ListView.java revision 8c3e0fc84f69e9fe704dc20dd6c2bab1ce43fe93
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import com.android.internal.R; 20import com.google.android.collect.Lists; 21 22import android.content.Context; 23import android.content.Intent; 24import android.content.res.TypedArray; 25import android.graphics.Canvas; 26import android.graphics.Paint; 27import android.graphics.PixelFormat; 28import android.graphics.Rect; 29import android.graphics.drawable.Drawable; 30import android.util.AttributeSet; 31import android.util.SparseBooleanArray; 32import android.view.FocusFinder; 33import android.view.KeyEvent; 34import android.view.MotionEvent; 35import android.view.SoundEffectConstants; 36import android.view.View; 37import android.view.ViewDebug; 38import android.view.ViewGroup; 39import android.view.ViewParent; 40import android.view.accessibility.AccessibilityEvent; 41import android.widget.RemoteViews.RemoteView; 42 43import java.util.ArrayList; 44 45/* 46 * Implementation Notes: 47 * 48 * Some terminology: 49 * 50 * index - index of the items that are currently visible 51 * position - index of the items in the cursor 52 */ 53 54 55/** 56 * A view that shows items in a vertically scrolling list. The items 57 * come from the {@link ListAdapter} associated with this view. 58 * 59 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-listview.html">List View 60 * tutorial</a>.</p> 61 * 62 * @attr ref android.R.styleable#ListView_entries 63 * @attr ref android.R.styleable#ListView_divider 64 * @attr ref android.R.styleable#ListView_dividerHeight 65 * @attr ref android.R.styleable#ListView_headerDividersEnabled 66 * @attr ref android.R.styleable#ListView_footerDividersEnabled 67 */ 68@RemoteView 69public class ListView extends AbsListView { 70 /** 71 * Used to indicate a no preference for a position type. 72 */ 73 static final int NO_POSITION = -1; 74 75 /** 76 * When arrow scrolling, ListView will never scroll more than this factor 77 * times the height of the list. 78 */ 79 private static final float MAX_SCROLL_FACTOR = 0.33f; 80 81 /** 82 * When arrow scrolling, need a certain amount of pixels to preview next 83 * items. This is usually the fading edge, but if that is small enough, 84 * we want to make sure we preview at least this many pixels. 85 */ 86 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 87 88 /** 89 * A class that represents a fixed view in a list, for example a header at the top 90 * or a footer at the bottom. 91 */ 92 public class FixedViewInfo { 93 /** The view to add to the list */ 94 public View view; 95 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 96 public Object data; 97 /** <code>true</code> if the fixed view should be selectable in the list */ 98 public boolean isSelectable; 99 } 100 101 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 102 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 103 104 Drawable mDivider; 105 int mDividerHeight; 106 107 private boolean mIsCacheColorOpaque; 108 private boolean mDividerIsOpaque; 109 110 private boolean mHeaderDividersEnabled; 111 private boolean mFooterDividersEnabled; 112 113 private boolean mAreAllItemsSelectable = true; 114 115 private boolean mItemsCanFocus = false; 116 117 // used for temporary calculations. 118 private final Rect mTempRect = new Rect(); 119 private Paint mDividerPaint; 120 121 // the single allocated result per list view; kinda cheesey but avoids 122 // allocating these thingies too often. 123 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 124 125 // Keeps focused children visible through resizes 126 private FocusSelector mFocusSelector; 127 128 public ListView(Context context) { 129 this(context, null); 130 } 131 132 public ListView(Context context, AttributeSet attrs) { 133 this(context, attrs, com.android.internal.R.attr.listViewStyle); 134 } 135 136 public ListView(Context context, AttributeSet attrs, int defStyle) { 137 super(context, attrs, defStyle); 138 139 TypedArray a = context.obtainStyledAttributes(attrs, 140 com.android.internal.R.styleable.ListView, defStyle, 0); 141 142 CharSequence[] entries = a.getTextArray( 143 com.android.internal.R.styleable.ListView_entries); 144 if (entries != null) { 145 setAdapter(new ArrayAdapter<CharSequence>(context, 146 com.android.internal.R.layout.simple_list_item_1, entries)); 147 } 148 149 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 150 if (d != null) { 151 // If a divider is specified use its intrinsic height for divider height 152 setDivider(d); 153 } 154 155 // Use the height specified, zero being the default 156 final int dividerHeight = a.getDimensionPixelSize( 157 com.android.internal.R.styleable.ListView_dividerHeight, 0); 158 if (dividerHeight != 0) { 159 setDividerHeight(dividerHeight); 160 } 161 162 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 163 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 164 165 a.recycle(); 166 } 167 168 /** 169 * @return The maximum amount a list view will scroll in response to 170 * an arrow event. 171 */ 172 public int getMaxScrollAmount() { 173 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 174 } 175 176 /** 177 * Make sure views are touching the top or bottom edge, as appropriate for 178 * our gravity 179 */ 180 private void adjustViewsUpOrDown() { 181 final int childCount = getChildCount(); 182 int delta; 183 184 if (childCount > 0) { 185 View child; 186 187 if (!mStackFromBottom) { 188 // Uh-oh -- we came up short. Slide all views up to make them 189 // align with the top 190 child = getChildAt(0); 191 delta = child.getTop() - mListPadding.top; 192 if (mFirstPosition != 0) { 193 // It's OK to have some space above the first item if it is 194 // part of the vertical spacing 195 delta -= mDividerHeight; 196 } 197 if (delta < 0) { 198 // We only are looking to see if we are too low, not too high 199 delta = 0; 200 } 201 } else { 202 // we are too high, slide all views down to align with bottom 203 child = getChildAt(childCount - 1); 204 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 205 206 if (mFirstPosition + childCount < mItemCount) { 207 // It's OK to have some space below the last item if it is 208 // part of the vertical spacing 209 delta += mDividerHeight; 210 } 211 212 if (delta > 0) { 213 delta = 0; 214 } 215 } 216 217 if (delta != 0) { 218 offsetChildrenTopAndBottom(-delta); 219 } 220 } 221 } 222 223 /** 224 * Add a fixed view to appear at the top of the list. If addHeaderView is 225 * called more than once, the views will appear in the order they were 226 * added. Views added using this call can take focus if they want. 227 * <p> 228 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 229 * the supplied cursor with one that will also account for header and footer 230 * views. 231 * 232 * @param v The view to add. 233 * @param data Data to associate with this view 234 * @param isSelectable whether the item is selectable 235 */ 236 public void addHeaderView(View v, Object data, boolean isSelectable) { 237 238 if (mAdapter != null) { 239 throw new IllegalStateException( 240 "Cannot add header view to list -- setAdapter has already been called."); 241 } 242 243 FixedViewInfo info = new FixedViewInfo(); 244 info.view = v; 245 info.data = data; 246 info.isSelectable = isSelectable; 247 mHeaderViewInfos.add(info); 248 } 249 250 /** 251 * Add a fixed view to appear at the top of the list. If addHeaderView is 252 * called more than once, the views will appear in the order they were 253 * added. Views added using this call can take focus if they want. 254 * <p> 255 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 256 * the supplied cursor with one that will also account for header and footer 257 * views. 