ListView.java revision 736c2756bf3c14ae9fef7255c119057f7a2be1ed
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 com.android.internal.R; 20import com.android.internal.util.Predicate; 21import com.google.android.collect.Lists; 22 23import android.content.Context; 24import android.content.Intent; 25import android.content.res.TypedArray; 26import android.graphics.Canvas; 27import android.graphics.Paint; 28import android.graphics.PixelFormat; 29import android.graphics.Rect; 30import android.graphics.drawable.Drawable; 31import android.util.AttributeSet; 32import android.util.SparseBooleanArray; 33import android.view.FocusFinder; 34import android.view.KeyEvent; 35import android.view.MotionEvent; 36import android.view.SoundEffectConstants; 37import android.view.View; 38import android.view.ViewDebug; 39import android.view.ViewGroup; 40import android.view.ViewParent; 41import android.view.accessibility.AccessibilityEvent; 42import android.widget.RemoteViews.RemoteView; 43 44import java.util.ArrayList; 45 46/* 47 * Implementation Notes: 48 * 49 * Some terminology: 50 * 51 * index - index of the items that are currently visible 52 * position - index of the items in the cursor 53 */ 54 55 56/** 57 * A view that shows items in a vertically scrolling list. The items 58 * come from the {@link ListAdapter} associated with this view. 59 * 60 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-listview.html">List View 61 * tutorial</a>.</p> 62 * 63 * @attr ref android.R.styleable#ListView_entries 64 * @attr ref android.R.styleable#ListView_divider 65 * @attr ref android.R.styleable#ListView_dividerHeight 66 * @attr ref android.R.styleable#ListView_headerDividersEnabled 67 * @attr ref android.R.styleable#ListView_footerDividersEnabled 68 */ 69@RemoteView 70public class ListView extends AbsListView { 71 /** 72 * Used to indicate a no preference for a position type. 73 */ 74 static final int NO_POSITION = -1; 75 76 /** 77 * When arrow scrolling, ListView will never scroll more than this factor 78 * times the height of the list. 79 */ 80 private static final float MAX_SCROLL_FACTOR = 0.33f; 81 82 /** 83 * When arrow scrolling, need a certain amount of pixels to preview next 84 * items. This is usually the fading edge, but if that is small enough, 85 * we want to make sure we preview at least this many pixels. 86 */ 87 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 88 89 /** 90 * A class that represents a fixed view in a list, for example a header at the top 91 * or a footer at the bottom. 92 */ 93 public class FixedViewInfo { 94 /** The view to add to the list */ 95 public View view; 96 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 97 public Object data; 98 /** <code>true</code> if the fixed view should be selectable in the list */ 99 public boolean isSelectable; 100 } 101 102 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 103 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 104 105 Drawable mDivider; 106 int mDividerHeight; 107 108 Drawable mOverScrollHeader; 109 Drawable mOverScrollFooter; 110 111 private boolean mIsCacheColorOpaque; 112 private boolean mDividerIsOpaque; 113 114 private boolean mHeaderDividersEnabled; 115 private boolean mFooterDividersEnabled; 116 117 private boolean mAreAllItemsSelectable = true; 118 119 private boolean mItemsCanFocus = false; 120 121 // used for temporary calculations. 122 private final Rect mTempRect = new Rect(); 123 private Paint mDividerPaint; 124 125 // the single allocated result per list view; kinda cheesey but avoids 126 // allocating these thingies too often. 127 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 128 129 // Keeps focused children visible through resizes 130 private FocusSelector mFocusSelector; 131 132 public ListView(Context context) { 133 this(context, null); 134 } 135 136 public ListView(Context context, AttributeSet attrs) { 137 this(context, attrs, com.android.internal.R.attr.listViewStyle); 138 } 139 140 public ListView(Context context, AttributeSet attrs, int defStyle) { 141 super(context, attrs, defStyle); 142 143 TypedArray a = context.obtainStyledAttributes(attrs, 144 com.android.internal.R.styleable.ListView, defStyle, 0); 145 146 CharSequence[] entries = a.getTextArray( 147 com.android.internal.R.styleable.ListView_entries); 148 if (entries != null) { 149 setAdapter(new ArrayAdapter<CharSequence>(context, 150 com.android.internal.R.layout.simple_list_item_1, entries)); 151 } 152 153 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 154 if (d != null) { 155 // If a divider is specified use its intrinsic height for divider height 156 setDivider(d); 157 } 158 159 final Drawable osHeader = a.getDrawable( 160 com.android.internal.R.styleable.ListView_overScrollHeader); 161 if (osHeader != null) { 162 setOverscrollHeader(osHeader); 163 } 164 165 final Drawable osFooter = a.getDrawable( 166 com.android.internal.R.styleable.ListView_overScrollFooter); 167 if (osFooter != null) { 168 setOverscrollFooter(osFooter); 169 } 170 171 // Use the height specified, zero being the default 172 final int dividerHeight = a.getDimensionPixelSize( 173 com.android.internal.R.styleable.ListView_dividerHeight, 0); 174 if (dividerHeight != 0) { 175 setDividerHeight(dividerHeight); 176 } 177 178 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 179 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 180 181 a.recycle(); 182 } 183 184 /** 185 * @return The maximum amount a list view will scroll in response to 186 * an arrow event. 187 */ 188 public int getMaxScrollAmount() { 189 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 190 } 191 192 /** 193 * Make sure views are touching the top or bottom edge, as appropriate for 194 * our gravity 195 */ 196 private void adjustViewsUpOrDown() { 197 final int childCount = getChildCount(); 198 int delta; 199 200 if (childCount > 0) { 201 View child; 202 203 if (!mStackFromBottom) { 204 // Uh-oh -- we came up short. Slide all views up to make them 205 // align with the top 206 child = getChildAt(0); 207 delta = child.getTop() - mListPadding.top; 208 if (mFirstPosition != 0) { 209 // It's OK to have some space above the first item if it is 210 // part of the vertical spacing 211 delta -= mDividerHeight; 212 } 213 if (delta < 0) { 214 // We only are looking to see if we are too low, not too high 215 delta = 0; 216 } 217 } else { 218 // we are too high, slide all views down to align with bottom 219 child = getChildAt(childCount - 1); 220 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 221 222 if (mFirstPosition + childCount < mItemCount) { 223 // It's OK to have some space below the last item if it is 224 // part of the vertical spacing 225 delta += mDividerHeight; 226 } 227 228 if (delta > 0) { 229 delta = 0; 230 } 231 } 232 233 if (delta != 0) { 234 offsetChildrenTopAndBottom(-delta); 235 } 236 } 237 } 238 239 /** 240 * Add a fixed view to appear at the top of the list. If addHeaderView is 241 * called more than once, the views will appear in the order they were 242 * added. Views added using this call can take focus if they want. 243 * <p> 244 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 245 * the supplied cursor with one that will also account for header and footer 246 * views. 247 * 248 * @param v The view to add. 249 * @param data Data to associate with this view 250 * @param isSelectable whether the item is selectable 251 */ 252 public void addHeaderView(View v, Object data, boolean isSelectable) { 253 254 if (mAdapter != null && ! (mAdapter instanceof HeaderViewListAdapter)) { 255 throw new IllegalStateException( 256 "Cannot add header view to list -- setAdapter has already been called."); 257 } 258 259 FixedViewInfo info = new FixedViewInfo(); 260 info.view = v; 261 info.data = data; 262 info.isSelectable = isSelectable; 263 mHeaderViewInfos.add(info); 264 265 // in the case of re-adding a header view, or adding one later on, 266 // we need to notify the observer 267 if (mDataSetObserver != null) { 268 mDataSetObserver.onChanged(); 269 } 270 } 271 272 /** 273 * Add a fixed view to appear at the top of the list. If addHeaderView is 274 * called more than once, the views will appear in the order they were 275 * added. Views added using this call can take focus if they want. 276 * <p> 277 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 278 * the supplied cursor with one that will also account for header and footer 279 * views. 280 * 281 * @param v The view to add. 282 */ 283 public void addHeaderView(View v) { 284 addHeaderView(v, null, true); 285 } 286 287 @Override 288 public int getHeaderViewsCount() { 289 return mHeaderViewInfos.size(); 290 } 291 292 /** 293 * Removes a previously-added header view. 294 * 295 * @param v The view to remove 296 * @return true if the view was removed, false if the view was not a header 297 * view 298 */ 299 public boolean removeHeaderView(View v) { 300 if (mHeaderViewInfos.size() > 0) { 301 boolean result = false; 302 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 303 if (mDataSetObserver != null) { 304 mDataSetObserver.onChanged(); 305 } 306 result = true; 307 } 308 removeFixedViewInfo(v, mHeaderViewInfos); 309 return result; 310 } 311 return false; 312 } 313 314 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 315 int len = where.size(); 316 for (int i = 0; i < len; ++i) { 317 FixedViewInfo info = where.get(i); 318 if (info.view == v) { 319 where.remove(i); 320 break; 321 } 322 } 323 } 324 325 /** 326 * Add a fixed view to appear at the bottom of the list. If addFooterView is 327 * called more than once, the views will appear in the order they were 328 * added. Views added using this call can take focus if they want. 329 * <p> 330 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 331 * the supplied cursor with one that will also account for header and footer 332 * views. 333 * 334 * @param v The view to add. 335 * @param data Data to associate with this view 336 * @param isSelectable true if the footer view can be selected 337 */ 338 public void addFooterView(View v, Object data, boolean isSelectable) { 339 340 // NOTE: do not enforce the adapter being null here, since unlike in 341 // addHeaderView, it was never enforced here, and so existing apps are 342 // relying on being able to add a footer and then calling setAdapter to 343 // force creation of the HeaderViewListAdapter wrapper 344 345 FixedViewInfo info = new FixedViewInfo(); 346 info.view = v; 347 info.data = data; 348 info.isSelectable = isSelectable; 349 mFooterViewInfos.add(info); 350 351 // in the case of re-adding a footer view, or adding one later on, 352 // we need to notify the observer 353 if (mDataSetObserver != null) { 354 mDataSetObserver.onChanged(); 355 } 356 } 357 358 /** 359 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 360 * than once, the views will appear in the order they were added. Views added using 361 * this call can take focus if they want. 362 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 363 * cursor with one that will also account for header and footer views. 364 * 365 * 366 * @param v The view to add. 367 */ 368 public void addFooterView(View v) { 369 addFooterView(v, null, true); 370 } 371 372 @Override 373 public int getFooterViewsCount() { 374 return mFooterViewInfos.size(); 375 } 376 377 /** 378 * Removes a previously-added footer view. 379 * 380 * @param v The view to remove 381 * @return 382 * true if the view was removed, false if the view was not a footer view 383 */ 384 public boolean removeFooterView(View v) { 385 if (mFooterViewInfos.size() > 0) { 386 boolean result = false; 387 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 388 if (mDataSetObserver != null) { 389 mDataSetObserver.onChanged(); 390 } 391 result = true; 392 } 393 removeFixedViewInfo(v, mFooterViewInfos); 394 return result; 395 } 396 return false; 397 } 398 399 /** 400 * Returns the adapter currently in use in this ListView. The returned adapter 401 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 402 * might be a {@link WrapperListAdapter}. 403 * 404 * @return The adapter currently used to display data in this ListView. 405 * 406 * @see #setAdapter(ListAdapter) 407 */ 408 @Override 409 public ListAdapter getAdapter() { 410 return mAdapter; 411 } 412 413 /** 414 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 415 * through the specified intent. 416 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 417 */ 418 @android.view.RemotableViewMethod 419 public void setRemoteViewsAdapter(Intent intent) { 420 super.setRemoteViewsAdapter(intent); 421 } 422 423 /** 424 * Sets the data behind this ListView. 425 * 426 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 427 * depending on the ListView features currently in use. For instance, adding 428 * headers and/or footers will cause the adapter to be wrapped. 429 * 430 * @param adapter The ListAdapter which is responsible for maintaining the 431 * data backing this list and for producing a view to represent an 432 * item in that data set. 433 * 434 * @see #getAdapter() 435 */ 436 @Override 437 public void setAdapter(ListAdapter adapter) { 438 if (mAdapter != null && mDataSetObserver != null) { 439 mAdapter.unregisterDataSetObserver(mDataSetObserver); 440 } 441 442 resetList(); 443 mRecycler.clear(); 444 445 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 446 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 447 } else { 448 mAdapter = adapter; 449 } 450 451 mOldSelectedPosition = INVALID_POSITION; 452 mOldSelectedRowId = INVALID_ROW_ID; 453 454 // AbsListView#setAdapter will update choice mode states. 