ListView.java revision d22db216fe7da01d70d4db3b3e76797aea64e956
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import android.os.Trace; 20import com.android.internal.R; 21import com.android.internal.util.Predicate; 22import com.google.android.collect.Lists; 23 24import android.content.Context; 25import android.content.Intent; 26import android.content.res.TypedArray; 27import android.graphics.Canvas; 28import android.graphics.Paint; 29import android.graphics.PixelFormat; 30import android.graphics.Rect; 31import android.graphics.drawable.Drawable; 32import android.util.AttributeSet; 33import android.util.MathUtils; 34import android.util.SparseBooleanArray; 35import android.view.FocusFinder; 36import android.view.KeyEvent; 37import android.view.SoundEffectConstants; 38import android.view.View; 39import android.view.ViewDebug; 40import android.view.ViewGroup; 41import android.view.ViewParent; 42import android.view.accessibility.AccessibilityEvent; 43import android.view.accessibility.AccessibilityNodeInfo; 44import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 45import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 46import android.widget.RemoteViews.RemoteView; 47 48import java.util.ArrayList; 49 50/* 51 * Implementation Notes: 52 * 53 * Some terminology: 54 * 55 * index - index of the items that are currently visible 56 * position - index of the items in the cursor 57 */ 58 59 60/** 61 * A view that shows items in a vertically scrolling list. The items 62 * come from the {@link ListAdapter} associated with this view. 63 * 64 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 65 * guide.</p> 66 * 67 * @attr ref android.R.styleable#ListView_entries 68 * @attr ref android.R.styleable#ListView_divider 69 * @attr ref android.R.styleable#ListView_dividerHeight 70 * @attr ref android.R.styleable#ListView_headerDividersEnabled 71 * @attr ref android.R.styleable#ListView_footerDividersEnabled 72 */ 73@RemoteView 74public class ListView extends AbsListView { 75 /** 76 * Used to indicate a no preference for a position type. 77 */ 78 static final int NO_POSITION = -1; 79 80 /** 81 * When arrow scrolling, ListView will never scroll more than this factor 82 * times the height of the list. 83 */ 84 private static final float MAX_SCROLL_FACTOR = 0.33f; 85 86 /** 87 * When arrow scrolling, need a certain amount of pixels to preview next 88 * items. This is usually the fading edge, but if that is small enough, 89 * we want to make sure we preview at least this many pixels. 90 */ 91 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 92 93 /** 94 * A class that represents a fixed view in a list, for example a header at the top 95 * or a footer at the bottom. 96 */ 97 public class FixedViewInfo { 98 /** The view to add to the list */ 99 public View view; 100 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 101 public Object data; 102 /** <code>true</code> if the fixed view should be selectable in the list */ 103 public boolean isSelectable; 104 } 105 106 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 107 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 108 109 Drawable mDivider; 110 int mDividerHeight; 111 112 Drawable mOverScrollHeader; 113 Drawable mOverScrollFooter; 114 115 private boolean mIsCacheColorOpaque; 116 private boolean mDividerIsOpaque; 117 118 private boolean mHeaderDividersEnabled; 119 private boolean mFooterDividersEnabled; 120 121 private boolean mAreAllItemsSelectable = true; 122 123 private boolean mItemsCanFocus = false; 124 125 // used for temporary calculations. 126 private final Rect mTempRect = new Rect(); 127 private Paint mDividerPaint; 128 129 // the single allocated result per list view; kinda cheesey but avoids 130 // allocating these thingies too often. 131 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 132 133 // Keeps focused children visible through resizes 134 private FocusSelector mFocusSelector; 135 136 public ListView(Context context) { 137 this(context, null); 138 } 139 140 public ListView(Context context, AttributeSet attrs) { 141 this(context, attrs, com.android.internal.R.attr.listViewStyle); 142 } 143 144 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 145 this(context, attrs, defStyleAttr, 0); 146 } 147 148 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 149 super(context, attrs, defStyleAttr, defStyleRes); 150 151 final TypedArray a = context.obtainStyledAttributes( 152 attrs, com.android.internal.R.styleable.ListView, defStyleAttr, defStyleRes); 153 154 CharSequence[] entries = a.getTextArray( 155 com.android.internal.R.styleable.ListView_entries); 156 if (entries != null) { 157 setAdapter(new ArrayAdapter<CharSequence>(context, 158 com.android.internal.R.layout.simple_list_item_1, entries)); 159 } 160 161 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 162 if (d != null) { 163 // If a divider is specified use its intrinsic height for divider height 164 setDivider(d); 165 } 166 167 final Drawable osHeader = a.getDrawable( 168 com.android.internal.R.styleable.ListView_overScrollHeader); 169 if (osHeader != null) { 170 setOverscrollHeader(osHeader); 171 } 172 173 final Drawable osFooter = a.getDrawable( 174 com.android.internal.R.styleable.ListView_overScrollFooter); 175 if (osFooter != null) { 176 setOverscrollFooter(osFooter); 177 } 178 179 // Use the height specified, zero being the default 180 final int dividerHeight = a.getDimensionPixelSize( 181 com.android.internal.R.styleable.ListView_dividerHeight, 0); 182 if (dividerHeight != 0) { 183 setDividerHeight(dividerHeight); 184 } 185 186 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 187 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 188 189 a.recycle(); 190 } 191 192 /** 193 * @return The maximum amount a list view will scroll in response to 194 * an arrow event. 195 */ 196 public int getMaxScrollAmount() { 197 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 198 } 199 200 /** 201 * Make sure views are touching the top or bottom edge, as appropriate for 202 * our gravity 203 */ 204 private void adjustViewsUpOrDown() { 205 final int childCount = getChildCount(); 206 int delta; 207 208 if (childCount > 0) { 209 View child; 210 211 if (!mStackFromBottom) { 212 // Uh-oh -- we came up short. Slide all views up to make them 213 // align with the top 214 child = getChildAt(0); 215 delta = child.getTop() - mListPadding.top; 216 if (mFirstPosition != 0) { 217 // It's OK to have some space above the first item if it is 218 // part of the vertical spacing 219 delta -= mDividerHeight; 220 } 221 if (delta < 0) { 222 // We only are looking to see if we are too low, not too high 223 delta = 0; 224 } 225 } else { 226 // we are too high, slide all views down to align with bottom 227 child = getChildAt(childCount - 1); 228 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 229 230 if (mFirstPosition + childCount < mItemCount) { 231 // It's OK to have some space below the last item if it is 232 // part of the vertical spacing 233 delta += mDividerHeight; 234 } 235 236 if (delta > 0) { 237 delta = 0; 238 } 239 } 240 241 if (delta != 0) { 242 offsetChildrenTopAndBottom(-delta); 243 } 244 } 245 } 246 247 /** 248 * Add a fixed view to appear at the top of the list. If this method is 249 * called more than once, the views will appear in the order they were 250 * added. Views added using this call can take focus if they want. 251 * <p> 252 * Note: When first introduced, this method could only be called before 253 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 254 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 255 * called at any time. If the ListView's adapter does not extend 256 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 257 * instance of {@link WrapperListAdapter}. 258 * 259 * @param v The view to add. 260 * @param data Data to associate with this view 261 * @param isSelectable whether the item is selectable 262 */ 263 public void addHeaderView(View v, Object data, boolean isSelectable) { 264 final FixedViewInfo info = new FixedViewInfo(); 265 info.view = v; 266 info.data = data; 267 info.isSelectable = isSelectable; 268 mHeaderViewInfos.add(info); 269 mAreAllItemsSelectable &= isSelectable; 270 271 // Wrap the adapter if it wasn't already wrapped. 272 if (mAdapter != null) { 273 if (!(mAdapter instanceof HeaderViewListAdapter)) { 274 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 275 } 276 277 // In the case of re-adding a header view, or adding one later on, 278 // we need to notify the observer. 279 if (mDataSetObserver != null) { 280 mDataSetObserver.onChanged(); 281 } 282 } 283 } 284 285 /** 286 * Add a fixed view to appear at the top of the list. If addHeaderView is 287 * called more than once, the views will appear in the order they were 288 * added. Views added using this call can take focus if they want. 289 * <p> 290 * Note: When first introduced, this method could only be called before 291 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 292 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 293 * called at any time. If the ListView's adapter does not extend 294 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 295 * instance of {@link WrapperListAdapter}. 296 * 297 * @param v The view to add. 298 */ 299 public void addHeaderView(View v) { 300 addHeaderView(v, null, true); 301 } 302 303 @Override 304 public int getHeaderViewsCount() { 305 return mHeaderViewInfos.size(); 306 } 307 308 /** 309 * Removes a previously-added header view. 310 * 311 * @param v The view to remove 312 * @return true if the view was removed, false if the view was not a header 313 * view 314 */ 315 public boolean removeHeaderView(View v) { 316 if (mHeaderViewInfos.size() > 0) { 317 boolean result = false; 318 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 319 if (mDataSetObserver != null) { 320 mDataSetObserver.onChanged(); 321 } 322 result = true; 323 } 324 removeFixedViewInfo(v, mHeaderViewInfos); 325 return result; 326 } 327 return false; 328 } 329 330 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 331 int len = where.size(); 332 for (int i = 0; i < len; ++i) { 333 FixedViewInfo info = where.get(i); 334 if (info.view == v) { 335 where.remove(i); 336 break; 337 } 338 } 339 } 340 341 /** 342 * Add a fixed view to appear at the bottom of the list. If addFooterView is 343 * called more than once, the views will appear in the order they were 344 * added. Views added using this call can take focus if they want. 345 * <p> 346 * Note: When first introduced, this method could only be called before 347 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 348 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 349 * called at any time. If the ListView's adapter does not extend 350 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 351 * instance of {@link WrapperListAdapter}. 352 * 353 * @param v The view to add. 354 * @param data Data to associate with this view 355 * @param isSelectable true if the footer view can be selected 356 */ 357 public void addFooterView(View v, Object data, boolean isSelectable) { 358 final FixedViewInfo info = new FixedViewInfo(); 359 info.view = v; 360 info.data = data; 361 info.isSelectable = isSelectable; 362 mFooterViewInfos.add(info); 363 mAreAllItemsSelectable &= isSelectable; 364 365 // Wrap the adapter if it wasn't already wrapped. 366 if (mAdapter != null) { 367 if (!(mAdapter instanceof HeaderViewListAdapter)) { 368 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 369 } 370 371 // In the case of re-adding a footer view, or adding one later on, 372 // we need to notify the observer. 373 if (mDataSetObserver != null) { 374 mDataSetObserver.onChanged(); 375 } 376 } 377 } 378 379 /** 380 * Add a fixed view to appear at the bottom of the list. If addFooterView is 381 * called more than once, the views will appear in the order they were 382 * added. Views added using this call can take focus if they want. 383 * <p> 384 * Note: When first introduced, this method could only be called before 385 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 386 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 387 * called at any time. If the ListView's adapter does not extend 388 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 389 * instance of {@link WrapperListAdapter}. 390 * 391 * @param v The view to add. 392 */ 393 public void addFooterView(View v) { 394 addFooterView(v, null, true); 395 } 396 397 @Override 398 public int getFooterViewsCount() { 399 return mFooterViewInfos.size(); 400 } 401 402 /** 403 * Removes a previously-added footer view. 404 * 405 * @param v The view to remove 406 * @return 407 * true if the view was removed, false if the view was not a footer view 408 */ 409 public boolean removeFooterView(View v) { 410 if (mFooterViewInfos.size() > 0) { 411 boolean result = false; 412 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 413 if (mDataSetObserver != null) { 414 mDataSetObserver.onChanged(); 415 } 416 result = true; 417 } 418 removeFixedViewInfo(v, mFooterViewInfos); 419 return result; 420 } 421 return false; 422 } 423 424 /** 425 * Returns the adapter currently in use in this ListView. The returned adapter 426 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 427 * might be a {@link WrapperListAdapter}. 428 * 429 * @return The adapter currently used to display data in this ListView. 430 * 431 * @see #setAdapter(ListAdapter) 432 */ 433 @Override 434 public ListAdapter getAdapter() { 435 return mAdapter; 436 } 437 438 /** 439 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 440 * through the specified intent. 441 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 442 */ 443 @android.view.RemotableViewMethod 444 public void setRemoteViewsAdapter(Intent intent) { 445 super.setRemoteViewsAdapter(intent); 446 } 447 448 /** 449 * Sets the data behind this ListView. 450 * 451 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 452 * depending on the ListView features currently in use. For instance, adding 453 * headers and/or footers will cause the adapter to be wrapped. 454 * 455 * @param adapter The ListAdapter which is responsible for maintaining the 456 * data backing this list and for producing a view to represent an 457 * item in that data set. 458 * 459 * @see #getAdapter() 460 */ 461 @Override 462 public void setAdapter(ListAdapter adapter) { 463 if (mAdapter != null && mDataSetObserver != null) { 464 mAdapter.unregisterDataSetObserver(mDataSetObserver); 465 } 466 467 resetList(); 468 mRecycler.clear(); 469 470 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 471 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 472 } else { 473 mAdapter = adapter; 474 } 475 476 mOldSelectedPosition = INVALID_POSITION; 477 mOldSelectedRowId = INVALID_ROW_ID; 478 479 // AbsListView#setAdapter will update choice mode states. 