ListView.java revision 56032a37df89511c8d3b3b3c79818e2c86dedb92
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.accessibility.AccessibilityEvent; 43import android.view.accessibility.AccessibilityNodeInfo; 44import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 45import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 46import android.widget.RemoteViews.RemoteView; 47 48import java.util.ArrayList; 49 50/* 51 * Implementation Notes: 52 * 53 * Some terminology: 54 * 55 * index - index of the items that are currently visible 56 * position - index of the items in the cursor 57 */ 58 59 60/** 61 * A view that shows items in a vertically scrolling list. The items 62 * come from the {@link ListAdapter} associated with this view. 63 * 64 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 65 * guide.</p> 66 * 67 * @attr ref android.R.styleable#ListView_entries 68 * @attr ref android.R.styleable#ListView_divider 69 * @attr ref android.R.styleable#ListView_dividerHeight 70 * @attr ref android.R.styleable#ListView_headerDividersEnabled 71 * @attr ref android.R.styleable#ListView_footerDividersEnabled 72 */ 73@RemoteView 74public class ListView extends AbsListView { 75 /** 76 * Used to indicate a no preference for a position type. 77 */ 78 static final int NO_POSITION = -1; 79 80 /** 81 * When arrow scrolling, ListView will never scroll more than this factor 82 * times the height of the list. 83 */ 84 private static final float MAX_SCROLL_FACTOR = 0.33f; 85 86 /** 87 * When arrow scrolling, need a certain amount of pixels to preview next 88 * items. This is usually the fading edge, but if that is small enough, 89 * we want to make sure we preview at least this many pixels. 90 */ 91 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 92 93 /** 94 * A class that represents a fixed view in a list, for example a header at the top 95 * or a footer at the bottom. 96 */ 97 public class FixedViewInfo { 98 /** The view to add to the list */ 99 public View view; 100 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 101 public Object data; 102 /** <code>true</code> if the fixed view should be selectable in the list */ 103 public boolean isSelectable; 104 } 105 106 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 107 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 108 109 Drawable mDivider; 110 int mDividerHeight; 111 112 Drawable mOverScrollHeader; 113 Drawable mOverScrollFooter; 114 115 private boolean mIsCacheColorOpaque; 116 private boolean mDividerIsOpaque; 117 118 private boolean mHeaderDividersEnabled; 119 private boolean mFooterDividersEnabled; 120 121 private boolean mAreAllItemsSelectable = true; 122 123 private boolean mItemsCanFocus = false; 124 125 // used for temporary calculations. 126 private final Rect mTempRect = new Rect(); 127 private Paint mDividerPaint; 128 129 // the single allocated result per list view; kinda cheesey but avoids 130 // allocating these thingies too often. 131 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 132 133 // Keeps focused children visible through resizes 134 private FocusSelector mFocusSelector; 135 136 public ListView(Context context) { 137 this(context, null); 138 } 139 140 public ListView(Context context, AttributeSet attrs) { 141 this(context, attrs, com.android.internal.R.attr.listViewStyle); 142 } 143 144 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 145 this(context, attrs, defStyleAttr, 0); 146 } 147 148 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 149 super(context, attrs, defStyleAttr, defStyleRes); 150 151 final TypedArray a = context.obtainStyledAttributes( 152 attrs, com.android.internal.R.styleable.ListView, defStyleAttr, defStyleRes); 153 154 CharSequence[] entries = a.getTextArray( 155 com.android.internal.R.styleable.ListView_entries); 156 if (entries != null) { 157 setAdapter(new ArrayAdapter<CharSequence>(context, 158 com.android.internal.R.layout.simple_list_item_1, entries)); 159 } 160 161 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 162 if (d != null) { 163 // If a divider is specified use its intrinsic height for divider height 164 setDivider(d); 165 } 166 167 final Drawable osHeader = a.getDrawable( 168 com.android.internal.R.styleable.ListView_overScrollHeader); 169 if (osHeader != null) { 170 setOverscrollHeader(osHeader); 171 } 172 173 final Drawable osFooter = a.getDrawable( 174 com.android.internal.R.styleable.ListView_overScrollFooter); 175 if (osFooter != null) { 176 setOverscrollFooter(osFooter); 177 } 178 179 // Use the height specified, zero being the default 180 final int dividerHeight = a.getDimensionPixelSize( 181 com.android.internal.R.styleable.ListView_dividerHeight, 0); 182 if (dividerHeight != 0) { 183 setDividerHeight(dividerHeight); 184 } 185 186 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 187 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 188 189 a.recycle(); 190 } 191 192 /** 193 * @return The maximum amount a list view will scroll in response to 194 * an arrow event. 195 */ 196 public int getMaxScrollAmount() { 197 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 198 } 199 200 /** 201 * Make sure views are touching the top or bottom edge, as appropriate for 202 * our gravity 203 */ 204 private void adjustViewsUpOrDown() { 205 final int childCount = getChildCount(); 206 int delta; 207 208 if (childCount > 0) { 209 View child; 210 211 if (!mStackFromBottom) { 212 // Uh-oh -- we came up short. Slide all views up to make them 213 // align with the top 214 child = getChildAt(0); 215 delta = child.getTop() - mListPadding.top; 216 if (mFirstPosition != 0) { 217 // It's OK to have some space above the first item if it is 218 // part of the vertical spacing 219 delta -= mDividerHeight; 220 } 221 if (delta < 0) { 222 // We only are looking to see if we are too low, not too high 223 delta = 0; 224 } 225 } else { 226 // we are too high, slide all views down to align with bottom 227 child = getChildAt(childCount - 1); 228 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 229 230 if (mFirstPosition + childCount < mItemCount) { 231 // It's OK to have some space below the last item if it is 232 // part of the vertical spacing 233 delta += mDividerHeight; 234 } 235 236 if (delta > 0) { 237 delta = 0; 238 } 239 } 240 241 if (delta != 0) { 242 offsetChildrenTopAndBottom(-delta); 243 } 244 } 245 } 246 247 /** 248 * Add a fixed view to appear at the top of the list. If this method is 249 * called more than once, the views will appear in the order they were 250 * added. Views added using this call can take focus if they want. 251 * <p> 252 * Note: When first introduced, this method could only be called before 253 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 254 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 255 * called at any time. If the ListView's adapter does not extend 256 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 257 * instance of {@link WrapperListAdapter}. 258 * 259 * @param v The view to add. 260 * @param data Data to associate with this view 261 * @param isSelectable whether the item is selectable 262 */ 263 public void addHeaderView(View v, Object data, boolean isSelectable) { 264 final FixedViewInfo info = new FixedViewInfo(); 265 info.view = v; 266 info.data = data; 267 info.isSelectable = isSelectable; 268 mHeaderViewInfos.add(info); 269 mAreAllItemsSelectable &= isSelectable; 270 271 // Wrap the adapter if it wasn't already wrapped. 272 if (mAdapter != null) { 273 if (!(mAdapter instanceof HeaderViewListAdapter)) { 274 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 275 } 276 277 // In the case of re-adding a header view, or adding one later on, 278 // we need to notify the observer. 279 if (mDataSetObserver != null) { 280 mDataSetObserver.onChanged(); 281 } 282 } 283 } 284 285 /** 286 * Add a fixed view to appear at the top of the list. If addHeaderView is 287 * called more than once, the views will appear in the order they were 288 * added. Views added using this call can take focus if they want. 289 * <p> 290 * Note: When first introduced, this method could only be called before 291 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 292 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 293 * called at any time. If the ListView's adapter does not extend 294 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 295 * instance of {@link WrapperListAdapter}. 296 * 297 * @param v The view to add. 298 */ 299 public void addHeaderView(View v) { 300 addHeaderView(v, null, true); 301 } 302 303 @Override 304 public int getHeaderViewsCount() { 305 return mHeaderViewInfos.size(); 306 } 307 308 /** 309 * Removes a previously-added header view. 310 * 311 * @param v The view to remove 312 * @return true if the view was removed, false if the view was not a header 313 * view 314 */ 315 public boolean removeHeaderView(View v) { 316 if (mHeaderViewInfos.size() > 0) { 317 boolean result = false; 318 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 319 if (mDataSetObserver != null) { 320 mDataSetObserver.onChanged(); 321 } 322 result = true; 323 } 324 removeFixedViewInfo(v, mHeaderViewInfos); 325 return result; 326 } 327 return false; 328 } 329 330 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 331 int len = where.size(); 332 for (int i = 0; i < len; ++i) { 333 FixedViewInfo info = where.get(i); 334 if (info.view == v) { 335 where.remove(i); 336 break; 337 } 338 } 339 } 340 341 /** 342 * Add a fixed view to appear at the bottom of the list. If addFooterView is 343 * called more than once, the views will appear in the order they were 344 * added. Views added using this call can take focus if they want. 345 * <p> 346 * Note: When first introduced, this method could only be called before 347 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 348 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 349 * called at any time. If the ListView's adapter does not extend 350 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 351 * instance of {@link WrapperListAdapter}. 352 * 353 * @param v The view to add. 354 * @param data Data to associate with this view 355 * @param isSelectable true if the footer view can be selected 356 */ 357 public void addFooterView(View v, Object data, boolean isSelectable) { 358 final FixedViewInfo info = new FixedViewInfo(); 359 info.view = v; 360 info.data = data; 361 info.isSelectable = isSelectable; 362 mFooterViewInfos.add(info); 363 mAreAllItemsSelectable &= isSelectable; 364 365 // Wrap the adapter if it wasn't already wrapped. 366 if (mAdapter != null) { 367 if (!(mAdapter instanceof HeaderViewListAdapter)) { 368 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 369 } 370 371 // In the case of re-adding a footer view, or adding one later on, 372 // we need to notify the observer. 373 if (mDataSetObserver != null) { 374 mDataSetObserver.onChanged(); 375 } 376 } 377 } 378 379 /** 380 * Add a fixed view to appear at the bottom of the list. If addFooterView is 381 * called more than once, the views will appear in the order they were 382 * added. Views added using this call can take focus if they want. 383 * <p> 384 * Note: When first introduced, this method could only be called before 385 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 386 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 387 * called at any time. If the ListView's adapter does not extend 388 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 389 * instance of {@link WrapperListAdapter}. 390 * 391 * @param v The view to add. 392 */ 393 public void addFooterView(View v) { 394 addFooterView(v, null, true); 395 } 396 397 @Override 398 public int getFooterViewsCount() { 399 return mFooterViewInfos.size(); 400 } 401 402 /** 403 * Removes a previously-added footer view. 404 * 405 * @param v The view to remove 406 * @return 407 * true if the view was removed, false if the view was not a footer view 408 */ 409 public boolean removeFooterView(View v) { 410 if (mFooterViewInfos.size() > 0) { 411 boolean result = false; 412 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 413 if (mDataSetObserver != null) { 414 mDataSetObserver.onChanged(); 415 } 416 result = true; 417 } 418 removeFixedViewInfo(v, mFooterViewInfos); 419 return result; 420 } 421 return false; 422 } 423 424 /** 425 * Returns the adapter currently in use in this ListView. The returned adapter 426 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 427 * might be a {@link WrapperListAdapter}. 428 * 429 * @return The adapter currently used to display data in this ListView. 430 * 431 * @see #setAdapter(ListAdapter) 432 */ 433 @Override 434 public ListAdapter getAdapter() { 435 return mAdapter; 436 } 437 438 /** 439 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 440 * through the specified intent. 441 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 442 */ 443 @android.view.RemotableViewMethod 444 public void setRemoteViewsAdapter(Intent intent) { 445 super.setRemoteViewsAdapter(intent); 446 } 447 448 /** 449 * Sets the data behind this ListView. 450 * 451 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 452 * depending on the ListView features currently in use. For instance, adding 453 * headers and/or footers will cause the adapter to be wrapped. 454 * 455 * @param adapter The ListAdapter which is responsible for maintaining the 456 * data backing this list and for producing a view to represent an 457 * item in that data set. 458 * 459 * @see #getAdapter() 460 */ 461 @Override 462 public void setAdapter(ListAdapter adapter) { 463 if (mAdapter != null && mDataSetObserver != null) { 464 mAdapter.unregisterDataSetObserver(mDataSetObserver); 465 } 466 467 resetList(); 468 mRecycler.clear(); 469 470 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 471 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 472 } else { 473 mAdapter = adapter; 474 } 475 476 mOldSelectedPosition = INVALID_POSITION; 477 mOldSelectedRowId = INVALID_ROW_ID; 478 479 // AbsListView#setAdapter will update choice mode states. 