455 super.setAdapter(adapter); 456 457 if (mAdapter != null) { 458 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 459 mOldItemCount = mItemCount; 460 mItemCount = mAdapter.getCount(); 461 checkFocus(); 462 463 mDataSetObserver = new AdapterDataSetObserver(); 464 mAdapter.registerDataSetObserver(mDataSetObserver); 465 466 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 467 468 int position; 469 if (mStackFromBottom) { 470 position = lookForSelectablePosition(mItemCount - 1, false); 471 } else { 472 position = lookForSelectablePosition(0, true); 473 } 474 setSelectedPositionInt(position); 475 setNextSelectedPositionInt(position); 476 477 if (mItemCount == 0) { 478 // Nothing selected 479 checkSelectionChanged(); 480 } 481 } else { 482 mAreAllItemsSelectable = true; 483 checkFocus(); 484 // Nothing selected 485 checkSelectionChanged(); 486 } 487 488 requestLayout(); 489 } 490 491 492 /** 493 * The list is empty. Clear everything out. 494 */ 495 @Override 496 void resetList() { 497 // The parent's resetList() will remove all views from the layout so we need to 498 // cleanup the state of our footers and headers 499 clearRecycledState(mHeaderViewInfos); 500 clearRecycledState(mFooterViewInfos); 501 502 super.resetList(); 503 504 mLayoutMode = LAYOUT_NORMAL; 505 } 506 507 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 508 if (infos != null) { 509 final int count = infos.size(); 510 511 for (int i = 0; i < count; i++) { 512 final View child = infos.get(i).view; 513 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 514 if (p != null) { 515 p.recycledHeaderFooter = false; 516 } 517 } 518 } 519 } 520 521 /** 522 * @return Whether the list needs to show the top fading edge 523 */ 524 private boolean showingTopFadingEdge() { 525 final int listTop = mScrollY + mListPadding.top; 526 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 527 } 528 529 /** 530 * @return Whether the list needs to show the bottom fading edge 531 */ 532 private boolean showingBottomFadingEdge() { 533 final int childCount = getChildCount(); 534 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 535 final int lastVisiblePosition = mFirstPosition + childCount - 1; 536 537 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 538 539 return (lastVisiblePosition < mItemCount - 1) 540 || (bottomOfBottomChild < listBottom); 541 } 542 543 544 @Override 545 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 546 547 int rectTopWithinChild = rect.top; 548 549 // offset so rect is in coordinates of the this view 550 rect.offset(child.getLeft(), child.getTop()); 551 rect.offset(-child.getScrollX(), -child.getScrollY()); 552 553 final int height = getHeight(); 554 int listUnfadedTop = getScrollY(); 555 int listUnfadedBottom = listUnfadedTop + height; 556 final int fadingEdge = getVerticalFadingEdgeLength(); 557 558 if (showingTopFadingEdge()) { 559 // leave room for top fading edge as long as rect isn't at very top 560 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 561 listUnfadedTop += fadingEdge; 562 } 563 } 564 565 int childCount = getChildCount(); 566 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 567 568 if (showingBottomFadingEdge()) { 569 // leave room for bottom fading edge as long as rect isn't at very bottom 570 if ((mSelectedPosition < mItemCount - 1) 571 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 572 listUnfadedBottom -= fadingEdge; 573 } 574 } 575 576 int scrollYDelta = 0; 577 578 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 579 // need to MOVE DOWN to get it in view: move down just enough so 580 // that the entire rectangle is in view (or at least the first 581 // screen size chunk). 582 583 if (rect.height() > height) { 584 // just enough to get screen size chunk on 585 scrollYDelta += (rect.top - listUnfadedTop); 586 } else { 587 // get entire rect at bottom of screen 588 scrollYDelta += (rect.bottom - listUnfadedBottom); 589 } 590 591 // make sure we aren't scrolling beyond the end of our children 592 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 593 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 594 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 595 // need to MOVE UP to get it in view: move up just enough so that 596 // entire rectangle is in view (or at least the first screen 597 // size chunk of it). 598 599 if (rect.height() > height) { 600 // screen size chunk 601 scrollYDelta -= (listUnfadedBottom - rect.bottom); 602 } else { 603 // entire rect at top 604 scrollYDelta -= (listUnfadedTop - rect.top); 605 } 606 607 // make sure we aren't scrolling any further than the top our children 608 int top = getChildAt(0).getTop(); 609 int deltaToTop = top - listUnfadedTop; 610 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 611 } 612 613 final boolean scroll = scrollYDelta != 0; 614 if (scroll) { 615 scrollListItemsBy(-scrollYDelta); 616 positionSelector(INVALID_POSITION, child); 617 mSelectedTop = child.getTop(); 618 invalidate(); 619 } 620 return scroll; 621 } 622 623 /** 624 * {@inheritDoc} 625 */ 626 @Override 627 void fillGap(boolean down) { 628 final int count = getChildCount(); 629 if (down) { 630 int paddingTop = 0; 631 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 632 paddingTop = getListPaddingTop(); 633 } 634 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 635 paddingTop; 636 fillDown(mFirstPosition + count, startOffset); 637 correctTooHigh(getChildCount()); 638 } else { 639 int paddingBottom = 0; 640 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 641 paddingBottom = getListPaddingBottom(); 642 } 643 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 644 getHeight() - paddingBottom; 645 fillUp(mFirstPosition - 1, startOffset); 646 correctTooLow(getChildCount()); 647 } 648 } 649 650 /** 651 * Fills the list from pos down to the end of the list view. 652 * 653 * @param pos The first position to put in the list 654 * 655 * @param nextTop The location where the top of the item associated with pos 656 * should be drawn 657 * 658 * @return The view that is currently selected, if it happens to be in the 659 * range that we draw. 660 */ 661 private View fillDown(int pos, int nextTop) { 662 View selectedView = null; 663 664 int end = (mBottom - mTop); 665 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 666 end -= mListPadding.bottom; 667 } 668 669 while (nextTop < end && pos < mItemCount) { 670 // is this the selected item? 671 boolean selected = pos == mSelectedPosition; 672 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 673 674 nextTop = child.getBottom() + mDividerHeight; 675 if (selected) { 676 selectedView = child; 677 } 678 pos++; 679 } 680 681 return selectedView; 682 } 683 684 /** 685 * Fills the list from pos up to the top of the list view. 686 * 687 * @param pos The first position to put in the list 688 * 689 * @param nextBottom The location where the bottom of the item associated 690 * with pos should be drawn 691 * 692 * @return The view that is currently selected 693 */ 694 private View fillUp(int pos, int nextBottom) { 695 View selectedView = null; 696 697 int end = 0; 698 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 699 end = mListPadding.top; 700 } 701 702 while (nextBottom > end && pos >= 0) { 703 // is this the selected item? 704 boolean selected = pos == mSelectedPosition; 705 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 706 nextBottom = child.getTop() - mDividerHeight; 707 if (selected) { 708 selectedView = child; 709 } 710 pos--; 711 } 712 713 mFirstPosition = pos + 1; 714 715 return selectedView; 716 } 717 718 /** 719 * Fills the list from top to bottom, starting with mFirstPosition 720 * 721 * @param nextTop The location where the top of the first item should be 722 * drawn 723 * 724 * @return The view that is currently selected 725 */ 726 private View fillFromTop(int nextTop) { 727 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 728 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 729 if (mFirstPosition < 0) { 730 mFirstPosition = 0; 731 } 732 return fillDown(mFirstPosition, nextTop); 733 } 734 735 736 /** 737 * Put mSelectedPosition in the middle of the screen and then build up and 738 * down from there. This method forces mSelectedPosition to the center. 739 * 740 * @param childrenTop Top of the area in which children can be drawn, as 741 * measured in pixels 742 * @param childrenBottom Bottom of the area in which children can be drawn, 743 * as measured in pixels 744 * @return Currently selected view 745 */ 746 private View fillFromMiddle(int childrenTop, int childrenBottom) { 747 int height = childrenBottom - childrenTop; 748 749 int position = reconcileSelectedPosition(); 750 751 View sel = makeAndAddView(position, childrenTop, true, 752 mListPadding.left, true); 753 mFirstPosition = position; 754 755 int selHeight = sel.getMeasuredHeight(); 756 if (selHeight <= height) { 757 sel.offsetTopAndBottom((height - selHeight) / 2); 758 } 759 760 fillAboveAndBelow(sel, position); 761 762 if (!mStackFromBottom) { 763 correctTooHigh(getChildCount()); 764 } else { 765 correctTooLow(getChildCount()); 766 } 767 768 return sel; 769 } 770 771 /** 772 * Once the selected view as been placed, fill up the visible area above and 773 * below it. 774 * 775 * @param sel The selected view 776 * @param position The position corresponding to sel 777 */ 778 private void fillAboveAndBelow(View sel, int position) { 779 final int dividerHeight = mDividerHeight; 780 if (!mStackFromBottom) { 781 fillUp(position - 1, sel.getTop() - dividerHeight); 782 adjustViewsUpOrDown(); 783 fillDown(position + 1, sel.getBottom() + dividerHeight); 784 } else { 785 fillDown(position + 1, sel.getBottom() + dividerHeight); 786 adjustViewsUpOrDown(); 787 fillUp(position - 1, sel.getTop() - dividerHeight); 788 } 789 } 790 791 792 /** 793 * Fills the grid based on positioning the new selection at a specific 794 * location. The selection may be moved so that it does not intersect the 795 * faded edges. The grid is then filled upwards and downwards from there. 796 * 797 * @param selectedTop Where the selected item should be 798 * @param childrenTop Where to start drawing children 799 * @param childrenBottom Last pixel where children can be drawn 800 * @return The view that currently has selection 801 */ 802 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 803 int fadingEdgeLength = getVerticalFadingEdgeLength(); 804 final int selectedPosition = mSelectedPosition; 805 806 View sel; 807 808 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 809 selectedPosition); 810 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 811 selectedPosition); 812 813 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 814 815 816 // Some of the newly selected item extends below the bottom of the list 817 if (sel.getBottom() > bottomSelectionPixel) { 818 // Find space available above the selection into which we can scroll 819 // upwards 820 final int spaceAbove = sel.getTop() - topSelectionPixel; 821 822 // Find space required to bring the bottom of the selected item 823 // fully into view 824 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 825 final int offset = Math.min(spaceAbove, spaceBelow); 826 827 // Now offset the selected item to get it into view 828 sel.offsetTopAndBottom(-offset); 829 } else if (sel.getTop() < topSelectionPixel) { 830 // Find space required to bring the top of the selected item fully 831 // into view 832 final int spaceAbove = topSelectionPixel - sel.getTop(); 833 834 // Find space available below the selection into which we can scroll 835 // downwards 836 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 837 final int offset = Math.min(spaceAbove, spaceBelow); 838 839 // Offset the selected item to get it into view 840 sel.offsetTopAndBottom(offset); 841 } 842 843 // Fill in views above and below 844 fillAboveAndBelow(sel, selectedPosition); 845 846 if (!mStackFromBottom) { 847 correctTooHigh(getChildCount()); 848 } else { 849 correctTooLow(getChildCount()); 850 } 851 852 return sel; 853 } 854 855 /** 856 * Calculate the bottom-most pixel we can draw the selection into 857 * 858 * @param childrenBottom Bottom pixel were children can be drawn 859 * @param fadingEdgeLength Length of the fading edge in pixels, if present 860 * @param selectedPosition The position that will be selected 861 * @return The bottom-most pixel we can draw the selection into 862 */ 863 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 864 int selectedPosition) { 865 int bottomSelectionPixel = childrenBottom; 866 if (selectedPosition != mItemCount - 1) { 867 bottomSelectionPixel -= fadingEdgeLength; 868 } 869 return bottomSelectionPixel; 870 } 871 872 /** 873 * Calculate the top-most pixel we can draw the selection into 874 * 875 * @param childrenTop Top pixel were children can be drawn 876 * @param fadingEdgeLength Length of the fading edge in pixels, if present 877 * @param selectedPosition The position that will be selected 878 * @return The top-most pixel we can draw the selection into 879 */ 880 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 881 // first pixel we can draw the selection into 882 int topSelectionPixel = childrenTop; 883 if (selectedPosition > 0) { 884 topSelectionPixel += fadingEdgeLength; 885 } 886 return topSelectionPixel; 887 } 888 889 /** 890 * Smoothly scroll to the specified adapter position. The view will 891 * scroll such that the indicated position is displayed. 892 * @param position Scroll to this adapter position. 893 */ 894 @android.view.RemotableViewMethod 895 public void smoothScrollToPosition(int position) { 896 super.smoothScrollToPosition(position); 897 } 898 899 /** 900 * Smoothly scroll to the specified adapter position offset. The view will 901 * scroll such that the indicated position is displayed. 902 * @param offset The amount to offset from the adapter position to scroll to. 903 */ 904 @android.view.RemotableViewMethod 905 public void smoothScrollByOffset(int offset) { 906 super.smoothScrollByOffset(offset); 907 } 908 909 /** 910 * Fills the list based on positioning the new selection relative to the old 911 * selection. The new selection will be placed at, above, or below the 912 * location of the new selection depending on how the selection is moving. 913 * The selection will then be pinned to the visible part of the screen, 914 * excluding the edges that are faded. The list is then filled upwards and 915 * downwards from there. 