480 super.setAdapter(adapter); 481 482 if (mAdapter != null) { 483 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 484 mOldItemCount = mItemCount; 485 mItemCount = mAdapter.getCount(); 486 checkFocus(); 487 488 mDataSetObserver = new AdapterDataSetObserver(); 489 mAdapter.registerDataSetObserver(mDataSetObserver); 490 491 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 492 493 int position; 494 if (mStackFromBottom) { 495 position = lookForSelectablePosition(mItemCount - 1, false); 496 } else { 497 position = lookForSelectablePosition(0, true); 498 } 499 setSelectedPositionInt(position); 500 setNextSelectedPositionInt(position); 501 502 if (mItemCount == 0) { 503 // Nothing selected 504 checkSelectionChanged(); 505 } 506 } else { 507 mAreAllItemsSelectable = true; 508 checkFocus(); 509 // Nothing selected 510 checkSelectionChanged(); 511 } 512 513 requestLayout(); 514 } 515 516 /** 517 * The list is empty. Clear everything out. 518 */ 519 @Override 520 void resetList() { 521 // The parent's resetList() will remove all views from the layout so we need to 522 // cleanup the state of our footers and headers 523 clearRecycledState(mHeaderViewInfos); 524 clearRecycledState(mFooterViewInfos); 525 526 super.resetList(); 527 528 mLayoutMode = LAYOUT_NORMAL; 529 } 530 531 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 532 if (infos != null) { 533 final int count = infos.size(); 534 535 for (int i = 0; i < count; i++) { 536 final View child = infos.get(i).view; 537 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 538 if (p != null) { 539 p.recycledHeaderFooter = false; 540 } 541 } 542 } 543 } 544 545 /** 546 * @return Whether the list needs to show the top fading edge 547 */ 548 private boolean showingTopFadingEdge() { 549 final int listTop = mScrollY + mListPadding.top; 550 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 551 } 552 553 /** 554 * @return Whether the list needs to show the bottom fading edge 555 */ 556 private boolean showingBottomFadingEdge() { 557 final int childCount = getChildCount(); 558 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 559 final int lastVisiblePosition = mFirstPosition + childCount - 1; 560 561 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 562 563 return (lastVisiblePosition < mItemCount - 1) 564 || (bottomOfBottomChild < listBottom); 565 } 566 567 568 @Override 569 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 570 571 int rectTopWithinChild = rect.top; 572 573 // offset so rect is in coordinates of the this view 574 rect.offset(child.getLeft(), child.getTop()); 575 rect.offset(-child.getScrollX(), -child.getScrollY()); 576 577 final int height = getHeight(); 578 int listUnfadedTop = getScrollY(); 579 int listUnfadedBottom = listUnfadedTop + height; 580 final int fadingEdge = getVerticalFadingEdgeLength(); 581 582 if (showingTopFadingEdge()) { 583 // leave room for top fading edge as long as rect isn't at very top 584 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 585 listUnfadedTop += fadingEdge; 586 } 587 } 588 589 int childCount = getChildCount(); 590 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 591 592 if (showingBottomFadingEdge()) { 593 // leave room for bottom fading edge as long as rect isn't at very bottom 594 if ((mSelectedPosition < mItemCount - 1) 595 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 596 listUnfadedBottom -= fadingEdge; 597 } 598 } 599 600 int scrollYDelta = 0; 601 602 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 603 // need to MOVE DOWN to get it in view: move down just enough so 604 // that the entire rectangle is in view (or at least the first 605 // screen size chunk). 606 607 if (rect.height() > height) { 608 // just enough to get screen size chunk on 609 scrollYDelta += (rect.top - listUnfadedTop); 610 } else { 611 // get entire rect at bottom of screen 612 scrollYDelta += (rect.bottom - listUnfadedBottom); 613 } 614 615 // make sure we aren't scrolling beyond the end of our children 616 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 617 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 618 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 619 // need to MOVE UP to get it in view: move up just enough so that 620 // entire rectangle is in view (or at least the first screen 621 // size chunk of it). 622 623 if (rect.height() > height) { 624 // screen size chunk 625 scrollYDelta -= (listUnfadedBottom - rect.bottom); 626 } else { 627 // entire rect at top 628 scrollYDelta -= (listUnfadedTop - rect.top); 629 } 630 631 // make sure we aren't scrolling any further than the top our children 632 int top = getChildAt(0).getTop(); 633 int deltaToTop = top - listUnfadedTop; 634 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 635 } 636 637 final boolean scroll = scrollYDelta != 0; 638 if (scroll) { 639 scrollListItemsBy(-scrollYDelta); 640 positionSelector(INVALID_POSITION, child); 641 mSelectedTop = child.getTop(); 642 invalidate(); 643 } 644 return scroll; 645 } 646 647 /** 648 * {@inheritDoc} 649 */ 650 @Override 651 void fillGap(boolean down) { 652 final int count = getChildCount(); 653 if (down) { 654 int paddingTop = 0; 655 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 656 paddingTop = getListPaddingTop(); 657 } 658 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 659 paddingTop; 660 fillDown(mFirstPosition + count, startOffset); 661 correctTooHigh(getChildCount()); 662 } else { 663 int paddingBottom = 0; 664 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 665 paddingBottom = getListPaddingBottom(); 666 } 667 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 668 getHeight() - paddingBottom; 669 fillUp(mFirstPosition - 1, startOffset); 670 correctTooLow(getChildCount()); 671 } 672 } 673 674 /** 675 * Fills the list from pos down to the end of the list view. 676 * 677 * @param pos The first position to put in the list 678 * 679 * @param nextTop The location where the top of the item associated with pos 680 * should be drawn 681 * 682 * @return The view that is currently selected, if it happens to be in the 683 * range that we draw. 684 */ 685 private View fillDown(int pos, int nextTop) { 686 View selectedView = null; 687 688 int end = (mBottom - mTop); 689 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 690 end -= mListPadding.bottom; 691 } 692 693 while (nextTop < end && pos < mItemCount) { 694 // is this the selected item? 695 boolean selected = pos == mSelectedPosition; 696 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 697 698 nextTop = child.getBottom() + mDividerHeight; 699 if (selected) { 700 selectedView = child; 701 } 702 pos++; 703 } 704 705 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 706 return selectedView; 707 } 708 709 /** 710 * Fills the list from pos up to the top of the list view. 711 * 712 * @param pos The first position to put in the list 713 * 714 * @param nextBottom The location where the bottom of the item associated 715 * with pos should be drawn 716 * 717 * @return The view that is currently selected 718 */ 719 private View fillUp(int pos, int nextBottom) { 720 View selectedView = null; 721 722 int end = 0; 723 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 724 end = mListPadding.top; 725 } 726 727 while (nextBottom > end && pos >= 0) { 728 // is this the selected item? 729 boolean selected = pos == mSelectedPosition; 730 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 731 nextBottom = child.getTop() - mDividerHeight; 732 if (selected) { 733 selectedView = child; 734 } 735 pos--; 736 } 737 738 mFirstPosition = pos + 1; 739 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 740 return selectedView; 741 } 742 743 /** 744 * Fills the list from top to bottom, starting with mFirstPosition 745 * 746 * @param nextTop The location where the top of the first item should be 747 * drawn 748 * 749 * @return The view that is currently selected 750 */ 751 private View fillFromTop(int nextTop) { 752 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 753 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 754 if (mFirstPosition < 0) { 755 mFirstPosition = 0; 756 } 757 return fillDown(mFirstPosition, nextTop); 758 } 759 760 761 /** 762 * Put mSelectedPosition in the middle of the screen and then build up and 763 * down from there. This method forces mSelectedPosition to the center. 764 * 765 * @param childrenTop Top of the area in which children can be drawn, as 766 * measured in pixels 767 * @param childrenBottom Bottom of the area in which children can be drawn, 768 * as measured in pixels 769 * @return Currently selected view 770 */ 771 private View fillFromMiddle(int childrenTop, int childrenBottom) { 772 int height = childrenBottom - childrenTop; 773 774 int position = reconcileSelectedPosition(); 775 776 View sel = makeAndAddView(position, childrenTop, true, 777 mListPadding.left, true); 778 mFirstPosition = position; 779 780 int selHeight = sel.getMeasuredHeight(); 781 if (selHeight <= height) { 782 sel.offsetTopAndBottom((height - selHeight) / 2); 783 } 784 785 fillAboveAndBelow(sel, position); 786 787 if (!mStackFromBottom) { 788 correctTooHigh(getChildCount()); 789 } else { 790 correctTooLow(getChildCount()); 791 } 792 793 return sel; 794 } 795 796 /** 797 * Once the selected view as been placed, fill up the visible area above and 798 * below it. 799 * 800 * @param sel The selected view 801 * @param position The position corresponding to sel 802 */ 803 private void fillAboveAndBelow(View sel, int position) { 804 final int dividerHeight = mDividerHeight; 805 if (!mStackFromBottom) { 806 fillUp(position - 1, sel.getTop() - dividerHeight); 807 adjustViewsUpOrDown(); 808 fillDown(position + 1, sel.getBottom() + dividerHeight); 809 } else { 810 fillDown(position + 1, sel.getBottom() + dividerHeight); 811 adjustViewsUpOrDown(); 812 fillUp(position - 1, sel.getTop() - dividerHeight); 813 } 814 } 815 816 817 /** 818 * Fills the grid based on positioning the new selection at a specific 819 * location. The selection may be moved so that it does not intersect the 820 * faded edges. The grid is then filled upwards and downwards from there. 821 * 822 * @param selectedTop Where the selected item should be 823 * @param childrenTop Where to start drawing children 824 * @param childrenBottom Last pixel where children can be drawn 825 * @return The view that currently has selection 826 */ 827 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 828 int fadingEdgeLength = getVerticalFadingEdgeLength(); 829 final int selectedPosition = mSelectedPosition; 830 831 View sel; 832 833 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 834 selectedPosition); 835 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 836 selectedPosition); 837 838 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 839 840 841 // Some of the newly selected item extends below the bottom of the list 842 if (sel.getBottom() > bottomSelectionPixel) { 843 // Find space available above the selection into which we can scroll 844 // upwards 845 final int spaceAbove = sel.getTop() - topSelectionPixel; 846 847 // Find space required to bring the bottom of the selected item 848 // fully into view 849 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 850 final int offset = Math.min(spaceAbove, spaceBelow); 851 852 // Now offset the selected item to get it into view 853 sel.offsetTopAndBottom(-offset); 854 } else if (sel.getTop() < topSelectionPixel) { 855 // Find space required to bring the top of the selected item fully 856 // into view 857 final int spaceAbove = topSelectionPixel - sel.getTop(); 858 859 // Find space available below the selection into which we can scroll 860 // downwards 861 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 862 final int offset = Math.min(spaceAbove, spaceBelow); 863 864 // Offset the selected item to get it into view 865 sel.offsetTopAndBottom(offset); 866 } 867 868 // Fill in views above and below 869 fillAboveAndBelow(sel, selectedPosition); 870 871 if (!mStackFromBottom) { 872 correctTooHigh(getChildCount()); 873 } else { 874 correctTooLow(getChildCount()); 875 } 876 877 return sel; 878 } 879 880 /** 881 * Calculate the bottom-most pixel we can draw the selection into 882 * 883 * @param childrenBottom Bottom pixel were children can be drawn 884 * @param fadingEdgeLength Length of the fading edge in pixels, if present 885 * @param selectedPosition The position that will be selected 886 * @return The bottom-most pixel we can draw the selection into 887 */ 888 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 889 int selectedPosition) { 890 int bottomSelectionPixel = childrenBottom; 891 if (selectedPosition != mItemCount - 1) { 892 bottomSelectionPixel -= fadingEdgeLength; 893 } 894 return bottomSelectionPixel; 895 } 896 897 /** 898 * Calculate the top-most pixel we can draw the selection into 899 * 900 * @param childrenTop Top pixel were children can be drawn 901 * @param fadingEdgeLength Length of the fading edge in pixels, if present 902 * @param selectedPosition The position that will be selected 903 * @return The top-most pixel we can draw the selection into 904 */ 905 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 906 // first pixel we can draw the selection into 907 int topSelectionPixel = childrenTop; 908 if (selectedPosition > 0) { 909 topSelectionPixel += fadingEdgeLength; 910 } 911 return topSelectionPixel; 912 } 913 914 /** 915 * Smoothly scroll to the specified adapter position. The view will 916 * scroll such that the indicated position is displayed. 917 * @param position Scroll to this adapter position. 918 */ 919 @android.view.RemotableViewMethod 920 public void smoothScrollToPosition(int position) { 921 super.smoothScrollToPosition(position); 922 } 923 924 /** 925 * Smoothly scroll to the specified adapter position offset. The view will 926 * scroll such that the indicated position is displayed. 927 * @param offset The amount to offset from the adapter position to scroll to. 928 */ 929 @android.view.RemotableViewMethod 930 public void smoothScrollByOffset(int offset) { 931 super.smoothScrollByOffset(offset); 932 } 933 934 /** 935 * Fills the list based on positioning the new selection relative to the old 936 * selection. The new selection will be placed at, above, or below the 937 * location of the new selection depending on how the selection is moving. 938 * The selection will then be pinned to the visible part of the screen, 939 * excluding the edges that are faded. The list is then filled upwards and 940 * downwards from there. 