480 super.setAdapter(adapter); 481 482 if (mAdapter != null) { 483 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 484 mOldItemCount = mItemCount; 485 mItemCount = mAdapter.getCount(); 486 checkFocus(); 487 488 mDataSetObserver = new AdapterDataSetObserver(); 489 mAdapter.registerDataSetObserver(mDataSetObserver); 490 491 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 492 493 int position; 494 if (mStackFromBottom) { 495 position = lookForSelectablePosition(mItemCount - 1, false); 496 } else { 497 position = lookForSelectablePosition(0, true); 498 } 499 setSelectedPositionInt(position); 500 setNextSelectedPositionInt(position); 501 502 if (mItemCount == 0) { 503 // Nothing selected 504 checkSelectionChanged(); 505 } 506 } else { 507 mAreAllItemsSelectable = true; 508 checkFocus(); 509 // Nothing selected 510 checkSelectionChanged(); 511 } 512 513 requestLayout(); 514 } 515 516 /** 517 * The list is empty. Clear everything out. 518 */ 519 @Override 520 void resetList() { 521 // The parent's resetList() will remove all views from the layout so we need to 522 // cleanup the state of our footers and headers 523 clearRecycledState(mHeaderViewInfos); 524 clearRecycledState(mFooterViewInfos); 525 526 super.resetList(); 527 528 mLayoutMode = LAYOUT_NORMAL; 529 } 530 531 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 532 if (infos != null) { 533 final int count = infos.size(); 534 535 for (int i = 0; i < count; i++) { 536 final View child = infos.get(i).view; 537 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 538 if (p != null) { 539 p.recycledHeaderFooter = false; 540 } 541 } 542 } 543 } 544 545 /** 546 * @return Whether the list needs to show the top fading edge 547 */ 548 private boolean showingTopFadingEdge() { 549 final int listTop = mScrollY + mListPadding.top; 550 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 551 } 552 553 /** 554 * @return Whether the list needs to show the bottom fading edge 555 */ 556 private boolean showingBottomFadingEdge() { 557 final int childCount = getChildCount(); 558 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 559 final int lastVisiblePosition = mFirstPosition + childCount - 1; 560 561 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 562 563 return (lastVisiblePosition < mItemCount - 1) 564 || (bottomOfBottomChild < listBottom); 565 } 566 567 568 @Override 569 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 570 571 int rectTopWithinChild = rect.top; 572 573 // offset so rect is in coordinates of the this view 574 rect.offset(child.getLeft(), child.getTop()); 575 rect.offset(-child.getScrollX(), -child.getScrollY()); 576 577 final int height = getHeight(); 578 int listUnfadedTop = getScrollY(); 579 int listUnfadedBottom = listUnfadedTop + height; 580 final int fadingEdge = getVerticalFadingEdgeLength(); 581 582 if (showingTopFadingEdge()) { 583 // leave room for top fading edge as long as rect isn't at very top 584 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 585 listUnfadedTop += fadingEdge; 586 } 587 } 588 589 int childCount = getChildCount(); 590 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 591 592 if (showingBottomFadingEdge()) { 593 // leave room for bottom fading edge as long as rect isn't at very bottom 594 if ((mSelectedPosition < mItemCount - 1) 595 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 596 listUnfadedBottom -= fadingEdge; 597 } 598 } 599 600 int scrollYDelta = 0; 601 602 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 603 // need to MOVE DOWN to get it in view: move down just enough so 604 // that the entire rectangle is in view (or at least the first 605 // screen size chunk). 606 607 if (rect.height() > height) { 608 // just enough to get screen size chunk on 609 scrollYDelta += (rect.top - listUnfadedTop); 610 } else { 611 // get entire rect at bottom of screen 612 scrollYDelta += (rect.bottom - listUnfadedBottom); 613 } 614 615 // make sure we aren't scrolling beyond the end of our children 616 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 617 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 618 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 619 // need to MOVE UP to get it in view: move up just enough so that 620 // entire rectangle is in view (or at least the first screen 621 // size chunk of it). 622 623 if (rect.height() > height) { 624 // screen size chunk 625 scrollYDelta -= (listUnfadedBottom - rect.bottom); 626 } else { 627 // entire rect at top 628 scrollYDelta -= (listUnfadedTop - rect.top); 629 } 630 631 // make sure we aren't scrolling any further than the top our children 632 int top = getChildAt(0).getTop(); 633 int deltaToTop = top - listUnfadedTop; 634 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 635 } 636 637 final boolean scroll = scrollYDelta != 0; 638 if (scroll) { 639 scrollListItemsBy(-scrollYDelta); 640 positionSelector(INVALID_POSITION, child); 641 mSelectedTop = child.getTop(); 642 invalidate(); 643 } 644 return scroll; 645 } 646 647 /** 648 * {@inheritDoc} 649 */ 650 @Override 651 void fillGap(boolean down) { 652 final int count = getChildCount(); 653 if (down) { 654 int paddingTop = 0; 655 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 656 paddingTop = getListPaddingTop(); 657 } 658 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 659 paddingTop; 660 fillDown(mFirstPosition + count, startOffset); 661 correctTooHigh(getChildCount()); 662 } else { 663 int paddingBottom = 0; 664 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 665 paddingBottom = getListPaddingBottom(); 666 } 667 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 668 getHeight() - paddingBottom; 669 fillUp(mFirstPosition - 1, startOffset); 670 correctTooLow(getChildCount()); 671 } 672 } 673 674 /** 675 * Fills the list from pos down to the end of the list view. 676 * 677 * @param pos The first position to put in the list 678 * 679 * @param nextTop The location where the top of the item associated with pos 680 * should be drawn 681 * 682 * @return The view that is currently selected, if it happens to be in the 683 * range that we draw. 684 */ 685 private View fillDown(int pos, int nextTop) { 686 View selectedView = null; 687 688 int end = (mBottom - mTop); 689 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 690 end -= mListPadding.bottom; 691 } 692 693 while (nextTop < end && pos < mItemCount) { 694 // is this the selected item? 695 boolean selected = pos == mSelectedPosition; 696 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 697 698 nextTop = child.getBottom() + mDividerHeight; 699 if (selected) { 700 selectedView = child; 701 } 702 pos++; 703 } 704 705 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 706 return selectedView; 707 } 708 709 /** 710 * Fills the list from pos up to the top of the list view. 711 * 712 * @param pos The first position to put in the list 713 * 714 * @param nextBottom The location where the bottom of the item associated 715 * with pos should be drawn 716 * 717 * @return The view that is currently selected 718 */ 719 private View fillUp(int pos, int nextBottom) { 720 View selectedView = null; 721 722 int end = 0; 723 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 724 end = mListPadding.top; 725 } 726 727 while (nextBottom > end && pos >= 0) { 728 // is this the selected item? 729 boolean selected = pos == mSelectedPosition; 730 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 731 nextBottom = child.getTop() - mDividerHeight; 732 if (selected) { 733 selectedView = child; 734 } 735 pos--; 736 } 737 738 mFirstPosition = pos + 1; 739 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 740 return selectedView; 741 } 742 743 /** 744 * Fills the list from top to bottom, starting with mFirstPosition 745 * 746 * @param nextTop The location where the top of the first item should be 747 * drawn 748 * 749 * @return The view that is currently selected 750 */ 751 private View fillFromTop(int nextTop) { 752 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 753 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 754 if (mFirstPosition < 0) { 755 mFirstPosition = 0; 756 } 757 return fillDown(mFirstPosition, nextTop); 758 } 759 760 761 /** 762 * Put mSelectedPosition in the middle of the screen and then build up and 763 * down from there. This method forces mSelectedPosition to the center. 764 * 765 * @param childrenTop Top of the area in which children can be drawn, as 766 * measured in pixels 767 * @param childrenBottom Bottom of the area in which children can be drawn, 768 * as measured in pixels 769 * @return Currently selected view 770 */ 771 private View fillFromMiddle(int childrenTop, int childrenBottom) { 772 int height = childrenBottom - childrenTop; 773 774 int position = reconcileSelectedPosition(); 775 776 View sel = makeAndAddView(position, childrenTop, true, 777 mListPadding.left, true); 778 mFirstPosition = position; 779 780 int selHeight = sel.getMeasuredHeight(); 781 if (selHeight <= height) { 782 sel.offsetTopAndBottom((height - selHeight) / 2); 783 } 784 785 fillAboveAndBelow(sel, position); 786 787 if (!mStackFromBottom) { 788 correctTooHigh(getChildCount()); 789 } else { 790 correctTooLow(getChildCount()); 791 } 792 793 return sel; 794 } 795 796 /** 797 * Once the selected view as been placed, fill up the visible area above and 798 * below it. 799 * 800 * @param sel The selected view 801 * @param position The position corresponding to sel 802 */ 803 private void fillAboveAndBelow(View sel, int position) { 804 final int dividerHeight = mDividerHeight; 805 if (!mStackFromBottom) { 806 fillUp(position - 1, sel.getTop() - dividerHeight); 807 adjustViewsUpOrDown(); 808 fillDown(position + 1, sel.getBottom() + dividerHeight); 809 } else { 810 fillDown(position + 1, sel.getBottom() + dividerHeight); 811 adjustViewsUpOrDown(); 812 fillUp(position - 1, sel.getTop() - dividerHeight); 813 } 814 } 815 816 817 /** 818 * Fills the grid based on positioning the new selection at a specific 819 * location. The selection may be moved so that it does not intersect the 820 * faded edges. The grid is then filled upwards and downwards from there. 821 * 822 * @param selectedTop Where the selected item should be 823 * @param childrenTop Where to start drawing children 824 * @param childrenBottom Last pixel where children can be drawn 825 * @return The view that currently has selection 826 */ 827 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 828 int fadingEdgeLength = getVerticalFadingEdgeLength(); 829 final int selectedPosition = mSelectedPosition; 830 831 View sel; 832 833 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 834 selectedPosition); 835 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 836 selectedPosition); 837 838 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 839 840 841 // Some of the newly selected item extends below the bottom of the list 842 if (sel.getBottom() > bottomSelectionPixel) { 843 // Find space available above the selection into which we can scroll 844 // upwards 845 final int spaceAbove = sel.getTop() - topSelectionPixel; 846 847 // Find space required to bring the bottom of the selected item 848 // fully into view 849 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 850 final int offset = Math.min(spaceAbove, spaceBelow); 851 852 // Now offset the selected item to get it into view 853 sel.offsetTopAndBottom(-offset); 854 } else if (sel.getTop() < topSelectionPixel) { 855 // Find space required to bring the top of the selected item fully 856 // into view 857 final int spaceAbove = topSelectionPixel - sel.getTop(); 858 859 // Find space available below the selection into which we can scroll 860 // downwards 861 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 862 final int offset = Math.min(spaceAbove, spaceBelow); 863 864 // Offset the selected item to get it into view 865 sel.offsetTopAndBottom(offset); 866 } 867 868 // Fill in views above and below 869 fillAboveAndBelow(sel, selectedPosition); 870 871 if (!mStackFromBottom) { 872 correctTooHigh(getChildCount()); 873 } else { 874 correctTooLow(getChildCount()); 875 } 876 877 return sel; 878 } 879 880 /** 881 * Calculate the bottom-most pixel we can draw the selection into 882 * 883 * @param childrenBottom Bottom pixel were children can be drawn 884 * @param fadingEdgeLength Length of the fading edge in pixels, if present 885 * @param selectedPosition The position that will be selected 886 * @return The bottom-most pixel we can draw the selection into 887 */ 888 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 889 int selectedPosition) { 890 int bottomSelectionPixel = childrenBottom; 891 if (selectedPosition != mItemCount - 1) { 892 bottomSelectionPixel -= fadingEdgeLength; 893 } 894 return bottomSelectionPixel; 895 } 896 897 /** 898 * Calculate the top-most pixel we can draw the selection into 899 * 900 * @param childrenTop Top pixel were children can be drawn 901 * @param fadingEdgeLength Length of the fading edge in pixels, if present 902 * @param selectedPosition The position that will be selected 903 * @return The top-most pixel we can draw the selection into 904 */ 905 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 906 // first pixel we can draw the selection into 907 int topSelectionPixel = childrenTop; 908 if (selectedPosition > 0) { 909 topSelectionPixel += fadingEdgeLength; 910 } 911 return topSelectionPixel; 912 } 913 914 /** 915 * Smoothly scroll to the specified adapter position. The view will 916 * scroll such that the indicated position is displayed. 917 * @param position Scroll to this adapter position. 918 */ 919 @android.view.RemotableViewMethod 920 public void smoothScrollToPosition(int position) { 921 super.smoothScrollToPosition(position); 922 } 923 924 /** 925 * Smoothly scroll to the specified adapter position offset. The view will 926 * scroll such that the indicated position is displayed. 927 * @param offset The amount to offset from the adapter position to scroll to. 928 */ 929 @android.view.RemotableViewMethod 930 public void smoothScrollByOffset(int offset) { 931 super.smoothScrollByOffset(offset); 932 } 933 934 /** 935 * Fills the list based on positioning the new selection relative to the old 936 * selection. The new selection will be placed at, above, or below the 937 * location of the new selection depending on how the selection is moving. 938 * The selection will then be pinned to the visible part of the screen, 939 * excluding the edges that are faded. The list is then filled upwards and 940 * downwards from there. 