258 * 259 * @param v The view to add. 260 */ 261 public void addHeaderView(View v) { 262 addHeaderView(v, null, true); 263 } 264 265 @Override 266 public int getHeaderViewsCount() { 267 return mHeaderViewInfos.size(); 268 } 269 270 /** 271 * Removes a previously-added header view. 272 * 273 * @param v The view to remove 274 * @return true if the view was removed, false if the view was not a header 275 * view 276 */ 277 public boolean removeHeaderView(View v) { 278 if (mHeaderViewInfos.size() > 0) { 279 boolean result = false; 280 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 281 mDataSetObserver.onChanged(); 282 result = true; 283 } 284 removeFixedViewInfo(v, mHeaderViewInfos); 285 return result; 286 } 287 return false; 288 } 289 290 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 291 int len = where.size(); 292 for (int i = 0; i < len; ++i) { 293 FixedViewInfo info = where.get(i); 294 if (info.view == v) { 295 where.remove(i); 296 break; 297 } 298 } 299 } 300 301 /** 302 * Add a fixed view to appear at the bottom of the list. If addFooterView is 303 * called more than once, the views will appear in the order they were 304 * added. Views added using this call can take focus if they want. 305 * <p> 306 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 307 * the supplied cursor with one that will also account for header and footer 308 * views. 309 * 310 * @param v The view to add. 311 * @param data Data to associate with this view 312 * @param isSelectable true if the footer view can be selected 313 */ 314 public void addFooterView(View v, Object data, boolean isSelectable) { 315 FixedViewInfo info = new FixedViewInfo(); 316 info.view = v; 317 info.data = data; 318 info.isSelectable = isSelectable; 319 mFooterViewInfos.add(info); 320 321 // in the case of re-adding a footer view, or adding one later on, 322 // we need to notify the observer 323 if (mDataSetObserver != null) { 324 mDataSetObserver.onChanged(); 325 } 326 } 327 328 /** 329 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 330 * than once, the views will appear in the order they were added. Views added using 331 * this call can take focus if they want. 332 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 333 * cursor with one that will also account for header and footer views. 334 * 335 * 336 * @param v The view to add. 337 */ 338 public void addFooterView(View v) { 339 addFooterView(v, null, true); 340 } 341 342 @Override 343 public int getFooterViewsCount() { 344 return mFooterViewInfos.size(); 345 } 346 347 /** 348 * Removes a previously-added footer view. 349 * 350 * @param v The view to remove 351 * @return 352 * true if the view was removed, false if the view was not a footer view 353 */ 354 public boolean removeFooterView(View v) { 355 if (mFooterViewInfos.size() > 0) { 356 boolean result = false; 357 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 358 mDataSetObserver.onChanged(); 359 result = true; 360 } 361 removeFixedViewInfo(v, mFooterViewInfos); 362 return result; 363 } 364 return false; 365 } 366 367 /** 368 * Returns the adapter currently in use in this ListView. The returned adapter 369 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 370 * might be a {@link WrapperListAdapter}. 371 * 372 * @return The adapter currently used to display data in this ListView. 373 * 374 * @see #setAdapter(ListAdapter) 375 */ 376 @Override 377 public ListAdapter getAdapter() { 378 return mAdapter; 379 } 380 381 /** 382 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 383 * through the specified intent. 384 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 385 */ 386 @android.view.RemotableViewMethod 387 public void setRemoteViewsAdapter(Intent intent) { 388 super.setRemoteViewsAdapter(intent); 389 } 390 391 /** 392 * Sets the data behind this ListView. 393 * 394 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 395 * depending on the ListView features currently in use. For instance, adding 396 * headers and/or footers will cause the adapter to be wrapped. 397 * 398 * @param adapter The ListAdapter which is responsible for maintaining the 399 * data backing this list and for producing a view to represent an 400 * item in that data set. 401 * 402 * @see #getAdapter() 403 */ 404 @Override 405 public void setAdapter(ListAdapter adapter) { 406 if (mAdapter != null && mDataSetObserver != null) { 407 mAdapter.unregisterDataSetObserver(mDataSetObserver); 408 } 409 410 resetList(); 411 mRecycler.clear(); 412 413 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 414 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 415 } else { 416 mAdapter = adapter; 417 } 418 419 mOldSelectedPosition = INVALID_POSITION; 420 mOldSelectedRowId = INVALID_ROW_ID; 421 422 // AbsListView#setAdapter will update choice mode states. 423 super.setAdapter(adapter); 424 425 if (mAdapter != null) { 426 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 427 mOldItemCount = mItemCount; 428 mItemCount = mAdapter.getCount(); 429 checkFocus(); 430 431 mDataSetObserver = new AdapterDataSetObserver(); 432 mAdapter.registerDataSetObserver(mDataSetObserver); 433 434 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 435 436 int position; 437 if (mStackFromBottom) { 438 position = lookForSelectablePosition(mItemCount - 1, false); 439 } else { 440 position = lookForSelectablePosition(0, true); 441 } 442 setSelectedPositionInt(position); 443 setNextSelectedPositionInt(position); 444 445 if (mItemCount == 0) { 446 // Nothing selected 447 checkSelectionChanged(); 448 } 449 } else { 450 mAreAllItemsSelectable = true; 451 checkFocus(); 452 // Nothing selected 453 checkSelectionChanged(); 454 } 455 456 requestLayout(); 457 } 458 459 460 /** 461 * The list is empty. Clear everything out. 462 */ 463 @Override 464 void resetList() { 465 // The parent's resetList() will remove all views from the layout so we need to 466 // cleanup the state of our footers and headers 467 clearRecycledState(mHeaderViewInfos); 468 clearRecycledState(mFooterViewInfos); 469 470 super.resetList(); 471 472 mLayoutMode = LAYOUT_NORMAL; 473 } 474 475 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 476 if (infos != null) { 477 final int count = infos.size(); 478 479 for (int i = 0; i < count; i++) { 480 final View child = infos.get(i).view; 481 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 482 if (p != null) { 483 p.recycledHeaderFooter = false; 484 } 485 } 486 } 487 } 488 489 /** 490 * @return Whether the list needs to show the top fading edge 491 */ 492 private boolean showingTopFadingEdge() { 493 final int listTop = mScrollY + mListPadding.top; 494 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 495 } 496 497 /** 498 * @return Whether the list needs to show the bottom fading edge 499 */ 500 private boolean showingBottomFadingEdge() { 501 final int childCount = getChildCount(); 502 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 503 final int lastVisiblePosition = mFirstPosition + childCount - 1; 504 505 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 506 507 return (lastVisiblePosition < mItemCount - 1) 508 || (bottomOfBottomChild < listBottom); 509 } 510 511 512 @Override 513 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 514 515 int rectTopWithinChild = rect.top; 516 517 // offset so rect is in coordinates of the this view 518 rect.offset(child.getLeft(), child.getTop()); 519 rect.offset(-child.getScrollX(), -child.getScrollY()); 520 521 final int height = getHeight(); 522 int listUnfadedTop = getScrollY(); 523 int listUnfadedBottom = listUnfadedTop + height; 524 final int fadingEdge = getVerticalFadingEdgeLength(); 525 526 if (showingTopFadingEdge()) { 527 // leave room for top fading edge as long as rect isn't at very top 528 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 529 listUnfadedTop += fadingEdge; 530 } 531 } 532 533 int childCount = getChildCount(); 534 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 535 536 if (showingBottomFadingEdge()) { 537 // leave room for bottom fading edge as long as rect isn't at very bottom 538 if ((mSelectedPosition < mItemCount - 1) 539 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 540 listUnfadedBottom -= fadingEdge; 541 } 542 } 543 544 int scrollYDelta = 0; 545 546 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 547 // need to MOVE DOWN to get it in view: move down just enough so 548 // that the entire rectangle is in view (or at least the first 549 // screen size chunk). 