941 * 942 * @param oldSel The old selected view. Useful for trying to put the new 943 * selection in the same place 944 * @param newSel The view that is to become selected. Useful for trying to 945 * put the new selection in the same place 946 * @param delta Which way we are moving 947 * @param childrenTop Where to start drawing children 948 * @param childrenBottom Last pixel where children can be drawn 949 * @return The view that currently has selection 950 */ 951 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 952 int childrenBottom) { 953 int fadingEdgeLength = getVerticalFadingEdgeLength(); 954 final int selectedPosition = mSelectedPosition; 955 956 View sel; 957 958 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 959 selectedPosition); 960 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 961 selectedPosition); 962 963 if (delta > 0) { 964 /* 965 * Case 1: Scrolling down. 966 */ 967 968 /* 969 * Before After 970 * | | | | 971 * +-------+ +-------+ 972 * | A | | A | 973 * | 1 | => +-------+ 974 * +-------+ | B | 975 * | B | | 2 | 976 * +-------+ +-------+ 977 * | | | | 978 * 979 * Try to keep the top of the previously selected item where it was. 980 * oldSel = A 981 * sel = B 982 */ 983 984 // Put oldSel (A) where it belongs 985 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 986 mListPadding.left, false); 987 988 final int dividerHeight = mDividerHeight; 989 990 // Now put the new selection (B) below that 991 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 992 mListPadding.left, true); 993 994 // Some of the newly selected item extends below the bottom of the list 995 if (sel.getBottom() > bottomSelectionPixel) { 996 997 // Find space available above the selection into which we can scroll upwards 998 int spaceAbove = sel.getTop() - topSelectionPixel; 999 1000 // Find space required to bring the bottom of the selected item fully into view 1001 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1002 1003 // Don't scroll more than half the height of the list 1004 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1005 int offset = Math.min(spaceAbove, spaceBelow); 1006 offset = Math.min(offset, halfVerticalSpace); 1007 1008 // We placed oldSel, so offset that item 1009 oldSel.offsetTopAndBottom(-offset); 1010 // Now offset the selected item to get it into view 1011 sel.offsetTopAndBottom(-offset); 1012 } 1013 1014 // Fill in views above and below 1015 if (!mStackFromBottom) { 1016 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1017 adjustViewsUpOrDown(); 1018 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1019 } else { 1020 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1021 adjustViewsUpOrDown(); 1022 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1023 } 1024 } else if (delta < 0) { 1025 /* 1026 * Case 2: Scrolling up. 1027 */ 1028 1029 /* 1030 * Before After 1031 * | | | | 1032 * +-------+ +-------+ 1033 * | A | | A | 1034 * +-------+ => | 1 | 1035 * | B | +-------+ 1036 * | 2 | | B | 1037 * +-------+ +-------+ 1038 * | | | | 1039 * 1040 * Try to keep the top of the item about to become selected where it was. 1041 * newSel = A 1042 * olSel = B 1043 */ 1044 1045 if (newSel != null) { 1046 // Try to position the top of newSel (A) where it was before it was selected 1047 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1048 true); 1049 } else { 1050 // If (A) was not on screen and so did not have a view, position 1051 // it above the oldSel (B) 1052 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1053 true); 1054 } 1055 1056 // Some of the newly selected item extends above the top of the list 1057 if (sel.getTop() < topSelectionPixel) { 1058 // Find space required to bring the top of the selected item fully into view 1059 int spaceAbove = topSelectionPixel - sel.getTop(); 1060 1061 // Find space available below the selection into which we can scroll downwards 1062 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1063 1064 // Don't scroll more than half the height of the list 1065 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1066 int offset = Math.min(spaceAbove, spaceBelow); 1067 offset = Math.min(offset, halfVerticalSpace); 1068 1069 // Offset the selected item to get it into view 1070 sel.offsetTopAndBottom(offset); 1071 } 1072 1073 // Fill in views above and below 1074 fillAboveAndBelow(sel, selectedPosition); 1075 } else { 1076 1077 int oldTop = oldSel.getTop(); 1078 1079 /* 1080 * Case 3: Staying still 1081 */ 1082 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1083 1084 // We're staying still... 1085 if (oldTop < childrenTop) { 1086 // ... but the top of the old selection was off screen. 1087 // (This can happen if the data changes size out from under us) 1088 int newBottom = sel.getBottom(); 1089 if (newBottom < childrenTop + 20) { 1090 // Not enough visible -- bring it onscreen 1091 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1092 } 1093 } 1094 1095 // Fill in views above and below 1096 fillAboveAndBelow(sel, selectedPosition); 1097 } 1098 1099 return sel; 1100 } 1101 1102 private class FocusSelector implements Runnable { 1103 private int mPosition; 1104 private int mPositionTop; 1105 1106 public FocusSelector setup(int position, int top) { 1107 mPosition = position; 1108 mPositionTop = top; 1109 return this; 1110 } 1111 1112 public void run() { 1113 setSelectionFromTop(mPosition, mPositionTop); 1114 } 1115 } 1116 1117 @Override 1118 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1119 if (getChildCount() > 0) { 1120 View focusedChild = getFocusedChild(); 1121 if (focusedChild != null) { 1122 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1123 final int childBottom = focusedChild.getBottom(); 1124 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1125 final int top = focusedChild.getTop() - offset; 1126 if (mFocusSelector == null) { 1127 mFocusSelector = new FocusSelector(); 1128 } 1129 post(mFocusSelector.setup(childPosition, top)); 1130 } 1131 } 1132 super.onSizeChanged(w, h, oldw, oldh); 1133 } 1134 1135 @Override 1136 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1137 // Sets up mListPadding 1138 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1139 1140 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1141 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1142 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1143 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1144 1145 int childWidth = 0; 1146 int childHeight = 0; 1147 int childState = 0; 1148 1149 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1150 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1151 heightMode == MeasureSpec.UNSPECIFIED)) { 1152 final View child = obtainView(0, mIsScrap); 1153 1154 measureScrapChild(child, 0, widthMeasureSpec); 1155 1156 childWidth = child.getMeasuredWidth(); 1157 childHeight = child.getMeasuredHeight(); 1158 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1159 1160 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1161 ((LayoutParams) child.getLayoutParams()).viewType)) { 1162 mRecycler.addScrapView(child, -1); 1163 } 1164 } 1165 1166 if (widthMode == MeasureSpec.UNSPECIFIED) { 1167 widthSize = mListPadding.left + mListPadding.right + childWidth + 1168 getVerticalScrollbarWidth(); 1169 } else { 1170 widthSize |= (childState&MEASURED_STATE_MASK); 1171 } 1172 1173 if (heightMode == MeasureSpec.UNSPECIFIED) { 1174 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1175 getVerticalFadingEdgeLength() * 2; 1176 } 1177 1178 if (heightMode == MeasureSpec.AT_MOST) { 1179 // TODO: after first layout we should maybe start at the first visible position, not 0 1180 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1181 } 1182 1183 setMeasuredDimension(widthSize , heightSize); 1184 mWidthMeasureSpec = widthMeasureSpec; 1185 } 1186 1187 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1188 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1189 if (p == null) { 1190 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1191 child.setLayoutParams(p); 1192 } 1193 p.viewType = mAdapter.getItemViewType(position); 1194 p.forceAdd = true; 1195 1196 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1197 mListPadding.left + mListPadding.right, p.width); 1198 int lpHeight = p.height; 1199 int childHeightSpec; 1200 if (lpHeight > 0) { 1201 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1202 } else { 1203 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1204 } 1205 child.measure(childWidthSpec, childHeightSpec); 1206 } 1207 1208 /** 1209 * @return True to recycle the views used to measure this ListView in 1210 * UNSPECIFIED/AT_MOST modes, false otherwise. 1211 * @hide 1212 */ 1213 @ViewDebug.ExportedProperty(category = "list") 1214 protected boolean recycleOnMeasure() { 1215 return true; 1216 } 1217 1218 /** 1219 * Measures the height of the given range of children (inclusive) and 1220 * returns the height with this ListView's padding and divider heights 1221 * included. If maxHeight is provided, the measuring will stop when the 1222 * current height reaches maxHeight. 1223 * 1224 * @param widthMeasureSpec The width measure spec to be given to a child's 1225 * {@link View#measure(int, int)}. 1226 * @param startPosition The position of the first child to be shown. 1227 * @param endPosition The (inclusive) position of the last child to be 1228 * shown. Specify {@link #NO_POSITION} if the last child should be 1229 * the last available child from the adapter. 1230 * @param maxHeight The maximum height that will be returned (if all the 1231 * children don't fit in this value, this value will be 1232 * returned). 1233 * @param disallowPartialChildPosition In general, whether the returned 1234 * height should only contain entire children. This is more 1235 * powerful--it is the first inclusive position at which partial 1236 * children will not be allowed. Example: it looks nice to have 1237 * at least 3 completely visible children, and in portrait this 1238 * will most likely fit; but in landscape there could be times 1239 * when even 2 children can not be completely shown, so a value 1240 * of 2 (remember, inclusive) would be good (assuming 1241 * startPosition is 0). 1242 * @return The height of this ListView with the given children. 1243 */ 1244 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1245 final int maxHeight, int disallowPartialChildPosition) { 1246 1247 final ListAdapter adapter = mAdapter; 1248 if (adapter == null) { 1249 return mListPadding.top + mListPadding.bottom; 1250 } 1251 1252 // Include the padding of the list 1253 int returnedHeight = mListPadding.top + mListPadding.bottom; 1254 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1255 // The previous height value that was less than maxHeight and contained 1256 // no partial children 1257 int prevHeightWithoutPartialChild = 0; 1258 int i; 1259 View child; 1260 1261 // mItemCount - 1 since endPosition parameter is inclusive 1262 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1263 final AbsListView.RecycleBin recycleBin = mRecycler; 1264 final boolean recyle = recycleOnMeasure(); 1265 final boolean[] isScrap = mIsScrap; 1266 1267 for (i = startPosition; i <= endPosition; ++i) { 1268 child = obtainView(i, isScrap); 1269 1270 measureScrapChild(child, i, widthMeasureSpec); 1271 1272 if (i > 0) { 1273 // Count the divider for all but one child 1274 returnedHeight += dividerHeight; 1275 } 1276 1277 // Recycle the view before we possibly return from the method 1278 if (recyle && recycleBin.shouldRecycleViewType( 1279 ((LayoutParams) child.getLayoutParams()).viewType)) { 1280 recycleBin.addScrapView(child, -1); 1281 } 1282 1283 returnedHeight += child.getMeasuredHeight(); 1284 1285 if (returnedHeight >= maxHeight) { 1286 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1287 // then the i'th position did not fit completely. 1288 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1289 && (i > disallowPartialChildPosition) // We've past the min pos 1290 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1291 && (returnedHeight != maxHeight) // i'th child did not fit completely 1292 ? prevHeightWithoutPartialChild 1293 : maxHeight; 1294 } 1295 1296 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1297 prevHeightWithoutPartialChild = returnedHeight; 1298 } 1299 } 1300 1301 // At this point, we went through the range of children, and they each 1302 // completely fit, so return the returnedHeight 1303 return returnedHeight; 1304 } 1305 1306 @Override 1307 int findMotionRow(int y) { 1308 int childCount = getChildCount(); 1309 if (childCount > 0) { 1310 if (!mStackFromBottom) { 1311 for (int i = 0; i < childCount; i++) { 1312 View v = getChildAt(i); 1313 if (y <= v.getBottom()) { 1314 return mFirstPosition + i; 1315 } 1316 } 1317 } else { 1318 for (int i = childCount - 1; i >= 0; i--) { 1319 View v = getChildAt(i); 1320 if (y >= v.getTop()) { 1321 return mFirstPosition + i; 1322 } 1323 } 1324 } 1325 } 1326 return INVALID_POSITION; 1327 } 1328 1329 /** 1330 * Put a specific item at a specific location on the screen and then build 1331 * up and down from there. 1332 * 1333 * @param position The reference view to use as the starting point 1334 * @param top Pixel offset from the top of this view to the top of the 1335 * reference view. 1336 * 1337 * @return The selected view, or null if the selected view is outside the 1338 * visible area. 1339 */ 1340 private View fillSpecific(int position, int top) { 1341 boolean tempIsSelected = position == mSelectedPosition; 1342 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1343 // Possibly changed again in fillUp if we add rows above this one. 1344 mFirstPosition = position; 1345 1346 View above; 1347 View below; 1348 1349 final int dividerHeight = mDividerHeight; 1350 if (!mStackFromBottom) { 1351 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1352 // This will correct for the top of the first view not touching the top of the list 1353 adjustViewsUpOrDown(); 1354 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1355 int childCount = getChildCount(); 1356 if (childCount > 0) { 1357 correctTooHigh(childCount); 1358 } 1359 } else { 1360 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1361 // This will correct for the bottom of the last view not touching the bottom of the list 1362 adjustViewsUpOrDown(); 1363 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1364 int childCount = getChildCount(); 1365 if (childCount > 0) { 1366 correctTooLow(childCount); 1367 } 1368 } 1369 1370 if (tempIsSelected) { 1371 return temp; 1372 } else if (above != null) { 1373 return above; 1374 } else { 1375 return below; 1376 } 1377 } 1378 1379 /** 1380 * Check if we have dragged the bottom of the list too high (we have pushed the 1381 * top element off the top of the screen when we did not need to). Correct by sliding 1382 * everything back down. 1383 * 1384 * @param childCount Number of children 1385 */ 1386 private void correctTooHigh(int childCount) { 1387 // First see if the last item is visible. If it is not, it is OK for the 1388 // top of the list to be pushed up. 1389 int lastPosition = mFirstPosition + childCount - 1; 1390 if (lastPosition == mItemCount - 1 && childCount > 0) { 1391 1392 // Get the last child ... 1393 final View lastChild = getChildAt(childCount - 1); 1394 1395 // ... and its bottom edge 1396 final int lastBottom = lastChild.getBottom(); 1397 1398 // This is bottom of our drawable area 1399 final int end = (mBottom - mTop) - mListPadding.bottom; 1400 1401 // This is how far the bottom edge of the last view is from the bottom of the 1402 // drawable area 1403 int bottomOffset = end - lastBottom; 1404 View firstChild = getChildAt(0); 1405 final int firstTop = firstChild.getTop(); 1406 1407 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1408 // first row or the first row is scrolled off the top of the drawable area 1409 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1410 if (mFirstPosition == 0) { 1411 // Don't pull the top too far down 1412 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1413 } 1414 // Move everything down 1415 offsetChildrenTopAndBottom(bottomOffset); 1416 if (mFirstPosition > 0) { 1417 // Fill the gap that was opened above mFirstPosition with more rows, if 1418 // possible 1419 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1420 // Close up the remaining gap 1421 adjustViewsUpOrDown(); 1422 } 1423 1424 } 1425 } 1426 } 1427 1428 /** 1429 * Check if we have dragged the bottom of the list too low (we have pushed the 1430 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1431 * everything back up. 1432 * 1433 * @param childCount Number of children 1434 */ 1435 private void correctTooLow(int childCount) { 1436 // First see if the first item is visible. If it is not, it is OK for the 1437 // bottom of the list to be pushed down. 1438 if (mFirstPosition == 0 && childCount > 0) { 1439 1440 // Get the first child ... 