916 * 917 * @param oldSel The old selected view. Useful for trying to put the new 918 * selection in the same place 919 * @param newSel The view that is to become selected. Useful for trying to 920 * put the new selection in the same place 921 * @param delta Which way we are moving 922 * @param childrenTop Where to start drawing children 923 * @param childrenBottom Last pixel where children can be drawn 924 * @return The view that currently has selection 925 */ 926 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 927 int childrenBottom) { 928 int fadingEdgeLength = getVerticalFadingEdgeLength(); 929 final int selectedPosition = mSelectedPosition; 930 931 View sel; 932 933 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 934 selectedPosition); 935 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 936 selectedPosition); 937 938 if (delta > 0) { 939 /* 940 * Case 1: Scrolling down. 941 */ 942 943 /* 944 * Before After 945 * | | | | 946 * +-------+ +-------+ 947 * | A | | A | 948 * | 1 | => +-------+ 949 * +-------+ | B | 950 * | B | | 2 | 951 * +-------+ +-------+ 952 * | | | | 953 * 954 * Try to keep the top of the previously selected item where it was. 955 * oldSel = A 956 * sel = B 957 */ 958 959 // Put oldSel (A) where it belongs 960 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 961 mListPadding.left, false); 962 963 final int dividerHeight = mDividerHeight; 964 965 // Now put the new selection (B) below that 966 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 967 mListPadding.left, true); 968 969 // Some of the newly selected item extends below the bottom of the list 970 if (sel.getBottom() > bottomSelectionPixel) { 971 972 // Find space available above the selection into which we can scroll upwards 973 int spaceAbove = sel.getTop() - topSelectionPixel; 974 975 // Find space required to bring the bottom of the selected item fully into view 976 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 977 978 // Don't scroll more than half the height of the list 979 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 980 int offset = Math.min(spaceAbove, spaceBelow); 981 offset = Math.min(offset, halfVerticalSpace); 982 983 // We placed oldSel, so offset that item 984 oldSel.offsetTopAndBottom(-offset); 985 // Now offset the selected item to get it into view 986 sel.offsetTopAndBottom(-offset); 987 } 988 989 // Fill in views above and below 990 if (!mStackFromBottom) { 991 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 992 adjustViewsUpOrDown(); 993 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 994 } else { 995 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 996 adjustViewsUpOrDown(); 997 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 998 } 999 } else if (delta < 0) { 1000 /* 1001 * Case 2: Scrolling up. 1002 */ 1003 1004 /* 1005 * Before After 1006 * | | | | 1007 * +-------+ +-------+ 1008 * | A | | A | 1009 * +-------+ => | 1 | 1010 * | B | +-------+ 1011 * | 2 | | B | 1012 * +-------+ +-------+ 1013 * | | | | 1014 * 1015 * Try to keep the top of the item about to become selected where it was. 1016 * newSel = A 1017 * olSel = B 1018 */ 1019 1020 if (newSel != null) { 1021 // Try to position the top of newSel (A) where it was before it was selected 1022 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1023 true); 1024 } else { 1025 // If (A) was not on screen and so did not have a view, position 1026 // it above the oldSel (B) 1027 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1028 true); 1029 } 1030 1031 // Some of the newly selected item extends above the top of the list 1032 if (sel.getTop() < topSelectionPixel) { 1033 // Find space required to bring the top of the selected item fully into view 1034 int spaceAbove = topSelectionPixel - sel.getTop(); 1035 1036 // Find space available below the selection into which we can scroll downwards 1037 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1038 1039 // Don't scroll more than half the height of the list 1040 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1041 int offset = Math.min(spaceAbove, spaceBelow); 1042 offset = Math.min(offset, halfVerticalSpace); 1043 1044 // Offset the selected item to get it into view 1045 sel.offsetTopAndBottom(offset); 1046 } 1047 1048 // Fill in views above and below 1049 fillAboveAndBelow(sel, selectedPosition); 1050 } else { 1051 1052 int oldTop = oldSel.getTop(); 1053 1054 /* 1055 * Case 3: Staying still 1056 */ 1057 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1058 1059 // We're staying still... 1060 if (oldTop < childrenTop) { 1061 // ... but the top of the old selection was off screen. 1062 // (This can happen if the data changes size out from under us) 1063 int newBottom = sel.getBottom(); 1064 if (newBottom < childrenTop + 20) { 1065 // Not enough visible -- bring it onscreen 1066 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1067 } 1068 } 1069 1070 // Fill in views above and below 1071 fillAboveAndBelow(sel, selectedPosition); 1072 } 1073 1074 return sel; 1075 } 1076 1077 private class FocusSelector implements Runnable { 1078 private int mPosition; 1079 private int mPositionTop; 1080 1081 public FocusSelector setup(int position, int top) { 1082 mPosition = position; 1083 mPositionTop = top; 1084 return this; 1085 } 1086 1087 public void run() { 1088 setSelectionFromTop(mPosition, mPositionTop); 1089 } 1090 } 1091 1092 @Override 1093 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1094 if (getChildCount() > 0) { 1095 View focusedChild = getFocusedChild(); 1096 if (focusedChild != null) { 1097 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1098 final int childBottom = focusedChild.getBottom(); 1099 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1100 final int top = focusedChild.getTop() - offset; 1101 if (mFocusSelector == null) { 1102 mFocusSelector = new FocusSelector(); 1103 } 1104 post(mFocusSelector.setup(childPosition, top)); 1105 } 1106 } 1107 super.onSizeChanged(w, h, oldw, oldh); 1108 } 1109 1110 @Override 1111 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1112 // Sets up mListPadding 1113 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1114 1115 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1116 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1117 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1118 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1119 1120 int childWidth = 0; 1121 int childHeight = 0; 1122 int childState = 0; 1123 1124 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1125 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1126 heightMode == MeasureSpec.UNSPECIFIED)) { 1127 final View child = obtainView(0, mIsScrap); 1128 1129 measureScrapChild(child, 0, widthMeasureSpec); 1130 1131 childWidth = child.getMeasuredWidth(); 1132 childHeight = child.getMeasuredHeight(); 1133 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1134 1135 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1136 ((LayoutParams) child.getLayoutParams()).viewType)) { 1137 mRecycler.addScrapView(child, -1); 1138 } 1139 } 1140 1141 if (widthMode == MeasureSpec.UNSPECIFIED) { 1142 widthSize = mListPadding.left + mListPadding.right + childWidth + 1143 getVerticalScrollbarWidth(); 1144 } else { 1145 widthSize |= (childState&MEASURED_STATE_MASK); 1146 } 1147 1148 if (heightMode == MeasureSpec.UNSPECIFIED) { 1149 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1150 getVerticalFadingEdgeLength() * 2; 1151 } 1152 1153 if (heightMode == MeasureSpec.AT_MOST) { 1154 // TODO: after first layout we should maybe start at the first visible position, not 0 1155 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1156 } 1157 1158 setMeasuredDimension(widthSize , heightSize); 1159 mWidthMeasureSpec = widthMeasureSpec; 1160 } 1161 1162 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1163 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1164 if (p == null) { 1165 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1166 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1167 child.setLayoutParams(p); 1168 } 1169 p.viewType = mAdapter.getItemViewType(position); 1170 p.forceAdd = true; 1171 1172 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1173 mListPadding.left + mListPadding.right, p.width); 1174 int lpHeight = p.height; 1175 int childHeightSpec; 1176 if (lpHeight > 0) { 1177 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1178 } else { 1179 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1180 } 1181 child.measure(childWidthSpec, childHeightSpec); 1182 } 1183 1184 /** 1185 * @return True to recycle the views used to measure this ListView in 1186 * UNSPECIFIED/AT_MOST modes, false otherwise. 1187 * @hide 1188 */ 1189 @ViewDebug.ExportedProperty(category = "list") 1190 protected boolean recycleOnMeasure() { 1191 return true; 1192 } 1193 1194 /** 1195 * Measures the height of the given range of children (inclusive) and 1196 * returns the height with this ListView's padding and divider heights 1197 * included. If maxHeight is provided, the measuring will stop when the 1198 * current height reaches maxHeight. 1199 * 1200 * @param widthMeasureSpec The width measure spec to be given to a child's 1201 * {@link View#measure(int, int)}. 1202 * @param startPosition The position of the first child to be shown. 1203 * @param endPosition The (inclusive) position of the last child to be 1204 * shown. Specify {@link #NO_POSITION} if the last child should be 1205 * the last available child from the adapter. 1206 * @param maxHeight The maximum height that will be returned (if all the 1207 * children don't fit in this value, this value will be 1208 * returned). 1209 * @param disallowPartialChildPosition In general, whether the returned 1210 * height should only contain entire children. This is more 1211 * powerful--it is the first inclusive position at which partial 1212 * children will not be allowed. Example: it looks nice to have 1213 * at least 3 completely visible children, and in portrait this 1214 * will most likely fit; but in landscape there could be times 1215 * when even 2 children can not be completely shown, so a value 1216 * of 2 (remember, inclusive) would be good (assuming 1217 * startPosition is 0). 1218 * @return The height of this ListView with the given children. 1219 */ 1220 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1221 final int maxHeight, int disallowPartialChildPosition) { 1222 1223 final ListAdapter adapter = mAdapter; 1224 if (adapter == null) { 1225 return mListPadding.top + mListPadding.bottom; 1226 } 1227 1228 // Include the padding of the list 1229 int returnedHeight = mListPadding.top + mListPadding.bottom; 1230 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1231 // The previous height value that was less than maxHeight and contained 1232 // no partial children 1233 int prevHeightWithoutPartialChild = 0; 1234 int i; 1235 View child; 1236 1237 // mItemCount - 1 since endPosition parameter is inclusive 1238 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1239 final AbsListView.RecycleBin recycleBin = mRecycler; 1240 final boolean recyle = recycleOnMeasure(); 1241 final boolean[] isScrap = mIsScrap; 1242 1243 for (i = startPosition; i <= endPosition; ++i) { 1244 child = obtainView(i, isScrap); 1245 1246 measureScrapChild(child, i, widthMeasureSpec); 1247 1248 if (i > 0) { 1249 // Count the divider for all but one child 1250 returnedHeight += dividerHeight; 1251 } 1252 1253 // Recycle the view before we possibly return from the method 1254 if (recyle && recycleBin.shouldRecycleViewType( 1255 ((LayoutParams) child.getLayoutParams()).viewType)) { 1256 recycleBin.addScrapView(child, -1); 1257 } 1258 1259 returnedHeight += child.getMeasuredHeight(); 1260 1261 if (returnedHeight >= maxHeight) { 1262 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1263 // then the i'th position did not fit completely. 1264 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1265 && (i > disallowPartialChildPosition) // We've past the min pos 1266 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1267 && (returnedHeight != maxHeight) // i'th child did not fit completely 1268 ? prevHeightWithoutPartialChild 1269 : maxHeight; 1270 } 1271 1272 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1273 prevHeightWithoutPartialChild = returnedHeight; 1274 } 1275 } 1276 1277 // At this point, we went through the range of children, and they each 1278 // completely fit, so return the returnedHeight 1279 return returnedHeight; 1280 } 1281 1282 @Override 1283 int findMotionRow(int y) { 1284 int childCount = getChildCount(); 1285 if (childCount > 0) { 1286 if (!mStackFromBottom) { 1287 for (int i = 0; i < childCount; i++) { 1288 View v = getChildAt(i); 1289 if (y <= v.getBottom()) { 1290 return mFirstPosition + i; 1291 } 1292 } 1293 } else { 1294 for (int i = childCount - 1; i >= 0; i--) { 1295 View v = getChildAt(i); 1296 if (y >= v.getTop()) { 1297 return mFirstPosition + i; 1298 } 1299 } 1300 } 1301 } 1302 return INVALID_POSITION; 1303 } 1304 1305 /** 1306 * Put a specific item at a specific location on the screen and then build 1307 * up and down from there. 1308 * 1309 * @param position The reference view to use as the starting point 1310 * @param top Pixel offset from the top of this view to the top of the 1311 * reference view. 1312 * 1313 * @return The selected view, or null if the selected view is outside the 1314 * visible area. 1315 */ 1316 private View fillSpecific(int position, int top) { 1317 boolean tempIsSelected = position == mSelectedPosition; 1318 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1319 // Possibly changed again in fillUp if we add rows above this one. 1320 mFirstPosition = position; 1321 1322 View above; 1323 View below; 1324 1325 final int dividerHeight = mDividerHeight; 1326 if (!mStackFromBottom) { 1327 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1328 // This will correct for the top of the first view not touching the top of the list 1329 adjustViewsUpOrDown(); 1330 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1331 int childCount = getChildCount(); 1332 if (childCount > 0) { 1333 correctTooHigh(childCount); 1334 } 1335 } else { 1336 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1337 // This will correct for the bottom of the last view not touching the bottom of the list 1338 adjustViewsUpOrDown(); 1339 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1340 int childCount = getChildCount(); 1341 if (childCount > 0) { 1342 correctTooLow(childCount); 1343 } 1344 } 1345 1346 if (tempIsSelected) { 1347 return temp; 1348 } else if (above != null) { 1349 return above; 1350 } else { 1351 return below; 1352 } 1353 } 1354 1355 /** 1356 * Check if we have dragged the bottom of the list too high (we have pushed the 1357 * top element off the top of the screen when we did not need to). Correct by sliding 1358 * everything back down. 1359 * 1360 * @param childCount Number of children 1361 */ 1362 private void correctTooHigh(int childCount) { 1363 // First see if the last item is visible. If it is not, it is OK for the 1364 // top of the list to be pushed up. 1365 int lastPosition = mFirstPosition + childCount - 1; 1366 if (lastPosition == mItemCount - 1 && childCount > 0) { 1367 1368 // Get the last child ... 