550 551 if (rect.height() > height) { 552 // just enough to get screen size chunk on 553 scrollYDelta += (rect.top - listUnfadedTop); 554 } else { 555 // get entire rect at bottom of screen 556 scrollYDelta += (rect.bottom - listUnfadedBottom); 557 } 558 559 // make sure we aren't scrolling beyond the end of our children 560 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 561 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 562 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 563 // need to MOVE UP to get it in view: move up just enough so that 564 // entire rectangle is in view (or at least the first screen 565 // size chunk of it). 566 567 if (rect.height() > height) { 568 // screen size chunk 569 scrollYDelta -= (listUnfadedBottom - rect.bottom); 570 } else { 571 // entire rect at top 572 scrollYDelta -= (listUnfadedTop - rect.top); 573 } 574 575 // make sure we aren't scrolling any further than the top our children 576 int top = getChildAt(0).getTop(); 577 int deltaToTop = top - listUnfadedTop; 578 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 579 } 580 581 final boolean scroll = scrollYDelta != 0; 582 if (scroll) { 583 scrollListItemsBy(-scrollYDelta); 584 positionSelector(INVALID_POSITION, child); 585 mSelectedTop = child.getTop(); 586 invalidate(); 587 } 588 return scroll; 589 } 590 591 /** 592 * {@inheritDoc} 593 */ 594 @Override 595 void fillGap(boolean down) { 596 final int count = getChildCount(); 597 if (down) { 598 int paddingTop = 0; 599 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 600 paddingTop = getListPaddingTop(); 601 } 602 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 603 paddingTop; 604 fillDown(mFirstPosition + count, startOffset); 605 correctTooHigh(getChildCount()); 606 } else { 607 int paddingBottom = 0; 608 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 609 paddingBottom = getListPaddingBottom(); 610 } 611 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 612 getHeight() - paddingBottom; 613 fillUp(mFirstPosition - 1, startOffset); 614 correctTooLow(getChildCount()); 615 } 616 } 617 618 /** 619 * Fills the list from pos down to the end of the list view. 620 * 621 * @param pos The first position to put in the list 622 * 623 * @param nextTop The location where the top of the item associated with pos 624 * should be drawn 625 * 626 * @return The view that is currently selected, if it happens to be in the 627 * range that we draw. 628 */ 629 private View fillDown(int pos, int nextTop) { 630 View selectedView = null; 631 632 int end = (mBottom - mTop); 633 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 634 end -= mListPadding.bottom; 635 } 636 637 while (nextTop < end && pos < mItemCount) { 638 // is this the selected item? 639 boolean selected = pos == mSelectedPosition; 640 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 641 642 nextTop = child.getBottom() + mDividerHeight; 643 if (selected) { 644 selectedView = child; 645 } 646 pos++; 647 } 648 649 return selectedView; 650 } 651 652 /** 653 * Fills the list from pos up to the top of the list view. 654 * 655 * @param pos The first position to put in the list 656 * 657 * @param nextBottom The location where the bottom of the item associated 658 * with pos should be drawn 659 * 660 * @return The view that is currently selected 661 */ 662 private View fillUp(int pos, int nextBottom) { 663 View selectedView = null; 664 665 int end = 0; 666 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 667 end = mListPadding.top; 668 } 669 670 while (nextBottom > end && pos >= 0) { 671 // is this the selected item? 672 boolean selected = pos == mSelectedPosition; 673 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 674 nextBottom = child.getTop() - mDividerHeight; 675 if (selected) { 676 selectedView = child; 677 } 678 pos--; 679 } 680 681 mFirstPosition = pos + 1; 682 683 return selectedView; 684 } 685 686 /** 687 * Fills the list from top to bottom, starting with mFirstPosition 688 * 689 * @param nextTop The location where the top of the first item should be 690 * drawn 691 * 692 * @return The view that is currently selected 693 */ 694 private View fillFromTop(int nextTop) { 695 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 696 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 697 if (mFirstPosition < 0) { 698 mFirstPosition = 0; 699 } 700 return fillDown(mFirstPosition, nextTop); 701 } 702 703 704 /** 705 * Put mSelectedPosition in the middle of the screen and then build up and 706 * down from there. This method forces mSelectedPosition to the center. 707 * 708 * @param childrenTop Top of the area in which children can be drawn, as 709 * measured in pixels 710 * @param childrenBottom Bottom of the area in which children can be drawn, 711 * as measured in pixels 712 * @return Currently selected view 713 */ 714 private View fillFromMiddle(int childrenTop, int childrenBottom) { 715 int height = childrenBottom - childrenTop; 716 717 int position = reconcileSelectedPosition(); 718 719 View sel = makeAndAddView(position, childrenTop, true, 720 mListPadding.left, true); 721 mFirstPosition = position; 722 723 int selHeight = sel.getMeasuredHeight(); 724 if (selHeight <= height) { 725 sel.offsetTopAndBottom((height - selHeight) / 2); 726 } 727 728 fillAboveAndBelow(sel, position); 729 730 if (!mStackFromBottom) { 731 correctTooHigh(getChildCount()); 732 } else { 733 correctTooLow(getChildCount()); 734 } 735 736 return sel; 737 } 738 739 /** 740 * Once the selected view as been placed, fill up the visible area above and 741 * below it. 742 * 743 * @param sel The selected view 744 * @param position The position corresponding to sel 745 */ 746 private void fillAboveAndBelow(View sel, int position) { 747 final int dividerHeight = mDividerHeight; 748 if (!mStackFromBottom) { 749 fillUp(position - 1, sel.getTop() - dividerHeight); 750 adjustViewsUpOrDown(); 751 fillDown(position + 1, sel.getBottom() + dividerHeight); 752 } else { 753 fillDown(position + 1, sel.getBottom() + dividerHeight); 754 adjustViewsUpOrDown(); 755 fillUp(position - 1, sel.getTop() - dividerHeight); 756 } 757 } 758 759 760 /** 761 * Fills the grid based on positioning the new selection at a specific 762 * location. The selection may be moved so that it does not intersect the 763 * faded edges. The grid is then filled upwards and downwards from there. 764 * 765 * @param selectedTop Where the selected item should be 766 * @param childrenTop Where to start drawing children 767 * @param childrenBottom Last pixel where children can be drawn 768 * @return The view that currently has selection 769 */ 770 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 771 int fadingEdgeLength = getVerticalFadingEdgeLength(); 772 final int selectedPosition = mSelectedPosition; 773 774 View sel; 775 776 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 777 selectedPosition); 778 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 779 selectedPosition); 780 781 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 782 783 784 // Some of the newly selected item extends below the bottom of the list 785 if (sel.getBottom() > bottomSelectionPixel) { 786 // Find space available above the selection into which we can scroll 787 // upwards 788 final int spaceAbove = sel.getTop() - topSelectionPixel; 789 790 // Find space required to bring the bottom of the selected item 791 // fully into view 792 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 793 final int offset = Math.min(spaceAbove, spaceBelow); 794 795 // Now offset the selected item to get it into view 796 sel.offsetTopAndBottom(-offset); 797 } else if (sel.getTop() < topSelectionPixel) { 798 // Find space required to bring the top of the selected item fully 799 // into view 800 final int spaceAbove = topSelectionPixel - sel.getTop(); 801 802 // Find space available below the selection into which we can scroll 803 // downwards 804 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 805 final int offset = Math.min(spaceAbove, spaceBelow); 