1441 final View firstChild = getChildAt(0); 1442 1443 // ... and its top edge 1444 final int firstTop = firstChild.getTop(); 1445 1446 // This is top of our drawable area 1447 final int start = mListPadding.top; 1448 1449 // This is bottom of our drawable area 1450 final int end = (mBottom - mTop) - mListPadding.bottom; 1451 1452 // This is how far the top edge of the first view is from the top of the 1453 // drawable area 1454 int topOffset = firstTop - start; 1455 View lastChild = getChildAt(childCount - 1); 1456 final int lastBottom = lastChild.getBottom(); 1457 int lastPosition = mFirstPosition + childCount - 1; 1458 1459 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1460 // last row or the last row is scrolled off the bottom of the drawable area 1461 if (topOffset > 0) { 1462 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1463 if (lastPosition == mItemCount - 1) { 1464 // Don't pull the bottom too far up 1465 topOffset = Math.min(topOffset, lastBottom - end); 1466 } 1467 // Move everything up 1468 offsetChildrenTopAndBottom(-topOffset); 1469 if (lastPosition < mItemCount - 1) { 1470 // Fill the gap that was opened below the last position with more rows, if 1471 // possible 1472 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1473 // Close up the remaining gap 1474 adjustViewsUpOrDown(); 1475 } 1476 } else if (lastPosition == mItemCount - 1) { 1477 adjustViewsUpOrDown(); 1478 } 1479 } 1480 } 1481 } 1482 1483 @Override 1484 protected void layoutChildren() { 1485 final boolean blockLayoutRequests = mBlockLayoutRequests; 1486 if (blockLayoutRequests) { 1487 return; 1488 } 1489 1490 mBlockLayoutRequests = true; 1491 1492 try { 1493 super.layoutChildren(); 1494 1495 invalidate(); 1496 1497 if (mAdapter == null) { 1498 resetList(); 1499 invokeOnItemScrollListener(); 1500 return; 1501 } 1502 1503 final int childrenTop = mListPadding.top; 1504 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1505 final int childCount = getChildCount(); 1506 1507 int index = 0; 1508 int delta = 0; 1509 1510 View sel; 1511 View oldSel = null; 1512 View oldFirst = null; 1513 View newSel = null; 1514 1515 // Remember stuff we will need down below 1516 switch (mLayoutMode) { 1517 case LAYOUT_SET_SELECTION: 1518 index = mNextSelectedPosition - mFirstPosition; 1519 if (index >= 0 && index < childCount) { 1520 newSel = getChildAt(index); 1521 } 1522 break; 1523 case LAYOUT_FORCE_TOP: 1524 case LAYOUT_FORCE_BOTTOM: 1525 case LAYOUT_SPECIFIC: 1526 case LAYOUT_SYNC: 1527 break; 1528 case LAYOUT_MOVE_SELECTION: 1529 default: 1530 // Remember the previously selected view 1531 index = mSelectedPosition - mFirstPosition; 1532 if (index >= 0 && index < childCount) { 1533 oldSel = getChildAt(index); 1534 } 1535 1536 // Remember the previous first child 1537 oldFirst = getChildAt(0); 1538 1539 if (mNextSelectedPosition >= 0) { 1540 delta = mNextSelectedPosition - mSelectedPosition; 1541 } 1542 1543 // Caution: newSel might be null 1544 newSel = getChildAt(index + delta); 1545 } 1546 1547 1548 boolean dataChanged = mDataChanged; 1549 if (dataChanged) { 1550 handleDataChanged(); 1551 } 1552 1553 // Handle the empty set by removing all views that are visible 1554 // and calling it a day 1555 if (mItemCount == 0) { 1556 resetList(); 1557 invokeOnItemScrollListener(); 1558 return; 1559 } else if (mItemCount != mAdapter.getCount()) { 1560 throw new IllegalStateException("The content of the adapter has changed but " 1561 + "ListView did not receive a notification. Make sure the content of " 1562 + "your adapter is not modified from a background thread, but only from " 1563 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1564 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1565 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1566 } 1567 1568 setSelectedPositionInt(mNextSelectedPosition); 1569 1570 // Remember which child, if any, had accessibility focus. 1571 final int accessibilityFocusPosition; 1572 final View accessFocusedChild = getAccessibilityFocusedChild(); 1573 if (accessFocusedChild != null) { 1574 accessibilityFocusPosition = getPositionForView(accessFocusedChild); 1575 accessFocusedChild.setHasTransientState(true); 1576 } else { 1577 accessibilityFocusPosition = INVALID_POSITION; 1578 } 1579 1580 // Ensure the child containing focus, if any, has transient state. 1581 // If the list data hasn't changed, or if the adapter has stable 1582 // IDs, this will maintain focus. 1583 final View focusedChild = getFocusedChild(); 1584 if (focusedChild != null) { 1585 focusedChild.setHasTransientState(true); 1586 } 1587 1588 // Pull all children into the RecycleBin. 1589 // These views will be reused if possible 1590 final int firstPosition = mFirstPosition; 1591 final RecycleBin recycleBin = mRecycler; 1592 if (dataChanged) { 1593 for (int i = 0; i < childCount; i++) { 1594 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1595 } 1596 } else { 1597 recycleBin.fillActiveViews(childCount, firstPosition); 1598 } 1599 1600 // Clear out old views 1601 detachAllViewsFromParent(); 1602 recycleBin.removeSkippedScrap(); 1603 1604 switch (mLayoutMode) { 1605 case LAYOUT_SET_SELECTION: 1606 if (newSel != null) { 1607 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1608 } else { 1609 sel = fillFromMiddle(childrenTop, childrenBottom); 1610 } 1611 break; 1612 case LAYOUT_SYNC: 1613 sel = fillSpecific(mSyncPosition, mSpecificTop); 1614 break; 1615 case LAYOUT_FORCE_BOTTOM: 1616 sel = fillUp(mItemCount - 1, childrenBottom); 1617 adjustViewsUpOrDown(); 1618 break; 1619 case LAYOUT_FORCE_TOP: 1620 mFirstPosition = 0; 1621 sel = fillFromTop(childrenTop); 1622 adjustViewsUpOrDown(); 1623 break; 1624 case LAYOUT_SPECIFIC: 1625 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1626 break; 1627 case LAYOUT_MOVE_SELECTION: 1628 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1629 break; 1630 default: 1631 if (childCount == 0) { 1632 if (!mStackFromBottom) { 1633 final int position = lookForSelectablePosition(0, true); 1634 setSelectedPositionInt(position); 1635 sel = fillFromTop(childrenTop); 1636 } else { 1637 final int position = lookForSelectablePosition(mItemCount - 1, false); 1638 setSelectedPositionInt(position); 1639 sel = fillUp(mItemCount - 1, childrenBottom); 1640 } 1641 } else { 1642 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1643 sel = fillSpecific(mSelectedPosition, 1644 oldSel == null ? childrenTop : oldSel.getTop()); 1645 } else if (mFirstPosition < mItemCount) { 1646 sel = fillSpecific(mFirstPosition, 1647 oldFirst == null ? childrenTop : oldFirst.getTop()); 1648 } else { 1649 sel = fillSpecific(0, childrenTop); 1650 } 1651 } 1652 break; 1653 } 1654 1655 // Flush any cached views that did not get reused above 1656 recycleBin.scrapActiveViews(); 1657 1658 if (sel != null) { 1659 final boolean shouldPlaceFocus = mItemsCanFocus && hasFocus(); 1660 final boolean maintainedFocus = focusedChild != null && focusedChild.hasFocus(); 1661 if (shouldPlaceFocus && !maintainedFocus && !sel.hasFocus()) { 1662 if (sel.requestFocus()) { 1663 // Successfully placed focus, clear selection. 1664 sel.setSelected(false); 1665 mSelectorRect.setEmpty(); 1666 } else { 1667 // Failed to place focus, clear current (invalid) focus. 1668 final View focused = getFocusedChild(); 1669 if (focused != null) { 1670 focused.clearFocus(); 1671 } 1672 positionSelector(INVALID_POSITION, sel); 1673 } 1674 } else { 1675 positionSelector(INVALID_POSITION, sel); 1676 } 1677 mSelectedTop = sel.getTop(); 1678 } else { 1679 // If the user's finger is down, select the motion position. 1680 // Otherwise, clear selection. 1681 if (mTouchMode == TOUCH_MODE_TAP || mTouchMode == TOUCH_MODE_DONE_WAITING) { 1682 final View child = getChildAt(mMotionPosition - mFirstPosition); 1683 if (child != null) { 1684 positionSelector(mMotionPosition, child); 1685 } 1686 } else { 1687 mSelectedTop = 0; 1688 mSelectorRect.setEmpty(); 1689 } 1690 } 1691 1692 if (accessFocusedChild != null) { 1693 accessFocusedChild.setHasTransientState(false); 1694 1695 // If we failed to maintain accessibility focus on the previous 1696 // view, attempt to restore it to the previous position. 1697 if (!accessFocusedChild.isAccessibilityFocused() 1698 && accessibilityFocusPosition != INVALID_POSITION) { 1699 // Bound the position within the visible children. 1700 final int position = MathUtils.constrain( 1701 accessibilityFocusPosition - mFirstPosition, 0, getChildCount() - 1); 1702 final View restoreView = getChildAt(position); 1703 if (restoreView != null) { 1704 restoreView.requestAccessibilityFocus(); 1705 } 1706 } 1707 } 1708 1709 if (focusedChild != null) { 1710 focusedChild.setHasTransientState(false); 1711 } 1712 1713 mLayoutMode = LAYOUT_NORMAL; 1714 mDataChanged = false; 1715 if (mPositionScrollAfterLayout != null) { 1716 post(mPositionScrollAfterLayout); 1717 mPositionScrollAfterLayout = null; 1718 } 1719 mNeedSync = false; 1720 setNextSelectedPositionInt(mSelectedPosition); 1721 1722 updateScrollIndicators(); 1723 1724 if (mItemCount > 0) { 1725 checkSelectionChanged(); 1726 } 1727 1728 invokeOnItemScrollListener(); 1729 } finally { 1730 if (!blockLayoutRequests) { 1731 mBlockLayoutRequests = false; 1732 } 1733 } 1734 } 1735 1736 /** 1737 * Obtain the view and add it to our list of children. The view can be made 1738 * fresh, converted from an unused view, or used as is if it was in the 1739 * recycle bin. 1740 * 1741 * @param position Logical position in the list 1742 * @param y Top or bottom edge of the view to add 1743 * @param flow If flow is true, align top edge to y. If false, align bottom 1744 * edge to y. 1745 * @param childrenLeft Left edge where children should be positioned 1746 * @param selected Is this position selected? 1747 * @return View that was added 1748 */ 1749 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1750 boolean selected) { 1751 View child; 1752 1753 1754 if (!mDataChanged) { 1755 // Try to use an existing view for this position 1756 child = mRecycler.getActiveView(position); 1757 if (child != null) { 1758 // Found it -- we're using an existing child 1759 // This just needs to be positioned 1760 setupChild(child, position, y, flow, childrenLeft, selected, true); 1761 1762 return child; 1763 } 1764 } 1765 1766 // Make a new view for this position, or convert an unused view if possible 1767 child = obtainView(position, mIsScrap); 1768 1769 // This needs to be positioned and measured 1770 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1771 1772 return child; 1773 } 1774 1775 /** 1776 * Add a view as a child and make sure it is measured (if necessary) and 1777 * positioned properly. 1778 * 1779 * @param child The view to add 1780 * @param position The position of this child 1781 * @param y The y position relative to which this view will be positioned 1782 * @param flowDown If true, align top edge to y. If false, align bottom 1783 * edge to y. 1784 * @param childrenLeft Left edge where children should be positioned 1785 * @param selected Is this position selected? 1786 * @param recycled Has this view been pulled from the recycle bin? If so it 1787 * does not need to be remeasured. 1788 */ 1789 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1790 boolean selected, boolean recycled) { 1791 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1792 1793 final boolean isSelected = selected && shouldShowSelector(); 1794 final boolean updateChildSelected = isSelected != child.isSelected(); 1795 final int mode = mTouchMode; 1796 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1797 mMotionPosition == position; 1798 final boolean updateChildPressed = isPressed != child.isPressed(); 1799 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1800 1801 // Respect layout params that are already in the view. Otherwise make some up... 1802 // noinspection unchecked 1803 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1804 if (p == null) { 1805 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1806 } 1807 p.viewType = mAdapter.getItemViewType(position); 1808 1809 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1810 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1811 attachViewToParent(child, flowDown ? -1 : 0, p); 1812 } else { 1813 p.forceAdd = false; 1814 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1815 p.recycledHeaderFooter = true; 1816 } 1817 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1818 } 1819 1820 if (updateChildSelected) { 1821 child.setSelected(isSelected); 1822 } 1823 1824 if (updateChildPressed) { 1825 child.setPressed(isPressed); 1826 } 1827 1828 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1829 if (child instanceof Checkable) { 1830 ((Checkable) child).setChecked(mCheckStates.get(position)); 1831 } else if (getContext().getApplicationInfo().targetSdkVersion 1832 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1833 child.setActivated(mCheckStates.get(position)); 1834 } 1835 } 1836 1837 if (needToMeasure) { 1838 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1839 mListPadding.left + mListPadding.right, p.width); 1840 int lpHeight = p.height; 1841 int childHeightSpec; 1842 if (lpHeight > 0) { 1843 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1844 } else { 1845 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1846 } 1847 child.measure(childWidthSpec, childHeightSpec); 1848 } else { 1849 cleanupLayoutState(child); 1850 } 1851 1852 final int w = child.getMeasuredWidth(); 1853 final int h = child.getMeasuredHeight(); 1854 final int childTop = flowDown ? y : y - h; 1855 1856 if (needToMeasure) { 1857 final int childRight = childrenLeft + w; 1858 final int childBottom = childTop + h; 1859 child.layout(childrenLeft, childTop, childRight, childBottom); 1860 } else { 1861 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1862 child.offsetTopAndBottom(childTop - child.getTop()); 1863 } 1864 1865 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1866 child.setDrawingCacheEnabled(true); 1867 } 1868 1869 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1870 != position) { 1871 child.jumpDrawablesToCurrentState(); 1872 } 1873 1874 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1875 } 1876 1877 @Override 1878 protected boolean canAnimate() { 1879 return super.canAnimate() && mItemCount > 0; 1880 } 1881 1882 /** 1883 * Sets the currently selected item. If in touch mode, the item will not be selected 1884 * but it will still be positioned appropriately. If the specified selection position 1885 * is less than 0, then the item at position 0 will be selected. 1886 * 1887 * @param position Index (starting at 0) of the data item to be selected. 1888 */ 1889 @Override 1890 public void setSelection(int position) { 1891 setSelectionFromTop(position, 0); 1892 } 1893 1894 /** 1895 * Makes the item at the supplied position selected. 