1369 final View lastChild = getChildAt(childCount - 1); 1370 1371 // ... and its bottom edge 1372 final int lastBottom = lastChild.getBottom(); 1373 1374 // This is bottom of our drawable area 1375 final int end = (mBottom - mTop) - mListPadding.bottom; 1376 1377 // This is how far the bottom edge of the last view is from the bottom of the 1378 // drawable area 1379 int bottomOffset = end - lastBottom; 1380 View firstChild = getChildAt(0); 1381 final int firstTop = firstChild.getTop(); 1382 1383 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1384 // first row or the first row is scrolled off the top of the drawable area 1385 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1386 if (mFirstPosition == 0) { 1387 // Don't pull the top too far down 1388 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1389 } 1390 // Move everything down 1391 offsetChildrenTopAndBottom(bottomOffset); 1392 if (mFirstPosition > 0) { 1393 // Fill the gap that was opened above mFirstPosition with more rows, if 1394 // possible 1395 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1396 // Close up the remaining gap 1397 adjustViewsUpOrDown(); 1398 } 1399 1400 } 1401 } 1402 } 1403 1404 /** 1405 * Check if we have dragged the bottom of the list too low (we have pushed the 1406 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1407 * everything back up. 1408 * 1409 * @param childCount Number of children 1410 */ 1411 private void correctTooLow(int childCount) { 1412 // First see if the first item is visible. If it is not, it is OK for the 1413 // bottom of the list to be pushed down. 1414 if (mFirstPosition == 0 && childCount > 0) { 1415 1416 // Get the first child ... 1417 final View firstChild = getChildAt(0); 1418 1419 // ... and its top edge 1420 final int firstTop = firstChild.getTop(); 1421 1422 // This is top of our drawable area 1423 final int start = mListPadding.top; 1424 1425 // This is bottom of our drawable area 1426 final int end = (mBottom - mTop) - mListPadding.bottom; 1427 1428 // This is how far the top edge of the first view is from the top of the 1429 // drawable area 1430 int topOffset = firstTop - start; 1431 View lastChild = getChildAt(childCount - 1); 1432 final int lastBottom = lastChild.getBottom(); 1433 int lastPosition = mFirstPosition + childCount - 1; 1434 1435 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1436 // last row or the last row is scrolled off the bottom of the drawable area 1437 if (topOffset > 0) { 1438 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1439 if (lastPosition == mItemCount - 1) { 1440 // Don't pull the bottom too far up 1441 topOffset = Math.min(topOffset, lastBottom - end); 1442 } 1443 // Move everything up 1444 offsetChildrenTopAndBottom(-topOffset); 1445 if (lastPosition < mItemCount - 1) { 1446 // Fill the gap that was opened below the last position with more rows, if 1447 // possible 1448 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1449 // Close up the remaining gap 1450 adjustViewsUpOrDown(); 1451 } 1452 } else if (lastPosition == mItemCount - 1) { 1453 adjustViewsUpOrDown(); 1454 } 1455 } 1456 } 1457 } 1458 1459 @Override 1460 protected void layoutChildren() { 1461 final boolean blockLayoutRequests = mBlockLayoutRequests; 1462 if (!blockLayoutRequests) { 1463 mBlockLayoutRequests = true; 1464 } else { 1465 return; 1466 } 1467 1468 try { 1469 super.layoutChildren(); 1470 1471 invalidate(); 1472 1473 if (mAdapter == null) { 1474 resetList(); 1475 invokeOnItemScrollListener(); 1476 return; 1477 } 1478 1479 int childrenTop = mListPadding.top; 1480 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1481 1482 int childCount = getChildCount(); 1483 int index = 0; 1484 int delta = 0; 1485 1486 View sel; 1487 View oldSel = null; 1488 View oldFirst = null; 1489 View newSel = null; 1490 1491 View focusLayoutRestoreView = null; 1492 1493 // Remember stuff we will need down below 1494 switch (mLayoutMode) { 1495 case LAYOUT_SET_SELECTION: 1496 index = mNextSelectedPosition - mFirstPosition; 1497 if (index >= 0 && index < childCount) { 1498 newSel = getChildAt(index); 1499 } 1500 break; 1501 case LAYOUT_FORCE_TOP: 1502 case LAYOUT_FORCE_BOTTOM: 1503 case LAYOUT_SPECIFIC: 1504 case LAYOUT_SYNC: 1505 break; 1506 case LAYOUT_MOVE_SELECTION: 1507 default: 1508 // Remember the previously selected view 1509 index = mSelectedPosition - mFirstPosition; 1510 if (index >= 0 && index < childCount) { 1511 oldSel = getChildAt(index); 1512 } 1513 1514 // Remember the previous first child 1515 oldFirst = getChildAt(0); 1516 1517 if (mNextSelectedPosition >= 0) { 1518 delta = mNextSelectedPosition - mSelectedPosition; 1519 } 1520 1521 // Caution: newSel might be null 1522 newSel = getChildAt(index + delta); 1523 } 1524 1525 1526 boolean dataChanged = mDataChanged; 1527 if (dataChanged) { 1528 handleDataChanged(); 1529 } 1530 1531 // Handle the empty set by removing all views that are visible 1532 // and calling it a day 1533 if (mItemCount == 0) { 1534 resetList(); 1535 invokeOnItemScrollListener(); 1536 return; 1537 } else if (mItemCount != mAdapter.getCount()) { 1538 throw new IllegalStateException("The content of the adapter has changed but " 1539 + "ListView did not receive a notification. Make sure the content of " 1540 + "your adapter is not modified from a background thread, but only " 1541 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1542 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1543 } 1544 1545 setSelectedPositionInt(mNextSelectedPosition); 1546 1547 // Pull all children into the RecycleBin. 1548 // These views will be reused if possible 1549 final int firstPosition = mFirstPosition; 1550 final RecycleBin recycleBin = mRecycler; 1551 1552 // reset the focus restoration 1553 View focusLayoutRestoreDirectChild = null; 1554 1555 // Don't put header or footer views into the Recycler. Those are 1556 // already cached in mHeaderViews; 1557 if (dataChanged) { 1558 for (int i = 0; i < childCount; i++) { 1559 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1560 if (ViewDebug.TRACE_RECYCLER) { 1561 ViewDebug.trace(getChildAt(i), 1562 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1563 } 1564 } 1565 } else { 1566 recycleBin.fillActiveViews(childCount, firstPosition); 1567 } 1568 1569 // take focus back to us temporarily to avoid the eventual 1570 // call to clear focus when removing the focused child below 1571 // from messing things up when ViewRoot assigns focus back 1572 // to someone else 1573 final View focusedChild = getFocusedChild(); 1574 if (focusedChild != null) { 1575 // TODO: in some cases focusedChild.getParent() == null 1576 1577 // we can remember the focused view to restore after relayout if the 1578 // data hasn't changed, or if the focused position is a header or footer 1579 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1580 focusLayoutRestoreDirectChild = focusedChild; 1581 // remember the specific view that had focus 1582 focusLayoutRestoreView = findFocus(); 1583 if (focusLayoutRestoreView != null) { 1584 // tell it we are going to mess with it 1585 focusLayoutRestoreView.onStartTemporaryDetach(); 1586 } 1587 } 1588 requestFocus(); 1589 } 1590 1591 // Clear out old views 1592 detachAllViewsFromParent(); 1593 1594 switch (mLayoutMode) { 1595 case LAYOUT_SET_SELECTION: 1596 if (newSel != null) { 1597 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1598 } else { 1599 sel = fillFromMiddle(childrenTop, childrenBottom); 1600 } 1601 break; 1602 case LAYOUT_SYNC: 1603 sel = fillSpecific(mSyncPosition, mSpecificTop); 1604 break; 1605 case LAYOUT_FORCE_BOTTOM: 1606 sel = fillUp(mItemCount - 1, childrenBottom); 1607 adjustViewsUpOrDown(); 1608 break; 1609 case LAYOUT_FORCE_TOP: 1610 mFirstPosition = 0; 1611 sel = fillFromTop(childrenTop); 1612 adjustViewsUpOrDown(); 1613 break; 1614 case LAYOUT_SPECIFIC: 1615 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1616 break; 1617 case LAYOUT_MOVE_SELECTION: 1618 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1619 break; 1620 default: 1621 if (childCount == 0) { 1622 if (!mStackFromBottom) { 1623 final int position = lookForSelectablePosition(0, true); 1624 setSelectedPositionInt(position); 1625 sel = fillFromTop(childrenTop); 1626 } else { 1627 final int position = lookForSelectablePosition(mItemCount - 1, false); 1628 setSelectedPositionInt(position); 1629 sel = fillUp(mItemCount - 1, childrenBottom); 1630 } 1631 } else { 1632 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1633 sel = fillSpecific(mSelectedPosition, 1634 oldSel == null ? childrenTop : oldSel.getTop()); 1635 } else if (mFirstPosition < mItemCount) { 1636 sel = fillSpecific(mFirstPosition, 1637 oldFirst == null ? childrenTop : oldFirst.getTop()); 1638 } else { 1639 sel = fillSpecific(0, childrenTop); 1640 } 1641 } 1642 break; 1643 } 1644 1645 // Flush any cached views that did not get reused above 1646 recycleBin.scrapActiveViews(); 1647 1648 if (sel != null) { 1649 // the current selected item should get focus if items 1650 // are focusable 1651 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1652 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1653 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1654 if (!focusWasTaken) { 1655 // selected item didn't take focus, fine, but still want 1656 // to make sure something else outside of the selected view 1657 // has focus 1658 final View focused = getFocusedChild(); 1659 if (focused != null) { 1660 focused.clearFocus(); 1661 } 1662 positionSelector(INVALID_POSITION, sel); 1663 } else { 1664 sel.setSelected(false); 1665 mSelectorRect.setEmpty(); 1666 } 1667 } else { 1668 positionSelector(INVALID_POSITION, sel); 1669 } 1670 mSelectedTop = sel.getTop(); 1671 } else { 1672 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1673 View child = getChildAt(mMotionPosition - mFirstPosition); 1674 if (child != null) positionSelector(mMotionPosition, child); 1675 } else { 1676 mSelectedTop = 0; 1677 mSelectorRect.setEmpty(); 1678 } 1679 1680 // even if there is not selected position, we may need to restore 1681 // focus (i.e. something focusable in touch mode) 1682 if (hasFocus() && focusLayoutRestoreView != null) { 1683 focusLayoutRestoreView.requestFocus(); 1684 } 1685 } 1686 1687 // tell focus view we are done mucking with it, if it is still in 1688 // our view hierarchy. 1689 if (focusLayoutRestoreView != null 1690 && focusLayoutRestoreView.getWindowToken() != null) { 1691 focusLayoutRestoreView.onFinishTemporaryDetach(); 1692 } 1693 1694 mLayoutMode = LAYOUT_NORMAL; 1695 mDataChanged = false; 1696 mNeedSync = false; 1697 setNextSelectedPositionInt(mSelectedPosition); 1698 1699 updateScrollIndicators(); 1700 1701 if (mItemCount > 0) { 1702 checkSelectionChanged(); 1703 } 1704 1705 invokeOnItemScrollListener(); 1706 } finally { 1707 if (!blockLayoutRequests) { 1708 mBlockLayoutRequests = false; 1709 } 1710 } 1711 } 1712 1713 /** 1714 * @param child a direct child of this list. 1715 * @return Whether child is a header or footer view. 1716 */ 1717 private boolean isDirectChildHeaderOrFooter(View child) { 1718 1719 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1720 final int numHeaders = headers.size(); 1721 for (int i = 0; i < numHeaders; i++) { 1722 if (child == headers.get(i).view) { 1723 return true; 1724 } 1725 } 1726 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1727 final int numFooters = footers.size(); 1728 for (int i = 0; i < numFooters; i++) { 1729 if (child == footers.get(i).view) { 1730 return true; 1731 } 1732 } 1733 return false; 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 if (ViewDebug.TRACE_RECYCLER) { 1759 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1760 position, getChildCount()); 1761 } 1762 1763 // Found it -- we're using an existing child 1764 // This just needs to be positioned 1765 setupChild(child, position, y, flow, childrenLeft, selected, true); 1766 1767 return child; 1768 } 1769 } 1770 1771 // Make a new view for this position, or convert an unused view if possible 1772 child = obtainView(position, mIsScrap); 1773 1774 // This needs to be positioned and measured 1775 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1776 1777 return child; 1778 } 1779 1780 /** 1781 * Add a view as a child and make sure it is measured (if necessary) and 1782 * positioned properly. 1783 * 1784 * @param child The view to add 1785 * @param position The position of this child 1786 * @param y The y position relative to which this view will be positioned 1787 * @param flowDown If true, align top edge to y. If false, align bottom 1788 * edge to y. 1789 * @param childrenLeft Left edge where children should be positioned 1790 * @param selected Is this position selected? 1791 * @param recycled Has this view been pulled from the recycle bin? If so it 1792 * does not need to be remeasured. 