806 807 // Offset the selected item to get it into view 808 sel.offsetTopAndBottom(offset); 809 } 810 811 // Fill in views above and below 812 fillAboveAndBelow(sel, selectedPosition); 813 814 if (!mStackFromBottom) { 815 correctTooHigh(getChildCount()); 816 } else { 817 correctTooLow(getChildCount()); 818 } 819 820 return sel; 821 } 822 823 /** 824 * Calculate the bottom-most pixel we can draw the selection into 825 * 826 * @param childrenBottom Bottom pixel were children can be drawn 827 * @param fadingEdgeLength Length of the fading edge in pixels, if present 828 * @param selectedPosition The position that will be selected 829 * @return The bottom-most pixel we can draw the selection into 830 */ 831 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 832 int selectedPosition) { 833 int bottomSelectionPixel = childrenBottom; 834 if (selectedPosition != mItemCount - 1) { 835 bottomSelectionPixel -= fadingEdgeLength; 836 } 837 return bottomSelectionPixel; 838 } 839 840 /** 841 * Calculate the top-most pixel we can draw the selection into 842 * 843 * @param childrenTop Top pixel were children can be drawn 844 * @param fadingEdgeLength Length of the fading edge in pixels, if present 845 * @param selectedPosition The position that will be selected 846 * @return The top-most pixel we can draw the selection into 847 */ 848 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 849 // first pixel we can draw the selection into 850 int topSelectionPixel = childrenTop; 851 if (selectedPosition > 0) { 852 topSelectionPixel += fadingEdgeLength; 853 } 854 return topSelectionPixel; 855 } 856 857 /** 858 * Smoothly scroll to the specified adapter position. The view will 859 * scroll such that the indicated position is displayed. 860 * @param position Scroll to this adapter position. 861 */ 862 @android.view.RemotableViewMethod 863 public void smoothScrollToPosition(int position) { 864 super.smoothScrollToPosition(position); 865 } 866 867 /** 868 * Smoothly scroll to the specified adapter position offset. The view will 869 * scroll such that the indicated position is displayed. 870 * @param offset The amount to offset from the adapter position to scroll to. 871 */ 872 @android.view.RemotableViewMethod 873 public void smoothScrollByOffset(int offset) { 874 super.smoothScrollByOffset(offset); 875 } 876 877 /** 878 * Fills the list based on positioning the new selection relative to the old 879 * selection. The new selection will be placed at, above, or below the 880 * location of the new selection depending on how the selection is moving. 881 * The selection will then be pinned to the visible part of the screen, 882 * excluding the edges that are faded. The list is then filled upwards and 883 * downwards from there. 884 * 885 * @param oldSel The old selected view. Useful for trying to put the new 886 * selection in the same place 887 * @param newSel The view that is to become selected. Useful for trying to 888 * put the new selection in the same place 889 * @param delta Which way we are moving 890 * @param childrenTop Where to start drawing children 891 * @param childrenBottom Last pixel where children can be drawn 892 * @return The view that currently has selection 893 */ 894 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 895 int childrenBottom) { 896 int fadingEdgeLength = getVerticalFadingEdgeLength(); 897 final int selectedPosition = mSelectedPosition; 898 899 View sel; 900 901 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 902 selectedPosition); 903 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 904 selectedPosition); 905 906 if (delta > 0) { 907 /* 908 * Case 1: Scrolling down. 909 */ 910 911 /* 912 * Before After 913 * | | | | 914 * +-------+ +-------+ 915 * | A | | A | 916 * | 1 | => +-------+ 917 * +-------+ | B | 918 * | B | | 2 | 919 * +-------+ +-------+ 920 * | | | | 921 * 922 * Try to keep the top of the previously selected item where it was. 923 * oldSel = A 924 * sel = B 925 */ 926 927 // Put oldSel (A) where it belongs 928 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 929 mListPadding.left, false); 930 931 final int dividerHeight = mDividerHeight; 932 933 // Now put the new selection (B) below that 934 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 935 mListPadding.left, true); 936 937 // Some of the newly selected item extends below the bottom of the list 938 if (sel.getBottom() > bottomSelectionPixel) { 939 940 // Find space available above the selection into which we can scroll upwards 941 int spaceAbove = sel.getTop() - topSelectionPixel; 942 943 // Find space required to bring the bottom of the selected item fully into view 944 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 945 946 // Don't scroll more than half the height of the list 947 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 948 int offset = Math.min(spaceAbove, spaceBelow); 949 offset = Math.min(offset, halfVerticalSpace); 950 951 // We placed oldSel, so offset that item 952 oldSel.offsetTopAndBottom(-offset); 953 // Now offset the selected item to get it into view 954 sel.offsetTopAndBottom(-offset); 955 } 956 957 // Fill in views above and below 958 if (!mStackFromBottom) { 959 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 960 adjustViewsUpOrDown(); 961 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 962 } else { 963 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 964 adjustViewsUpOrDown(); 965 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 966 } 967 } else if (delta < 0) { 968 /* 969 * Case 2: Scrolling up. 970 */ 971 972 /* 973 * Before After 974 * | | | | 975 * +-------+ +-------+ 976 * | A | | A | 977 * +-------+ => | 1 | 978 * | B | +-------+ 979 * | 2 | | B | 980 * +-------+ +-------+ 981 * | | | | 982 * 983 * Try to keep the top of the item about to become selected where it was. 984 * newSel = A 985 * olSel = B 986 */ 987 988 if (newSel != null) { 989 // Try to position the top of newSel (A) where it was before it was selected 990 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 991 true); 992 } else { 993 // If (A) was not on screen and so did not have a view, position 994 // it above the oldSel (B) 995 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 996 true); 997 } 998 999 // Some of the newly selected item extends above the top of the list 1000 if (sel.getTop() < topSelectionPixel) { 1001 // Find space required to bring the top of the selected item fully into view 1002 int spaceAbove = topSelectionPixel - sel.getTop(); 1003 1004 // Find space available below the selection into which we can scroll downwards 1005 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1006 1007 // Don't scroll more than half the height of the list 1008 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1009 int offset = Math.min(spaceAbove, spaceBelow); 1010 offset = Math.min(offset, halfVerticalSpace); 1011 1012 // Offset the selected item to get it into view 1013 sel.offsetTopAndBottom(offset); 1014 } 1015 1016 // Fill in views above and below 1017 fillAboveAndBelow(sel, selectedPosition); 1018 } else { 1019 1020 int oldTop = oldSel.getTop(); 1021 1022 /* 1023 * Case 3: Staying still 1024 */ 1025 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1026 1027 // We're staying still... 1028 if (oldTop < childrenTop) { 1029 // ... but the top of the old selection was off screen. 