1896 * 1897 * @param position the position of the item to select 1898 */ 1899 @Override 1900 void setSelectionInt(int position) { 1901 setNextSelectedPositionInt(position); 1902 boolean awakeScrollbars = false; 1903 1904 final int selectedPosition = mSelectedPosition; 1905 1906 if (selectedPosition >= 0) { 1907 if (position == selectedPosition - 1) { 1908 awakeScrollbars = true; 1909 } else if (position == selectedPosition + 1) { 1910 awakeScrollbars = true; 1911 } 1912 } 1913 1914 if (mPositionScroller != null) { 1915 mPositionScroller.stop(); 1916 } 1917 1918 layoutChildren(); 1919 1920 if (awakeScrollbars) { 1921 awakenScrollBars(); 1922 } 1923 } 1924 1925 /** 1926 * Find a position that can be selected (i.e., is not a separator). 1927 * 1928 * @param position The starting position to look at. 1929 * @param lookDown Whether to look down for other positions. 1930 * @return The next selectable position starting at position and then searching either up or 1931 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1932 */ 1933 @Override 1934 int lookForSelectablePosition(int position, boolean lookDown) { 1935 final ListAdapter adapter = mAdapter; 1936 if (adapter == null || isInTouchMode()) { 1937 return INVALID_POSITION; 1938 } 1939 1940 final int count = adapter.getCount(); 1941 if (!mAreAllItemsSelectable) { 1942 if (lookDown) { 1943 position = Math.max(0, position); 1944 while (position < count && !adapter.isEnabled(position)) { 1945 position++; 1946 } 1947 } else { 1948 position = Math.min(position, count - 1); 1949 while (position >= 0 && !adapter.isEnabled(position)) { 1950 position--; 1951 } 1952 } 1953 } 1954 1955 if (position < 0 || position >= count) { 1956 return INVALID_POSITION; 1957 } 1958 1959 return position; 1960 } 1961 1962 /** 1963 * Find a position that can be selected (i.e., is not a separator). If there 1964 * are no selectable positions in the specified direction from the starting 1965 * position, searches in the opposite direction from the starting position 1966 * to the current position. 1967 * 1968 * @param current the current position 1969 * @param position the starting position 1970 * @param lookDown whether to look down for other positions 1971 * @return the next selectable position, or {@link #INVALID_POSITION} if 1972 * nothing can be found 1973 */ 1974 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 1975 final ListAdapter adapter = mAdapter; 1976 if (adapter == null || isInTouchMode()) { 1977 return INVALID_POSITION; 1978 } 1979 1980 // First check after the starting position in the specified direction. 1981 final int after = lookForSelectablePosition(position, lookDown); 1982 if (after != INVALID_POSITION) { 1983 return after; 1984 } 1985 1986 // Then check between the starting position and the current position. 1987 final int count = adapter.getCount(); 1988 current = MathUtils.constrain(current, -1, count - 1); 1989 if (lookDown) { 1990 position = Math.min(position - 1, count - 1); 1991 while ((position > current) && !adapter.isEnabled(position)) { 1992 position--; 1993 } 1994 if (position <= current) { 1995 return INVALID_POSITION; 1996 } 1997 } else { 1998 position = Math.max(0, position + 1); 1999 while ((position < current) && !adapter.isEnabled(position)) { 2000 position++; 2001 } 2002 if (position >= current) { 2003 return INVALID_POSITION; 2004 } 2005 } 2006 2007 return position; 2008 } 2009 2010 /** 2011 * setSelectionAfterHeaderView set the selection to be the first list item 2012 * after the header views. 2013 */ 2014 public void setSelectionAfterHeaderView() { 2015 final int count = mHeaderViewInfos.size(); 2016 if (count > 0) { 2017 mNextSelectedPosition = 0; 2018 return; 2019 } 2020 2021 if (mAdapter != null) { 2022 setSelection(count); 2023 } else { 2024 mNextSelectedPosition = count; 2025 mLayoutMode = LAYOUT_SET_SELECTION; 2026 } 2027 2028 } 2029 2030 @Override 2031 public boolean dispatchKeyEvent(KeyEvent event) { 2032 // Dispatch in the normal way 2033 boolean handled = super.dispatchKeyEvent(event); 2034 if (!handled) { 2035 // If we didn't handle it... 2036 View focused = getFocusedChild(); 2037 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2038 // ... and our focused child didn't handle it 2039 // ... give it to ourselves so we can scroll if necessary 2040 handled = onKeyDown(event.getKeyCode(), event); 2041 } 2042 } 2043 return handled; 2044 } 2045 2046 @Override 2047 public boolean onKeyDown(int keyCode, KeyEvent event) { 2048 return commonKey(keyCode, 1, event); 2049 } 2050 2051 @Override 2052 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2053 return commonKey(keyCode, repeatCount, event); 2054 } 2055 2056 @Override 2057 public boolean onKeyUp(int keyCode, KeyEvent event) { 2058 return commonKey(keyCode, 1, event); 2059 } 2060 2061 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2062 if (mAdapter == null || !isAttachedToWindow()) { 2063 return false; 2064 } 2065 2066 if (mDataChanged) { 2067 layoutChildren(); 2068 } 2069 2070 boolean handled = false; 2071 int action = event.getAction(); 2072 2073 if (action != KeyEvent.ACTION_UP) { 2074 switch (keyCode) { 2075 case KeyEvent.KEYCODE_DPAD_UP: 2076 if (event.hasNoModifiers()) { 2077 handled = resurrectSelectionIfNeeded(); 2078 if (!handled) { 2079 while (count-- > 0) { 2080 if (arrowScroll(FOCUS_UP)) { 2081 handled = true; 2082 } else { 2083 break; 2084 } 2085 } 2086 } 2087 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2088 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2089 } 2090 break; 2091 2092 case KeyEvent.KEYCODE_DPAD_DOWN: 2093 if (event.hasNoModifiers()) { 2094 handled = resurrectSelectionIfNeeded(); 2095 if (!handled) { 2096 while (count-- > 0) { 2097 if (arrowScroll(FOCUS_DOWN)) { 2098 handled = true; 2099 } else { 2100 break; 2101 } 2102 } 2103 } 2104 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2105 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2106 } 2107 break; 2108 2109 case KeyEvent.KEYCODE_DPAD_LEFT: 2110 if (event.hasNoModifiers()) { 2111 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2112 } 2113 break; 2114 2115 case KeyEvent.KEYCODE_DPAD_RIGHT: 2116 if (event.hasNoModifiers()) { 2117 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2118 } 2119 break; 2120 2121 case KeyEvent.KEYCODE_DPAD_CENTER: 2122 case KeyEvent.KEYCODE_ENTER: 2123 if (event.hasNoModifiers()) { 2124 handled = resurrectSelectionIfNeeded(); 2125 if (!handled 2126 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2127 keyPressed(); 2128 handled = true; 2129 } 2130 } 2131 break; 2132 2133 case KeyEvent.KEYCODE_SPACE: 2134 if (mPopup == null || !mPopup.isShowing()) { 2135 if (event.hasNoModifiers()) { 2136 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2137 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2138 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2139 } 2140 handled = true; 2141 } 2142 break; 2143 2144 case KeyEvent.KEYCODE_PAGE_UP: 2145 if (event.hasNoModifiers()) { 2146 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2147 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2148 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2149 } 2150 break; 2151 2152 case KeyEvent.KEYCODE_PAGE_DOWN: 2153 if (event.hasNoModifiers()) { 2154 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2155 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2156 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2157 } 2158 break; 2159 2160 case KeyEvent.KEYCODE_MOVE_HOME: 2161 if (event.hasNoModifiers()) { 2162 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2163 } 2164 break; 2165 2166 case KeyEvent.KEYCODE_MOVE_END: 2167 if (event.hasNoModifiers()) { 2168 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2169 } 2170 break; 2171 2172 case KeyEvent.KEYCODE_TAB: 2173 // XXX Sometimes it is useful to be able to TAB through the items in 2174 // a ListView sequentially. Unfortunately this can create an 2175 // asymmetry in TAB navigation order unless the list selection 2176 // always reverts to the top or bottom when receiving TAB focus from 2177 // another widget. Leaving this behavior disabled for now but 2178 // perhaps it should be configurable (and more comprehensive). 2179 if (false) { 2180 if (event.hasNoModifiers()) { 2181 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2182 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2183 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2184 } 2185 } 2186 break; 2187 } 2188 } 2189 2190 if (handled) { 2191 return true; 2192 } 2193 2194 if (sendToTextFilter(keyCode, count, event)) { 2195 return true; 2196 } 2197 2198 switch (action) { 2199 case KeyEvent.ACTION_DOWN: 2200 return super.onKeyDown(keyCode, event); 2201 2202 case KeyEvent.ACTION_UP: 2203 return super.onKeyUp(keyCode, event); 2204 2205 case KeyEvent.ACTION_MULTIPLE: 2206 return super.onKeyMultiple(keyCode, count, event); 2207 2208 default: // shouldn't happen 2209 return false; 2210 } 2211 } 2212 2213 /** 2214 * Scrolls up or down by the number of items currently present on screen. 2215 * 2216 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2217 * @return whether selection was moved 2218 */ 2219 boolean pageScroll(int direction) { 2220 final int nextPage; 2221 final boolean down; 2222 2223 if (direction == FOCUS_UP) { 2224 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2225 down = false; 2226 } else if (direction == FOCUS_DOWN) { 2227 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2228 down = true; 2229 } else { 2230 return false; 2231 } 2232 2233 if (nextPage >= 0) { 2234 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2235 if (position >= 0) { 2236 mLayoutMode = LAYOUT_SPECIFIC; 2237 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2238 2239 if (down && (position > (mItemCount - getChildCount()))) { 2240 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2241 } 2242 2243 if (!down && (position < getChildCount())) { 2244 mLayoutMode = LAYOUT_FORCE_TOP; 2245 } 2246 2247 setSelectionInt(position); 2248 invokeOnItemScrollListener(); 2249 if (!awakenScrollBars()) { 2250 invalidate(); 2251 } 2252 2253 return true; 2254 } 2255 } 2256 2257 return false; 2258 } 2259 2260 /** 2261 * Go to the last or first item if possible (not worrying about panning 2262 * across or navigating within the internal focus of the currently selected 2263 * item.) 2264 * 2265 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2266 * @return whether selection was moved 2267 */ 2268 boolean fullScroll(int direction) { 2269 boolean moved = false; 2270 if (direction == FOCUS_UP) { 2271 if (mSelectedPosition != 0) { 2272 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2273 if (position >= 0) { 2274 mLayoutMode = LAYOUT_FORCE_TOP; 2275 setSelectionInt(position); 2276 invokeOnItemScrollListener(); 2277 } 2278 moved = true; 2279 } 2280 } else if (direction == FOCUS_DOWN) { 2281 final int lastItem = (mItemCount - 1); 2282 if (mSelectedPosition < lastItem) { 2283 final int position = lookForSelectablePositionAfter( 2284 mSelectedPosition, lastItem, false); 2285 if (position >= 0) { 2286 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2287 setSelectionInt(position); 2288 invokeOnItemScrollListener(); 2289 } 2290 moved = true; 2291 } 2292 } 2293 2294 if (moved && !awakenScrollBars()) { 2295 awakenScrollBars(); 2296 invalidate(); 2297 } 2298 2299 return moved; 2300 } 2301 2302 /** 2303 * To avoid horizontal focus searches changing the selected item, we 2304 * manually focus search within the selected item (as applicable), and 2305 * prevent focus from jumping to something within another item. 2306 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2307 * @return Whether this consumes the key event. 2308 */ 2309 private boolean handleHorizontalFocusWithinListItem(int direction) { 2310 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2311 throw new IllegalArgumentException("direction must be one of" 2312 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2313 } 2314 2315 final int numChildren = getChildCount(); 2316 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2317 final View selectedView = getSelectedView(); 2318 if (selectedView != null && selectedView.hasFocus() && 2319 selectedView instanceof ViewGroup) { 2320 2321 final View currentFocus = selectedView.findFocus(); 2322 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2323 (ViewGroup) selectedView, currentFocus, direction); 2324 if (nextFocus != null) { 2325 // do the math to get interesting rect in next focus' coordinates 2326 currentFocus.getFocusedRect(mTempRect); 2327 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2328 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2329 if (nextFocus.requestFocus(direction, mTempRect)) { 2330 return true; 2331 } 2332 } 2333 // we are blocking the key from being handled (by returning true) 2334 // if the global result is going to be some other view within this 2335 // list. this is to acheive the overall goal of having 2336 // horizontal d-pad navigation remain in the current item. 2337 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2338 (ViewGroup) getRootView(), currentFocus, direction); 2339 if (globalNextFocus != null) { 2340 return isViewAncestorOf(globalNextFocus, this); 2341 } 2342 } 2343 } 2344 return false; 2345 } 2346 2347 /** 2348 * Scrolls to the next or previous item if possible. 2349 * 2350 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2351 * 2352 * @return whether selection was moved 2353 */ 2354 boolean arrowScroll(int direction) { 2355 try { 2356 mInLayout = true; 2357 final boolean handled = arrowScrollImpl(direction); 2358 if (handled) { 2359 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2360 } 2361 return handled; 2362 } finally { 2363 mInLayout = false; 2364 } 2365 } 2366 2367 /** 2368 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2369 * to move to. This return a position in the direction given if the selected item 2370 * is fully visible. 2371 * 2372 * @param selectedView Current selected view to move from 2373 * @param selectedPos Current selected position to move from 2374 * @param direction Direction to move in 2375 * @return Desired selected position after moving in the given direction 2376 */ 2377 private final int nextSelectedPositionForDirection( 2378 View selectedView, int selectedPos, int direction) { 2379 int nextSelected; 2380 2381 if (direction == View.FOCUS_DOWN) { 2382 final int listBottom = getHeight() - mListPadding.bottom; 2383 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2384 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2385 selectedPos + 1 : 2386 mFirstPosition; 2387 } else { 2388 return INVALID_POSITION; 2389 } 2390 } else { 2391 final int listTop = mListPadding.top; 2392 if (selectedView != null && selectedView.getTop() >= listTop) { 2393 final int lastPos = mFirstPosition + getChildCount() - 1; 2394 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2395 selectedPos - 1 : 2396 lastPos; 2397 } else { 2398 return INVALID_POSITION; 2399 } 2400 } 2401 2402 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2403 return INVALID_POSITION; 2404 } 2405 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2406 } 2407 2408 /** 2409 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2410 * whether there are focusable items etc. 2411 * 2412 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2413 * @return Whether any scrolling, selection or focus change occured. 