941 * 942 * @param oldSel The old selected view. Useful for trying to put the new 943 * selection in the same place 944 * @param newSel The view that is to become selected. Useful for trying to 945 * put the new selection in the same place 946 * @param delta Which way we are moving 947 * @param childrenTop Where to start drawing children 948 * @param childrenBottom Last pixel where children can be drawn 949 * @return The view that currently has selection 950 */ 951 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 952 int childrenBottom) { 953 int fadingEdgeLength = getVerticalFadingEdgeLength(); 954 final int selectedPosition = mSelectedPosition; 955 956 View sel; 957 958 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 959 selectedPosition); 960 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 961 selectedPosition); 962 963 if (delta > 0) { 964 /* 965 * Case 1: Scrolling down. 966 */ 967 968 /* 969 * Before After 970 * | | | | 971 * +-------+ +-------+ 972 * | A | | A | 973 * | 1 | => +-------+ 974 * +-------+ | B | 975 * | B | | 2 | 976 * +-------+ +-------+ 977 * | | | | 978 * 979 * Try to keep the top of the previously selected item where it was. 980 * oldSel = A 981 * sel = B 982 */ 983 984 // Put oldSel (A) where it belongs 985 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 986 mListPadding.left, false); 987 988 final int dividerHeight = mDividerHeight; 989 990 // Now put the new selection (B) below that 991 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 992 mListPadding.left, true); 993 994 // Some of the newly selected item extends below the bottom of the list 995 if (sel.getBottom() > bottomSelectionPixel) { 996 997 // Find space available above the selection into which we can scroll upwards 998 int spaceAbove = sel.getTop() - topSelectionPixel; 999 1000 // Find space required to bring the bottom of the selected item fully into view 1001 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1002 1003 // Don't scroll more than half the height of the list 1004 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1005 int offset = Math.min(spaceAbove, spaceBelow); 1006 offset = Math.min(offset, halfVerticalSpace); 1007 1008 // We placed oldSel, so offset that item 1009 oldSel.offsetTopAndBottom(-offset); 1010 // Now offset the selected item to get it into view 1011 sel.offsetTopAndBottom(-offset); 1012 } 1013 1014 // Fill in views above and below 1015 if (!mStackFromBottom) { 1016 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1017 adjustViewsUpOrDown(); 1018 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1019 } else { 1020 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1021 adjustViewsUpOrDown(); 1022 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1023 } 1024 } else if (delta < 0) { 1025 /* 1026 * Case 2: Scrolling up. 1027 */ 1028 1029 /* 1030 * Before After 1031 * | | | | 1032 * +-------+ +-------+ 1033 * | A | | A | 1034 * +-------+ => | 1 | 1035 * | B | +-------+ 1036 * | 2 | | B | 1037 * +-------+ +-------+ 1038 * | | | | 1039 * 1040 * Try to keep the top of the item about to become selected where it was. 1041 * newSel = A 1042 * olSel = B 1043 */ 1044 1045 if (newSel != null) { 1046 // Try to position the top of newSel (A) where it was before it was selected 1047 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1048 true); 1049 } else { 1050 // If (A) was not on screen and so did not have a view, position 1051 // it above the oldSel (B) 1052 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1053 true); 1054 } 1055 1056 // Some of the newly selected item extends above the top of the list 1057 if (sel.getTop() < topSelectionPixel) { 1058 // Find space required to bring the top of the selected item fully into view 1059 int spaceAbove = topSelectionPixel - sel.getTop(); 1060 1061 // Find space available below the selection into which we can scroll downwards 1062 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1063 1064 // Don't scroll more than half the height of the list 1065 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1066 int offset = Math.min(spaceAbove, spaceBelow); 1067 offset = Math.min(offset, halfVerticalSpace); 1068 1069 // Offset the selected item to get it into view 1070 sel.offsetTopAndBottom(offset); 1071 } 1072 1073 // Fill in views above and below 1074 fillAboveAndBelow(sel, selectedPosition); 1075 } else { 1076 1077 int oldTop = oldSel.getTop(); 1078 1079 /* 1080 * Case 3: Staying still 1081 */ 1082 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1083 1084 // We're staying still... 1085 if (oldTop < childrenTop) { 1086 // ... but the top of the old selection was off screen. 1087 // (This can happen if the data changes size out from under us) 1088 int newBottom = sel.getBottom(); 1089 if (newBottom < childrenTop + 20) { 1090 // Not enough visible -- bring it onscreen 1091 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1092 } 1093 } 1094 1095 // Fill in views above and below 1096 fillAboveAndBelow(sel, selectedPosition); 1097 } 1098 1099 return sel; 1100 } 1101 1102 private class FocusSelector implements Runnable { 1103 private int mPosition; 1104 private int mPositionTop; 1105 1106 public FocusSelector setup(int position, int top) { 1107 mPosition = position; 1108 mPositionTop = top; 1109 return this; 1110 } 1111 1112 public void run() { 1113 setSelectionFromTop(mPosition, mPositionTop); 1114 } 1115 } 1116 1117 @Override 1118 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1119 if (getChildCount() > 0) { 1120 View focusedChild = getFocusedChild(); 1121 if (focusedChild != null) { 1122 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1123 final int childBottom = focusedChild.getBottom(); 1124 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1125 final int top = focusedChild.getTop() - offset; 1126 if (mFocusSelector == null) { 1127 mFocusSelector = new FocusSelector(); 1128 } 1129 post(mFocusSelector.setup(childPosition, top)); 1130 } 1131 } 1132 super.onSizeChanged(w, h, oldw, oldh); 1133 } 1134 1135 @Override 1136 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1137 // Sets up mListPadding 1138 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1139 1140 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1141 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1142 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1143 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1144 1145 int childWidth = 0; 1146 int childHeight = 0; 1147 int childState = 0; 1148 1149 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1150 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1151 heightMode == MeasureSpec.UNSPECIFIED)) { 1152 final View child = obtainView(0, mIsScrap); 1153 1154 measureScrapChild(child, 0, widthMeasureSpec); 1155 1156 childWidth = child.getMeasuredWidth(); 1157 childHeight = child.getMeasuredHeight(); 1158 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1159 1160 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1161 ((LayoutParams) child.getLayoutParams()).viewType)) { 1162 mRecycler.addScrapView(child, -1); 1163 } 1164 } 1165 1166 if (widthMode == MeasureSpec.UNSPECIFIED) { 1167 widthSize = mListPadding.left + mListPadding.right + childWidth + 1168 getVerticalScrollbarWidth(); 1169 } else { 1170 widthSize |= (childState&MEASURED_STATE_MASK); 1171 } 1172 1173 if (heightMode == MeasureSpec.UNSPECIFIED) { 1174 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1175 getVerticalFadingEdgeLength() * 2; 1176 } 1177 1178 if (heightMode == MeasureSpec.AT_MOST) { 1179 // TODO: after first layout we should maybe start at the first visible position, not 0 1180 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1181 } 1182 1183 setMeasuredDimension(widthSize , heightSize); 1184 mWidthMeasureSpec = widthMeasureSpec; 1185 } 1186 1187 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1188 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1189 if (p == null) { 1190 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1191 child.setLayoutParams(p); 1192 } 1193 p.viewType = mAdapter.getItemViewType(position); 1194 p.forceAdd = true; 1195 1196 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1197 mListPadding.left + mListPadding.right, p.width); 1198 int lpHeight = p.height; 1199 int childHeightSpec; 1200 if (lpHeight > 0) { 1201 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1202 } else { 1203 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1204 } 1205 child.measure(childWidthSpec, childHeightSpec); 1206 } 1207 1208 /** 1209 * @return True to recycle the views used to measure this ListView in 1210 * UNSPECIFIED/AT_MOST modes, false otherwise. 1211 * @hide 1212 */ 1213 @ViewDebug.ExportedProperty(category = "list") 1214 protected boolean recycleOnMeasure() { 1215 return true; 1216 } 1217 1218 /** 1219 * Measures the height of the given range of children (inclusive) and 1220 * returns the height with this ListView's padding and divider heights 1221 * included. If maxHeight is provided, the measuring will stop when the 1222 * current height reaches maxHeight. 1223 * 1224 * @param widthMeasureSpec The width measure spec to be given to a child's 1225 * {@link View#measure(int, int)}. 1226 * @param startPosition The position of the first child to be shown. 1227 * @param endPosition The (inclusive) position of the last child to be 1228 * shown. Specify {@link #NO_POSITION} if the last child should be 1229 * the last available child from the adapter. 1230 * @param maxHeight The maximum height that will be returned (if all the 1231 * children don't fit in this value, this value will be 1232 * returned). 1233 * @param disallowPartialChildPosition In general, whether the returned 1234 * height should only contain entire children. This is more 1235 * powerful--it is the first inclusive position at which partial 1236 * children will not be allowed. Example: it looks nice to have 1237 * at least 3 completely visible children, and in portrait this 1238 * will most likely fit; but in landscape there could be times 1239 * when even 2 children can not be completely shown, so a value 1240 * of 2 (remember, inclusive) would be good (assuming 1241 * startPosition is 0). 1242 * @return The height of this ListView with the given children. 1243 */ 1244 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1245 final int maxHeight, int disallowPartialChildPosition) { 1246 1247 final ListAdapter adapter = mAdapter; 1248 if (adapter == null) { 1249 return mListPadding.top + mListPadding.bottom; 1250 } 1251 1252 // Include the padding of the list 1253 int returnedHeight = mListPadding.top + mListPadding.bottom; 1254 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1255 // The previous height value that was less than maxHeight and contained 1256 // no partial children 1257 int prevHeightWithoutPartialChild = 0; 1258 int i; 1259 View child; 1260 1261 // mItemCount - 1 since endPosition parameter is inclusive 1262 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1263 final AbsListView.RecycleBin recycleBin = mRecycler; 1264 final boolean recyle = recycleOnMeasure(); 1265 final boolean[] isScrap = mIsScrap; 1266 1267 for (i = startPosition; i <= endPosition; ++i) { 1268 child = obtainView(i, isScrap); 1269 1270 measureScrapChild(child, i, widthMeasureSpec); 1271 1272 if (i > 0) { 1273 // Count the divider for all but one child 1274 returnedHeight += dividerHeight; 1275 } 1276 1277 // Recycle the view before we possibly return from the method 1278 if (recyle && recycleBin.shouldRecycleViewType( 1279 ((LayoutParams) child.getLayoutParams()).viewType)) { 1280 recycleBin.addScrapView(child, -1); 1281 } 1282 1283 returnedHeight += child.getMeasuredHeight(); 1284 1285 if (returnedHeight >= maxHeight) { 1286 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1287 // then the i'th position did not fit completely. 1288 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1289 && (i > disallowPartialChildPosition) // We've past the min pos 1290 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1291 && (returnedHeight != maxHeight) // i'th child did not fit completely 1292 ? prevHeightWithoutPartialChild 1293 : maxHeight; 1294 } 1295 1296 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1297 prevHeightWithoutPartialChild = returnedHeight; 1298 } 1299 } 1300 1301 // At this point, we went through the range of children, and they each 1302 // completely fit, so return the returnedHeight 1303 return returnedHeight; 1304 } 1305 1306 @Override 1307 int findMotionRow(int y) { 1308 int childCount = getChildCount(); 1309 if (childCount > 0) { 1310 if (!mStackFromBottom) { 1311 for (int i = 0; i < childCount; i++) { 1312 View v = getChildAt(i); 1313 if (y <= v.getBottom()) { 1314 return mFirstPosition + i; 1315 } 1316 } 1317 } else { 1318 for (int i = childCount - 1; i >= 0; i--) { 1319 View v = getChildAt(i); 1320 if (y >= v.getTop()) { 1321 return mFirstPosition + i; 1322 } 1323 } 1324 } 1325 } 1326 return INVALID_POSITION; 1327 } 1328 1329 /** 1330 * Put a specific item at a specific location on the screen and then build 1331 * up and down from there. 1332 * 1333 * @param position The reference view to use as the starting point 1334 * @param top Pixel offset from the top of this view to the top of the 1335 * reference view. 1336 * 1337 * @return The selected view, or null if the selected view is outside the 1338 * visible area. 1339 */ 1340 private View fillSpecific(int position, int top) { 1341 boolean tempIsSelected = position == mSelectedPosition; 1342 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1343 // Possibly changed again in fillUp if we add rows above this one. 1344 mFirstPosition = position; 1345 1346 View above; 1347 View below; 1348 1349 final int dividerHeight = mDividerHeight; 1350 if (!mStackFromBottom) { 1351 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1352 // This will correct for the top of the first view not touching the top of the list 1353 adjustViewsUpOrDown(); 1354 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1355 int childCount = getChildCount(); 1356 if (childCount > 0) { 1357 correctTooHigh(childCount); 1358 } 1359 } else { 1360 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1361 // This will correct for the bottom of the last view not touching the bottom of the list 1362 adjustViewsUpOrDown(); 1363 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1364 int childCount = getChildCount(); 1365 if (childCount > 0) { 1366 correctTooLow(childCount); 1367 } 1368 } 1369 1370 if (tempIsSelected) { 1371 return temp; 1372 } else if (above != null) { 1373 return above; 1374 } else { 1375 return below; 1376 } 1377 } 1378 1379 /** 1380 * Check if we have dragged the bottom of the list too high (we have pushed the 1381 * top element off the top of the screen when we did not need to). Correct by sliding 1382 * everything back down. 1383 * 1384 * @param childCount Number of children 1385 */ 1386 private void correctTooHigh(int childCount) { 1387 // First see if the last item is visible. If it is not, it is OK for the 1388 // top of the list to be pushed up. 1389 int lastPosition = mFirstPosition + childCount - 1; 1390 if (lastPosition == mItemCount - 1 && childCount > 0) { 1391 1392 // Get the last child ... 1393 final View lastChild = getChildAt(childCount - 1); 1394 1395 // ... and its bottom edge 1396 final int lastBottom = lastChild.getBottom(); 1397 1398 // This is bottom of our drawable area 1399 final int end = (mBottom - mTop) - mListPadding.bottom; 1400 1401 // This is how far the bottom edge of the last view is from the bottom of the 1402 // drawable area 1403 int bottomOffset = end - lastBottom; 1404 View firstChild = getChildAt(0); 1405 final int firstTop = firstChild.getTop(); 1406 1407 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1408 // first row or the first row is scrolled off the top of the drawable area 1409 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1410 if (mFirstPosition == 0) { 1411 // Don't pull the top too far down 1412 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1413 } 1414 // Move everything down 1415 offsetChildrenTopAndBottom(bottomOffset); 1416 if (mFirstPosition > 0) { 1417 // Fill the gap that was opened above mFirstPosition with more rows, if 1418 // possible 1419 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1420 // Close up the remaining gap 1421 adjustViewsUpOrDown(); 1422 } 1423 1424 } 1425 } 1426 } 1427 1428 /** 1429 * Check if we have dragged the bottom of the list too low (we have pushed the 1430 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1431 * everything back up. 1432 * 1433 * @param childCount Number of children 1434 */ 1435 private void correctTooLow(int childCount) { 1436 // First see if the first item is visible. If it is not, it is OK for the 1437 // bottom of the list to be pushed down. 1438 if (mFirstPosition == 0 && childCount > 0) { 1439 1440 // Get the first child ... 