1793 */ 1794 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1795 boolean selected, boolean recycled) { 1796 final boolean isSelected = selected && shouldShowSelector(); 1797 final boolean updateChildSelected = isSelected != child.isSelected(); 1798 final int mode = mTouchMode; 1799 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1800 mMotionPosition == position; 1801 final boolean updateChildPressed = isPressed != child.isPressed(); 1802 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1803 1804 // Respect layout params that are already in the view. Otherwise make some up... 1805 // noinspection unchecked 1806 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1807 if (p == null) { 1808 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1809 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1810 } 1811 p.viewType = mAdapter.getItemViewType(position); 1812 1813 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1814 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1815 attachViewToParent(child, flowDown ? -1 : 0, p); 1816 } else { 1817 p.forceAdd = false; 1818 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1819 p.recycledHeaderFooter = true; 1820 } 1821 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1822 } 1823 1824 if (updateChildSelected) { 1825 child.setSelected(isSelected); 1826 } 1827 1828 if (updateChildPressed) { 1829 child.setPressed(isPressed); 1830 } 1831 1832 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1833 if (child instanceof Checkable) { 1834 ((Checkable) child).setChecked(mCheckStates.get(position)); 1835 } else if (getContext().getApplicationInfo().targetSdkVersion 1836 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1837 child.setActivated(mCheckStates.get(position)); 1838 } 1839 } 1840 1841 if (needToMeasure) { 1842 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1843 mListPadding.left + mListPadding.right, p.width); 1844 int lpHeight = p.height; 1845 int childHeightSpec; 1846 if (lpHeight > 0) { 1847 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1848 } else { 1849 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1850 } 1851 child.measure(childWidthSpec, childHeightSpec); 1852 } else { 1853 cleanupLayoutState(child); 1854 } 1855 1856 final int w = child.getMeasuredWidth(); 1857 final int h = child.getMeasuredHeight(); 1858 final int childTop = flowDown ? y : y - h; 1859 1860 if (needToMeasure) { 1861 final int childRight = childrenLeft + w; 1862 final int childBottom = childTop + h; 1863 child.layout(childrenLeft, childTop, childRight, childBottom); 1864 } else { 1865 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1866 child.offsetTopAndBottom(childTop - child.getTop()); 1867 } 1868 1869 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1870 child.setDrawingCacheEnabled(true); 1871 } 1872 1873 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1874 != position) { 1875 child.jumpDrawablesToCurrentState(); 1876 } 1877 } 1878 1879 @Override 1880 protected boolean canAnimate() { 1881 return super.canAnimate() && mItemCount > 0; 1882 } 1883 1884 /** 1885 * Sets the currently selected item. If in touch mode, the item will not be selected 1886 * but it will still be positioned appropriately. If the specified selection position 1887 * is less than 0, then the item at position 0 will be selected. 1888 * 1889 * @param position Index (starting at 0) of the data item to be selected. 1890 */ 1891 @Override 1892 public void setSelection(int position) { 1893 setSelectionFromTop(position, 0); 1894 } 1895 1896 /** 1897 * Sets the selected item and positions the selection y pixels from the top edge 1898 * of the ListView. (If in touch mode, the item will not be selected but it will 1899 * still be positioned appropriately.) 1900 * 1901 * @param position Index (starting at 0) of the data item to be selected. 1902 * @param y The distance from the top edge of the ListView (plus padding) that the 1903 * item will be positioned. 1904 */ 1905 public void setSelectionFromTop(int position, int y) { 1906 if (mAdapter == null) { 1907 return; 1908 } 1909 1910 if (!isInTouchMode()) { 1911 position = lookForSelectablePosition(position, true); 1912 if (position >= 0) { 1913 setNextSelectedPositionInt(position); 1914 } 1915 } else { 1916 mResurrectToPosition = position; 1917 } 1918 1919 if (position >= 0) { 1920 mLayoutMode = LAYOUT_SPECIFIC; 1921 mSpecificTop = mListPadding.top + y; 1922 1923 if (mNeedSync) { 1924 mSyncPosition = position; 1925 mSyncRowId = mAdapter.getItemId(position); 1926 } 1927 1928 requestLayout(); 1929 } 1930 } 1931 1932 /** 1933 * Makes the item at the supplied position selected. 1934 * 1935 * @param position the position of the item to select 1936 */ 1937 @Override 1938 void setSelectionInt(int position) { 1939 setNextSelectedPositionInt(position); 1940 boolean awakeScrollbars = false; 1941 1942 final int selectedPosition = mSelectedPosition; 1943 1944 if (selectedPosition >= 0) { 1945 if (position == selectedPosition - 1) { 1946 awakeScrollbars = true; 1947 } else if (position == selectedPosition + 1) { 1948 awakeScrollbars = true; 1949 } 1950 } 1951 1952 layoutChildren(); 1953 1954 if (awakeScrollbars) { 1955 awakenScrollBars(); 1956 } 1957 } 1958 1959 /** 1960 * Find a position that can be selected (i.e., is not a separator). 1961 * 1962 * @param position The starting position to look at. 1963 * @param lookDown Whether to look down for other positions. 1964 * @return The next selectable position starting at position and then searching either up or 1965 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1966 */ 1967 @Override 1968 int lookForSelectablePosition(int position, boolean lookDown) { 1969 final ListAdapter adapter = mAdapter; 1970 if (adapter == null || isInTouchMode()) { 1971 return INVALID_POSITION; 1972 } 1973 1974 final int count = adapter.getCount(); 1975 if (!mAreAllItemsSelectable) { 1976 if (lookDown) { 1977 position = Math.max(0, position); 1978 while (position < count && !adapter.isEnabled(position)) { 1979 position++; 1980 } 1981 } else { 1982 position = Math.min(position, count - 1); 1983 while (position >= 0 && !adapter.isEnabled(position)) { 1984 position--; 1985 } 1986 } 1987 1988 if (position < 0 || position >= count) { 1989 return INVALID_POSITION; 1990 } 1991 return position; 1992 } else { 1993 if (position < 0 || position >= count) { 1994 return INVALID_POSITION; 1995 } 1996 return position; 1997 } 1998 } 1999 2000 @Override 2001 public void onPopulateAccessibilityEvent(AccessibilityEvent event) { 2002 super.onPopulateAccessibilityEvent(event); 2003 2004 // If the item count is less than 15 then subtract disabled items from the count and 2005 // position. Otherwise ignore disabled items. 2006 int itemCount = 0; 2007 int currentItemIndex = getSelectedItemPosition(); 2008 2009 ListAdapter adapter = getAdapter(); 2010 if (adapter != null) { 2011 final int count = adapter.getCount(); 2012 if (count < 15) { 2013 for (int i = 0; i < count; i++) { 2014 if (adapter.isEnabled(i)) { 2015 itemCount++; 2016 } else if (i <= currentItemIndex) { 2017 currentItemIndex--; 2018 } 2019 } 2020 } else { 2021 itemCount = count; 2022 } 2023 } 2024 2025 event.setItemCount(itemCount); 2026 event.setCurrentItemIndex(currentItemIndex); 2027 } 2028 2029 /** 2030 * setSelectionAfterHeaderView set the selection to be the first list item 2031 * after the header views. 2032 */ 2033 public void setSelectionAfterHeaderView() { 2034 final int count = mHeaderViewInfos.size(); 2035 if (count > 0) { 2036 mNextSelectedPosition = 0; 2037 return; 2038 } 2039 2040 if (mAdapter != null) { 2041 setSelection(count); 2042 } else { 2043 mNextSelectedPosition = count; 2044 mLayoutMode = LAYOUT_SET_SELECTION; 2045 } 2046 2047 } 2048 2049 @Override 2050 public boolean dispatchKeyEvent(KeyEvent event) { 2051 // Dispatch in the normal way 2052 boolean handled = super.dispatchKeyEvent(event); 2053 if (!handled) { 2054 // If we didn't handle it... 2055 View focused = getFocusedChild(); 2056 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2057 // ... and our focused child didn't handle it 2058 // ... give it to ourselves so we can scroll if necessary 2059 handled = onKeyDown(event.getKeyCode(), event); 2060 } 2061 } 2062 return handled; 2063 } 2064 2065 @Override 2066 public boolean onKeyDown(int keyCode, KeyEvent event) { 2067 return commonKey(keyCode, 1, event); 2068 } 2069 2070 @Override 2071 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2072 return commonKey(keyCode, repeatCount, event); 2073 } 2074 2075 @Override 2076 public boolean onKeyUp(int keyCode, KeyEvent event) { 2077 return commonKey(keyCode, 1, event); 2078 } 2079 2080 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2081 if (mAdapter == null) { 2082 return false; 2083 } 2084 2085 if (mDataChanged) { 2086 layoutChildren(); 2087 } 2088 2089 boolean handled = false; 2090 int action = event.getAction(); 2091 2092 if (action != KeyEvent.ACTION_UP) { 2093 switch (keyCode) { 2094 case KeyEvent.KEYCODE_DPAD_UP: 2095 if (event.hasNoModifiers()) { 2096 handled = resurrectSelectionIfNeeded(); 2097 if (!handled) { 2098 while (count-- > 0) { 2099 if (arrowScroll(FOCUS_UP)) { 2100 handled = true; 2101 } else { 2102 break; 2103 } 2104 } 2105 } 2106 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2107 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2108 } 2109 break; 2110 2111 case KeyEvent.KEYCODE_DPAD_DOWN: 2112 if (event.hasNoModifiers()) { 2113 handled = resurrectSelectionIfNeeded(); 2114 if (!handled) { 2115 while (count-- > 0) { 2116 if (arrowScroll(FOCUS_DOWN)) { 2117 handled = true; 2118 } else { 2119 break; 2120 } 2121 } 2122 } 2123 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2124 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2125 } 2126 break; 2127 2128 case KeyEvent.KEYCODE_DPAD_LEFT: 2129 if (event.hasNoModifiers()) { 2130 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2131 } 2132 break; 2133 2134 case KeyEvent.KEYCODE_DPAD_RIGHT: 2135 if (event.hasNoModifiers()) { 2136 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2137 } 2138 break; 2139 2140 case KeyEvent.KEYCODE_DPAD_CENTER: 2141 case KeyEvent.KEYCODE_ENTER: 2142 if (event.hasNoModifiers()) { 2143 handled = resurrectSelectionIfNeeded(); 2144 if (!handled 2145 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2146 keyPressed(); 2147 handled = true; 2148 } 2149 } 2150 break; 2151 2152 case KeyEvent.KEYCODE_SPACE: 2153 if (mPopup == null || !mPopup.isShowing()) { 2154 if (event.hasNoModifiers()) { 2155 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2156 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2157 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2158 } 2159 handled = true; 2160 } 2161 break; 2162 2163 case KeyEvent.KEYCODE_PAGE_UP: 2164 if (event.hasNoModifiers()) { 2165 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2166 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2167 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2168 } 2169 break; 2170 2171 case KeyEvent.KEYCODE_PAGE_DOWN: 2172 if (event.hasNoModifiers()) { 2173 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2174 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2175 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2176 } 2177 break; 2178 2179 case KeyEvent.KEYCODE_MOVE_HOME: 2180 if (event.hasNoModifiers()) { 2181 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2182 } 2183 break; 2184 2185 case KeyEvent.KEYCODE_MOVE_END: 2186 if (event.hasNoModifiers()) { 2187 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2188 } 2189 break; 2190 2191 case KeyEvent.KEYCODE_TAB: 2192 // XXX Sometimes it is useful to be able to TAB through the items in 2193 // a ListView sequentially. Unfortunately this can create an 2194 // asymmetry in TAB navigation order unless the list selection 2195 // always reverts to the top or bottom when receiving TAB focus from 2196 // another widget. Leaving this behavior disabled for now but 2197 // perhaps it should be configurable (and more comprehensive). 2198 if (false) { 2199 if (event.hasNoModifiers()) { 2200 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2201 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2202 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2203 } 2204 } 2205 break; 2206 } 2207 } 2208 2209 if (handled) { 2210 return true; 2211 } 2212 2213 if (sendToTextFilter(keyCode, count, event)) { 2214 return true; 2215 } 2216 2217 switch (action) { 2218 case KeyEvent.ACTION_DOWN: 2219 return super.onKeyDown(keyCode, event); 2220 2221 case KeyEvent.ACTION_UP: 2222 return super.onKeyUp(keyCode, event); 2223 2224 case KeyEvent.ACTION_MULTIPLE: 2225 return super.onKeyMultiple(keyCode, count, event); 2226 2227 default: // shouldn't happen 2228 return false; 2229 } 2230 } 2231 2232 /** 2233 * Scrolls up or down by the number of items currently present on screen. 2234 * 2235 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2236 * @return whether selection was moved 2237 */ 2238 boolean pageScroll(int direction) { 2239 int nextPage = -1; 2240 boolean down = false; 2241 2242 if (direction == FOCUS_UP) { 2243 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2244 } else if (direction == FOCUS_DOWN) { 2245 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2246 down = true; 2247 } 2248 2249 if (nextPage >= 0) { 2250 int position = lookForSelectablePosition(nextPage, down); 2251 if (position >= 0) { 2252 mLayoutMode = LAYOUT_SPECIFIC; 2253 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2254 2255 if (down && position > mItemCount - getChildCount()) { 2256 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2257 } 2258 2259 if (!down && position < getChildCount()) { 2260 mLayoutMode = LAYOUT_FORCE_TOP; 2261 } 2262 2263 setSelectionInt(position); 2264 invokeOnItemScrollListener(); 2265 if (!awakenScrollBars()) { 2266 invalidate(); 2267 } 2268 2269 return true; 2270 } 2271 } 2272 2273 return false; 2274 } 2275 2276 /** 2277 * Go to the last or first item if possible (not worrying about panning across or navigating 2278 * within the internal focus of the currently selected item.) 2279 * 2280 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2281 * 2282 * @return whether selection was moved 2283 */ 2284 boolean fullScroll(int direction) { 2285 boolean moved = false; 2286 if (direction == FOCUS_UP) { 2287 if (mSelectedPosition != 0) { 2288 int position = lookForSelectablePosition(0, true); 2289 if (position >= 0) { 2290 mLayoutMode = LAYOUT_FORCE_TOP; 2291 setSelectionInt(position); 2292 invokeOnItemScrollListener(); 2293 } 2294 moved = true; 2295 } 2296 } else if (direction == FOCUS_DOWN) { 2297 if (mSelectedPosition < mItemCount - 1) { 2298 int position = lookForSelectablePosition(mItemCount - 1, true); 2299 if (position >= 0) { 2300 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2301 setSelectionInt(position); 2302 invokeOnItemScrollListener(); 2303 } 2304 moved = true; 2305 } 2306 } 2307 2308 if (moved && !awakenScrollBars()) { 2309 awakenScrollBars(); 2310 invalidate(); 2311 } 2312 2313 return moved; 2314 } 2315 2316 /** 2317 * To avoid horizontal focus searches changing the selected item, we 2318 * manually focus search within the selected item (as applicable), and 2319 * prevent focus from jumping to something within another item. 2320 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2321 * @return Whether this consumes the key event. 