2414 */ 2415 private boolean arrowScrollImpl(int direction) { 2416 if (getChildCount() <= 0) { 2417 return false; 2418 } 2419 2420 View selectedView = getSelectedView(); 2421 int selectedPos = mSelectedPosition; 2422 2423 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2424 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2425 2426 // if we are moving focus, we may OVERRIDE the default behavior 2427 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2428 if (focusResult != null) { 2429 nextSelectedPosition = focusResult.getSelectedPosition(); 2430 amountToScroll = focusResult.getAmountToScroll(); 2431 } 2432 2433 boolean needToRedraw = focusResult != null; 2434 if (nextSelectedPosition != INVALID_POSITION) { 2435 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2436 setSelectedPositionInt(nextSelectedPosition); 2437 setNextSelectedPositionInt(nextSelectedPosition); 2438 selectedView = getSelectedView(); 2439 selectedPos = nextSelectedPosition; 2440 if (mItemsCanFocus && focusResult == null) { 2441 // there was no new view found to take focus, make sure we 2442 // don't leave focus with the old selection 2443 final View focused = getFocusedChild(); 2444 if (focused != null) { 2445 focused.clearFocus(); 2446 } 2447 } 2448 needToRedraw = true; 2449 checkSelectionChanged(); 2450 } 2451 2452 if (amountToScroll > 0) { 2453 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2454 needToRedraw = true; 2455 } 2456 2457 // if we didn't find a new focusable, make sure any existing focused 2458 // item that was panned off screen gives up focus. 2459 if (mItemsCanFocus && (focusResult == null) 2460 && selectedView != null && selectedView.hasFocus()) { 2461 final View focused = selectedView.findFocus(); 2462 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2463 focused.clearFocus(); 2464 } 2465 } 2466 2467 // if the current selection is panned off, we need to remove the selection 2468 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2469 && !isViewAncestorOf(selectedView, this)) { 2470 selectedView = null; 2471 hideSelector(); 2472 2473 // but we don't want to set the ressurect position (that would make subsequent 2474 // unhandled key events bring back the item we just scrolled off!) 2475 mResurrectToPosition = INVALID_POSITION; 2476 } 2477 2478 if (needToRedraw) { 2479 if (selectedView != null) { 2480 positionSelector(selectedPos, selectedView); 2481 mSelectedTop = selectedView.getTop(); 2482 } 2483 if (!awakenScrollBars()) { 2484 invalidate(); 2485 } 2486 invokeOnItemScrollListener(); 2487 return true; 2488 } 2489 2490 return false; 2491 } 2492 2493 /** 2494 * When selection changes, it is possible that the previously selected or the 2495 * next selected item will change its size. If so, we need to offset some folks, 2496 * and re-layout the items as appropriate. 2497 * 2498 * @param selectedView The currently selected view (before changing selection). 2499 * should be <code>null</code> if there was no previous selection. 2500 * @param direction Either {@link android.view.View#FOCUS_UP} or 2501 * {@link android.view.View#FOCUS_DOWN}. 2502 * @param newSelectedPosition The position of the next selection. 2503 * @param newFocusAssigned whether new focus was assigned. This matters because 2504 * when something has focus, we don't want to show selection (ugh). 2505 */ 2506 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2507 boolean newFocusAssigned) { 2508 if (newSelectedPosition == INVALID_POSITION) { 2509 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2510 } 2511 2512 // whether or not we are moving down or up, we want to preserve the 2513 // top of whatever view is on top: 2514 // - moving down: the view that had selection 2515 // - moving up: the view that is getting selection 2516 View topView; 2517 View bottomView; 2518 int topViewIndex, bottomViewIndex; 2519 boolean topSelected = false; 2520 final int selectedIndex = mSelectedPosition - mFirstPosition; 2521 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2522 if (direction == View.FOCUS_UP) { 2523 topViewIndex = nextSelectedIndex; 2524 bottomViewIndex = selectedIndex; 2525 topView = getChildAt(topViewIndex); 2526 bottomView = selectedView; 2527 topSelected = true; 2528 } else { 2529 topViewIndex = selectedIndex; 2530 bottomViewIndex = nextSelectedIndex; 2531 topView = selectedView; 2532 bottomView = getChildAt(bottomViewIndex); 2533 } 2534 2535 final int numChildren = getChildCount(); 2536 2537 // start with top view: is it changing size? 2538 if (topView != null) { 2539 topView.setSelected(!newFocusAssigned && topSelected); 2540 measureAndAdjustDown(topView, topViewIndex, numChildren); 2541 } 2542 2543 // is the bottom view changing size? 2544 if (bottomView != null) { 2545 bottomView.setSelected(!newFocusAssigned && !topSelected); 2546 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2547 } 2548 } 2549 2550 /** 2551 * Re-measure a child, and if its height changes, lay it out preserving its 2552 * top, and adjust the children below it appropriately. 2553 * @param child The child 2554 * @param childIndex The view group index of the child. 2555 * @param numChildren The number of children in the view group. 2556 */ 2557 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2558 int oldHeight = child.getHeight(); 2559 measureItem(child); 2560 if (child.getMeasuredHeight() != oldHeight) { 2561 // lay out the view, preserving its top 2562 relayoutMeasuredItem(child); 2563 2564 // adjust views below appropriately 2565 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2566 for (int i = childIndex + 1; i < numChildren; i++) { 2567 getChildAt(i).offsetTopAndBottom(heightDelta); 2568 } 2569 } 2570 } 2571 2572 /** 2573 * Measure a particular list child. 2574 * TODO: unify with setUpChild. 2575 * @param child The child. 2576 */ 2577 private void measureItem(View child) { 2578 ViewGroup.LayoutParams p = child.getLayoutParams(); 2579 if (p == null) { 2580 p = new ViewGroup.LayoutParams( 2581 ViewGroup.LayoutParams.MATCH_PARENT, 2582 ViewGroup.LayoutParams.WRAP_CONTENT); 2583 } 2584 2585 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2586 mListPadding.left + mListPadding.right, p.width); 2587 int lpHeight = p.height; 2588 int childHeightSpec; 2589 if (lpHeight > 0) { 2590 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2591 } else { 2592 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2593 } 2594 child.measure(childWidthSpec, childHeightSpec); 2595 } 2596 2597 /** 2598 * Layout a child that has been measured, preserving its top position. 2599 * TODO: unify with setUpChild. 2600 * @param child The child. 2601 */ 2602 private void relayoutMeasuredItem(View child) { 2603 final int w = child.getMeasuredWidth(); 2604 final int h = child.getMeasuredHeight(); 2605 final int childLeft = mListPadding.left; 2606 final int childRight = childLeft + w; 2607 final int childTop = child.getTop(); 2608 final int childBottom = childTop + h; 2609 child.layout(childLeft, childTop, childRight, childBottom); 2610 } 2611 2612 /** 2613 * @return The amount to preview next items when arrow srolling. 2614 */ 2615 private int getArrowScrollPreviewLength() { 2616 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2617 } 2618 2619 /** 2620 * Determine how much we need to scroll in order to get the next selected view 2621 * visible, with a fading edge showing below as applicable. The amount is 2622 * capped at {@link #getMaxScrollAmount()} . 2623 * 2624 * @param direction either {@link android.view.View#FOCUS_UP} or 2625 * {@link android.view.View#FOCUS_DOWN}. 2626 * @param nextSelectedPosition The position of the next selection, or 2627 * {@link #INVALID_POSITION} if there is no next selectable position 2628 * @return The amount to scroll. Note: this is always positive! Direction 2629 * needs to be taken into account when actually scrolling. 2630 */ 2631 private int amountToScroll(int direction, int nextSelectedPosition) { 2632 final int listBottom = getHeight() - mListPadding.bottom; 2633 final int listTop = mListPadding.top; 2634 2635 int numChildren = getChildCount(); 2636 2637 if (direction == View.FOCUS_DOWN) { 2638 int indexToMakeVisible = numChildren - 1; 2639 if (nextSelectedPosition != INVALID_POSITION) { 2640 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2641 } 2642 while (numChildren <= indexToMakeVisible) { 2643 // Child to view is not attached yet. 2644 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2645 numChildren++; 2646 } 2647 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2648 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2649 2650 int goalBottom = listBottom; 2651 if (positionToMakeVisible < mItemCount - 1) { 2652 goalBottom -= getArrowScrollPreviewLength(); 2653 } 2654 2655 if (viewToMakeVisible.getBottom() <= goalBottom) { 2656 // item is fully visible. 2657 return 0; 2658 } 2659 2660 if (nextSelectedPosition != INVALID_POSITION 2661 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2662 // item already has enough of it visible, changing selection is good enough 2663 return 0; 2664 } 2665 2666 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2667 2668 if ((mFirstPosition + numChildren) == mItemCount) { 2669 // last is last in list -> make sure we don't scroll past it 2670 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2671 amountToScroll = Math.min(amountToScroll, max); 2672 } 2673 2674 return Math.min(amountToScroll, getMaxScrollAmount()); 2675 } else { 2676 int indexToMakeVisible = 0; 2677 if (nextSelectedPosition != INVALID_POSITION) { 2678 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2679 } 2680 while (indexToMakeVisible < 0) { 2681 // Child to view is not attached yet. 2682 addViewAbove(getChildAt(0), mFirstPosition); 2683 mFirstPosition--; 2684 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2685 } 2686 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2687 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2688 int goalTop = listTop; 2689 if (positionToMakeVisible > 0) { 2690 goalTop += getArrowScrollPreviewLength(); 2691 } 2692 if (viewToMakeVisible.getTop() >= goalTop) { 2693 // item is fully visible. 2694 return 0; 2695 } 2696 2697 if (nextSelectedPosition != INVALID_POSITION && 2698 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2699 // item already has enough of it visible, changing selection is good enough 2700 return 0; 2701 } 2702 2703 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2704 if (mFirstPosition == 0) { 2705 // first is first in list -> make sure we don't scroll past it 2706 final int max = listTop - getChildAt(0).getTop(); 2707 amountToScroll = Math.min(amountToScroll, max); 2708 } 2709 return Math.min(amountToScroll, getMaxScrollAmount()); 2710 } 2711 } 2712 2713 /** 2714 * Holds results of focus aware arrow scrolling. 2715 */ 2716 static private class ArrowScrollFocusResult { 2717 private int mSelectedPosition; 2718 private int mAmountToScroll; 2719 2720 /** 2721 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2722 */ 2723 void populate(int selectedPosition, int amountToScroll) { 2724 mSelectedPosition = selectedPosition; 2725 mAmountToScroll = amountToScroll; 2726 } 2727 2728 public int getSelectedPosition() { 2729 return mSelectedPosition; 2730 } 2731 2732 public int getAmountToScroll() { 2733 return mAmountToScroll; 2734 } 2735 } 2736 2737 /** 2738 * @param direction either {@link android.view.View#FOCUS_UP} or 2739 * {@link android.view.View#FOCUS_DOWN}. 2740 * @return The position of the next selectable position of the views that 2741 * are currently visible, taking into account the fact that there might 2742 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2743 * selectable view on screen in the given direction. 2744 */ 2745 private int lookForSelectablePositionOnScreen(int direction) { 2746 final int firstPosition = mFirstPosition; 2747 if (direction == View.FOCUS_DOWN) { 2748 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2749 mSelectedPosition + 1 : 2750 firstPosition; 2751 if (startPos >= mAdapter.getCount()) { 2752 return INVALID_POSITION; 2753 } 2754 if (startPos < firstPosition) { 2755 startPos = firstPosition; 2756 } 2757 2758 final int lastVisiblePos = getLastVisiblePosition(); 2759 final ListAdapter adapter = getAdapter(); 2760 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2761 if (adapter.isEnabled(pos) 2762 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2763 return pos; 2764 } 2765 } 2766 } else { 2767 int last = firstPosition + getChildCount() - 1; 2768 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2769 mSelectedPosition - 1 : 2770 firstPosition + getChildCount() - 1; 2771 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2772 return INVALID_POSITION; 2773 } 2774 if (startPos > last) { 2775 startPos = last; 2776 } 2777 2778 final ListAdapter adapter = getAdapter(); 2779 for (int pos = startPos; pos >= firstPosition; pos--) { 2780 if (adapter.isEnabled(pos) 2781 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2782 return pos; 2783 } 2784 } 2785 } 2786 return INVALID_POSITION; 2787 } 2788 2789 /** 2790 * Do an arrow scroll based on focus searching. If a new view is 2791 * given focus, return the selection delta and amount to scroll via 2792 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2793 * 2794 * @param direction either {@link android.view.View#FOCUS_UP} or 2795 * {@link android.view.View#FOCUS_DOWN}. 2796 * @return The result if focus has changed, or <code>null</code>. 2797 */ 2798 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2799 final View selectedView = getSelectedView(); 2800 View newFocus; 2801 if (selectedView != null && selectedView.hasFocus()) { 2802 View oldFocus = selectedView.findFocus(); 2803 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2804 } else { 2805 if (direction == View.FOCUS_DOWN) { 2806 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2807 final int listTop = mListPadding.top + 2808 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2809 final int ySearchPoint = 2810 (selectedView != null && selectedView.getTop() > listTop) ? 2811 selectedView.getTop() : 2812 listTop; 2813 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2814 } else { 2815 final boolean bottomFadingEdgeShowing = 2816 (mFirstPosition + getChildCount() - 1) < mItemCount; 2817 final int listBottom = getHeight() - mListPadding.bottom - 2818 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2819 final int ySearchPoint = 2820 (selectedView != null && selectedView.getBottom() < listBottom) ? 2821 selectedView.getBottom() : 2822 listBottom; 2823 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2824 } 2825 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2826 } 2827 2828 if (newFocus != null) { 2829 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2830 2831 // if the focus change is in a different new position, make sure 2832 // we aren't jumping over another selectable position 2833 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2834 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2835 if (selectablePosition != INVALID_POSITION && 2836 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2837 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2838 return null; 2839 } 2840 } 2841 2842 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2843 2844 final int maxScrollAmount = getMaxScrollAmount(); 2845 if (focusScroll < maxScrollAmount) { 2846 // not moving too far, safe to give next view focus 2847 newFocus.requestFocus(direction); 2848 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2849 return mArrowScrollFocusResult; 2850 } else if (distanceToView(newFocus) < maxScrollAmount){ 2851 // Case to consider: 2852 // too far to get entire next focusable on screen, but by going 2853 // max scroll amount, we are getting it at least partially in view, 2854 // so give it focus and scroll the max ammount. 