1441 final View firstChild = getChildAt(0); 1442 1443 // ... and its top edge 1444 final int firstTop = firstChild.getTop(); 1445 1446 // This is top of our drawable area 1447 final int start = mListPadding.top; 1448 1449 // This is bottom of our drawable area 1450 final int end = (mBottom - mTop) - mListPadding.bottom; 1451 1452 // This is how far the top edge of the first view is from the top of the 1453 // drawable area 1454 int topOffset = firstTop - start; 1455 View lastChild = getChildAt(childCount - 1); 1456 final int lastBottom = lastChild.getBottom(); 1457 int lastPosition = mFirstPosition + childCount - 1; 1458 1459 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1460 // last row or the last row is scrolled off the bottom of the drawable area 1461 if (topOffset > 0) { 1462 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1463 if (lastPosition == mItemCount - 1) { 1464 // Don't pull the bottom too far up 1465 topOffset = Math.min(topOffset, lastBottom - end); 1466 } 1467 // Move everything up 1468 offsetChildrenTopAndBottom(-topOffset); 1469 if (lastPosition < mItemCount - 1) { 1470 // Fill the gap that was opened below the last position with more rows, if 1471 // possible 1472 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1473 // Close up the remaining gap 1474 adjustViewsUpOrDown(); 1475 } 1476 } else if (lastPosition == mItemCount - 1) { 1477 adjustViewsUpOrDown(); 1478 } 1479 } 1480 } 1481 } 1482 1483 @Override 1484 protected void layoutChildren() { 1485 final boolean blockLayoutRequests = mBlockLayoutRequests; 1486 if (blockLayoutRequests) { 1487 return; 1488 } 1489 1490 mBlockLayoutRequests = true; 1491 1492 try { 1493 super.layoutChildren(); 1494 1495 invalidate(); 1496 1497 if (mAdapter == null) { 1498 resetList(); 1499 invokeOnItemScrollListener(); 1500 return; 1501 } 1502 1503 final int childrenTop = mListPadding.top; 1504 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1505 final int childCount = getChildCount(); 1506 1507 int index = 0; 1508 int delta = 0; 1509 1510 View sel; 1511 View oldSel = null; 1512 View oldFirst = null; 1513 View newSel = null; 1514 1515 // Remember stuff we will need down below 1516 switch (mLayoutMode) { 1517 case LAYOUT_SET_SELECTION: 1518 index = mNextSelectedPosition - mFirstPosition; 1519 if (index >= 0 && index < childCount) { 1520 newSel = getChildAt(index); 1521 } 1522 break; 1523 case LAYOUT_FORCE_TOP: 1524 case LAYOUT_FORCE_BOTTOM: 1525 case LAYOUT_SPECIFIC: 1526 case LAYOUT_SYNC: 1527 break; 1528 case LAYOUT_MOVE_SELECTION: 1529 default: 1530 // Remember the previously selected view 1531 index = mSelectedPosition - mFirstPosition; 1532 if (index >= 0 && index < childCount) { 1533 oldSel = getChildAt(index); 1534 } 1535 1536 // Remember the previous first child 1537 oldFirst = getChildAt(0); 1538 1539 if (mNextSelectedPosition >= 0) { 1540 delta = mNextSelectedPosition - mSelectedPosition; 1541 } 1542 1543 // Caution: newSel might be null 1544 newSel = getChildAt(index + delta); 1545 } 1546 1547 1548 boolean dataChanged = mDataChanged; 1549 if (dataChanged) { 1550 handleDataChanged(); 1551 } 1552 1553 // Handle the empty set by removing all views that are visible 1554 // and calling it a day 1555 if (mItemCount == 0) { 1556 resetList(); 1557 invokeOnItemScrollListener(); 1558 return; 1559 } else if (mItemCount != mAdapter.getCount()) { 1560 throw new IllegalStateException("The content of the adapter has changed but " 1561 + "ListView did not receive a notification. Make sure the content of " 1562 + "your adapter is not modified from a background thread, but only from " 1563 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1564 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1565 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1566 } 1567 1568 setSelectedPositionInt(mNextSelectedPosition); 1569 1570 // Remember which child, if any, had accessibility focus. 1571 final int accessibilityFocusPosition; 1572 final View accessFocusedChild = getAccessibilityFocusedChild(); 1573 if (accessFocusedChild != null) { 1574 accessibilityFocusPosition = getPositionForView(accessFocusedChild); 1575 accessFocusedChild.setHasTransientState(true); 1576 } else { 1577 accessibilityFocusPosition = INVALID_POSITION; 1578 } 1579 1580 // Ensure the child containing focus, if any, has transient state. 1581 // If the list data hasn't changed, or if the adapter has stable 1582 // IDs, this will maintain focus. 1583 final View focusedChild = getFocusedChild(); 1584 if (focusedChild != null) { 1585 focusedChild.setHasTransientState(true); 1586 } 1587 1588 // Pull all children into the RecycleBin. 1589 // These views will be reused if possible 1590 final int firstPosition = mFirstPosition; 1591 final RecycleBin recycleBin = mRecycler; 1592 if (dataChanged) { 1593 for (int i = 0; i < childCount; i++) { 1594 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1595 } 1596 } else { 1597 recycleBin.fillActiveViews(childCount, firstPosition); 1598 } 1599 1600 // Clear out old views 1601 detachAllViewsFromParent(); 1602 recycleBin.removeSkippedScrap(); 1603 1604 switch (mLayoutMode) { 1605 case LAYOUT_SET_SELECTION: 1606 if (newSel != null) { 1607 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1608 } else { 1609 sel = fillFromMiddle(childrenTop, childrenBottom); 1610 } 1611 break; 1612 case LAYOUT_SYNC: 1613 sel = fillSpecific(mSyncPosition, mSpecificTop); 1614 break; 1615 case LAYOUT_FORCE_BOTTOM: 1616 sel = fillUp(mItemCount - 1, childrenBottom); 1617 adjustViewsUpOrDown(); 1618 break; 1619 case LAYOUT_FORCE_TOP: 1620 mFirstPosition = 0; 1621 sel = fillFromTop(childrenTop); 1622 adjustViewsUpOrDown(); 1623 break; 1624 case LAYOUT_SPECIFIC: 1625 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1626 break; 1627 case LAYOUT_MOVE_SELECTION: 1628 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1629 break; 1630 default: 1631 if (childCount == 0) { 1632 if (!mStackFromBottom) { 1633 final int position = lookForSelectablePosition(0, true); 1634 setSelectedPositionInt(position); 1635 sel = fillFromTop(childrenTop); 1636 } else { 1637 final int position = lookForSelectablePosition(mItemCount - 1, false); 1638 setSelectedPositionInt(position); 1639 sel = fillUp(mItemCount - 1, childrenBottom); 1640 } 1641 } else { 1642 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1643 sel = fillSpecific(mSelectedPosition, 1644 oldSel == null ? childrenTop : oldSel.getTop()); 1645 } else if (mFirstPosition < mItemCount) { 1646 sel = fillSpecific(mFirstPosition, 1647 oldFirst == null ? childrenTop : oldFirst.getTop()); 1648 } else { 1649 sel = fillSpecific(0, childrenTop); 1650 } 1651 } 1652 break; 1653 } 1654 1655 // Flush any cached views that did not get reused above 1656 recycleBin.scrapActiveViews(); 1657 1658 if (sel != null) { 1659 final boolean shouldPlaceFocus = mItemsCanFocus && hasFocus(); 1660 final boolean maintainedFocus = focusedChild != null && focusedChild.hasFocus(); 1661 if (shouldPlaceFocus && !maintainedFocus && !sel.hasFocus()) { 1662 if (sel.requestFocus()) { 1663 // Successfully placed focus, clear selection. 1664 sel.setSelected(false); 1665 mSelectorRect.setEmpty(); 1666 } else { 1667 // Failed to place focus, clear current (invalid) focus. 1668 final View focused = getFocusedChild(); 1669 if (focused != null) { 1670 focused.clearFocus(); 1671 } 1672 positionSelector(INVALID_POSITION, sel); 1673 } 1674 } else { 1675 positionSelector(INVALID_POSITION, sel); 1676 } 1677 mSelectedTop = sel.getTop(); 1678 } else { 1679 // If the user's finger is down, select the motion position. 1680 // Otherwise, clear selection. 1681 if (mTouchMode == TOUCH_MODE_TAP || mTouchMode == TOUCH_MODE_DONE_WAITING) { 1682 final View child = getChildAt(mMotionPosition - mFirstPosition); 1683 if (child != null) { 1684 positionSelector(mMotionPosition, child); 1685 } 1686 } else { 1687 mSelectedTop = 0; 1688 mSelectorRect.setEmpty(); 1689 } 1690 } 1691 1692 if (accessFocusedChild != null) { 1693 accessFocusedChild.setHasTransientState(false); 1694 1695 // If we failed to maintain accessibility focus on the previous 1696 // view, attempt to restore it to the previous position. 1697 if (!accessFocusedChild.isAccessibilityFocused() 1698 && accessibilityFocusPosition != INVALID_POSITION) { 1699 // Bound the position within the visible children. 1700 final int position = MathUtils.constrain( 1701 accessibilityFocusPosition - mFirstPosition, 0, getChildCount() - 1); 1702 final View restoreView = getChildAt(position); 1703 if (restoreView != null) { 1704 restoreView.requestAccessibilityFocus(); 1705 } 1706 } 1707 } 1708 1709 if (focusedChild != null) { 1710 focusedChild.setHasTransientState(false); 1711 } 1712 1713 mLayoutMode = LAYOUT_NORMAL; 1714 mDataChanged = false; 1715 if (mPositionScrollAfterLayout != null) { 1716 post(mPositionScrollAfterLayout); 1717 mPositionScrollAfterLayout = null; 1718 } 1719 mNeedSync = false; 1720 setNextSelectedPositionInt(mSelectedPosition); 1721 1722 updateScrollIndicators(); 1723 1724 if (mItemCount > 0) { 1725 checkSelectionChanged(); 1726 } 1727 1728 invokeOnItemScrollListener(); 1729 } finally { 1730 if (!blockLayoutRequests) { 1731 mBlockLayoutRequests = false; 1732 } 1733 } 1734 } 1735 1736 /** 1737 * Obtain the view and add it to our list of children. The view can be made 1738 * fresh, converted from an unused view, or used as is if it was in the 1739 * recycle bin. 1740 * 1741 * @param position Logical position in the list 1742 * @param y Top or bottom edge of the view to add 1743 * @param flow If flow is true, align top edge to y. If false, align bottom 1744 * edge to y. 1745 * @param childrenLeft Left edge where children should be positioned 1746 * @param selected Is this position selected? 1747 * @return View that was added 1748 */ 1749 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1750 boolean selected) { 1751 View child; 1752 1753 1754 if (!mDataChanged) { 1755 // Try to use an existing view for this position 1756 child = mRecycler.getActiveView(position); 1757 if (child != null) { 1758 // Found it -- we're using an existing child 1759 // This just needs to be positioned 1760 setupChild(child, position, y, flow, childrenLeft, selected, true); 1761 1762 return child; 1763 } 1764 } 1765 1766 // Make a new view for this position, or convert an unused view if possible 1767 child = obtainView(position, mIsScrap); 1768 1769 // This needs to be positioned and measured 1770 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1771 1772 return child; 1773 } 1774 1775 /** 1776 * Add a view as a child and make sure it is measured (if necessary) and 1777 * positioned properly. 1778 * 1779 * @param child The view to add 1780 * @param position The position of this child 1781 * @param y The y position relative to which this view will be positioned 1782 * @param flowDown If true, align top edge to y. If false, align bottom 1783 * edge to y. 1784 * @param childrenLeft Left edge where children should be positioned 1785 * @param selected Is this position selected? 1786 * @param recycled Has this view been pulled from the recycle bin? If so it 1787 * does not need to be remeasured. 1788 */ 1789 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1790 boolean selected, boolean recycled) { 1791 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1792 1793 final boolean isSelected = selected && shouldShowSelector(); 1794 final boolean updateChildSelected = isSelected != child.isSelected(); 1795 final int mode = mTouchMode; 1796 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1797 mMotionPosition == position; 1798 final boolean updateChildPressed = isPressed != child.isPressed(); 1799 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1800 1801 // Respect layout params that are already in the view. Otherwise make some up... 1802 // noinspection unchecked 1803 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1804 if (p == null) { 1805 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1806 } 1807 p.viewType = mAdapter.getItemViewType(position); 1808 1809 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1810 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1811 attachViewToParent(child, flowDown ? -1 : 0, p); 1812 } else { 1813 p.forceAdd = false; 1814 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1815 p.recycledHeaderFooter = true; 1816 } 1817 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1818 } 1819 1820 if (updateChildSelected) { 1821 child.setSelected(isSelected); 1822 } 1823 1824 if (updateChildPressed) { 1825 child.setPressed(isPressed); 1826 } 1827 1828 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1829 if (child instanceof Checkable) { 1830 ((Checkable) child).setChecked(mCheckStates.get(position)); 1831 } else if (getContext().getApplicationInfo().targetSdkVersion 1832 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1833 child.setActivated(mCheckStates.get(position)); 1834 } 1835 } 1836 1837 if (needToMeasure) { 1838 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1839 mListPadding.left + mListPadding.right, p.width); 1840 int lpHeight = p.height; 1841 int childHeightSpec; 1842 if (lpHeight > 0) { 1843 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1844 } else { 1845 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1846 } 1847 child.measure(childWidthSpec, childHeightSpec); 1848 } else { 1849 cleanupLayoutState(child); 1850 } 1851 1852 final int w = child.getMeasuredWidth(); 1853 final int h = child.getMeasuredHeight(); 1854 final int childTop = flowDown ? y : y - h; 1855 1856 if (needToMeasure) { 1857 final int childRight = childrenLeft + w; 1858 final int childBottom = childTop + h; 1859 child.layout(childrenLeft, childTop, childRight, childBottom); 1860 } else { 1861 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1862 child.offsetTopAndBottom(childTop - child.getTop()); 1863 } 1864 1865 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1866 child.setDrawingCacheEnabled(true); 1867 } 1868 1869 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1870 != position) { 1871 child.jumpDrawablesToCurrentState(); 1872 } 1873 1874 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1875 } 1876 1877 @Override 1878 protected boolean canAnimate() { 1879 return super.canAnimate() && mItemCount > 0; 1880 } 1881 1882 /** 1883 * Sets the currently selected item. If in touch mode, the item will not be selected 1884 * but it will still be positioned appropriately. If the specified selection position 1885 * is less than 0, then the item at position 0 will be selected. 