2322 */ 2323 private boolean handleHorizontalFocusWithinListItem(int direction) { 2324 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2325 throw new IllegalArgumentException("direction must be one of" 2326 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2327 } 2328 2329 final int numChildren = getChildCount(); 2330 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2331 final View selectedView = getSelectedView(); 2332 if (selectedView != null && selectedView.hasFocus() && 2333 selectedView instanceof ViewGroup) { 2334 2335 final View currentFocus = selectedView.findFocus(); 2336 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2337 (ViewGroup) selectedView, currentFocus, direction); 2338 if (nextFocus != null) { 2339 // do the math to get interesting rect in next focus' coordinates 2340 currentFocus.getFocusedRect(mTempRect); 2341 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2342 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2343 if (nextFocus.requestFocus(direction, mTempRect)) { 2344 return true; 2345 } 2346 } 2347 // we are blocking the key from being handled (by returning true) 2348 // if the global result is going to be some other view within this 2349 // list. this is to acheive the overall goal of having 2350 // horizontal d-pad navigation remain in the current item. 2351 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2352 (ViewGroup) getRootView(), currentFocus, direction); 2353 if (globalNextFocus != null) { 2354 return isViewAncestorOf(globalNextFocus, this); 2355 } 2356 } 2357 } 2358 return false; 2359 } 2360 2361 /** 2362 * Scrolls to the next or previous item if possible. 2363 * 2364 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2365 * 2366 * @return whether selection was moved 2367 */ 2368 boolean arrowScroll(int direction) { 2369 try { 2370 mInLayout = true; 2371 final boolean handled = arrowScrollImpl(direction); 2372 if (handled) { 2373 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2374 } 2375 return handled; 2376 } finally { 2377 mInLayout = false; 2378 } 2379 } 2380 2381 /** 2382 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2383 * whether there are focusable items etc. 2384 * 2385 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2386 * @return Whether any scrolling, selection or focus change occured. 2387 */ 2388 private boolean arrowScrollImpl(int direction) { 2389 if (getChildCount() <= 0) { 2390 return false; 2391 } 2392 2393 View selectedView = getSelectedView(); 2394 int selectedPos = mSelectedPosition; 2395 2396 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2397 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2398 2399 // if we are moving focus, we may OVERRIDE the default behavior 2400 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2401 if (focusResult != null) { 2402 nextSelectedPosition = focusResult.getSelectedPosition(); 2403 amountToScroll = focusResult.getAmountToScroll(); 2404 } 2405 2406 boolean needToRedraw = focusResult != null; 2407 if (nextSelectedPosition != INVALID_POSITION) { 2408 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2409 setSelectedPositionInt(nextSelectedPosition); 2410 setNextSelectedPositionInt(nextSelectedPosition); 2411 selectedView = getSelectedView(); 2412 selectedPos = nextSelectedPosition; 2413 if (mItemsCanFocus && focusResult == null) { 2414 // there was no new view found to take focus, make sure we 2415 // don't leave focus with the old selection 2416 final View focused = getFocusedChild(); 2417 if (focused != null) { 2418 focused.clearFocus(); 2419 } 2420 } 2421 needToRedraw = true; 2422 checkSelectionChanged(); 2423 } 2424 2425 if (amountToScroll > 0) { 2426 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2427 needToRedraw = true; 2428 } 2429 2430 // if we didn't find a new focusable, make sure any existing focused 2431 // item that was panned off screen gives up focus. 2432 if (mItemsCanFocus && (focusResult == null) 2433 && selectedView != null && selectedView.hasFocus()) { 2434 final View focused = selectedView.findFocus(); 2435 if (distanceToView(focused) > 0) { 2436 focused.clearFocus(); 2437 } 2438 } 2439 2440 // if the current selection is panned off, we need to remove the selection 2441 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2442 && !isViewAncestorOf(selectedView, this)) { 2443 selectedView = null; 2444 hideSelector(); 2445 2446 // but we don't want to set the ressurect position (that would make subsequent 2447 // unhandled key events bring back the item we just scrolled off!) 2448 mResurrectToPosition = INVALID_POSITION; 2449 } 2450 2451 if (needToRedraw) { 2452 if (selectedView != null) { 2453 positionSelector(selectedPos, selectedView); 2454 mSelectedTop = selectedView.getTop(); 2455 } 2456 if (!awakenScrollBars()) { 2457 invalidate(); 2458 } 2459 invokeOnItemScrollListener(); 2460 return true; 2461 } 2462 2463 return false; 2464 } 2465 2466 /** 2467 * When selection changes, it is possible that the previously selected or the 2468 * next selected item will change its size. If so, we need to offset some folks, 2469 * and re-layout the items as appropriate. 2470 * 2471 * @param selectedView The currently selected view (before changing selection). 2472 * should be <code>null</code> if there was no previous selection. 2473 * @param direction Either {@link android.view.View#FOCUS_UP} or 2474 * {@link android.view.View#FOCUS_DOWN}. 2475 * @param newSelectedPosition The position of the next selection. 2476 * @param newFocusAssigned whether new focus was assigned. This matters because 2477 * when something has focus, we don't want to show selection (ugh). 2478 */ 2479 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2480 boolean newFocusAssigned) { 2481 if (newSelectedPosition == INVALID_POSITION) { 2482 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2483 } 2484 2485 // whether or not we are moving down or up, we want to preserve the 2486 // top of whatever view is on top: 2487 // - moving down: the view that had selection 2488 // - moving up: the view that is getting selection 2489 View topView; 2490 View bottomView; 2491 int topViewIndex, bottomViewIndex; 2492 boolean topSelected = false; 2493 final int selectedIndex = mSelectedPosition - mFirstPosition; 2494 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2495 if (direction == View.FOCUS_UP) { 2496 topViewIndex = nextSelectedIndex; 2497 bottomViewIndex = selectedIndex; 2498 topView = getChildAt(topViewIndex); 2499 bottomView = selectedView; 2500 topSelected = true; 2501 } else { 2502 topViewIndex = selectedIndex; 2503 bottomViewIndex = nextSelectedIndex; 2504 topView = selectedView; 2505 bottomView = getChildAt(bottomViewIndex); 2506 } 2507 2508 final int numChildren = getChildCount(); 2509 2510 // start with top view: is it changing size? 2511 if (topView != null) { 2512 topView.setSelected(!newFocusAssigned && topSelected); 2513 measureAndAdjustDown(topView, topViewIndex, numChildren); 2514 } 2515 2516 // is the bottom view changing size? 2517 if (bottomView != null) { 2518 bottomView.setSelected(!newFocusAssigned && !topSelected); 2519 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2520 } 2521 } 2522 2523 /** 2524 * Re-measure a child, and if its height changes, lay it out preserving its 2525 * top, and adjust the children below it appropriately. 2526 * @param child The child 2527 * @param childIndex The view group index of the child. 2528 * @param numChildren The number of children in the view group. 2529 */ 2530 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2531 int oldHeight = child.getHeight(); 2532 measureItem(child); 2533 if (child.getMeasuredHeight() != oldHeight) { 2534 // lay out the view, preserving its top 2535 relayoutMeasuredItem(child); 2536 2537 // adjust views below appropriately 2538 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2539 for (int i = childIndex + 1; i < numChildren; i++) { 2540 getChildAt(i).offsetTopAndBottom(heightDelta); 2541 } 2542 } 2543 } 2544 2545 /** 2546 * Measure a particular list child. 2547 * TODO: unify with setUpChild. 2548 * @param child The child. 2549 */ 2550 private void measureItem(View child) { 2551 ViewGroup.LayoutParams p = child.getLayoutParams(); 2552 if (p == null) { 2553 p = new ViewGroup.LayoutParams( 2554 ViewGroup.LayoutParams.MATCH_PARENT, 2555 ViewGroup.LayoutParams.WRAP_CONTENT); 2556 } 2557 2558 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2559 mListPadding.left + mListPadding.right, p.width); 2560 int lpHeight = p.height; 2561 int childHeightSpec; 2562 if (lpHeight > 0) { 2563 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2564 } else { 2565 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2566 } 2567 child.measure(childWidthSpec, childHeightSpec); 2568 } 2569 2570 /** 2571 * Layout a child that has been measured, preserving its top position. 2572 * TODO: unify with setUpChild. 2573 * @param child The child. 2574 */ 2575 private void relayoutMeasuredItem(View child) { 2576 final int w = child.getMeasuredWidth(); 2577 final int h = child.getMeasuredHeight(); 2578 final int childLeft = mListPadding.left; 2579 final int childRight = childLeft + w; 2580 final int childTop = child.getTop(); 2581 final int childBottom = childTop + h; 2582 child.layout(childLeft, childTop, childRight, childBottom); 2583 } 2584 2585 /** 2586 * @return The amount to preview next items when arrow srolling. 2587 */ 2588 private int getArrowScrollPreviewLength() { 2589 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2590 } 2591 2592 /** 2593 * Determine how much we need to scroll in order to get the next selected view 2594 * visible, with a fading edge showing below as applicable. The amount is 2595 * capped at {@link #getMaxScrollAmount()} . 2596 * 2597 * @param direction either {@link android.view.View#FOCUS_UP} or 2598 * {@link android.view.View#FOCUS_DOWN}. 2599 * @param nextSelectedPosition The position of the next selection, or 2600 * {@link #INVALID_POSITION} if there is no next selectable position 2601 * @return The amount to scroll. Note: this is always positive! Direction 2602 * needs to be taken into account when actually scrolling. 2603 */ 2604 private int amountToScroll(int direction, int nextSelectedPosition) { 2605 final int listBottom = getHeight() - mListPadding.bottom; 2606 final int listTop = mListPadding.top; 2607 2608 final int numChildren = getChildCount(); 2609 2610 if (direction == View.FOCUS_DOWN) { 2611 int indexToMakeVisible = numChildren - 1; 2612 if (nextSelectedPosition != INVALID_POSITION) { 2613 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2614 } 2615 2616 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2617 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2618 2619 int goalBottom = listBottom; 2620 if (positionToMakeVisible < mItemCount - 1) { 2621 goalBottom -= getArrowScrollPreviewLength(); 2622 } 2623 2624 if (viewToMakeVisible.getBottom() <= goalBottom) { 2625 // item is fully visible. 2626 return 0; 2627 } 2628 2629 if (nextSelectedPosition != INVALID_POSITION 2630 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2631 // item already has enough of it visible, changing selection is good enough 2632 return 0; 2633 } 2634 2635 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2636 2637 if ((mFirstPosition + numChildren) == mItemCount) { 2638 // last is last in list -> make sure we don't scroll past it 2639 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2640 amountToScroll = Math.min(amountToScroll, max); 2641 } 2642 2643 return Math.min(amountToScroll, getMaxScrollAmount()); 2644 } else { 2645 int indexToMakeVisible = 0; 2646 if (nextSelectedPosition != INVALID_POSITION) { 2647 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2648 } 2649 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2650 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2651 int goalTop = listTop; 2652 if (positionToMakeVisible > 0) { 2653 goalTop += getArrowScrollPreviewLength(); 2654 } 2655 if (viewToMakeVisible.getTop() >= goalTop) { 2656 // item is fully visible. 2657 return 0; 2658 } 2659 2660 if (nextSelectedPosition != INVALID_POSITION && 2661 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2662 // item already has enough of it visible, changing selection is good enough 2663 return 0; 2664 } 2665 2666 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2667 if (mFirstPosition == 0) { 2668 // first is first in list -> make sure we don't scroll past it 2669 final int max = listTop - getChildAt(0).getTop(); 2670 amountToScroll = Math.min(amountToScroll, max); 2671 } 2672 return Math.min(amountToScroll, getMaxScrollAmount()); 2673 } 2674 } 2675 2676 /** 2677 * Holds results of focus aware arrow scrolling. 2678 */ 2679 static private class ArrowScrollFocusResult { 2680 private int mSelectedPosition; 2681 private int mAmountToScroll; 2682 2683 /** 2684 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2685 */ 2686 void populate(int selectedPosition, int amountToScroll) { 2687 mSelectedPosition = selectedPosition; 2688 mAmountToScroll = amountToScroll; 2689 } 2690 2691 public int getSelectedPosition() { 2692 return mSelectedPosition; 2693 } 2694 2695 public int getAmountToScroll() { 2696 return mAmountToScroll; 2697 } 2698 } 2699 2700 /** 2701 * @param direction either {@link android.view.View#FOCUS_UP} or 2702 * {@link android.view.View#FOCUS_DOWN}. 2703 * @return The position of the next selectable position of the views that 2704 * are currently visible, taking into account the fact that there might 2705 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2706 * selectable view on screen in the given direction. 