2855 newFocus.requestFocus(direction); 2856 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2857 return mArrowScrollFocusResult; 2858 } 2859 } 2860 return null; 2861 } 2862 2863 /** 2864 * @param newFocus The view that would have focus. 2865 * @return the position that contains newFocus 2866 */ 2867 private int positionOfNewFocus(View newFocus) { 2868 final int numChildren = getChildCount(); 2869 for (int i = 0; i < numChildren; i++) { 2870 final View child = getChildAt(i); 2871 if (isViewAncestorOf(newFocus, child)) { 2872 return mFirstPosition + i; 2873 } 2874 } 2875 throw new IllegalArgumentException("newFocus is not a child of any of the" 2876 + " children of the list!"); 2877 } 2878 2879 /** 2880 * Return true if child is an ancestor of parent, (or equal to the parent). 2881 */ 2882 private boolean isViewAncestorOf(View child, View parent) { 2883 if (child == parent) { 2884 return true; 2885 } 2886 2887 final ViewParent theParent = child.getParent(); 2888 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2889 } 2890 2891 /** 2892 * Determine how much we need to scroll in order to get newFocus in view. 2893 * @param direction either {@link android.view.View#FOCUS_UP} or 2894 * {@link android.view.View#FOCUS_DOWN}. 2895 * @param newFocus The view that would take focus. 2896 * @param positionOfNewFocus The position of the list item containing newFocus 2897 * @return The amount to scroll. Note: this is always positive! Direction 2898 * needs to be taken into account when actually scrolling. 2899 */ 2900 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2901 int amountToScroll = 0; 2902 newFocus.getDrawingRect(mTempRect); 2903 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2904 if (direction == View.FOCUS_UP) { 2905 if (mTempRect.top < mListPadding.top) { 2906 amountToScroll = mListPadding.top - mTempRect.top; 2907 if (positionOfNewFocus > 0) { 2908 amountToScroll += getArrowScrollPreviewLength(); 2909 } 2910 } 2911 } else { 2912 final int listBottom = getHeight() - mListPadding.bottom; 2913 if (mTempRect.bottom > listBottom) { 2914 amountToScroll = mTempRect.bottom - listBottom; 2915 if (positionOfNewFocus < mItemCount - 1) { 2916 amountToScroll += getArrowScrollPreviewLength(); 2917 } 2918 } 2919 } 2920 return amountToScroll; 2921 } 2922 2923 /** 2924 * Determine the distance to the nearest edge of a view in a particular 2925 * direction. 2926 * 2927 * @param descendant A descendant of this list. 2928 * @return The distance, or 0 if the nearest edge is already on screen. 2929 */ 2930 private int distanceToView(View descendant) { 2931 int distance = 0; 2932 descendant.getDrawingRect(mTempRect); 2933 offsetDescendantRectToMyCoords(descendant, mTempRect); 2934 final int listBottom = mBottom - mTop - mListPadding.bottom; 2935 if (mTempRect.bottom < mListPadding.top) { 2936 distance = mListPadding.top - mTempRect.bottom; 2937 } else if (mTempRect.top > listBottom) { 2938 distance = mTempRect.top - listBottom; 2939 } 2940 return distance; 2941 } 2942 2943 2944 /** 2945 * Scroll the children by amount, adding a view at the end and removing 2946 * views that fall off as necessary. 2947 * 2948 * @param amount The amount (positive or negative) to scroll. 2949 */ 2950 private void scrollListItemsBy(int amount) { 2951 offsetChildrenTopAndBottom(amount); 2952 2953 final int listBottom = getHeight() - mListPadding.bottom; 2954 final int listTop = mListPadding.top; 2955 final AbsListView.RecycleBin recycleBin = mRecycler; 2956 2957 if (amount < 0) { 2958 // shifted items up 2959 2960 // may need to pan views into the bottom space 2961 int numChildren = getChildCount(); 2962 View last = getChildAt(numChildren - 1); 2963 while (last.getBottom() < listBottom) { 2964 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2965 if (lastVisiblePosition < mItemCount - 1) { 2966 last = addViewBelow(last, lastVisiblePosition); 2967 numChildren++; 2968 } else { 2969 break; 2970 } 2971 } 2972 2973 // may have brought in the last child of the list that is skinnier 2974 // than the fading edge, thereby leaving space at the end. need 2975 // to shift back 2976 if (last.getBottom() < listBottom) { 2977 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2978 } 2979 2980 // top views may be panned off screen 2981 View first = getChildAt(0); 2982 while (first.getBottom() < listTop) { 2983 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2984 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2985 recycleBin.addScrapView(first, mFirstPosition); 2986 } 2987 detachViewFromParent(first); 2988 first = getChildAt(0); 2989 mFirstPosition++; 2990 } 2991 } else { 2992 // shifted items down 2993 View first = getChildAt(0); 2994 2995 // may need to pan views into top 2996 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2997 first = addViewAbove(first, mFirstPosition); 2998 mFirstPosition--; 2999 } 3000 3001 // may have brought the very first child of the list in too far and 3002 // need to shift it back 3003 if (first.getTop() > listTop) { 3004 offsetChildrenTopAndBottom(listTop - first.getTop()); 3005 } 3006 3007 int lastIndex = getChildCount() - 1; 3008 View last = getChildAt(lastIndex); 3009 3010 // bottom view may be panned off screen 3011 while (last.getTop() > listBottom) { 3012 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3013 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3014 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3015 } 3016 detachViewFromParent(last); 3017 last = getChildAt(--lastIndex); 3018 } 3019 } 3020 } 3021 3022 private View addViewAbove(View theView, int position) { 3023 int abovePosition = position - 1; 3024 View view = obtainView(abovePosition, mIsScrap); 3025 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3026 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3027 false, mIsScrap[0]); 3028 return view; 3029 } 3030 3031 private View addViewBelow(View theView, int position) { 3032 int belowPosition = position + 1; 3033 View view = obtainView(belowPosition, mIsScrap); 3034 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3035 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3036 false, mIsScrap[0]); 3037 return view; 3038 } 3039 3040 /** 3041 * Indicates that the views created by the ListAdapter can contain focusable 3042 * items. 3043 * 3044 * @param itemsCanFocus true if items can get focus, false otherwise 3045 */ 3046 public void setItemsCanFocus(boolean itemsCanFocus) { 3047 mItemsCanFocus = itemsCanFocus; 3048 if (!itemsCanFocus) { 3049 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3050 } 3051 } 3052 3053 /** 3054 * @return Whether the views created by the ListAdapter can contain focusable 3055 * items. 3056 */ 3057 public boolean getItemsCanFocus() { 3058 return mItemsCanFocus; 3059 } 3060 3061 @Override 3062 public boolean isOpaque() { 3063 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3064 hasOpaqueScrollbars()) || super.isOpaque(); 3065 if (retValue) { 3066 // only return true if the list items cover the entire area of the view 3067 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3068 View first = getChildAt(0); 3069 if (first == null || first.getTop() > listTop) { 3070 return false; 3071 } 3072 final int listBottom = getHeight() - 3073 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3074 View last = getChildAt(getChildCount() - 1); 3075 if (last == null || last.getBottom() < listBottom) { 3076 return false; 3077 } 3078 } 3079 return retValue; 3080 } 3081 3082 @Override 3083 public void setCacheColorHint(int color) { 3084 final boolean opaque = (color >>> 24) == 0xFF; 3085 mIsCacheColorOpaque = opaque; 3086 if (opaque) { 3087 if (mDividerPaint == null) { 3088 mDividerPaint = new Paint(); 3089 } 3090 mDividerPaint.setColor(color); 3091 } 3092 super.setCacheColorHint(color); 3093 } 3094 3095 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3096 final int height = drawable.getMinimumHeight(); 3097 3098 canvas.save(); 3099 canvas.clipRect(bounds); 3100 3101 final int span = bounds.bottom - bounds.top; 3102 if (span < height) { 3103 bounds.top = bounds.bottom - height; 3104 } 3105 3106 drawable.setBounds(bounds); 3107 drawable.draw(canvas); 3108 3109 canvas.restore(); 3110 } 3111 3112 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3113 final int height = drawable.getMinimumHeight(); 3114 3115 canvas.save(); 3116 canvas.clipRect(bounds); 3117 3118 final int span = bounds.bottom - bounds.top; 3119 if (span < height) { 3120 bounds.bottom = bounds.top + height; 3121 } 3122 3123 drawable.setBounds(bounds); 3124 drawable.draw(canvas); 3125 3126 canvas.restore(); 3127 } 3128 3129 @Override 3130 protected void dispatchDraw(Canvas canvas) { 3131 if (mCachingStarted) { 3132 mCachingActive = true; 3133 } 3134 3135 // Draw the dividers 3136 final int dividerHeight = mDividerHeight; 3137 final Drawable overscrollHeader = mOverScrollHeader; 3138 final Drawable overscrollFooter = mOverScrollFooter; 3139 final boolean drawOverscrollHeader = overscrollHeader != null; 3140 final boolean drawOverscrollFooter = overscrollFooter != null; 3141 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3142 3143 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3144 // Only modify the top and bottom in the loop, we set the left and right here 3145 final Rect bounds = mTempRect; 3146 bounds.left = mPaddingLeft; 3147 bounds.right = mRight - mLeft - mPaddingRight; 3148 3149 final int count = getChildCount(); 3150 final int headerCount = mHeaderViewInfos.size(); 3151 final int itemCount = mItemCount; 3152 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3153 final boolean headerDividers = mHeaderDividersEnabled; 3154 final boolean footerDividers = mFooterDividersEnabled; 3155 final int first = mFirstPosition; 3156 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3157 final ListAdapter adapter = mAdapter; 3158 // If the list is opaque *and* the background is not, we want to 3159 // fill a rect where the dividers would be for non-selectable items 3160 // If the list is opaque and the background is also opaque, we don't 3161 // need to draw anything since the background will do it for us 3162 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3163 3164 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3165 mDividerPaint = new Paint(); 3166 mDividerPaint.setColor(getCacheColorHint()); 3167 } 3168 final Paint paint = mDividerPaint; 3169 3170 int effectivePaddingTop = 0; 3171 int effectivePaddingBottom = 0; 3172 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3173 effectivePaddingTop = mListPadding.top; 3174 effectivePaddingBottom = mListPadding.bottom; 3175 } 3176 3177 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3178 if (!mStackFromBottom) { 3179 int bottom = 0; 3180 3181 // Draw top divider or header for overscroll 3182 final int scrollY = mScrollY; 3183 if (count > 0 && scrollY < 0) { 3184 if (drawOverscrollHeader) { 3185 bounds.bottom = 0; 3186 bounds.top = scrollY; 3187 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3188 } else if (drawDividers) { 3189 bounds.bottom = 0; 3190 bounds.top = -dividerHeight; 3191 drawDivider(canvas, bounds, -1); 3192 } 3193 } 3194 3195 for (int i = 0; i < count; i++) { 3196 final int itemIndex = (first + i); 3197 final boolean isHeader = (itemIndex < headerCount); 3198 final boolean isFooter = (itemIndex >= footerLimit); 3199 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3200 final View child = getChildAt(i); 3201 bottom = child.getBottom(); 3202 final boolean isLastItem = (i == (count - 1)); 3203 3204 if (drawDividers && (bottom < listBottom) 3205 && !(drawOverscrollFooter && isLastItem)) { 3206 final int nextIndex = (itemIndex + 1); 3207 // Draw dividers between enabled items, headers 3208 // and/or footers when enabled and requested, and 3209 // after the last enabled item. 3210 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3211 && (nextIndex >= headerCount)) && (isLastItem 3212 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3213 && (nextIndex < footerLimit)))) { 3214 bounds.top = bottom; 3215 bounds.bottom = bottom + dividerHeight; 3216 drawDivider(canvas, bounds, i); 3217 } else if (fillForMissingDividers) { 3218 bounds.top = bottom; 3219 bounds.bottom = bottom + dividerHeight; 3220 canvas.drawRect(bounds, paint); 3221 } 3222 } 3223 } 3224 } 3225 3226 final int overFooterBottom = mBottom + mScrollY; 3227 if (drawOverscrollFooter && first + count == itemCount && 3228 overFooterBottom > bottom) { 3229 bounds.top = bottom; 3230 bounds.bottom = overFooterBottom; 3231 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3232 } 3233 } else { 3234 int top; 3235 3236 final int scrollY = mScrollY; 3237 3238 if (count > 0 && drawOverscrollHeader) { 3239 bounds.top = scrollY; 3240 bounds.bottom = getChildAt(0).getTop(); 3241 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3242 } 3243 3244 final int start = drawOverscrollHeader ? 1 : 0; 3245 for (int i = start; i < count; i++) { 3246 final int itemIndex = (first + i); 3247 final boolean isHeader = (itemIndex < headerCount); 3248 final boolean isFooter = (itemIndex >= footerLimit); 3249 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3250 final View child = getChildAt(i); 3251 top = child.getTop(); 3252 if (drawDividers && (top > effectivePaddingTop)) { 3253 final boolean isFirstItem = (i == start); 3254 final int previousIndex = (itemIndex - 1); 3255 // Draw dividers between enabled items, headers 3256 // and/or footers when enabled and requested, and 3257 // before the first enabled item. 3258 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3259 && (previousIndex >= headerCount)) && (isFirstItem || 3260 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3261 && (previousIndex < footerLimit)))) { 3262 bounds.top = top - dividerHeight; 3263 bounds.bottom = top; 3264 // Give the method the child ABOVE the divider, 3265 // so we subtract one from our child position. 3266 // Give -1 when there is no child above the 3267 // divider. 3268 drawDivider(canvas, bounds, i - 1); 3269 } else if (fillForMissingDividers) { 3270 bounds.top = top - dividerHeight; 3271 bounds.bottom = top; 3272 canvas.drawRect(bounds, paint); 3273 } 3274 } 3275 } 3276 } 3277 3278 if (count > 0 && scrollY > 0) { 3279 if (drawOverscrollFooter) { 3280 final int absListBottom = mBottom; 3281 bounds.top = absListBottom; 3282 bounds.bottom = absListBottom + scrollY; 3283 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3284 } else if (drawDividers) { 3285 bounds.top = listBottom; 3286 bounds.bottom = listBottom + dividerHeight; 3287 drawDivider(canvas, bounds, -1); 3288 } 3289 } 3290 } 3291 } 3292 3293 // Draw the indicators (these should be drawn above the dividers) and children 3294 super.dispatchDraw(canvas); 3295 } 3296 3297 @Override 3298 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3299 boolean more = super.drawChild(canvas, child, drawingTime); 3300 if (mCachingActive && child.mCachingFailed) { 3301 mCachingActive = false; 3302 } 3303 return more; 3304 } 3305 3306 /** 3307 * Draws a divider for the given child in the given bounds. 