1886 * 1887 * @param position Index (starting at 0) of the data item to be selected. 1888 */ 1889 @Override 1890 public void setSelection(int position) { 1891 setSelectionFromTop(position, 0); 1892 } 1893 1894 /** 1895 * Sets the selected item and positions the selection y pixels from the top edge 1896 * of the ListView. (If in touch mode, the item will not be selected but it will 1897 * still be positioned appropriately.) 1898 * 1899 * @param position Index (starting at 0) of the data item to be selected. 1900 * @param y The distance from the top edge of the ListView (plus padding) that the 1901 * item will be positioned. 1902 */ 1903 public void setSelectionFromTop(int position, int y) { 1904 if (mAdapter == null) { 1905 return; 1906 } 1907 1908 if (!isInTouchMode()) { 1909 position = lookForSelectablePosition(position, true); 1910 if (position >= 0) { 1911 setNextSelectedPositionInt(position); 1912 } 1913 } else { 1914 mResurrectToPosition = position; 1915 } 1916 1917 if (position >= 0) { 1918 mLayoutMode = LAYOUT_SPECIFIC; 1919 mSpecificTop = mListPadding.top + y; 1920 1921 if (mNeedSync) { 1922 mSyncPosition = position; 1923 mSyncRowId = mAdapter.getItemId(position); 1924 } 1925 1926 if (mPositionScroller != null) { 1927 mPositionScroller.stop(); 1928 } 1929 requestLayout(); 1930 } 1931 } 1932 1933 /** 1934 * Makes the item at the supplied position selected. 1935 * 1936 * @param position the position of the item to select 1937 */ 1938 @Override 1939 void setSelectionInt(int position) { 1940 setNextSelectedPositionInt(position); 1941 boolean awakeScrollbars = false; 1942 1943 final int selectedPosition = mSelectedPosition; 1944 1945 if (selectedPosition >= 0) { 1946 if (position == selectedPosition - 1) { 1947 awakeScrollbars = true; 1948 } else if (position == selectedPosition + 1) { 1949 awakeScrollbars = true; 1950 } 1951 } 1952 1953 if (mPositionScroller != null) { 1954 mPositionScroller.stop(); 1955 } 1956 1957 layoutChildren(); 1958 1959 if (awakeScrollbars) { 1960 awakenScrollBars(); 1961 } 1962 } 1963 1964 /** 1965 * Find a position that can be selected (i.e., is not a separator). 1966 * 1967 * @param position The starting position to look at. 1968 * @param lookDown Whether to look down for other positions. 1969 * @return The next selectable position starting at position and then searching either up or 1970 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1971 */ 1972 @Override 1973 int lookForSelectablePosition(int position, boolean lookDown) { 1974 final ListAdapter adapter = mAdapter; 1975 if (adapter == null || isInTouchMode()) { 1976 return INVALID_POSITION; 1977 } 1978 1979 final int count = adapter.getCount(); 1980 if (!mAreAllItemsSelectable) { 1981 if (lookDown) { 1982 position = Math.max(0, position); 1983 while (position < count && !adapter.isEnabled(position)) { 1984 position++; 1985 } 1986 } else { 1987 position = Math.min(position, count - 1); 1988 while (position >= 0 && !adapter.isEnabled(position)) { 1989 position--; 1990 } 1991 } 1992 } 1993 1994 if (position < 0 || position >= count) { 1995 return INVALID_POSITION; 1996 } 1997 1998 return position; 1999 } 2000 2001 /** 2002 * Find a position that can be selected (i.e., is not a separator). If there 2003 * are no selectable positions in the specified direction from the starting 2004 * position, searches in the opposite direction from the starting position 2005 * to the current position. 2006 * 2007 * @param current the current position 2008 * @param position the starting position 2009 * @param lookDown whether to look down for other positions 2010 * @return the next selectable position, or {@link #INVALID_POSITION} if 2011 * nothing can be found 2012 */ 2013 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2014 final ListAdapter adapter = mAdapter; 2015 if (adapter == null || isInTouchMode()) { 2016 return INVALID_POSITION; 2017 } 2018 2019 // First check after the starting position in the specified direction. 2020 final int after = lookForSelectablePosition(position, lookDown); 2021 if (after != INVALID_POSITION) { 2022 return after; 2023 } 2024 2025 // Then check between the starting position and the current position. 2026 final int count = adapter.getCount(); 2027 current = MathUtils.constrain(current, -1, count - 1); 2028 if (lookDown) { 2029 position = Math.min(position - 1, count - 1); 2030 while ((position > current) && !adapter.isEnabled(position)) { 2031 position--; 2032 } 2033 if (position <= current) { 2034 return INVALID_POSITION; 2035 } 2036 } else { 2037 position = Math.max(0, position + 1); 2038 while ((position < current) && !adapter.isEnabled(position)) { 2039 position++; 2040 } 2041 if (position >= current) { 2042 return INVALID_POSITION; 2043 } 2044 } 2045 2046 return position; 2047 } 2048 2049 /** 2050 * setSelectionAfterHeaderView set the selection to be the first list item 2051 * after the header views. 2052 */ 2053 public void setSelectionAfterHeaderView() { 2054 final int count = mHeaderViewInfos.size(); 2055 if (count > 0) { 2056 mNextSelectedPosition = 0; 2057 return; 2058 } 2059 2060 if (mAdapter != null) { 2061 setSelection(count); 2062 } else { 2063 mNextSelectedPosition = count; 2064 mLayoutMode = LAYOUT_SET_SELECTION; 2065 } 2066 2067 } 2068 2069 @Override 2070 public boolean dispatchKeyEvent(KeyEvent event) { 2071 // Dispatch in the normal way 2072 boolean handled = super.dispatchKeyEvent(event); 2073 if (!handled) { 2074 // If we didn't handle it... 2075 View focused = getFocusedChild(); 2076 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2077 // ... and our focused child didn't handle it 2078 // ... give it to ourselves so we can scroll if necessary 2079 handled = onKeyDown(event.getKeyCode(), event); 2080 } 2081 } 2082 return handled; 2083 } 2084 2085 @Override 2086 public boolean onKeyDown(int keyCode, KeyEvent event) { 2087 return commonKey(keyCode, 1, event); 2088 } 2089 2090 @Override 2091 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2092 return commonKey(keyCode, repeatCount, event); 2093 } 2094 2095 @Override 2096 public boolean onKeyUp(int keyCode, KeyEvent event) { 2097 return commonKey(keyCode, 1, event); 2098 } 2099 2100 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2101 if (mAdapter == null || !isAttachedToWindow()) { 2102 return false; 2103 } 2104 2105 if (mDataChanged) { 2106 layoutChildren(); 2107 } 2108 2109 boolean handled = false; 2110 int action = event.getAction(); 2111 2112 if (action != KeyEvent.ACTION_UP) { 2113 switch (keyCode) { 2114 case KeyEvent.KEYCODE_DPAD_UP: 2115 if (event.hasNoModifiers()) { 2116 handled = resurrectSelectionIfNeeded(); 2117 if (!handled) { 2118 while (count-- > 0) { 2119 if (arrowScroll(FOCUS_UP)) { 2120 handled = true; 2121 } else { 2122 break; 2123 } 2124 } 2125 } 2126 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2127 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2128 } 2129 break; 2130 2131 case KeyEvent.KEYCODE_DPAD_DOWN: 2132 if (event.hasNoModifiers()) { 2133 handled = resurrectSelectionIfNeeded(); 2134 if (!handled) { 2135 while (count-- > 0) { 2136 if (arrowScroll(FOCUS_DOWN)) { 2137 handled = true; 2138 } else { 2139 break; 2140 } 2141 } 2142 } 2143 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2144 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2145 } 2146 break; 2147 2148 case KeyEvent.KEYCODE_DPAD_LEFT: 2149 if (event.hasNoModifiers()) { 2150 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2151 } 2152 break; 2153 2154 case KeyEvent.KEYCODE_DPAD_RIGHT: 2155 if (event.hasNoModifiers()) { 2156 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2157 } 2158 break; 2159 2160 case KeyEvent.KEYCODE_DPAD_CENTER: 2161 case KeyEvent.KEYCODE_ENTER: 2162 if (event.hasNoModifiers()) { 2163 handled = resurrectSelectionIfNeeded(); 2164 if (!handled 2165 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2166 keyPressed(); 2167 handled = true; 2168 } 2169 } 2170 break; 2171 2172 case KeyEvent.KEYCODE_SPACE: 2173 if (mPopup == null || !mPopup.isShowing()) { 2174 if (event.hasNoModifiers()) { 2175 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2176 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2177 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2178 } 2179 handled = true; 2180 } 2181 break; 2182 2183 case KeyEvent.KEYCODE_PAGE_UP: 2184 if (event.hasNoModifiers()) { 2185 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2186 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2187 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2188 } 2189 break; 2190 2191 case KeyEvent.KEYCODE_PAGE_DOWN: 2192 if (event.hasNoModifiers()) { 2193 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2194 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2195 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2196 } 2197 break; 2198 2199 case KeyEvent.KEYCODE_MOVE_HOME: 2200 if (event.hasNoModifiers()) { 2201 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2202 } 2203 break; 2204 2205 case KeyEvent.KEYCODE_MOVE_END: 2206 if (event.hasNoModifiers()) { 2207 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2208 } 2209 break; 2210 2211 case KeyEvent.KEYCODE_TAB: 2212 // XXX Sometimes it is useful to be able to TAB through the items in 2213 // a ListView sequentially. Unfortunately this can create an 2214 // asymmetry in TAB navigation order unless the list selection 2215 // always reverts to the top or bottom when receiving TAB focus from 2216 // another widget. Leaving this behavior disabled for now but 2217 // perhaps it should be configurable (and more comprehensive). 2218 if (false) { 2219 if (event.hasNoModifiers()) { 2220 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2221 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2222 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2223 } 2224 } 2225 break; 2226 } 2227 } 2228 2229 if (handled) { 2230 return true; 2231 } 2232 2233 if (sendToTextFilter(keyCode, count, event)) { 2234 return true; 2235 } 2236 2237 switch (action) { 2238 case KeyEvent.ACTION_DOWN: 2239 return super.onKeyDown(keyCode, event); 2240 2241 case KeyEvent.ACTION_UP: 2242 return super.onKeyUp(keyCode, event); 2243 2244 case KeyEvent.ACTION_MULTIPLE: 2245 return super.onKeyMultiple(keyCode, count, event); 2246 2247 default: // shouldn't happen 2248 return false; 2249 } 2250 } 2251 2252 /** 2253 * Scrolls up or down by the number of items currently present on screen. 2254 * 2255 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2256 * @return whether selection was moved 2257 */ 2258 boolean pageScroll(int direction) { 2259 final int nextPage; 2260 final boolean down; 2261 2262 if (direction == FOCUS_UP) { 2263 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2264 down = false; 2265 } else if (direction == FOCUS_DOWN) { 2266 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2267 down = true; 2268 } else { 2269 return false; 2270 } 2271 2272 if (nextPage >= 0) { 2273 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2274 if (position >= 0) { 2275 mLayoutMode = LAYOUT_SPECIFIC; 2276 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2277 2278 if (down && (position > (mItemCount - getChildCount()))) { 2279 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2280 } 2281 2282 if (!down && (position < getChildCount())) { 2283 mLayoutMode = LAYOUT_FORCE_TOP; 2284 } 2285 2286 setSelectionInt(position); 2287 invokeOnItemScrollListener(); 2288 if (!awakenScrollBars()) { 2289 invalidate(); 2290 } 2291 2292 return true; 2293 } 2294 } 2295 2296 return false; 2297 } 2298 2299 /** 2300 * Go to the last or first item if possible (not worrying about panning 2301 * across or navigating within the internal focus of the currently selected 2302 * item.) 2303 * 2304 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2305 * @return whether selection was moved 2306 */ 2307 boolean fullScroll(int direction) { 2308 boolean moved = false; 2309 if (direction == FOCUS_UP) { 2310 if (mSelectedPosition != 0) { 2311 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2312 if (position >= 0) { 2313 mLayoutMode = LAYOUT_FORCE_TOP; 2314 setSelectionInt(position); 2315 invokeOnItemScrollListener(); 2316 } 2317 moved = true; 2318 } 2319 } else if (direction == FOCUS_DOWN) { 2320 final int lastItem = (mItemCount - 1); 2321 if (mSelectedPosition < lastItem) { 2322 final int position = lookForSelectablePositionAfter( 2323 mSelectedPosition, lastItem, false); 2324 if (position >= 0) { 2325 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2326 setSelectionInt(position); 2327 invokeOnItemScrollListener(); 2328 } 2329 moved = true; 2330 } 2331 } 2332 2333 if (moved && !awakenScrollBars()) { 2334 awakenScrollBars(); 2335 invalidate(); 2336 } 2337 2338 return moved; 2339 } 2340 2341 /** 2342 * To avoid horizontal focus searches changing the selected item, we 2343 * manually focus search within the selected item (as applicable), and 2344 * prevent focus from jumping to something within another item. 2345 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2346 * @return Whether this consumes the key event. 2347 */ 2348 private boolean handleHorizontalFocusWithinListItem(int direction) { 2349 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2350 throw new IllegalArgumentException("direction must be one of" 2351 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2352 } 2353 2354 final int numChildren = getChildCount(); 2355 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2356 final View selectedView = getSelectedView(); 2357 if (selectedView != null && selectedView.hasFocus() && 2358 selectedView instanceof ViewGroup) { 2359 2360 final View currentFocus = selectedView.findFocus(); 2361 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2362 (ViewGroup) selectedView, currentFocus, direction); 2363 if (nextFocus != null) { 2364 // do the math to get interesting rect in next focus' coordinates 2365 currentFocus.getFocusedRect(mTempRect); 2366 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2367 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2368 if (nextFocus.requestFocus(direction, mTempRect)) { 2369 return true; 2370 } 2371 } 2372 // we are blocking the key from being handled (by returning true) 2373 // if the global result is going to be some other view within this 2374 // list. this is to acheive the overall goal of having 2375 // horizontal d-pad navigation remain in the current item. 2376 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2377 (ViewGroup) getRootView(), currentFocus, direction); 2378 if (globalNextFocus != null) { 2379 return isViewAncestorOf(globalNextFocus, this); 2380 } 2381 } 2382 } 2383 return false; 2384 } 2385 2386 /** 2387 * Scrolls to the next or previous item if possible. 