2707 */ 2708 private int lookForSelectablePositionOnScreen(int direction) { 2709 final int firstPosition = mFirstPosition; 2710 if (direction == View.FOCUS_DOWN) { 2711 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2712 mSelectedPosition + 1 : 2713 firstPosition; 2714 if (startPos >= mAdapter.getCount()) { 2715 return INVALID_POSITION; 2716 } 2717 if (startPos < firstPosition) { 2718 startPos = firstPosition; 2719 } 2720 2721 final int lastVisiblePos = getLastVisiblePosition(); 2722 final ListAdapter adapter = getAdapter(); 2723 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2724 if (adapter.isEnabled(pos) 2725 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2726 return pos; 2727 } 2728 } 2729 } else { 2730 int last = firstPosition + getChildCount() - 1; 2731 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2732 mSelectedPosition - 1 : 2733 firstPosition + getChildCount() - 1; 2734 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2735 return INVALID_POSITION; 2736 } 2737 if (startPos > last) { 2738 startPos = last; 2739 } 2740 2741 final ListAdapter adapter = getAdapter(); 2742 for (int pos = startPos; pos >= firstPosition; pos--) { 2743 if (adapter.isEnabled(pos) 2744 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2745 return pos; 2746 } 2747 } 2748 } 2749 return INVALID_POSITION; 2750 } 2751 2752 /** 2753 * Do an arrow scroll based on focus searching. If a new view is 2754 * given focus, return the selection delta and amount to scroll via 2755 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2756 * 2757 * @param direction either {@link android.view.View#FOCUS_UP} or 2758 * {@link android.view.View#FOCUS_DOWN}. 2759 * @return The result if focus has changed, or <code>null</code>. 2760 */ 2761 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2762 final View selectedView = getSelectedView(); 2763 View newFocus; 2764 if (selectedView != null && selectedView.hasFocus()) { 2765 View oldFocus = selectedView.findFocus(); 2766 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2767 } else { 2768 if (direction == View.FOCUS_DOWN) { 2769 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2770 final int listTop = mListPadding.top + 2771 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2772 final int ySearchPoint = 2773 (selectedView != null && selectedView.getTop() > listTop) ? 2774 selectedView.getTop() : 2775 listTop; 2776 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2777 } else { 2778 final boolean bottomFadingEdgeShowing = 2779 (mFirstPosition + getChildCount() - 1) < mItemCount; 2780 final int listBottom = getHeight() - mListPadding.bottom - 2781 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2782 final int ySearchPoint = 2783 (selectedView != null && selectedView.getBottom() < listBottom) ? 2784 selectedView.getBottom() : 2785 listBottom; 2786 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2787 } 2788 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2789 } 2790 2791 if (newFocus != null) { 2792 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2793 2794 // if the focus change is in a different new position, make sure 2795 // we aren't jumping over another selectable position 2796 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2797 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2798 if (selectablePosition != INVALID_POSITION && 2799 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2800 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2801 return null; 2802 } 2803 } 2804 2805 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2806 2807 final int maxScrollAmount = getMaxScrollAmount(); 2808 if (focusScroll < maxScrollAmount) { 2809 // not moving too far, safe to give next view focus 2810 newFocus.requestFocus(direction); 2811 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2812 return mArrowScrollFocusResult; 2813 } else if (distanceToView(newFocus) < maxScrollAmount){ 2814 // Case to consider: 2815 // too far to get entire next focusable on screen, but by going 2816 // max scroll amount, we are getting it at least partially in view, 2817 // so give it focus and scroll the max ammount. 2818 newFocus.requestFocus(direction); 2819 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2820 return mArrowScrollFocusResult; 2821 } 2822 } 2823 return null; 2824 } 2825 2826 /** 2827 * @param newFocus The view that would have focus. 2828 * @return the position that contains newFocus 2829 */ 2830 private int positionOfNewFocus(View newFocus) { 2831 final int numChildren = getChildCount(); 2832 for (int i = 0; i < numChildren; i++) { 2833 final View child = getChildAt(i); 2834 if (isViewAncestorOf(newFocus, child)) { 2835 return mFirstPosition + i; 2836 } 2837 } 2838 throw new IllegalArgumentException("newFocus is not a child of any of the" 2839 + " children of the list!"); 2840 } 2841 2842 /** 2843 * Return true if child is an ancestor of parent, (or equal to the parent). 2844 */ 2845 private boolean isViewAncestorOf(View child, View parent) { 2846 if (child == parent) { 2847 return true; 2848 } 2849 2850 final ViewParent theParent = child.getParent(); 2851 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2852 } 2853 2854 /** 2855 * Determine how much we need to scroll in order to get newFocus in view. 2856 * @param direction either {@link android.view.View#FOCUS_UP} or 2857 * {@link android.view.View#FOCUS_DOWN}. 2858 * @param newFocus The view that would take focus. 2859 * @param positionOfNewFocus The position of the list item containing newFocus 2860 * @return The amount to scroll. Note: this is always positive! Direction 2861 * needs to be taken into account when actually scrolling. 2862 */ 2863 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2864 int amountToScroll = 0; 2865 newFocus.getDrawingRect(mTempRect); 2866 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2867 if (direction == View.FOCUS_UP) { 2868 if (mTempRect.top < mListPadding.top) { 2869 amountToScroll = mListPadding.top - mTempRect.top; 2870 if (positionOfNewFocus > 0) { 2871 amountToScroll += getArrowScrollPreviewLength(); 2872 } 2873 } 2874 } else { 2875 final int listBottom = getHeight() - mListPadding.bottom; 2876 if (mTempRect.bottom > listBottom) { 2877 amountToScroll = mTempRect.bottom - listBottom; 2878 if (positionOfNewFocus < mItemCount - 1) { 2879 amountToScroll += getArrowScrollPreviewLength(); 2880 } 2881 } 2882 } 2883 return amountToScroll; 2884 } 2885 2886 /** 2887 * Determine the distance to the nearest edge of a view in a particular 2888 * direction. 2889 * 2890 * @param descendant A descendant of this list. 2891 * @return The distance, or 0 if the nearest edge is already on screen. 2892 */ 2893 private int distanceToView(View descendant) { 2894 int distance = 0; 2895 descendant.getDrawingRect(mTempRect); 2896 offsetDescendantRectToMyCoords(descendant, mTempRect); 2897 final int listBottom = mBottom - mTop - mListPadding.bottom; 2898 if (mTempRect.bottom < mListPadding.top) { 2899 distance = mListPadding.top - mTempRect.bottom; 2900 } else if (mTempRect.top > listBottom) { 2901 distance = mTempRect.top - listBottom; 2902 } 2903 return distance; 2904 } 2905 2906 2907 /** 2908 * Scroll the children by amount, adding a view at the end and removing 2909 * views that fall off as necessary. 2910 * 2911 * @param amount The amount (positive or negative) to scroll. 2912 */ 2913 private void scrollListItemsBy(int amount) { 2914 offsetChildrenTopAndBottom(amount); 2915 2916 final int listBottom = getHeight() - mListPadding.bottom; 2917 final int listTop = mListPadding.top; 2918 final AbsListView.RecycleBin recycleBin = mRecycler; 2919 2920 if (amount < 0) { 2921 // shifted items up 2922 2923 // may need to pan views into the bottom space 2924 int numChildren = getChildCount(); 2925 View last = getChildAt(numChildren - 1); 2926 while (last.getBottom() < listBottom) { 2927 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2928 if (lastVisiblePosition < mItemCount - 1) { 2929 last = addViewBelow(last, lastVisiblePosition); 2930 numChildren++; 2931 } else { 2932 break; 2933 } 2934 } 2935 2936 // may have brought in the last child of the list that is skinnier 2937 // than the fading edge, thereby leaving space at the end. need 2938 // to shift back 2939 if (last.getBottom() < listBottom) { 2940 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2941 } 2942 2943 // top views may be panned off screen 2944 View first = getChildAt(0); 2945 while (first.getBottom() < listTop) { 2946 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2947 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2948 detachViewFromParent(first); 2949 recycleBin.addScrapView(first, mFirstPosition); 2950 } else { 2951 removeViewInLayout(first); 2952 } 2953 first = getChildAt(0); 2954 mFirstPosition++; 2955 } 2956 } else { 2957 // shifted items down 2958 View first = getChildAt(0); 2959 2960 // may need to pan views into top 2961 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2962 first = addViewAbove(first, mFirstPosition); 2963 mFirstPosition--; 2964 } 2965 2966 // may have brought the very first child of the list in too far and 2967 // need to shift it back 2968 if (first.getTop() > listTop) { 2969 offsetChildrenTopAndBottom(listTop - first.getTop()); 2970 } 2971 2972 int lastIndex = getChildCount() - 1; 2973 View last = getChildAt(lastIndex); 2974 2975 // bottom view may be panned off screen 2976 while (last.getTop() > listBottom) { 2977 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2978 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2979 detachViewFromParent(last); 2980 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 2981 } else { 2982 removeViewInLayout(last); 2983 } 2984 last = getChildAt(--lastIndex); 2985 } 2986 } 2987 } 2988 2989 private View addViewAbove(View theView, int position) { 2990 int abovePosition = position - 1; 2991 View view = obtainView(abovePosition, mIsScrap); 2992 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2993 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2994 false, mIsScrap[0]); 2995 return view; 2996 } 2997 2998 private View addViewBelow(View theView, int position) { 2999 int belowPosition = position + 1; 3000 View view = obtainView(belowPosition, mIsScrap); 3001 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3002 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3003 false, mIsScrap[0]); 3004 return view; 3005 } 3006 3007 /** 3008 * Indicates that the views created by the ListAdapter can contain focusable 3009 * items. 3010 * 3011 * @param itemsCanFocus true if items can get focus, false otherwise 3012 */ 3013 public void setItemsCanFocus(boolean itemsCanFocus) { 3014 mItemsCanFocus = itemsCanFocus; 3015 if (!itemsCanFocus) { 3016 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3017 } 3018 } 3019 3020 /** 3021 * @return Whether the views created by the ListAdapter can contain focusable 3022 * items. 3023 */ 3024 public boolean getItemsCanFocus() { 3025 return mItemsCanFocus; 3026 } 3027 3028 @Override 3029 public boolean isOpaque() { 3030 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3031 hasOpaqueScrollbars()) || super.isOpaque(); 3032 if (retValue) { 3033 // only return true if the list items cover the entire area of the view 3034 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3035 View first = getChildAt(0); 3036 if (first == null || first.getTop() > listTop) { 3037 return false; 3038 } 3039 final int listBottom = getHeight() - 3040 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3041 View last = getChildAt(getChildCount() - 1); 3042 if (last == null || last.getBottom() < listBottom) { 3043 return false; 3044 } 3045 } 3046 return retValue; 3047 } 3048 3049 @Override 3050 public void setCacheColorHint(int color) { 3051 final boolean opaque = (color >>> 24) == 0xFF; 3052 mIsCacheColorOpaque = opaque; 3053 if (opaque) { 3054 if (mDividerPaint == null) { 3055 mDividerPaint = new Paint(); 3056 } 3057 mDividerPaint.setColor(color); 3058 } 3059 super.setCacheColorHint(color); 3060 } 3061 3062 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3063 final int height = drawable.getMinimumHeight(); 3064 3065 canvas.save(); 3066 canvas.clipRect(bounds); 3067 3068 final int span = bounds.bottom - bounds.top; 3069 if (span < height) { 3070 bounds.top = bounds.bottom - height; 3071 } 3072 3073 drawable.setBounds(bounds); 3074 drawable.draw(canvas); 3075 3076 canvas.restore(); 3077 } 3078 3079 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3080 final int height = drawable.getMinimumHeight(); 3081 3082 canvas.save(); 3083 canvas.clipRect(bounds); 3084 3085 final int span = bounds.bottom - bounds.top; 3086 if (span < height) { 3087 bounds.bottom = bounds.top + height; 3088 } 3089 3090 drawable.setBounds(bounds); 3091 drawable.draw(canvas); 3092 3093 canvas.restore(); 3094 } 3095 3096 @Override 3097 protected void dispatchDraw(Canvas canvas) { 3098 if (mCachingStarted) { 3099 mCachingActive = true; 3100 } 3101 3102 // Draw the dividers 3103 final int dividerHeight = mDividerHeight; 3104 final Drawable overscrollHeader = mOverScrollHeader; 3105 final Drawable overscrollFooter = mOverScrollFooter; 3106 final boolean drawOverscrollHeader = overscrollHeader != null; 3107 final boolean drawOverscrollFooter = overscrollFooter != null; 3108 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3109 3110 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3111 // Only modify the top and bottom in the loop, we set the left and right here 3112 final Rect bounds = mTempRect; 3113 bounds.left = mPaddingLeft; 3114 bounds.right = mRight - mLeft - mPaddingRight; 3115 3116 final int count = getChildCount(); 3117 final int headerCount = mHeaderViewInfos.size(); 3118 final int itemCount = mItemCount; 3119 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 3120 final boolean headerDividers = mHeaderDividersEnabled; 3121 final boolean footerDividers = mFooterDividersEnabled; 3122 final int first = mFirstPosition; 3123 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3124 final ListAdapter adapter = mAdapter; 3125 // If the list is opaque *and* the background is not, we want to 3126 // fill a rect where the dividers would be for non-selectable items 3127 // If the list is opaque and the background is also opaque, we don't 3128 // need to draw anything since the background will do it for us 3129 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3130 3131 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3132 mDividerPaint = new Paint(); 3133 mDividerPaint.setColor(getCacheColorHint()); 3134 } 3135 final Paint paint = mDividerPaint; 3136 3137 int effectivePaddingTop = 0; 3138 int effectivePaddingBottom = 0; 3139 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3140 effectivePaddingTop = mListPadding.top; 3141 effectivePaddingBottom = mListPadding.bottom; 3142 } 3143 3144 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3145 if (!mStackFromBottom) { 3146 int bottom = 0; 3147 3148 // Draw top divider or header for overscroll 3149 final int scrollY = mScrollY; 3150 if (count > 0 && scrollY < 0) { 3151 if (drawOverscrollHeader) { 3152 bounds.bottom = 0; 3153 bounds.top = scrollY; 3154 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3155 } else if (drawDividers) { 3156 bounds.bottom = 0; 3157 bounds.top = -dividerHeight; 3158 drawDivider(canvas, bounds, -1); 3159 } 3160 } 3161 3162 for (int i = 0; i < count; i++) { 3163 if ((headerDividers || first + i >= headerCount) && 3164 (footerDividers || first + i < footerLimit)) { 3165 View child = getChildAt(i); 3166 bottom = child.getBottom(); 3167 // Don't draw dividers next to items that are not enabled 3168 3169 if (drawDividers && 3170 (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) { 3171 if ((areAllItemsSelectable || 3172 (adapter.isEnabled(first + i) && (i == count - 1 || 3173 adapter.isEnabled(first + i + 1))))) { 3174 bounds.top = bottom; 3175 bounds.bottom = bottom + dividerHeight; 3176 drawDivider(canvas, bounds, i); 3177 } else if (fillForMissingDividers) { 3178 bounds.top = bottom; 3179 bounds.bottom = bottom + dividerHeight; 3180 canvas.drawRect(bounds, paint); 3181 } 3182 } 3183 } 3184 } 3185 3186 final int overFooterBottom = mBottom + mScrollY; 3187 if (drawOverscrollFooter && first + count == itemCount && 3188 overFooterBottom > bottom) { 3189 bounds.top = bottom; 3190 bounds.bottom = overFooterBottom; 3191 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3192 } 3193 } else { 3194 int top; 3195 3196 final int scrollY = mScrollY; 3197 3198 if (count > 0 && drawOverscrollHeader) { 3199 bounds.top = scrollY; 3200 bounds.bottom = getChildAt(0).getTop(); 3201 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3202 } 3203 3204 final int start = drawOverscrollHeader ? 