3308 * 3309 * @param canvas The canvas to draw to. 3310 * @param bounds The bounds of the divider. 3311 * @param childIndex The index of child (of the View) above the divider. 3312 * This will be -1 if there is no child above the divider to be 3313 * drawn. 3314 */ 3315 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3316 // This widget draws the same divider for all children 3317 final Drawable divider = mDivider; 3318 3319 divider.setBounds(bounds); 3320 divider.draw(canvas); 3321 } 3322 3323 /** 3324 * Returns the drawable that will be drawn between each item in the list. 3325 * 3326 * @return the current drawable drawn between list elements 3327 */ 3328 public Drawable getDivider() { 3329 return mDivider; 3330 } 3331 3332 /** 3333 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3334 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3335 * 3336 * @param divider The drawable to use. 3337 */ 3338 public void setDivider(Drawable divider) { 3339 if (divider != null) { 3340 mDividerHeight = divider.getIntrinsicHeight(); 3341 } else { 3342 mDividerHeight = 0; 3343 } 3344 mDivider = divider; 3345 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3346 requestLayout(); 3347 invalidate(); 3348 } 3349 3350 /** 3351 * @return Returns the height of the divider that will be drawn between each item in the list. 3352 */ 3353 public int getDividerHeight() { 3354 return mDividerHeight; 3355 } 3356 3357 /** 3358 * Sets the height of the divider that will be drawn between each item in the list. Calling 3359 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3360 * 3361 * @param height The new height of the divider in pixels. 3362 */ 3363 public void setDividerHeight(int height) { 3364 mDividerHeight = height; 3365 requestLayout(); 3366 invalidate(); 3367 } 3368 3369 /** 3370 * Enables or disables the drawing of the divider for header views. 3371 * 3372 * @param headerDividersEnabled True to draw the headers, false otherwise. 3373 * 3374 * @see #setFooterDividersEnabled(boolean) 3375 * @see #areHeaderDividersEnabled() 3376 * @see #addHeaderView(android.view.View) 3377 */ 3378 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3379 mHeaderDividersEnabled = headerDividersEnabled; 3380 invalidate(); 3381 } 3382 3383 /** 3384 * @return Whether the drawing of the divider for header views is enabled 3385 * 3386 * @see #setHeaderDividersEnabled(boolean) 3387 */ 3388 public boolean areHeaderDividersEnabled() { 3389 return mHeaderDividersEnabled; 3390 } 3391 3392 /** 3393 * Enables or disables the drawing of the divider for footer views. 3394 * 3395 * @param footerDividersEnabled True to draw the footers, false otherwise. 3396 * 3397 * @see #setHeaderDividersEnabled(boolean) 3398 * @see #areFooterDividersEnabled() 3399 * @see #addFooterView(android.view.View) 3400 */ 3401 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3402 mFooterDividersEnabled = footerDividersEnabled; 3403 invalidate(); 3404 } 3405 3406 /** 3407 * @return Whether the drawing of the divider for footer views is enabled 3408 * 3409 * @see #setFooterDividersEnabled(boolean) 3410 */ 3411 public boolean areFooterDividersEnabled() { 3412 return mFooterDividersEnabled; 3413 } 3414 3415 /** 3416 * Sets the drawable that will be drawn above all other list content. 3417 * This area can become visible when the user overscrolls the list. 3418 * 3419 * @param header The drawable to use 3420 */ 3421 public void setOverscrollHeader(Drawable header) { 3422 mOverScrollHeader = header; 3423 if (mScrollY < 0) { 3424 invalidate(); 3425 } 3426 } 3427 3428 /** 3429 * @return The drawable that will be drawn above all other list content 3430 */ 3431 public Drawable getOverscrollHeader() { 3432 return mOverScrollHeader; 3433 } 3434 3435 /** 3436 * Sets the drawable that will be drawn below all other list content. 3437 * This area can become visible when the user overscrolls the list, 3438 * or when the list's content does not fully fill the container area. 3439 * 3440 * @param footer The drawable to use 3441 */ 3442 public void setOverscrollFooter(Drawable footer) { 3443 mOverScrollFooter = footer; 3444 invalidate(); 3445 } 3446 3447 /** 3448 * @return The drawable that will be drawn below all other list content 3449 */ 3450 public Drawable getOverscrollFooter() { 3451 return mOverScrollFooter; 3452 } 3453 3454 @Override 3455 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3456 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3457 3458 final ListAdapter adapter = mAdapter; 3459 int closetChildIndex = -1; 3460 int closestChildTop = 0; 3461 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3462 previouslyFocusedRect.offset(mScrollX, mScrollY); 3463 3464 // Don't cache the result of getChildCount or mFirstPosition here, 3465 // it could change in layoutChildren. 3466 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3467 mLayoutMode = LAYOUT_NORMAL; 3468 layoutChildren(); 3469 } 3470 3471 // figure out which item should be selected based on previously 3472 // focused rect 3473 Rect otherRect = mTempRect; 3474 int minDistance = Integer.MAX_VALUE; 3475 final int childCount = getChildCount(); 3476 final int firstPosition = mFirstPosition; 3477 3478 for (int i = 0; i < childCount; i++) { 3479 // only consider selectable views 3480 if (!adapter.isEnabled(firstPosition + i)) { 3481 continue; 3482 } 3483 3484 View other = getChildAt(i); 3485 other.getDrawingRect(otherRect); 3486 offsetDescendantRectToMyCoords(other, otherRect); 3487 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3488 3489 if (distance < minDistance) { 3490 minDistance = distance; 3491 closetChildIndex = i; 3492 closestChildTop = other.getTop(); 3493 } 3494 } 3495 } 3496 3497 if (closetChildIndex >= 0) { 3498 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3499 } else { 3500 requestLayout(); 3501 } 3502 } 3503 3504 3505 /* 3506 * (non-Javadoc) 3507 * 3508 * Children specified in XML are assumed to be header views. After we have 3509 * parsed them move them out of the children list and into mHeaderViews. 3510 */ 3511 @Override 3512 protected void onFinishInflate() { 3513 super.onFinishInflate(); 3514 3515 int count = getChildCount(); 3516 if (count > 0) { 3517 for (int i = 0; i < count; ++i) { 3518 addHeaderView(getChildAt(i)); 3519 } 3520 removeAllViews(); 3521 } 3522 } 3523 3524 /* (non-Javadoc) 3525 * @see android.view.View#findViewById(int) 3526 * First look in our children, then in any header and footer views that may be scrolled off. 3527 */ 3528 @Override 3529 protected View findViewTraversal(int id) { 3530 View v; 3531 v = super.findViewTraversal(id); 3532 if (v == null) { 3533 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3534 if (v != null) { 3535 return v; 3536 } 3537 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3538 if (v != null) { 3539 return v; 3540 } 3541 } 3542 return v; 3543 } 3544 3545 /* (non-Javadoc) 3546 * 3547 * Look in the passed in list of headers or footers for the view. 3548 */ 3549 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3550 if (where != null) { 3551 int len = where.size(); 3552 View v; 3553 3554 for (int i = 0; i < len; i++) { 3555 v = where.get(i).view; 3556 3557 if (!v.isRootNamespace()) { 3558 v = v.findViewById(id); 3559 3560 if (v != null) { 3561 return v; 3562 } 3563 } 3564 } 3565 } 3566 return null; 3567 } 3568 3569 /* (non-Javadoc) 3570 * @see android.view.View#findViewWithTag(Object) 3571 * First look in our children, then in any header and footer views that may be scrolled off. 3572 */ 3573 @Override 3574 protected View findViewWithTagTraversal(Object tag) { 3575 View v; 3576 v = super.findViewWithTagTraversal(tag); 3577 if (v == null) { 3578 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3579 if (v != null) { 3580 return v; 3581 } 3582 3583 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3584 if (v != null) { 3585 return v; 3586 } 3587 } 3588 return v; 3589 } 3590 3591 /* (non-Javadoc) 3592 * 3593 * Look in the passed in list of headers or footers for the view with the tag. 3594 */ 3595 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3596 if (where != null) { 3597 int len = where.size(); 3598 View v; 3599 3600 for (int i = 0; i < len; i++) { 3601 v = where.get(i).view; 3602 3603 if (!v.isRootNamespace()) { 3604 v = v.findViewWithTag(tag); 3605 3606 if (v != null) { 3607 return v; 3608 } 3609 } 3610 } 3611 } 3612 return null; 3613 } 3614 3615 /** 3616 * @hide 3617 * @see android.view.View#findViewByPredicate(Predicate) 3618 * First look in our children, then in any header and footer views that may be scrolled off. 3619 */ 3620 @Override 3621 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3622 View v; 3623 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3624 if (v == null) { 3625 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3626 if (v != null) { 3627 return v; 3628 } 3629 3630 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3631 if (v != null) { 3632 return v; 3633 } 3634 } 3635 return v; 3636 } 3637 3638 /* (non-Javadoc) 3639 * 3640 * Look in the passed in list of headers or footers for the first view that matches 3641 * the predicate. 3642 */ 3643 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3644 Predicate<View> predicate, View childToSkip) { 3645 if (where != null) { 3646 int len = where.size(); 3647 View v; 3648 3649 for (int i = 0; i < len; i++) { 3650 v = where.get(i).view; 3651 3652 if (v != childToSkip && !v.isRootNamespace()) { 3653 v = v.findViewByPredicate(predicate); 3654 3655 if (v != null) { 3656 return v; 3657 } 3658 } 3659 } 3660 } 3661 return null; 3662 } 3663 3664 /** 3665 * Returns the set of checked items ids. The result is only valid if the 3666 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3667 * 3668 * @return A new array which contains the id of each checked item in the 3669 * list. 3670 * 3671 * @deprecated Use {@link #getCheckedItemIds()} instead. 3672 */ 3673 @Deprecated 3674 public long[] getCheckItemIds() { 3675 // Use new behavior that correctly handles stable ID mapping. 3676 if (mAdapter != null && mAdapter.hasStableIds()) { 3677 return getCheckedItemIds(); 3678 } 3679 3680 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3681 // Fall back to it to support legacy apps. 3682 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3683 final SparseBooleanArray states = mCheckStates; 3684 final int count = states.size(); 3685 final long[] ids = new long[count]; 3686 final ListAdapter adapter = mAdapter; 3687 3688 int checkedCount = 0; 3689 for (int i = 0; i < count; i++) { 3690 if (states.valueAt(i)) { 3691 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3692 } 3693 } 3694 3695 // Trim array if needed. mCheckStates may contain false values 3696 // resulting in checkedCount being smaller than count. 3697 if (checkedCount == count) { 3698 return ids; 3699 } else { 3700 final long[] result = new long[checkedCount]; 3701 System.arraycopy(ids, 0, result, 0, checkedCount); 3702 3703 return result; 3704 } 3705 } 3706 return new long[0]; 3707 } 3708 3709 @Override 3710 int getHeightForPosition(int position) { 3711 final int height = super.getHeightForPosition(position); 3712 if (shouldAdjustHeightForDivider(position)) { 3713 return height + mDividerHeight; 3714 } 3715 return height; 3716 } 3717 3718 private boolean shouldAdjustHeightForDivider(int itemIndex) { 3719 final int dividerHeight = mDividerHeight; 3720 final Drawable overscrollHeader = mOverScrollHeader; 3721 final Drawable overscrollFooter = mOverScrollFooter; 3722 final boolean drawOverscrollHeader = overscrollHeader != null; 3723 final boolean drawOverscrollFooter = overscrollFooter != null; 3724 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3725 3726 if (drawDividers) { 3727 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3728 final int itemCount = mItemCount; 3729 final int headerCount = mHeaderViewInfos.size(); 3730 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3731 final boolean isHeader = (itemIndex < headerCount); 3732 final boolean isFooter = (itemIndex >= footerLimit); 3733 final boolean headerDividers = mHeaderDividersEnabled; 3734 final boolean footerDividers = mFooterDividersEnabled; 3735 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3736 final ListAdapter adapter = mAdapter; 3737 if (!mStackFromBottom) { 3738 final boolean isLastItem = (itemIndex == (itemCount - 1)); 3739 if (!drawOverscrollFooter || !isLastItem) { 3740 final int nextIndex = itemIndex + 1; 3741 // Draw dividers between enabled items, headers 3742 // and/or footers when enabled and requested, and 3743 // after the last enabled item. 3744 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3745 && (nextIndex >= headerCount)) && (isLastItem 3746 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3747 && (nextIndex < footerLimit)))) { 3748 return true; 3749 } else if (fillForMissingDividers) { 3750 return true; 3751 } 3752 } 3753 } else { 3754 final int start = drawOverscrollHeader ? 1 : 0; 3755 final boolean isFirstItem = (itemIndex == start); 3756 if (!isFirstItem) { 3757 final int previousIndex = (itemIndex - 1); 3758 // Draw dividers between enabled items, headers 3759 // and/or footers when enabled and requested, and 3760 // before the first enabled item. 3761 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3762 && (previousIndex >= headerCount)) && (isFirstItem || 3763 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3764 && (previousIndex < footerLimit)))) { 3765 return true; 3766 } else if (fillForMissingDividers) { 3767 return true; 3768 } 3769 } 3770 } 3771 } 3772 } 3773 3774 return false; 3775 } 3776 3777 @Override 3778 AbsPositionScroller createPositionScroller() { 3779 return new ListViewPositionScroller(); 3780 } 3781 3782 @Override 3783 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 3784 super.onInitializeAccessibilityEvent(event); 3785 event.setClassName(ListView.class.getName()); 3786 } 3787 3788 @Override 3789 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 3790 super.onInitializeAccessibilityNodeInfo(info); 3791 info.setClassName(ListView.class.getName()); 3792 3793 final int count = getCount(); 3794 final CollectionInfo collectionInfo = CollectionInfo.obtain(1, count, false); 3795 info.setCollectionInfo(collectionInfo); 3796 } 3797 3798 @Override 3799 public void onInitializeAccessibilityNodeInfoForItem( 3800 View view, int position, AccessibilityNodeInfo info) { 3801 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3802 3803 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3804 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3805 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain(0, 1, position, 1, isHeading); 3806 info.setCollectionItemInfo(itemInfo); 3807 } 3808 3809 /** 3810 * Sub-position scroller that understands the layout of a ListView. 3811 */ 3812 class ListViewPositionScroller extends AbsSubPositionScroller { 3813 @Override 3814 public int getRowForPosition(int position) { 3815 return position; 3816 } 3817 3818 @Override 3819 public int getFirstPositionForRow(int row) { 3820 return row; 3821 } 3822 3823 @Override 3824 public int getHeightForRow(int row) { 3825 return getHeightForPosition(row); 3826 } 3827 } 3828} 3829