2388 * 2389 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2390 * 2391 * @return whether selection was moved 2392 */ 2393 boolean arrowScroll(int direction) { 2394 try { 2395 mInLayout = true; 2396 final boolean handled = arrowScrollImpl(direction); 2397 if (handled) { 2398 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2399 } 2400 return handled; 2401 } finally { 2402 mInLayout = false; 2403 } 2404 } 2405 2406 /** 2407 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2408 * to move to. This return a position in the direction given if the selected item 2409 * is fully visible. 2410 * 2411 * @param selectedView Current selected view to move from 2412 * @param selectedPos Current selected position to move from 2413 * @param direction Direction to move in 2414 * @return Desired selected position after moving in the given direction 2415 */ 2416 private final int nextSelectedPositionForDirection( 2417 View selectedView, int selectedPos, int direction) { 2418 int nextSelected; 2419 2420 if (direction == View.FOCUS_DOWN) { 2421 final int listBottom = getHeight() - mListPadding.bottom; 2422 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2423 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2424 selectedPos + 1 : 2425 mFirstPosition; 2426 } else { 2427 return INVALID_POSITION; 2428 } 2429 } else { 2430 final int listTop = mListPadding.top; 2431 if (selectedView != null && selectedView.getTop() >= listTop) { 2432 final int lastPos = mFirstPosition + getChildCount() - 1; 2433 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2434 selectedPos - 1 : 2435 lastPos; 2436 } else { 2437 return INVALID_POSITION; 2438 } 2439 } 2440 2441 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2442 return INVALID_POSITION; 2443 } 2444 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2445 } 2446 2447 /** 2448 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2449 * whether there are focusable items etc. 2450 * 2451 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2452 * @return Whether any scrolling, selection or focus change occured. 2453 */ 2454 private boolean arrowScrollImpl(int direction) { 2455 if (getChildCount() <= 0) { 2456 return false; 2457 } 2458 2459 View selectedView = getSelectedView(); 2460 int selectedPos = mSelectedPosition; 2461 2462 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2463 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2464 2465 // if we are moving focus, we may OVERRIDE the default behavior 2466 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2467 if (focusResult != null) { 2468 nextSelectedPosition = focusResult.getSelectedPosition(); 2469 amountToScroll = focusResult.getAmountToScroll(); 2470 } 2471 2472 boolean needToRedraw = focusResult != null; 2473 if (nextSelectedPosition != INVALID_POSITION) { 2474 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2475 setSelectedPositionInt(nextSelectedPosition); 2476 setNextSelectedPositionInt(nextSelectedPosition); 2477 selectedView = getSelectedView(); 2478 selectedPos = nextSelectedPosition; 2479 if (mItemsCanFocus && focusResult == null) { 2480 // there was no new view found to take focus, make sure we 2481 // don't leave focus with the old selection 2482 final View focused = getFocusedChild(); 2483 if (focused != null) { 2484 focused.clearFocus(); 2485 } 2486 } 2487 needToRedraw = true; 2488 checkSelectionChanged(); 2489 } 2490 2491 if (amountToScroll > 0) { 2492 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2493 needToRedraw = true; 2494 } 2495 2496 // if we didn't find a new focusable, make sure any existing focused 2497 // item that was panned off screen gives up focus. 2498 if (mItemsCanFocus && (focusResult == null) 2499 && selectedView != null && selectedView.hasFocus()) { 2500 final View focused = selectedView.findFocus(); 2501 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2502 focused.clearFocus(); 2503 } 2504 } 2505 2506 // if the current selection is panned off, we need to remove the selection 2507 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2508 && !isViewAncestorOf(selectedView, this)) { 2509 selectedView = null; 2510 hideSelector(); 2511 2512 // but we don't want to set the ressurect position (that would make subsequent 2513 // unhandled key events bring back the item we just scrolled off!) 2514 mResurrectToPosition = INVALID_POSITION; 2515 } 2516 2517 if (needToRedraw) { 2518 if (selectedView != null) { 2519 positionSelector(selectedPos, selectedView); 2520 mSelectedTop = selectedView.getTop(); 2521 } 2522 if (!awakenScrollBars()) { 2523 invalidate(); 2524 } 2525 invokeOnItemScrollListener(); 2526 return true; 2527 } 2528 2529 return false; 2530 } 2531 2532 /** 2533 * When selection changes, it is possible that the previously selected or the 2534 * next selected item will change its size. If so, we need to offset some folks, 2535 * and re-layout the items as appropriate. 2536 * 2537 * @param selectedView The currently selected view (before changing selection). 2538 * should be <code>null</code> if there was no previous selection. 2539 * @param direction Either {@link android.view.View#FOCUS_UP} or 2540 * {@link android.view.View#FOCUS_DOWN}. 2541 * @param newSelectedPosition The position of the next selection. 2542 * @param newFocusAssigned whether new focus was assigned. This matters because 2543 * when something has focus, we don't want to show selection (ugh). 2544 */ 2545 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2546 boolean newFocusAssigned) { 2547 if (newSelectedPosition == INVALID_POSITION) { 2548 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2549 } 2550 2551 // whether or not we are moving down or up, we want to preserve the 2552 // top of whatever view is on top: 2553 // - moving down: the view that had selection 2554 // - moving up: the view that is getting selection 2555 View topView; 2556 View bottomView; 2557 int topViewIndex, bottomViewIndex; 2558 boolean topSelected = false; 2559 final int selectedIndex = mSelectedPosition - mFirstPosition; 2560 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2561 if (direction == View.FOCUS_UP) { 2562 topViewIndex = nextSelectedIndex; 2563 bottomViewIndex = selectedIndex; 2564 topView = getChildAt(topViewIndex); 2565 bottomView = selectedView; 2566 topSelected = true; 2567 } else { 2568 topViewIndex = selectedIndex; 2569 bottomViewIndex = nextSelectedIndex; 2570 topView = selectedView; 2571 bottomView = getChildAt(bottomViewIndex); 2572 } 2573 2574 final int numChildren = getChildCount(); 2575 2576 // start with top view: is it changing size? 2577 if (topView != null) { 2578 topView.setSelected(!newFocusAssigned && topSelected); 2579 measureAndAdjustDown(topView, topViewIndex, numChildren); 2580 } 2581 2582 // is the bottom view changing size? 2583 if (bottomView != null) { 2584 bottomView.setSelected(!newFocusAssigned && !topSelected); 2585 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2586 } 2587 } 2588 2589 /** 2590 * Re-measure a child, and if its height changes, lay it out preserving its 2591 * top, and adjust the children below it appropriately. 2592 * @param child The child 2593 * @param childIndex The view group index of the child. 2594 * @param numChildren The number of children in the view group. 2595 */ 2596 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2597 int oldHeight = child.getHeight(); 2598 measureItem(child); 2599 if (child.getMeasuredHeight() != oldHeight) { 2600 // lay out the view, preserving its top 2601 relayoutMeasuredItem(child); 2602 2603 // adjust views below appropriately 2604 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2605 for (int i = childIndex + 1; i < numChildren; i++) { 2606 getChildAt(i).offsetTopAndBottom(heightDelta); 2607 } 2608 } 2609 } 2610 2611 /** 2612 * Measure a particular list child. 2613 * TODO: unify with setUpChild. 2614 * @param child The child. 2615 */ 2616 private void measureItem(View child) { 2617 ViewGroup.LayoutParams p = child.getLayoutParams(); 2618 if (p == null) { 2619 p = new ViewGroup.LayoutParams( 2620 ViewGroup.LayoutParams.MATCH_PARENT, 2621 ViewGroup.LayoutParams.WRAP_CONTENT); 2622 } 2623 2624 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2625 mListPadding.left + mListPadding.right, p.width); 2626 int lpHeight = p.height; 2627 int childHeightSpec; 2628 if (lpHeight > 0) { 2629 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2630 } else { 2631 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2632 } 2633 child.measure(childWidthSpec, childHeightSpec); 2634 } 2635 2636 /** 2637 * Layout a child that has been measured, preserving its top position. 2638 * TODO: unify with setUpChild. 2639 * @param child The child. 2640 */ 2641 private void relayoutMeasuredItem(View child) { 2642 final int w = child.getMeasuredWidth(); 2643 final int h = child.getMeasuredHeight(); 2644 final int childLeft = mListPadding.left; 2645 final int childRight = childLeft + w; 2646 final int childTop = child.getTop(); 2647 final int childBottom = childTop + h; 2648 child.layout(childLeft, childTop, childRight, childBottom); 2649 } 2650 2651 /** 2652 * @return The amount to preview next items when arrow srolling. 2653 */ 2654 private int getArrowScrollPreviewLength() { 2655 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2656 } 2657 2658 /** 2659 * Determine how much we need to scroll in order to get the next selected view 2660 * visible, with a fading edge showing below as applicable. The amount is 2661 * capped at {@link #getMaxScrollAmount()} . 2662 * 2663 * @param direction either {@link android.view.View#FOCUS_UP} or 2664 * {@link android.view.View#FOCUS_DOWN}. 2665 * @param nextSelectedPosition The position of the next selection, or 2666 * {@link #INVALID_POSITION} if there is no next selectable position 2667 * @return The amount to scroll. Note: this is always positive! Direction 2668 * needs to be taken into account when actually scrolling. 2669 */ 2670 private int amountToScroll(int direction, int nextSelectedPosition) { 2671 final int listBottom = getHeight() - mListPadding.bottom; 2672 final int listTop = mListPadding.top; 2673 2674 int numChildren = getChildCount(); 2675 2676 if (direction == View.FOCUS_DOWN) { 2677 int indexToMakeVisible = numChildren - 1; 2678 if (nextSelectedPosition != INVALID_POSITION) { 2679 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2680 } 2681 while (numChildren <= indexToMakeVisible) { 2682 // Child to view is not attached yet. 2683 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2684 numChildren++; 2685 } 2686 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2687 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2688 2689 int goalBottom = listBottom; 2690 if (positionToMakeVisible < mItemCount - 1) { 2691 goalBottom -= getArrowScrollPreviewLength(); 2692 } 2693 2694 if (viewToMakeVisible.getBottom() <= goalBottom) { 2695 // item is fully visible. 2696 return 0; 2697 } 2698 2699 if (nextSelectedPosition != INVALID_POSITION 2700 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2701 // item already has enough of it visible, changing selection is good enough 2702 return 0; 2703 } 2704 2705 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2706 2707 if ((mFirstPosition + numChildren) == mItemCount) { 2708 // last is last in list -> make sure we don't scroll past it 2709 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2710 amountToScroll = Math.min(amountToScroll, max); 2711 } 2712 2713 return Math.min(amountToScroll, getMaxScrollAmount()); 2714 } else { 2715 int indexToMakeVisible = 0; 2716 if (nextSelectedPosition != INVALID_POSITION) { 2717 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2718 } 2719 while (indexToMakeVisible < 0) { 2720 // Child to view is not attached yet. 2721 addViewAbove(getChildAt(0), mFirstPosition); 2722 mFirstPosition--; 2723 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2724 } 2725 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2726 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2727 int goalTop = listTop; 2728 if (positionToMakeVisible > 0) { 2729 goalTop += getArrowScrollPreviewLength(); 2730 } 2731 if (viewToMakeVisible.getTop() >= goalTop) { 2732 // item is fully visible. 2733 return 0; 2734 } 2735 2736 if (nextSelectedPosition != INVALID_POSITION && 2737 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2738 // item already has enough of it visible, changing selection is good enough 2739 return 0; 2740 } 2741 2742 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2743 if (mFirstPosition == 0) { 2744 // first is first in list -> make sure we don't scroll past it 2745 final int max = listTop - getChildAt(0).getTop(); 2746 amountToScroll = Math.min(amountToScroll, max); 2747 } 2748 return Math.min(amountToScroll, getMaxScrollAmount()); 2749 } 2750 } 2751 2752 /** 2753 * Holds results of focus aware arrow scrolling. 2754 */ 2755 static private class ArrowScrollFocusResult { 2756 private int mSelectedPosition; 2757 private int mAmountToScroll; 2758 2759 /** 2760 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2761 */ 2762 void populate(int selectedPosition, int amountToScroll) { 2763 mSelectedPosition = selectedPosition; 2764 mAmountToScroll = amountToScroll; 2765 } 2766 2767 public int getSelectedPosition() { 2768 return mSelectedPosition; 2769 } 2770 2771 public int getAmountToScroll() { 2772 return mAmountToScroll; 2773 } 2774 } 2775 2776 /** 2777 * @param direction either {@link android.view.View#FOCUS_UP} or 2778 * {@link android.view.View#FOCUS_DOWN}. 2779 * @return The position of the next selectable position of the views that 2780 * are currently visible, taking into account the fact that there might 2781 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2782 * selectable view on screen in the given direction. 2783 */ 2784 private int lookForSelectablePositionOnScreen(int direction) { 2785 final int firstPosition = mFirstPosition; 2786 if (direction == View.FOCUS_DOWN) { 2787 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2788 mSelectedPosition + 1 : 2789 firstPosition; 2790 if (startPos >= mAdapter.getCount()) { 2791 return INVALID_POSITION; 2792 } 2793 if (startPos < firstPosition) { 2794 startPos = firstPosition; 2795 } 2796 2797 final int lastVisiblePos = getLastVisiblePosition(); 2798 final ListAdapter adapter = getAdapter(); 2799 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2800 if (adapter.isEnabled(pos) 2801 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2802 return pos; 2803 } 2804 } 2805 } else { 2806 int last = firstPosition + getChildCount() - 1; 2807 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2808 mSelectedPosition - 1 : 2809 firstPosition + getChildCount() - 1; 2810 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2811 return INVALID_POSITION; 2812 } 2813 if (startPos > last) { 2814 startPos = last; 2815 } 2816 2817 final ListAdapter adapter = getAdapter(); 2818 for (int pos = startPos; pos >= firstPosition; pos--) { 2819 if (adapter.isEnabled(pos) 2820 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2821 return pos; 2822 } 2823 } 2824 } 2825 return INVALID_POSITION; 2826 } 2827 2828 /** 2829 * Do an arrow scroll based on focus searching. If a new view is 2830 * given focus, return the selection delta and amount to scroll via 2831 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2832 * 2833 * @param direction either {@link android.view.View#FOCUS_UP} or 2834 * {@link android.view.View#FOCUS_DOWN}. 