1030 // (This can happen if the data changes size out from under us) 1031 int newBottom = sel.getBottom(); 1032 if (newBottom < childrenTop + 20) { 1033 // Not enough visible -- bring it onscreen 1034 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1035 } 1036 } 1037 1038 // Fill in views above and below 1039 fillAboveAndBelow(sel, selectedPosition); 1040 } 1041 1042 return sel; 1043 } 1044 1045 private class FocusSelector implements Runnable { 1046 private int mPosition; 1047 private int mPositionTop; 1048 1049 public FocusSelector setup(int position, int top) { 1050 mPosition = position; 1051 mPositionTop = top; 1052 return this; 1053 } 1054 1055 public void run() { 1056 setSelectionFromTop(mPosition, mPositionTop); 1057 } 1058 } 1059 1060 @Override 1061 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1062 if (getChildCount() > 0) { 1063 View focusedChild = getFocusedChild(); 1064 if (focusedChild != null) { 1065 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1066 final int childBottom = focusedChild.getBottom(); 1067 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1068 final int top = focusedChild.getTop() - offset; 1069 if (mFocusSelector == null) { 1070 mFocusSelector = new FocusSelector(); 1071 } 1072 post(mFocusSelector.setup(childPosition, top)); 1073 } 1074 } 1075 super.onSizeChanged(w, h, oldw, oldh); 1076 } 1077 1078 @Override 1079 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1080 // Sets up mListPadding 1081 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1082 1083 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1084 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1085 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1086 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1087 1088 int childWidth = 0; 1089 int childHeight = 0; 1090 1091 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1092 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1093 heightMode == MeasureSpec.UNSPECIFIED)) { 1094 final View child = obtainView(0, mIsScrap); 1095 1096 measureScrapChild(child, 0, widthMeasureSpec); 1097 1098 childWidth = child.getMeasuredWidth(); 1099 childHeight = child.getMeasuredHeight(); 1100 1101 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1102 ((LayoutParams) child.getLayoutParams()).viewType)) { 1103 mRecycler.addScrapView(child, -1); 1104 } 1105 } 1106 1107 if (widthMode == MeasureSpec.UNSPECIFIED) { 1108 widthSize = mListPadding.left + mListPadding.right + childWidth + 1109 getVerticalScrollbarWidth(); 1110 } 1111 1112 if (heightMode == MeasureSpec.UNSPECIFIED) { 1113 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1114 getVerticalFadingEdgeLength() * 2; 1115 } 1116 1117 if (heightMode == MeasureSpec.AT_MOST) { 1118 // TODO: after first layout we should maybe start at the first visible position, not 0 1119 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1120 } 1121 1122 setMeasuredDimension(widthSize, heightSize); 1123 mWidthMeasureSpec = widthMeasureSpec; 1124 } 1125 1126 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1127 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1128 if (p == null) { 1129 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1130 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1131 child.setLayoutParams(p); 1132 } 1133 p.viewType = mAdapter.getItemViewType(position); 1134 p.forceAdd = true; 1135 1136 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1137 mListPadding.left + mListPadding.right, p.width); 1138 int lpHeight = p.height; 1139 int childHeightSpec; 1140 if (lpHeight > 0) { 1141 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1142 } else { 1143 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1144 } 1145 child.measure(childWidthSpec, childHeightSpec); 1146 } 1147 1148 /** 1149 * @return True to recycle the views used to measure this ListView in 1150 * UNSPECIFIED/AT_MOST modes, false otherwise. 1151 * @hide 1152 */ 1153 @ViewDebug.ExportedProperty(category = "list") 1154 protected boolean recycleOnMeasure() { 1155 return true; 1156 } 1157 1158 /** 1159 * Measures the height of the given range of children (inclusive) and 1160 * returns the height with this ListView's padding and divider heights 1161 * included. If maxHeight is provided, the measuring will stop when the 1162 * current height reaches maxHeight. 1163 * 1164 * @param widthMeasureSpec The width measure spec to be given to a child's 1165 * {@link View#measure(int, int)}. 1166 * @param startPosition The position of the first child to be shown. 1167 * @param endPosition The (inclusive) position of the last child to be 1168 * shown. Specify {@link #NO_POSITION} if the last child should be 1169 * the last available child from the adapter. 1170 * @param maxHeight The maximum height that will be returned (if all the 1171 * children don't fit in this value, this value will be 1172 * returned). 1173 * @param disallowPartialChildPosition In general, whether the returned 1174 * height should only contain entire children. This is more 1175 * powerful--it is the first inclusive position at which partial 1176 * children will not be allowed. Example: it looks nice to have 1177 * at least 3 completely visible children, and in portrait this 1178 * will most likely fit; but in landscape there could be times 1179 * when even 2 children can not be completely shown, so a value 1180 * of 2 (remember, inclusive) would be good (assuming 1181 * startPosition is 0). 1182 * @return The height of this ListView with the given children. 1183 */ 1184 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1185 final int maxHeight, int disallowPartialChildPosition) { 1186 1187 final ListAdapter adapter = mAdapter; 1188 if (adapter == null) { 1189 return mListPadding.top + mListPadding.bottom; 1190 } 1191 1192 // Include the padding of the list 1193 int returnedHeight = mListPadding.top + mListPadding.bottom; 1194 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1195 // The previous height value that was less than maxHeight and contained 1196 // no partial children 1197 int prevHeightWithoutPartialChild = 0; 1198 int i; 1199 View child; 1200 1201 // mItemCount - 1 since endPosition parameter is inclusive 1202 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1203 final AbsListView.RecycleBin recycleBin = mRecycler; 1204 final boolean recyle = recycleOnMeasure(); 1205 final boolean[] isScrap = mIsScrap; 1206 1207 for (i = startPosition; i <= endPosition; ++i) { 1208 child = obtainView(i, isScrap); 1209 1210 measureScrapChild(child, i, widthMeasureSpec); 1211 1212 if (i > 0) { 1213 // Count the divider for all but one child 1214 returnedHeight += dividerHeight; 1215 } 1216 1217 // Recycle the view before we possibly return from the method 1218 if (recyle && recycleBin.shouldRecycleViewType( 1219 ((LayoutParams) child.getLayoutParams()).viewType)) { 1220 recycleBin.addScrapView(child, -1); 1221 } 1222 1223 returnedHeight += child.getMeasuredHeight(); 1224 1225 if (returnedHeight >= maxHeight) { 1226 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1227 // then the i'th position did not fit completely. 1228 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1229 && (i > disallowPartialChildPosition) // We've past the min pos 1230 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1231 && (returnedHeight != maxHeight) // i'th child did not fit completely 1232 ? prevHeightWithoutPartialChild 1233 : maxHeight; 1234 } 1235 1236 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1237 prevHeightWithoutPartialChild = returnedHeight; 1238 } 1239 } 1240 1241 // At this point, we went through the range of children, and they each 1242 // completely fit, so return the returnedHeight 1243 return returnedHeight; 1244 } 1245 1246 @Override 1247 int findMotionRow(int y) { 1248 int childCount = getChildCount(); 1249 if (childCount > 0) { 1250 if (!mStackFromBottom) { 1251 for (int i = 0; i < childCount; i++) { 1252 View v = getChildAt(i); 1253 if (y <= v.getBottom()) { 1254 return mFirstPosition + i; 1255 } 1256 } 1257 } else { 1258 for (int i = childCount - 1; i >= 0; i--) { 1259 View v = getChildAt(i); 1260 if (y >= v.getTop()) { 1261 return mFirstPosition + i; 1262 } 1263 } 1264 } 1265 } 1266 return INVALID_POSITION; 1267 } 1268 1269 /** 1270 * Put a specific item at a specific location on the screen and then build 1271 * up and down from there. 