaderView(getChildAt(i)); 3559 } 3560 removeAllViews(); 3561 } 3562 } 3563 3564 /* (non-Javadoc) 3565 * @see android.view.View#findViewById(int) 3566 * First look in our children, then in any header and footer views that may be scrolled off. 3567 */ 3568 @Override 3569 protected View findViewTraversal(int id) { 3570 View v; 3571 v = super.findViewTraversal(id); 3572 if (v == null) { 3573 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3574 if (v != null) { 3575 return v; 3576 } 3577 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3578 if (v != null) { 3579 return v; 3580 } 3581 } 3582 return v; 3583 } 3584 3585 /* (non-Javadoc) 3586 * 3587 * Look in the passed in list of headers or footers for the view. 3588 */ 3589 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3590 if (where != null) { 3591 int len = where.size(); 3592 View v; 3593 3594 for (int i = 0; i < len; i++) { 3595 v = where.get(i).view; 3596 3597 if (!v.isRootNamespace()) { 3598 v = v.findViewById(id); 3599 3600 if (v != null) { 3601 return v; 3602 } 3603 } 3604 } 3605 } 3606 return null; 3607 } 3608 3609 /* (non-Javadoc) 3610 * @see android.view.View#findViewWithTag(Object) 3611 * First look in our children, then in any header and footer views that may be scrolled off. 3612 */ 3613 @Override 3614 protected View findViewWithTagTraversal(Object tag) { 3615 View v; 3616 v = super.findViewWithTagTraversal(tag); 3617 if (v == null) { 3618 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3619 if (v != null) { 3620 return v; 3621 } 3622 3623 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3624 if (v != null) { 3625 return v; 3626 } 3627 } 3628 return v; 3629 } 3630 3631 /* (non-Javadoc) 3632 * 3633 * Look in the passed in list of headers or footers for the view with the tag. 3634 */ 3635 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3636 if (where != null) { 3637 int len = where.size(); 3638 View v; 3639 3640 for (int i = 0; i < len; i++) { 3641 v = where.get(i).view; 3642 3643 if (!v.isRootNamespace()) { 3644 v = v.findViewWithTag(tag); 3645 3646 if (v != null) { 3647 return v; 3648 } 3649 } 3650 } 3651 } 3652 return null; 3653 } 3654 3655 /** 3656 * @hide 3657 * @see android.view.View#findViewByPredicate(Predicate) 3658 * First look in our children, then in any header and footer views that may be scrolled off. 3659 */ 3660 @Override 3661 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3662 View v; 3663 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3664 if (v == null) { 3665 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3666 if (v != null) { 3667 return v; 3668 } 3669 3670 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3671 if (v != null) { 3672 return v; 3673 } 3674 } 3675 return v; 3676 } 3677 3678 /* (non-Javadoc) 3679 * 3680 * Look in the passed in list of headers or footers for the first view that matches 3681 * the predicate. 3682 */ 3683 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3684 Predicate<View> predicate, View childToSkip) { 3685 if (where != null) { 3686 int len = where.size(); 3687 View v; 3688 3689 for (int i = 0; i < len; i++) { 3690 v = where.get(i).view; 3691 3692 if (v != childToSkip && !v.isRootNamespace()) { 3693 v = v.findViewByPredicate(predicate); 3694 3695 if (v != null) { 3696 return v; 3697 } 3698 } 3699 } 3700 } 3701 return null; 3702 } 3703 3704 /** 3705 * Returns the set of checked items ids. The result is only valid if the 3706 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3707 * 3708 * @return A new array which contains the id of each checked item in the 3709 * list. 3710 * 3711 * @deprecated Use {@link #getCheckedItemIds()} instead. 3712 */ 3713 @Deprecated 3714 public long[] getCheckItemIds() { 3715 // Use new behavior that correctly handles stable ID mapping. 3716 if (mAdapter != null && mAdapter.hasStableIds()) { 3717 return getCheckedItemIds(); 3718 } 3719 3720 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3721 // Fall back to it to support legacy apps. 3722 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3723 final SparseBooleanArray states = mCheckStates; 3724 final int count = states.size(); 3725 final long[] ids = new long[count]; 3726 final ListAdapter adapter = mAdapter; 3727 3728 int checkedCount = 0; 3729 for (int i = 0; i < count; i++) { 3730 if (states.valueAt(i)) { 3731 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3732 } 3733 } 3734 3735 // Trim array if needed. mCheckStates may contain false values 3736 // resulting in checkedCount being smaller than count. 3737 if (checkedCount == count) { 3738 return ids; 3739 } else { 3740 final long[] result = new long[checkedCount]; 3741 System.arraycopy(ids, 0, result, 0, checkedCount); 3742 3743 return result; 3744 } 3745 } 3746 return new long[0]; 3747 } 3748 3749 @Override 3750 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 3751 super.onInitializeAccessibilityEvent(event); 3752 event.setClassName(ListView.class.getName()); 3753 } 3754 3755 @Override 3756 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 3757 super.onInitializeAccessibilityNodeInfo(info); 3758 info.setClassName(ListView.class.getName()); 3759 3760 final int count = getCount(); 3761 final CollectionInfo collectionInfo = CollectionInfo.obtain(1, count, false); 3762 info.setCollectionInfo(collectionInfo); 3763 } 3764 3765 @Override 3766 public void onInitializeAccessibilityNodeInfoForItem( 3767 View view, int position, AccessibilityNodeInfo info) { 3768 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3769 3770 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3771 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3772 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain(0, 1, position, 1, isHeading); 3773 info.setCollectionItemInfo(itemInfo); 3774 } 3775} 3776