2835 * @return The result if focus has changed, or <code>null</code>. 2836 */ 2837 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2838 final View selectedView = getSelectedView(); 2839 View newFocus; 2840 if (selectedView != null && selectedView.hasFocus()) { 2841 View oldFocus = selectedView.findFocus(); 2842 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2843 } else { 2844 if (direction == View.FOCUS_DOWN) { 2845 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2846 final int listTop = mListPadding.top + 2847 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2848 final int ySearchPoint = 2849 (selectedView != null && selectedView.getTop() > listTop) ? 2850 selectedView.getTop() : 2851 listTop; 2852 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2853 } else { 2854 final boolean bottomFadingEdgeShowing = 2855 (mFirstPosition + getChildCount() - 1) < mItemCount; 2856 final int listBottom = getHeight() - mListPadding.bottom - 2857 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2858 final int ySearchPoint = 2859 (selectedView != null && selectedView.getBottom() < listBottom) ? 2860 selectedView.getBottom() : 2861 listBottom; 2862 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2863 } 2864 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2865 } 2866 2867 if (newFocus != null) { 2868 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2869 2870 // if the focus change is in a different new position, make sure 2871 // we aren't jumping over another selectable position 2872 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2873 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2874 if (selectablePosition != INVALID_POSITION && 2875 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2876 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2877 return null; 2878 } 2879 } 2880 2881 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2882 2883 final int maxScrollAmount = getMaxScrollAmount(); 2884 if (focusScroll < maxScrollAmount) { 2885 // not moving too far, safe to give next view focus 2886 newFocus.requestFocus(direction); 2887 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2888 return mArrowScrollFocusResult; 2889 } else if (distanceToView(newFocus) < maxScrollAmount){ 2890 // Case to consider: 2891 // too far to get entire next focusable on screen, but by going 2892 // max scroll amount, we are getting it at least partially in view, 2893 // so give it focus and scroll the max ammount. 2894 newFocus.requestFocus(direction); 2895 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2896 return mArrowScrollFocusResult; 2897 } 2898 } 2899 return null; 2900 } 2901 2902 /** 2903 * @param newFocus The view that would have focus. 2904 * @return the position that contains newFocus 2905 */ 2906 private int positionOfNewFocus(View newFocus) { 2907 final int numChildren = getChildCount(); 2908 for (int i = 0; i < numChildren; i++) { 2909 final View child = getChildAt(i); 2910 if (isViewAncestorOf(newFocus, child)) { 2911 return mFirstPosition + i; 2912 } 2913 } 2914 throw new IllegalArgumentException("newFocus is not a child of any of the" 2915 + " children of the list!"); 2916 } 2917 2918 /** 2919 * Return true if child is an ancestor of parent, (or equal to the parent). 2920 */ 2921 private boolean isViewAncestorOf(View child, View parent) { 2922 if (child == parent) { 2923 return true; 2924 } 2925 2926 final ViewParent theParent = child.getParent(); 2927 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2928 } 2929 2930 /** 2931 * Determine how much we need to scroll in order to get newFocus in view. 2932 * @param direction either {@link android.view.View#FOCUS_UP} or 2933 * {@link android.view.View#FOCUS_DOWN}. 2934 * @param newFocus The view that would take focus. 2935 * @param positionOfNewFocus The position of the list item containing newFocus 2936 * @return The amount to scroll. Note: this is always positive! Direction 2937 * needs to be taken into account when actually scrolling. 2938 */ 2939 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2940 int amountToScroll = 0; 2941 newFocus.getDrawingRect(mTempRect); 2942 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2943 if (direction == View.FOCUS_UP) { 2944 if (mTempRect.top < mListPadding.top) { 2945 amountToScroll = mListPadding.top - mTempRect.top; 2946 if (positionOfNewFocus > 0) { 2947 amountToScroll += getArrowScrollPreviewLength(); 2948 } 2949 } 2950 } else { 2951 final int listBottom = getHeight() - mListPadding.bottom; 2952 if (mTempRect.bottom > listBottom) { 2953 amountToScroll = mTempRect.bottom - listBottom; 2954 if (positionOfNewFocus < mItemCount - 1) { 2955 amountToScroll += getArrowScrollPreviewLength(); 2956 } 2957 } 2958 } 2959 return amountToScroll; 2960 } 2961 2962 /** 2963 * Determine the distance to the nearest edge of a view in a particular 2964 * direction. 2965 * 2966 * @param descendant A descendant of this list. 2967 * @return The distance, or 0 if the nearest edge is already on screen. 2968 */ 2969 private int distanceToView(View descendant) { 2970 int distance = 0; 2971 descendant.getDrawingRect(mTempRect); 2972 offsetDescendantRectToMyCoords(descendant, mTempRect); 2973 final int listBottom = mBottom - mTop - mListPadding.bottom; 2974 if (mTempRect.bottom < mListPadding.top) { 2975 distance = mListPadding.top - mTempRect.bottom; 2976 } else if (mTempRect.top > listBottom) { 2977 distance = mTempRect.top - listBottom; 2978 } 2979 return distance; 2980 } 2981 2982 2983 /** 2984 * Scroll the children by amount, adding a view at the end and removing 2985 * views that fall off as necessary. 2986 * 2987 * @param amount The amount (positive or negative) to scroll. 2988 */ 2989 private void scrollListItemsBy(int amount) { 2990 offsetChildrenTopAndBottom(amount); 2991 2992 final int listBottom = getHeight() - mListPadding.bottom; 2993 final int listTop = mListPadding.top; 2994 final AbsListView.RecycleBin recycleBin = mRecycler; 2995 2996 if (amount < 0) { 2997 // shifted items up 2998 2999 // may need to pan views into the bottom space 3000 int numChildren = getChildCount(); 3001 View last = getChildAt(numChildren - 1); 3002 while (last.getBottom() < listBottom) { 3003 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3004 if (lastVisiblePosition < mItemCount - 1) { 3005 last = addViewBelow(last, lastVisiblePosition); 3006 numChildren++; 3007 } else { 3008 break; 3009 } 3010 } 3011 3012 // may have brought in the last child of the list that is skinnier 3013 // than the fading edge, thereby leaving space at the end. need 3014 // to shift back 3015 if (last.getBottom() < listBottom) { 3016 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3017 } 3018 3019 // top views may be panned off screen 3020 View first = getChildAt(0); 3021 while (first.getBottom() < listTop) { 3022 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3023 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3024 recycleBin.addScrapView(first, mFirstPosition); 3025 } 3026 detachViewFromParent(first); 3027 first = getChildAt(0); 3028 mFirstPosition++; 3029 } 3030 } else { 3031 // shifted items down 3032 View first = getChildAt(0); 3033 3034 // may need to pan views into top 3035 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3036 first = addViewAbove(first, mFirstPosition); 3037 mFirstPosition--; 3038 } 3039 3040 // may have brought the very first child of the list in too far and 3041 // need to shift it back 3042 if (first.getTop() > listTop) { 3043 offsetChildrenTopAndBottom(listTop - first.getTop()); 3044 } 3045 3046 int lastIndex = getChildCount() - 1; 3047 View last = getChildAt(lastIndex); 3048 3049 // bottom view may be panned off screen 3050 while (last.getTop() > listBottom) { 3051 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3052 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3053 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3054 } 3055 detachViewFromParent(last); 3056 last = getChildAt(--lastIndex); 3057 } 3058 } 3059 } 3060 3061 private View addViewAbove(View theView, int position) { 3062 int abovePosition = position - 1; 3063 View view = obtainView(abovePosition, mIsScrap); 3064 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3065 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3066 false, mIsScrap[0]); 3067 return view; 3068 } 3069 3070 private View addViewBelow(View theView, int position) { 3071 int belowPosition = position + 1; 3072 View view = obtainView(belowPosition, mIsScrap); 3073 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3074 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3075 false, mIsScrap[0]); 3076 return view; 3077 } 3078 3079 /** 3080 * Indicates that the views created by the ListAdapter can contain focusable 3081 * items. 3082 * 3083 * @param itemsCanFocus true if items can get focus, false otherwise 3084 */ 3085 public void setItemsCanFocus(boolean itemsCanFocus) { 3086 mItemsCanFocus = itemsCanFocus; 3087 if (!itemsCanFocus) { 3088 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3089 } 3090 } 3091 3092 /** 3093 * @return Whether the views created by the ListAdapter can contain focusable 3094 * items. 3095 */ 3096 public boolean getItemsCanFocus() { 3097 return mItemsCanFocus; 3098 } 3099 3100 @Override 3101 public boolean isOpaque() { 3102 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3103 hasOpaqueScrollbars()) || super.isOpaque(); 3104 if (retValue) { 3105 // only return true if the list items cover the entire area of the view 3106 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3107 View first = getChildAt(0); 3108 if (first == null || first.getTop() > listTop) { 3109 return false; 3110 } 3111 final int listBottom = getHeight() - 3112 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3113 View last = getChildAt(getChildCount() - 1); 3114 if (last == null || last.getBottom() < listBottom) { 3115 return false; 3116 } 3117 } 3118 return retValue; 3119 } 3120 3121 @Override 3122 public void setCacheColorHint(int color) { 3123 final boolean opaque = (color >>> 24) == 0xFF; 3124 mIsCacheColorOpaque = opaque; 3125 if (opaque) { 3126 if (mDividerPaint == null) { 3127 mDividerPaint = new Paint(); 3128 } 3129 mDividerPaint.setColor(color); 3130 } 3131 super.setCacheColorHint(color); 3132 } 3133 3134 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3135 final int height = drawable.getMinimumHeight(); 3136 3137 canvas.save(); 3138 canvas.clipRect(bounds); 3139 3140 final int span = bounds.bottom - bounds.top; 3141 if (span < height) { 3142 bounds.top = bounds.bottom - height; 3143 } 3144 3145 drawable.setBounds(bounds); 3146 drawable.draw(canvas); 3147 3148 canvas.restore(); 3149 } 3150 3151 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3152 final int height = drawable.getMinimumHeight(); 3153 3154 canvas.save(); 3155 canvas.clipRect(bounds); 3156 3157 final int span = bounds.bottom - bounds.top; 3158 if (span < height) { 3159 bounds.bottom = bounds.top + height; 3160 } 3161 3162 drawable.setBounds(bounds); 3163 drawable.draw(canvas); 3164 3165 canvas.restore(); 3166 } 3167 3168 @Override 3169 protected void dispatchDraw(Canvas canvas) { 3170 if (mCachingStarted) { 3171 mCachingActive = true; 3172 } 3173 3174 // Draw the dividers 3175 final int dividerHeight = mDividerHeight; 3176 final Drawable overscrollHeader = mOverScrollHeader; 3177 final Drawable overscrollFooter = mOverScrollFooter; 3178 final boolean drawOverscrollHeader = overscrollHeader != null; 3179 final boolean drawOverscrollFooter = overscrollFooter != null; 3180 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3181 3182 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3183 // Only modify the top and bottom in the loop, we set the left and right here 3184 final Rect bounds = mTempRect; 3185 bounds.left = mPaddingLeft; 3186 bounds.right = mRight - mLeft - mPaddingRight; 3187 3188 final int count = getChildCount(); 3189 final int headerCount = mHeaderViewInfos.size(); 3190 final int itemCount = mItemCount; 3191 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3192 final boolean headerDividers = mHeaderDividersEnabled; 3193 final boolean footerDividers = mFooterDividersEnabled; 3194 final int first = mFirstPosition; 3195 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3196 final ListAdapter adapter = mAdapter; 3197 // If the list is opaque *and* the background is not, we want to 3198 // fill a rect where the dividers would be for non-selectable items 3199 // If the list is opaque and the background is also opaque, we don't 3200 // need to draw anything since the background will do it for us 3201 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3202 3203 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3204 mDividerPaint = new Paint(); 3205 mDividerPaint.setColor(getCacheColorHint()); 3206 } 3207 final Paint paint = mDividerPaint; 3208 3209 int effectivePaddingTop = 0; 3210 int effectivePaddingBottom = 0; 3211 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3212 effectivePaddingTop = mListPadding.top; 3213 effectivePaddingBottom = mListPadding.bottom; 3214 } 3215 3216 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3217 if (!mStackFromBottom) { 3218 int bottom = 0; 3219 3220 // Draw top divider or header for overscroll 3221 final int scrollY = mScrollY; 3222 if (count > 0 && scrollY < 0) { 3223 if (drawOverscrollHeader) { 3224 bounds.bottom = 0; 3225 bounds.top = scrollY; 3226 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3227 } else if (drawDividers) { 3228 bounds.bottom = 0; 3229 bounds.top = -dividerHeight; 3230 drawDivider(canvas, bounds, -1); 3231 } 3232 } 3233 3234 for (int i = 0; i < count; i++) { 3235 final int itemIndex = (first + i); 3236 final boolean isHeader = (itemIndex < headerCount); 3237 final boolean isFooter = (itemIndex >= footerLimit); 3238 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3239 final View child = getChildAt(i); 3240 bottom = child.getBottom(); 3241 final boolean isLastItem = (i == (count - 1)); 3242 3243 if (drawDividers && (bottom < listBottom) 3244 && !