1272 * 1273 * @param position The reference view to use as the starting point 1274 * @param top Pixel offset from the top of this view to the top of the 1275 * reference view. 1276 * 1277 * @return The selected view, or null if the selected view is outside the 1278 * visible area. 1279 */ 1280 private View fillSpecific(int position, int top) { 1281 boolean tempIsSelected = position == mSelectedPosition; 1282 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1283 // Possibly changed again in fillUp if we add rows above this one. 1284 mFirstPosition = position; 1285 1286 View above; 1287 View below; 1288 1289 final int dividerHeight = mDividerHeight; 1290 if (!mStackFromBottom) { 1291 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1292 // This will correct for the top of the first view not touching the top of the list 1293 adjustViewsUpOrDown(); 1294 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1295 int childCount = getChildCount(); 1296 if (childCount > 0) { 1297 correctTooHigh(childCount); 1298 } 1299 } else { 1300 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1301 // This will correct for the bottom of the last view not touching the bottom of the list 1302 adjustViewsUpOrDown(); 1303 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1304 int childCount = getChildCount(); 1305 if (childCount > 0) { 1306 correctTooLow(childCount); 1307 } 1308 } 1309 1310 if (tempIsSelected) { 1311 return temp; 1312 } else if (above != null) { 1313 return above; 1314 } else { 1315 return below; 1316 } 1317 } 1318 1319 /** 1320 * Check if we have dragged the bottom of the list too high (we have pushed the 1321 * top element off the top of the screen when we did not need to). Correct by sliding 1322 * everything back down. 1323 * 1324 * @param childCount Number of children 1325 */ 1326 private void correctTooHigh(int childCount) { 1327 // First see if the last item is visible. If it is not, it is OK for the 1328 // top of the list to be pushed up. 1329 int lastPosition = mFirstPosition + childCount - 1; 1330 if (lastPosition == mItemCount - 1 && childCount > 0) { 1331 1332 // Get the last child ... 1333 final View lastChild = getChildAt(childCount - 1); 1334 1335 // ... and its bottom edge 1336 final int lastBottom = lastChild.getBottom(); 1337 1338 // This is bottom of our drawable area 1339 final int end = (mBottom - mTop) - mListPadding.bottom; 1340 1341 // This is how far the bottom edge of the last view is from the bottom of the 1342 // drawable area 1343 int bottomOffset = end - lastBottom; 1344 View firstChild = getChildAt(0); 1345 final int firstTop = firstChild.getTop(); 1346 1347 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1348 // first row or the first row is scrolled off the top of the drawable area 1349 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1350 if (mFirstPosition == 0) { 1351 // Don't pull the top too far down 1352 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1353 } 1354 // Move everything down 1355 offsetChildrenTopAndBottom(bottomOffset); 1356 if (mFirstPosition > 0) { 1357 // Fill the gap that was opened above mFirstPosition with more rows, if 1358 // possible 1359 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1360 // Close up the remaining gap 1361 adjustViewsUpOrDown(); 1362 } 1363 1364 } 1365 } 1366 } 1367 1368 /** 1369 * Check if we have dragged the bottom of the list too low (we have pushed the 1370 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1371 * everything back up. 1372 * 1373 * @param childCount Number of children 1374 */ 1375 private void correctTooLow(int childCount) { 1376 // First see if the first item is visible. If it is not, it is OK for the 1377 // bottom of the list to be pushed down. 1378 if (mFirstPosition == 0 && childCount > 0) { 1379 1380 // Get the first child ... 1381 final View firstChild = getChildAt(0); 1382 1383 // ... and its top edge 1384 final int firstTop = firstChild.getTop(); 1385 1386 // This is top of our drawable area 1387 final int start = mListPadding.top; 1388 1389 // This is bottom of our drawable area 1390 final int end = (mBottom - mTop) - mListPadding.bottom; 1391 1392 // This is how far the top edge of the first view is from the top of the 1393 // drawable area 1394 int topOffset = firstTop - start; 1395 View lastChild = getChildAt(childCount - 1); 1396 final int lastBottom = lastChild.getBottom(); 1397 int lastPosition = mFirstPosition + childCount - 1; 1398 1399 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1400 // last row or the last row is scrolled off the bottom of the drawable area 1401 if (topOffset > 0) { 1402 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1403 if (lastPosition == mItemCount - 1) { 1404 // Don't pull the bottom too far up 1405 topOffset = Math.min(topOffset, lastBottom - end); 1406 } 1407 // Move everything up 1408 offsetChildrenTopAndBottom(-topOffset); 1409 if (lastPosition < mItemCount - 1) { 1410 // Fill the gap that was opened below the last position with more rows, if 1411 // possible 1412 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1413 // Close up the remaining gap 1414 adjustViewsUpOrDown(); 1415 } 1416 } else if (lastPosition == mItemCount - 1) { 1417 adjustViewsUpOrDown(); 1418 } 1419 } 1420 } 1421 } 1422 1423 @Override 1424 protected void layoutChildren() { 1425 final boolean blockLayoutRequests = mBlockLayoutRequests; 1426 if (!blockLayoutRequests) { 1427 mBlockLayoutRequests = true; 1428 } else { 1429 return; 1430 } 1431 1432 try { 1433 super.layoutChildren(); 1434 1435 invalidate(); 1436 1437 if (mAdapter == null) { 1438 resetList(); 1439 invokeOnItemScrollListener(); 1440 return; 1441 } 1442 1443 int childrenTop = mListPadding.top; 1444 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1445 1446 int childCount = getChildCount(); 1447 int index = 0; 1448 int delta = 0; 1449 1450 View sel; 1451 View oldSel = null; 1452 View oldFirst = null; 1453 View newSel = null; 1454 1455 View focusLayoutRestoreView = null; 1456 1457 // Remember stuff we will need down below 1458 switch (mLayoutMode) { 1459 case LAYOUT_SET_SELECTION: 1460 index = mNextSelectedPosition - mFirstPosition; 1461 if (index >= 0 && index < childCount) { 1462 newSel = getChildAt(index); 1463 } 1464 break; 1465 case LAYOUT_FORCE_TOP: 1466 case LAYOUT_FORCE_BOTTOM: 1467 case LAYOUT_SPECIFIC: 1468 case LAYOUT_SYNC: 1469 break; 1470 case LAYOUT_MOVE_SELECTION: 1471 default: 1472 // Remember the previously selected view 1473 index = mSelectedPosition - mFirstPosition; 1474 if (index >= 0 && index < childCount) { 1475 oldSel = getChildAt(index); 1476 } 1477 1478 // Remember the previous first child 1479 oldFirst = getChildAt(0); 1480 1481 if (mNextSelectedPosition >= 0) { 1482 delta = mNextSelectedPosition - mSelectedPosition; 1483 } 1484 1485 // Caution: newSel might be null 1486 newSel = getChildAt(index + delta); 1487 } 1488 1489 1490 boolean dataChanged = mDataChanged; 1491 if (dataChanged) { 1492 handleDataChanged(); 1493 } 1494 1495 // Handle the empty set by removing all views that are visible 1496 // and calling it a day 1497 if (mItemCount == 0) { 1498 resetList(); 1499 invokeOnItemScrollListener(); 1500 return; 1501 } else if (mItemCount != mAdapter.getCount()) { 1502 throw new IllegalStateException("The content of the adapter has changed but " 1503 + "ListView did not receive a notification. Make sure the content of " 1504 + "your adapter is not modified from a background thread, but only " 1505 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1506 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1507 } 1508 1509 setSelectedPositionInt(mNextSelectedPosition); 1510 1511 // Pull all children into the RecycleBin. 