1 : 0; 3205 for (int i = start; i < count; i++) { 3206 if ((headerDividers || first + i >= headerCount) && 3207 (footerDividers || first + i < footerLimit)) { 3208 View child = getChildAt(i); 3209 top = child.getTop(); 3210 // Don't draw dividers next to items that are not enabled 3211 if (top > effectivePaddingTop) { 3212 if ((areAllItemsSelectable || 3213 (adapter.isEnabled(first + i) && (i == count - 1 || 3214 adapter.isEnabled(first + i + 1))))) { 3215 bounds.top = top - dividerHeight; 3216 bounds.bottom = top; 3217 // Give the method the child ABOVE the divider, so we 3218 // subtract one from our child 3219 // position. Give -1 when there is no child above the 3220 // divider. 3221 drawDivider(canvas, bounds, i - 1); 3222 } else if (fillForMissingDividers) { 3223 bounds.top = top - dividerHeight; 3224 bounds.bottom = top; 3225 canvas.drawRect(bounds, paint); 3226 } 3227 } 3228 } 3229 } 3230 3231 if (count > 0 && scrollY > 0) { 3232 if (drawOverscrollFooter) { 3233 final int absListBottom = mBottom; 3234 bounds.top = absListBottom; 3235 bounds.bottom = absListBottom + scrollY; 3236 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3237 } else if (drawDividers) { 3238 bounds.top = listBottom; 3239 bounds.bottom = listBottom + dividerHeight; 3240 drawDivider(canvas, bounds, -1); 3241 } 3242 } 3243 } 3244 } 3245 3246 // Draw the indicators (these should be drawn above the dividers) and children 3247 super.dispatchDraw(canvas); 3248 } 3249 3250 @Override 3251 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3252 boolean more = super.drawChild(canvas, child, drawingTime); 3253 if (mCachingActive && child.mCachingFailed) { 3254 mCachingActive = false; 3255 } 3256 return more; 3257 } 3258 3259 /** 3260 * Draws a divider for the given child in the given bounds. 3261 * 3262 * @param canvas The canvas to draw to. 3263 * @param bounds The bounds of the divider. 3264 * @param childIndex The index of child (of the View) above the divider. 3265 * This will be -1 if there is no child above the divider to be 3266 * drawn. 3267 */ 3268 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3269 // This widget draws the same divider for all children 3270 final Drawable divider = mDivider; 3271 3272 divider.setBounds(bounds); 3273 divider.draw(canvas); 3274 } 3275 3276 /** 3277 * Returns the drawable that will be drawn between each item in the list. 3278 * 3279 * @return the current drawable drawn between list elements 3280 */ 3281 public Drawable getDivider() { 3282 return mDivider; 3283 } 3284 3285 /** 3286 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3287 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3288 * 3289 * @param divider The drawable to use. 3290 */ 3291 public void setDivider(Drawable divider) { 3292 if (divider != null) { 3293 mDividerHeight = divider.getIntrinsicHeight(); 3294 } else { 3295 mDividerHeight = 0; 3296 } 3297 mDivider = divider; 3298 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3299 requestLayout(); 3300 invalidate(); 3301 } 3302 3303 /** 3304 * @return Returns the height of the divider that will be drawn between each item in the list. 3305 */ 3306 public int getDividerHeight() { 3307 return mDividerHeight; 3308 } 3309 3310 /** 3311 * Sets the height of the divider that will be drawn between each item in the list. Calling 3312 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3313 * 3314 * @param height The new height of the divider in pixels. 3315 */ 3316 public void setDividerHeight(int height) { 3317 mDividerHeight = height; 3318 requestLayout(); 3319 invalidate(); 3320 } 3321 3322 /** 3323 * Enables or disables the drawing of the divider for header views. 3324 * 3325 * @param headerDividersEnabled True to draw the headers, false otherwise. 3326 * 3327 * @see #setFooterDividersEnabled(boolean) 3328 * @see #addHeaderView(android.view.View) 3329 */ 3330 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3331 mHeaderDividersEnabled = headerDividersEnabled; 3332 invalidate(); 3333 } 3334 3335 /** 3336 * Enables or disables the drawing of the divider for footer views. 3337 * 3338 * @param footerDividersEnabled True to draw the footers, false otherwise. 3339 * 3340 * @see #setHeaderDividersEnabled(boolean) 3341 * @see #addFooterView(android.view.View) 3342 */ 3343 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3344 mFooterDividersEnabled = footerDividersEnabled; 3345 invalidate(); 3346 } 3347 3348 /** 3349 * Sets the drawable that will be drawn above all other list content. 3350 * This area can become visible when the user overscrolls the list. 3351 * 3352 * @param header The drawable to use 3353 */ 3354 public void setOverscrollHeader(Drawable header) { 3355 mOverScrollHeader = header; 3356 if (mScrollY < 0) { 3357 invalidate(); 3358 } 3359 } 3360 3361 /** 3362 * @return The drawable that will be drawn above all other list content 3363 */ 3364 public Drawable getOverscrollHeader() { 3365 return mOverScrollHeader; 3366 } 3367 3368 /** 3369 * Sets the drawable that will be drawn below all other list content. 3370 * This area can become visible when the user overscrolls the list, 3371 * or when the list's content does not fully fill the container area. 3372 * 3373 * @param footer The drawable to use 3374 */ 3375 public void setOverscrollFooter(Drawable footer) { 3376 mOverScrollFooter = footer; 3377 invalidate(); 3378 } 3379 3380 /** 3381 * @return The drawable that will be drawn below all other list content 3382 */ 3383 public Drawable getOverscrollFooter() { 3384 return mOverScrollFooter; 3385 } 3386 3387 @Override 3388 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3389 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3390 3391 int closetChildIndex = -1; 3392 if (gainFocus && previouslyFocusedRect != null) { 3393 previouslyFocusedRect.offset(mScrollX, mScrollY); 3394 3395 final ListAdapter adapter = mAdapter; 3396 // Don't cache the result of getChildCount or mFirstPosition here, 3397 // it could change in layoutChildren. 3398 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3399 mLayoutMode = LAYOUT_NORMAL; 3400 layoutChildren(); 3401 } 3402 3403 // figure out which item should be selected based on previously 3404 // focused rect 3405 Rect otherRect = mTempRect; 3406 int minDistance = Integer.MAX_VALUE; 3407 final int childCount = getChildCount(); 3408 final int firstPosition = mFirstPosition; 3409 3410 for (int i = 0; i < childCount; i++) { 3411 // only consider selectable views 3412 if (!adapter.isEnabled(firstPosition + i)) { 3413 continue; 3414 } 3415 3416 View other = getChildAt(i); 3417 other.getDrawingRect(otherRect); 3418 offsetDescendantRectToMyCoords(other, otherRect); 3419 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3420 3421 if (distance < minDistance) { 3422 minDistance = distance; 3423 closetChildIndex = i; 3424 } 3425 } 3426 } 3427 3428 if (closetChildIndex >= 0) { 3429 setSelection(closetChildIndex + mFirstPosition); 3430 } else { 3431 requestLayout(); 3432 } 3433 } 3434 3435 3436 /* 3437 * (non-Javadoc) 3438 * 3439 * Children specified in XML are assumed to be header views. After we have 3440 * parsed them move them out of the children list and into mHeaderViews. 3441 */ 3442 @Override 3443 protected void onFinishInflate() { 3444 super.onFinishInflate(); 3445 3446 int count = getChildCount(); 3447 if (count > 0) { 3448 for (int i = 0; i < count; ++i) { 3449 addHeaderView(getChildAt(i)); 3450 } 3451 removeAllViews(); 3452 } 3453 } 3454 3455 /* (non-Javadoc) 3456 * @see android.view.View#findViewById(int) 3457 * First look in our children, then in any header and footer views that may be scrolled off. 3458 */ 3459 @Override 3460 protected View findViewTraversal(int id) { 3461 View v; 3462 v = super.findViewTraversal(id); 3463 if (v == null) { 3464 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3465 if (v != null) { 3466 return v; 3467 } 3468 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3469 if (v != null) { 3470 return v; 3471 } 3472 } 3473 return v; 3474 } 3475 3476 /* (non-Javadoc) 3477 * 3478 * Look in the passed in list of headers or footers for the view. 3479 */ 3480 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3481 if (where != null) { 3482 int len = where.size(); 3483 View v; 3484 3485 for (int i = 0; i < len; i++) { 3486 v = where.get(i).view; 3487 3488 if (!v.isRootNamespace()) { 3489 v = v.findViewById(id); 3490 3491 if (v != null) { 3492 return v; 3493 } 3494 } 3495 } 3496 } 3497 return null; 3498 } 3499 3500 /* (non-Javadoc) 3501 * @see android.view.View#findViewWithTag(Object) 3502 * First look in our children, then in any header and footer views that may be scrolled off. 3503 */ 3504 @Override 3505 protected View findViewWithTagTraversal(Object tag) { 3506 View v; 3507 v = super.findViewWithTagTraversal(tag); 3508 if (v == null) { 3509 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3510 if (v != null) { 3511 return v; 3512 } 3513 3514 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3515 if (v != null) { 3516 return v; 3517 } 3518 } 3519 return v; 3520 } 3521 3522 /* (non-Javadoc) 3523 * 3524 * Look in the passed in list of headers or footers for the view with the tag. 3525 */ 3526 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3527 if (where != null) { 3528 int len = where.size(); 3529 View v; 3530 3531 for (int i = 0; i < len; i++) { 3532 v = where.get(i).view; 3533 3534 if (!v.isRootNamespace()) { 3535 v = v.findViewWithTag(tag); 3536 3537 if (v != null) { 3538 return v; 3539 } 3540 } 3541 } 3542 } 3543 return null; 3544 } 3545 3546 /** 3547 * @hide 3548 * @see android.view.View#findViewByPredicate(Predicate) 3549 * First look in our children, then in any header and footer views that may be scrolled off. 3550 */ 3551 @Override 3552 protected View findViewByPredicateTraversal(Predicate<View> predicate) { 3553 View v; 3554 v = super.findViewByPredicateTraversal(predicate); 3555 if (v == null) { 3556 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate); 3557 if (v != null) { 3558 return v; 3559 } 3560 3561 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate); 3562 if (v != null) { 3563 return v; 3564 } 3565 } 3566 return v; 3567 } 3568 3569 /* (non-Javadoc) 3570 * 3571 * Look in the passed in list of headers or footers for the first view that matches 3572 * the predicate. 3573 */ 3574 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3575 Predicate<View> predicate) { 3576 if (where != null) { 3577 int len = where.size(); 3578 View v; 3579 3580 for (int i = 0; i < len; i++) { 3581 v = where.get(i).view; 3582 3583 if (!v.isRootNamespace()) { 3584 v = v.findViewByPredicate(predicate); 3585 3586 if (v != null) { 3587 return v; 3588 } 3589 } 3590 } 3591 } 3592 return null; 3593 } 3594 3595 @Override 3596 public boolean onTouchEvent(MotionEvent ev) { 3597 //noinspection SimplifiableIfStatement 3598 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3599 // Don't handle edge touches immediately -- they may actually belong to one of our 3600 // descendants. 3601 return false; 3602 } 3603 return super.onTouchEvent(ev); 3604 } 3605 3606 /** 3607 * Returns the set of checked items ids. The result is only valid if the 3608 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3609 * 3610 * @return A new array which contains the id of each checked item in the 3611 * list. 3612 * 3613 * @deprecated Use {@link #getCheckedItemIds()} instead. 3614 */ 3615 @Deprecated 3616 public long[] getCheckItemIds() { 3617 // Use new behavior that correctly handles stable ID mapping. 3618 if (mAdapter != null && mAdapter.hasStableIds()) { 3619 return getCheckedItemIds(); 3620 } 3621 3622 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3623 // Fall back to it to support legacy apps. 3624 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3625 final SparseBooleanArray states = mCheckStates; 3626 final int count = states.size(); 3627 final long[] ids = new long[count]; 3628 final ListAdapter adapter = mAdapter; 3629 3630 int checkedCount = 0; 3631 for (int i = 0; i < count; i++) { 3632 if (states.valueAt(i)) { 3633 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3634 } 3635 } 3636 3637 // Trim array if needed. mCheckStates may contain false values 3638 // resulting in checkedCount being smaller than count. 3639 if (checkedCount == count) { 3640 return ids; 3641 } else { 3642 final long[] result = new long[checkedCount]; 3643 System.arraycopy(ids, 0, result, 0, checkedCount); 3644 3645 return result; 3646 } 3647 } 3648 return new long[0]; 3649 } 3650} 3651