(drawOverscrollFooter && isLastItem)) { 3245 final int nextIndex = (itemIndex + 1); 3246 // Draw dividers between enabled items, headers 3247 // and/or footers when enabled and requested, and 3248 // after the last enabled item. 3249 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3250 && (nextIndex >= headerCount)) && (isLastItem 3251 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3252 && (nextIndex < footerLimit)))) { 3253 bounds.top = bottom; 3254 bounds.bottom = bottom + dividerHeight; 3255 drawDivider(canvas, bounds, i); 3256 } else if (fillForMissingDividers) { 3257 bounds.top = bottom; 3258 bounds.bottom = bottom + dividerHeight; 3259 canvas.drawRect(bounds, paint); 3260 } 3261 } 3262 } 3263 } 3264 3265 final int overFooterBottom = mBottom + mScrollY; 3266 if (drawOverscrollFooter && first + count == itemCount && 3267 overFooterBottom > bottom) { 3268 bounds.top = bottom; 3269 bounds.bottom = overFooterBottom; 3270 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3271 } 3272 } else { 3273 int top; 3274 3275 final int scrollY = mScrollY; 3276 3277 if (count > 0 && drawOverscrollHeader) { 3278 bounds.top = scrollY; 3279 bounds.bottom = getChildAt(0).getTop(); 3280 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3281 } 3282 3283 final int start = drawOverscrollHeader ? 1 : 0; 3284 for (int i = start; i < count; i++) { 3285 final int itemIndex = (first + i); 3286 final boolean isHeader = (itemIndex < headerCount); 3287 final boolean isFooter = (itemIndex >= footerLimit); 3288 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3289 final View child = getChildAt(i); 3290 top = child.getTop(); 3291 if (drawDividers && (top > effectivePaddingTop)) { 3292 final boolean isFirstItem = (i == start); 3293 final int previousIndex = (itemIndex - 1); 3294 // Draw dividers between enabled items, headers 3295 // and/or footers when enabled and requested, and 3296 // before the first enabled item. 3297 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3298 && (previousIndex >= headerCount)) && (isFirstItem || 3299 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3300 && (previousIndex < footerLimit)))) { 3301 bounds.top = top - dividerHeight; 3302 bounds.bottom = top; 3303 // Give the method the child ABOVE the divider, 3304 // so we subtract one from our child position. 3305 // Give -1 when there is no child above the 3306 // divider. 3307 drawDivider(canvas, bounds, i - 1); 3308 } else if (fillForMissingDividers) { 3309 bounds.top = top - dividerHeight; 3310 bounds.bottom = top; 3311 canvas.drawRect(bounds, paint); 3312 } 3313 } 3314 } 3315 } 3316 3317 if (count > 0 && scrollY > 0) { 3318 if (drawOverscrollFooter) { 3319 final int absListBottom = mBottom; 3320 bounds.top = absListBottom; 3321 bounds.bottom = absListBottom + scrollY; 3322 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3323 } else if (drawDividers) { 3324 bounds.top = listBottom; 3325 bounds.bottom = listBottom + dividerHeight; 3326 drawDivider(canvas, bounds, -1); 3327 } 3328 } 3329 } 3330 } 3331 3332 // Draw the indicators (these should be drawn above the dividers) and children 3333 super.dispatchDraw(canvas); 3334 } 3335 3336 @Override 3337 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3338 boolean more = super.drawChild(canvas, child, drawingTime); 3339 if (mCachingActive && child.mCachingFailed) { 3340 mCachingActive = false; 3341 } 3342 return more; 3343 } 3344 3345 /** 3346 * Draws a divider for the given child in the given bounds. 3347 * 3348 * @param canvas The canvas to draw to. 3349 * @param bounds The bounds of the divider. 3350 * @param childIndex The index of child (of the View) above the divider. 3351 * This will be -1 if there is no child above the divider to be 3352 * drawn. 3353 */ 3354 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3355 // This widget draws the same divider for all children 3356 final Drawable divider = mDivider; 3357 3358 divider.setBounds(bounds); 3359 divider.draw(canvas); 3360 } 3361 3362 /** 3363 * Returns the drawable that will be drawn between each item in the list. 3364 * 3365 * @return the current drawable drawn between list elements 3366 */ 3367 public Drawable getDivider() { 3368 return mDivider; 3369 } 3370 3371 /** 3372 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3373 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3374 * 3375 * @param divider The drawable to use. 3376 */ 3377 public void setDivider(Drawable divider) { 3378 if (divider != null) { 3379 mDividerHeight = divider.getIntrinsicHeight(); 3380 } else { 3381 mDividerHeight = 0; 3382 } 3383 mDivider = divider; 3384 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3385 requestLayout(); 3386 invalidate(); 3387 } 3388 3389 /** 3390 * @return Returns the height of the divider that will be drawn between each item in the list. 3391 */ 3392 public int getDividerHeight() { 3393 return mDividerHeight; 3394 } 3395 3396 /** 3397 * Sets the height of the divider that will be drawn between each item in the list. Calling 3398 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3399 * 3400 * @param height The new height of the divider in pixels. 3401 */ 3402 public void setDividerHeight(int height) { 3403 mDividerHeight = height; 3404 requestLayout(); 3405 invalidate(); 3406 } 3407 3408 /** 3409 * Enables or disables the drawing of the divider for header views. 3410 * 3411 * @param headerDividersEnabled True to draw the headers, false otherwise. 3412 * 3413 * @see #setFooterDividersEnabled(boolean) 3414 * @see #areHeaderDividersEnabled() 3415 * @see #addHeaderView(android.view.View) 3416 */ 3417 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3418 mHeaderDividersEnabled = headerDividersEnabled; 3419 invalidate(); 3420 } 3421 3422 /** 3423 * @return Whether the drawing of the divider for header views is enabled 3424 * 3425 * @see #setHeaderDividersEnabled(boolean) 3426 */ 3427 public boolean areHeaderDividersEnabled() { 3428 return mHeaderDividersEnabled; 3429 } 3430 3431 /** 3432 * Enables or disables the drawing of the divider for footer views. 3433 * 3434 * @param footerDividersEnabled True to draw the footers, false otherwise. 3435 * 3436 * @see #setHeaderDividersEnabled(boolean) 3437 * @see #areFooterDividersEnabled() 3438 * @see #addFooterView(android.view.View) 3439 */ 3440 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3441 mFooterDividersEnabled = footerDividersEnabled; 3442 invalidate(); 3443 } 3444 3445 /** 3446 * @return Whether the drawing of the divider for footer views is enabled 3447 * 3448 * @see #setFooterDividersEnabled(boolean) 3449 */ 3450 public boolean areFooterDividersEnabled() { 3451 return mFooterDividersEnabled; 3452 } 3453 3454 /** 3455 * Sets the drawable that will be drawn above all other list content. 3456 * This area can become visible when the user overscrolls the list. 3457 * 3458 * @param header The drawable to use 3459 */ 3460 public void setOverscrollHeader(Drawable header) { 3461 mOverScrollHeader = header; 3462 if (mScrollY < 0) { 3463 invalidate(); 3464 } 3465 } 3466 3467 /** 3468 * @return The drawable that will be drawn above all other list content 3469 */ 3470 public Drawable getOverscrollHeader() { 3471 return mOverScrollHeader; 3472 } 3473 3474 /** 3475 * Sets the drawable that will be drawn below all other list content. 3476 * This area can become visible when the user overscrolls the list, 3477 * or when the list's content does not fully fill the container area. 3478 * 3479 * @param footer The drawable to use 3480 */ 3481 public void setOverscrollFooter(Drawable footer) { 3482 mOverScrollFooter = footer; 3483 invalidate(); 3484 } 3485 3486 /** 3487 * @return The drawable that will be drawn below all other list content 3488 */ 3489 public Drawable getOverscrollFooter() { 3490 return mOverScrollFooter; 3491 } 3492 3493 @Override 3494 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3495 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3496 3497 final ListAdapter adapter = mAdapter; 3498 int closetChildIndex = -1; 3499 int closestChildTop = 0; 3500 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3501 previouslyFocusedRect.offset(mScrollX, mScrollY); 3502 3503 // Don't cache the result of getChildCount or mFirstPosition here, 3504 // it could change in layoutChildren. 3505 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3506 mLayoutMode = LAYOUT_NORMAL; 3507 layoutChildren(); 3508 } 3509 3510 // figure out which item should be selected based on previously 3511 // focused rect 3512 Rect otherRect = mTempRect; 3513 int minDistance = Integer.MAX_VALUE; 3514 final int childCount = getChildCount(); 3515 final int firstPosition = mFirstPosition; 3516 3517 for (int i = 0; i < childCount; i++) { 3518 // only consider selectable views 3519 if (!adapter.isEnabled(firstPosition + i)) { 3520 continue; 3521 } 3522 3523 View other = getChildAt(i); 3524 other.getDrawingRect(otherRect); 3525 offsetDescendantRectToMyCoords(other, otherRect); 3526 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3527 3528 if (distance < minDistance) { 3529 minDistance = distance; 3530 closetChildIndex = i; 3531 closestChildTop = other.getTop(); 3532 } 3533 } 3534 } 3535 3536 if (closetChildIndex >= 0) { 3537 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3538 } else { 3539 requestLayout(); 3540 } 3541 } 3542 3543 3544 /* 3545 * (non-Javadoc) 3546 * 3547 * Children specified in XML are assumed to be header views. After we have 3548 * parsed them move them out of the children list and into mHeaderViews. 3549 */ 3550 @Override 3551 protected void onFinishInflate() { 3552 super.onFinishInflate(); 3553 3554 int count = getChildCount(); 3555 if (count > 0) { 3556 for (int i = 0; i < count; ++i) { 3557 addHeaderView(getChildAt(i)); 3558 } 3559 removeAllViews(); 3560 } 3561 } 3562 3563 /* (non-Javadoc) 3564 * @see android.view.View#findViewById(int) 3565 * First look in our children, then in any header and footer views that may be scrolled off. 3566 */ 3567 @Override 3568 protected View findViewTraversal(int id) { 3569 View v; 3570 v = super.findViewTraversal(id); 3571 if (v == null) { 3572 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3573 if (v != null) { 3574 return v; 3575 } 3576 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3577 if (v != null) { 3578 return v; 3579 } 3580 } 3581 return v; 3582 } 3583 3584 /* (non-Javadoc) 3585 * 3586 * Look in the passed in list of headers or footers for the view. 3587 */ 3588 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3589 if (where != null) { 3590 int len = where.size(); 3591 View v; 3592 3593 for (int i = 0; i < len; i++) { 3594 v = where.get(i).view; 3595 3596 if (!v.isRootNamespace()) { 3597 v = v.findViewById(id); 3598 3599 if (v != null) { 3600 return v; 3601 } 3602 } 3603 } 3604 } 3605 return null; 3606 } 3607 3608 /* (non-Javadoc) 3609 * @see android.view.View#findViewWithTag(Object) 3610 * First look in our children, then in any header and footer views that may be scrolled off. 3611 */ 3612 @Override 3613 protected View findViewWithTagTraversal(Object tag) { 3614 View v; 3615 v = super.findViewWithTagTraversal(tag); 3616 if (v == null) { 3617 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3618 if (v != null) { 3619 return v; 3620 } 3621 3622 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3623 if (v != null) { 3624 return v; 3625 } 3626 } 3627 return v; 3628 } 3629 3630 /* (non-Javadoc) 3631 * 3632 * Look in the passed in list of headers or footers for the view with the tag. 3633 */ 3634 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3635 if (where != null) { 3636 int len = where.size(); 3637 View v; 3638 3639 for (int i = 0; i < len; i++) { 3640 v = where.get(i).view; 3641 3642 if (!v.isRootNamespace()) { 3643 v = v.findViewWithTag(tag); 3644 3645 if (v != null) { 3646 return v; 3647 } 3648 } 3649 } 3650 } 3651 return null; 3652 } 3653 3654 /** 3655 * @hide 3656 * @see android.view.View#findViewByPredicate(Predicate) 3657 * First look in our children, then in any header and footer views that may be scrolled off. 3658 */ 3659 @Override 3660 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3661 View v; 3662 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3663 if (v == null) { 3664 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3665 if (v != null) { 3666 return v; 3667 } 3668 3669 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3670 if (v != null) { 3671 return v; 3672 } 3673 } 3674 return v; 3675 } 3676 3677 /* (non-Javadoc) 3678 * 3679 * Look in the passed in list of headers or footers for the first view that matches 3680 * the predicate. 3681 */ 3682 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3683 Predicate<View> predicate, View childToSkip) { 3684 if (where != null) { 3685 int len = where.size(); 3686 View v; 3687 3688 for (int i = 0; i < len; i++) { 3689 v = where.get(i).view; 3690 3691 if (v != childToSkip && !v.isRootNamespace()) { 3692 v = v.findViewByPredicate(predicate); 3693 3694 if (v != null) { 3695 return v; 3696 } 3697 } 3698 } 3699 } 3700 return null; 3701 } 3702 3703 /** 3704 * Returns the set of checked items ids. The result is only valid if the 3705 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3706 * 3707 * @return A new array which contains the id of each checked item in the 3708 * list. 3709 * 3710 * @deprecated Use {@link #getCheckedItemIds()} instead. 3711 */ 3712 @Deprecated 3713 public long[] getCheckItemIds() { 3714 // Use new behavior that correctly handles stable ID mapping. 3715 if (mAdapter != null && mAdapter.hasStableIds()) { 3716 return getCheckedItemIds(); 3717 } 3718 3719 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3720 // Fall back to it to support legacy apps. 3721 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3722 final SparseBooleanArray states = mCheckStates; 3723 final int count = states.size(); 3724 final long[] ids = new long[count]; 3725 final ListAdapter adapter = mAdapter; 3726 3727 int checkedCount = 0; 3728 for (int i = 0; i < count; i++) { 3729 if (states.valueAt(i)) { 3730 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3731 } 3732 } 3733 3734 // Trim array if needed. mCheckStates may contain false values 3735 // resulting in checkedCount being smaller than count. 3736 if (checkedCount == count) { 3737 return ids; 3738 } else { 3739 final long[] result = new long[checkedCount]; 3740 System.arraycopy(ids, 0, result, 0, checkedCount); 3741 3742 return result; 3743 } 3744 } 3745 return new long[0]; 3746 } 3747 3748 @Override 3749 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 3750 super.onInitializeAccessibilityEvent(event); 3751 event.setClassName(ListView.class.getName()); 3752 } 3753 3754 @Override 3755 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 3756 super.onInitializeAccessibilityNodeInfo(info); 3757 info.setClassName(ListView.class.getName()); 3758 3759 final int count = getCount(); 3760 final CollectionInfo collectionInfo = CollectionInfo.obtain(1, count, false); 3761 info.setCollectionInfo(collectionInfo); 3762 } 3763 3764 @Override 3765 public void onInitializeAccessibilityNodeInfoForItem( 3766 View view, int position, AccessibilityNodeInfo info) { 3767 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3768 3769 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3770 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3771 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain(0, 1, position, 1, isHeading); 3772 info.setCollectionItemInfo(itemInfo); 3773 } 3774} 3775