1512 // These views will be reused if possible 1513 final int firstPosition = mFirstPosition; 1514 final RecycleBin recycleBin = mRecycler; 1515 1516 // reset the focus restoration 1517 View focusLayoutRestoreDirectChild = null; 1518 1519 1520 // Don't put header or footer views into the Recycler. Those are 1521 // already cached in mHeaderViews; 1522 if (dataChanged) { 1523 for (int i = 0; i < childCount; i++) { 1524 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1525 if (ViewDebug.TRACE_RECYCLER) { 1526 ViewDebug.trace(getChildAt(i), 1527 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1528 } 1529 } 1530 } else { 1531 recycleBin.fillActiveViews(childCount, firstPosition); 1532 } 1533 1534 // take focus back to us temporarily to avoid the eventual 1535 // call to clear focus when removing the focused child below 1536 // from messing things up when ViewRoot assigns focus back 1537 // to someone else 1538 final View focusedChild = getFocusedChild(); 1539 if (focusedChild != null) { 1540 // TODO: in some cases focusedChild.getParent() == null 1541 1542 // we can remember the focused view to restore after relayout if the 1543 // data hasn't changed, or if the focused position is a header or footer 1544 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1545 focusLayoutRestoreDirectChild = focusedChild; 1546 // remember the specific view that had focus 1547 focusLayoutRestoreView = findFocus(); 1548 if (focusLayoutRestoreView != null) { 1549 // tell it we are going to mess with it 1550 focusLayoutRestoreView.onStartTemporaryDetach(); 1551 } 1552 } 1553 requestFocus(); 1554 } 1555 1556 // Clear out old views 1557 detachAllViewsFromParent(); 1558 1559 switch (mLayoutMode) { 1560 case LAYOUT_SET_SELECTION: 1561 if (newSel != null) { 1562 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1563 } else { 1564 sel = fillFromMiddle(childrenTop, childrenBottom); 1565 } 1566 break; 1567 case LAYOUT_SYNC: 1568 sel = fillSpecific(mSyncPosition, mSpecificTop); 1569 break; 1570 case LAYOUT_FORCE_BOTTOM: 1571 sel = fillUp(mItemCount - 1, childrenBottom); 1572 adjustViewsUpOrDown(); 1573 break; 1574 case LAYOUT_FORCE_TOP: 1575 mFirstPosition = 0; 1576 sel = fillFromTop(childrenTop); 1577 adjustViewsUpOrDown(); 1578 break; 1579 case LAYOUT_SPECIFIC: 1580 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1581 break; 1582 case LAYOUT_MOVE_SELECTION: 1583 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1584 break; 1585 default: 1586 if (childCount == 0) { 1587 if (!mStackFromBottom) { 1588 final int position = lookForSelectablePosition(0, true); 1589 setSelectedPositionInt(position); 1590 sel = fillFromTop(childrenTop); 1591 } else { 1592 final int position = lookForSelectablePosition(mItemCount - 1, false); 1593 setSelectedPositionInt(position); 1594 sel = fillUp(mItemCount - 1, childrenBottom); 1595 } 1596 } else { 1597 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1598 sel = fillSpecific(mSelectedPosition, 1599 oldSel == null ? childrenTop : oldSel.getTop()); 1600 } else if (mFirstPosition < mItemCount) { 1601 sel = fillSpecific(mFirstPosition, 1602 oldFirst == null ? childrenTop : oldFirst.getTop()); 1603 } else { 1604 sel = fillSpecific(0, childrenTop); 1605 } 1606 } 1607 break; 1608 } 1609 1610 // Flush any cached views that did not get reused above 1611 recycleBin.scrapActiveViews(); 1612 1613 if (sel != null) { 1614 // the current selected item should get focus if items 1615 // are focusable 1616 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1617 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1618 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1619 if (!focusWasTaken) { 1620 // selected item didn't take focus, fine, but still want 1621 // to make sure something else outside of the selected view 1622 // has focus 1623 final View focused = getFocusedChild(); 1624 if (focused != null) { 1625 focused.clearFocus(); 1626 } 1627 positionSelector(INVALID_POSITION, sel); 1628 } else { 1629 sel.setSelected(false); 1630 mSelectorRect.setEmpty(); 1631 } 1632 } else { 1633 positionSelector(INVALID_POSITION, sel); 1634 } 1635 mSelectedTop = sel.getTop(); 1636 } else { 1637 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1638 View child = getChildAt(mMotionPosition - mFirstPosition); 1639 if (child != null) positionSelector(mMotionPosition, child); 1640 } else { 1641 mSelectedTop = 0; 1642 mSelectorRect.setEmpty(); 1643 } 1644 1645 // even if there is not selected position, we may need to restore 1646 // focus (i.e. something focusable in touch mode) 1647 if (hasFocus() && focusLayoutRestoreView != null) { 1648 focusLayoutRestoreView.requestFocus(); 1649 } 1650 } 1651 1652 // tell focus view we are done mucking with it, if it is still in 1653 // our view hierarchy. 1654 if (focusLayoutRestoreView != null 1655 && focusLayoutRestoreView.getWindowToken() != null) { 1656 focusLayoutRestoreView.onFinishTemporaryDetach(); 1657 } 1658 1659 mLayoutMode = LAYOUT_NORMAL; 1660 mDataChanged = false; 1661 mNeedSync = false; 1662 setNextSelectedPositionInt(mSelectedPosition); 1663 1664 updateScrollIndicators(); 1665 1666 if (mItemCount > 0) { 1667 checkSelectionChanged(); 1668 } 1669 1670 invokeOnItemScrollListener(); 1671 } finally { 1672 if (!blockLayoutRequests) { 1673 mBlockLayoutRequests = false; 1674 } 1675 } 1676 } 1677 1678 /** 1679 * @param child a direct child of this list. 1680 * @return Whether child is a header or footer view. 1681 */ 1682 private boolean isDirectChildHeaderOrFooter(View child) { 1683 1684 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1685 final int numHeaders = headers.size(); 1686 for (int i = 0; i < numHeaders; i++) { 1687 if (child == headers.get(i).view) { 1688 return true; 1689 } 1690 } 1691 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1692 final int numFooters = footers.size(); 1693 for (int i = 0; i < numFooters; i++) { 1694 if (child == footers.get(i).view) { 1695 return true; 1696 } 1697 } 1698 return false; 1699 } 1700 1701 /** 1702 * Obtain the view and add it to our list of children. The view can be made 1703 * fresh, converted from an unused view, or used as is if it was in the 1704 * recycle bin. 1705 * 1706 * @param position Logical position in the list 1707 * @param y Top or bottom edge of the view to add 1708 * @param flow If flow is true, align top edge to y. If false, align bottom 1709 * edge to y. 1710 * @param childrenLeft Left edge where children should be positioned 1711 * @param selected Is this position selected? 1712 * @return View that was added 1713 */ 1714 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1715 boolean selected) { 1716 View child; 1717 1718 1719 if (!mDataChanged) { 1720 // Try to use an existing view for this position 1721 child = mRecycler.getActiveView(position); 1722 if (child != null) { 1723 if (ViewDebug.TRACE_RECYCLER) { 1724 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1725 position, getChildCount()); 1726 } 1727 1728 // Found it -- we're using an existing child 1729 // This just needs to be positioned 1730 setupChild(child, position, y, flow, childrenLeft, selected, true); 1731 1732 return child; 1733 } 1734 } 1735 1736 // Make a new view for this position, or convert an unused view if possible 1737 child = obtainView(position, mIsScrap); 1738 1739 // This needs to be positioned and measured 1740 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1741 1742 return child; 1743 } 1744 1745 /** 1746 * Add a view as a child and make sure it is measured (if necessary) and 1747 * positioned properly. 1748 * 1749 * @param child The view to add 1750 * @param position The position of this child 1751 * @param y The y position relative to which this view will be positioned 1752 * @param flowDown If true, align top edge to y. If false, align bottom 1753 * edge to y. 1754 * @param childrenLeft Left edge where children should be positioned 1755 * @param selected Is this position selected? 1756 * @param recycled Has this view been pulled from the recycle bin? If so it 1757 * does not need to be remeasured. 1758 */ 1759 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1760 boolean selected, boolean recycled) { 1761 final boolean isSelected = selected && shouldShowSelector(); 1762 final boolean updateChildSelected = isSelected != child.isSelected(); 1763 final int mode = mTouchMode; 1764 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1765 mMotionPosition == position; 1766 final boolean updateChildPressed = isPressed != child.isPressed(); 1767 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1768 1769 // Respect layout params that are already in the view. Otherwise make some up... 1770 // noinspection unchecked 1771 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1772 if (p == null) { 1773 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1774 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1775 } 1776 p.viewType = mAdapter.getItemViewType(position); 1777 1778 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1779 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1780 attachViewToParent(child, flowDown ? -1 : 0, p); 1781 } else { 1782 p.forceAdd = false; 1783 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1784 p.recycledHeaderFooter = true; 1785 } 1786 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1787 } 1788 1789 if (updateChildSelected) { 1790 child.setSelected(isSelected); 1791 } 1792 1793 if (updateChildPressed) { 1794 child.setPressed(isPressed); 1795 } 1796 1797 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1798 if (child instanceof Checkable) { 1799 ((Checkable) child).setChecked(mCheckStates.get(position)); 1800 } else if (getContext().getApplicationInfo().targetSdkVersion 1801 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1802 child.setActivated(mCheckStates.get(position)); 1803 } 1804 } 1805 1806 if (needToMeasure) { 1807 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1808 mListPadding.left + mListPadding.right, p.width); 1809 int lpHeight = p.height; 1810 int childHeightSpec; 1811 if (lpHeight > 0) { 1812 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1813 } else { 1814 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1815 } 1816 child.measure(childWidthSpec, childHeightSpec); 1817 } else { 1818 cleanupLayoutState(child); 1819 } 1820 1821 final int w = child.getMeasuredWidth(); 1822 final int h = child.getMeasuredHeight(); 1823 final int childTop = flowDown ? y : y - h; 1824 1825 if (needToMeasure) { 1826 final int childRight = childrenLeft + w; 1827 final int childBottom = childTop + h; 1828 child.layout(childrenLeft, childTop, childRight, childBottom); 1829 } else { 1830 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1831 child.offsetTopAndBottom(childTop - child.getTop()); 1832 } 1833 1834 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1835 child.setDrawingCacheEnabled(true); 1836 } 1837 1838 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1839 != position) { 1840 child.jumpDrawablesToCurrentState(); 1841 } 1842 } 1843 1844 @Override 1845 protected boolean canAnimate() { 1846 return super.canAnimate() && mItemCount > 0; 1847 } 1848 1849 /** 1850 * Sets the currently selected item. If in touch mode, the item will not be selected 1851 * but it will still be positioned appropriately. If the specified selection position 1852 * is less than 0, then the item at position 0 will be selected. 1853 * 1854 * @param position Index (starting at 0) of the data item to be selected. 1855 */ 1856 @Override 1857 public void setSelection(int position) { 1858 setSelectionFromTop(position, 0); 1859 } 1860 1861 /** 1862 * Sets the selected item and positions the selection y pixels from the top edge 1863 * of the ListView. (If in touch mode, the item will not be selected but it will 1864 * still be positioned appropriately.) 1865 * 1866 * @param position Index (starting at 0) of the data item to be selected. 1867 * @param y The distance from the top edge of the ListView (plus padding) that the 1868 * item will be positioned. 1869 */ 1870 public void setSelectionFromTop(int position, int y) { 1871 if (mAdapter == null) { 1872 return; 1873 } 1874 1875 if (!isInTouchMode()) { 1876 position = lookForSelectablePosition(position, true); 1877 if (position >= 0) { 1878 setNextSelectedPositionInt(position); 1879 } 1880 } else { 1881 mResurrectToPosition = position; 1882 } 1883 1884 if (position >= 0) { 1885 mLayoutMode = LAYOUT_SPECIFIC; 1886 mSpecificTop = mListPadding.top + y; 1887 1888 if (mNeedSync) { 1889 mSyncPosition = position; 1890 mSyncRowId = mAdapter.getItemId(position); 1891 } 1892 1893 requestLayout(); 1894 } 1895 } 1896 1897 /** 1898 * Makes the item at the supplied position selected. 1899 * 1900 * @param position the position of the item to select 1901 */ 1902 @Override 1903 void setSelectionInt(int position) { 1904 setNextSelectedPositionInt(position); 1905 boolean awakeScrollbars = false; 1906 1907 final int selectedPosition = mSelectedPosition; 1908 1909 if (selectedPosition >= 0) { 1910 if (position == selectedPosition - 1) { 1911 awakeScrollbars = true; 1912 } else if (position == selectedPosition + 1) { 1913 awakeScrollbars = true; 1914 } 1915 } 1916 1917 layoutChildren(); 1918 1919 if (awakeScrollbars) { 1920 awakenScrollBars(); 1921 } 1922 } 1923 1924 /** 1925 * Find a position that can be selected (i.e., is not a separator). 1926 * 1927 * @param position The starting position to look at. 1928 * @param lookDown Whether to look down for other positions. 1929 * @return The next selectable position starting at position and then searching either up or 1930 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1931 */ 1932 @Override 1933 int lookForSelectablePosition(int position, boolean lookDown) { 1934 final ListAdapter adapter = mAdapter; 1935 if (adapter == null || isInTouchMode()) { 1936 return INVALID_POSITION; 1937 } 1938 1939 final int count = adapter.getCount(); 1940 if (!mAreAllItemsSelectable) { 1941 if (lookDown) { 1942 position = Math.max(0, position); 1943 while (position < count && !adapter.isEnabled(position)) { 1944 position++; 1945 } 1946 } else { 1947 position = Math.min(position, count - 1); 1948 while (position >= 0 && !adapter.isEnabled(position)) { 1949 position--; 1950 } 1951 } 1952 1953 if (position < 0 || position >= count) { 1954 return INVALID_POSITION; 1955 } 1956 return position; 1957 } else { 1958 if (position < 0 || position >= count) { 1959 return INVALID_POSITION; 1960 } 1961 return position; 1962 } 1963 } 1964 1965 @Override 1966 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1967 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1968 1969 // If the item count is less than 15 then subtract disabled items from the count and 1970 // position. Otherwise ignore disabled items. 1971 if (!populated) { 1972 int itemCount = 0; 1973 int currentItemIndex = getSelectedItemPosition(); 1974 1975 ListAdapter adapter = getAdapter(); 1976 if (adapter != null) { 1977 final int count = adapter.getCount(); 1978 if (count < 15) { 1979 for (int i = 0; i < count; i++) { 1980 if (adapter.isEnabled(i)) { 1981 itemCount++; 1982 } else if (i <= currentItemIndex) { 1983 currentItemIndex--; 1984 } 1985 } 1986 } else { 1987 itemCount = count; 1988 } 1989 } 1990 1991 event.setItemCount(itemCount); 1992 event.setCurrentItemIndex(currentItemIndex); 1993 } 1994 1995 return populated; 1996 } 1997 1998 /** 1999 * setSelectionAfterHeaderView set the selection to be the first list item 2000 * after the header views. 2001 */ 2002 public void setSelectionAfterHeaderView() { 2003 final int count = mHeaderViewInfos.size(); 2004 if (count > 0) { 2005 mNextSelectedPosition = 0; 2006 return; 2007 } 2008 2009 if (mAdapter != null) { 2010 setSelection(count); 2011 } else { 2012 mNextSelectedPosition = count; 2013 mLayoutMode = LAYOUT_SET_SELECTION; 2014 } 2015 2016 } 2017 2018 @Override 2019 public boolean dispatchKeyEvent(KeyEvent event) { 2020 // Dispatch in the normal way 2021 boolean handled = super.dispatchKeyEvent(event); 2022 if (!handled) { 2023 // If we didn't handle it... 2024 View focused = getFocusedChild(); 2025 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2026 // ... and our focused child didn't handle it 2027 // ... give it to ourselves so we can scroll if necessary 2028 handled = onKeyDown(event.getKeyCode(), event); 2029 } 2030 } 2031 return handled; 2032 } 2033 2034 @Override 2035 public boolean onKeyDown(int keyCode, KeyEvent event) { 2036 return commonKey(keyCode, 1, event); 2037 } 2038 2039 @Override 2040 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2041 return commonKey(keyCode, repeatCount, event); 2042 } 2043 2044 @Override 2045 public boolean onKeyUp(int keyCode, KeyEvent event) { 2046 return commonKey(keyCode, 1, event); 2047 } 2048 2049 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2050 if (mAdapter == null) { 2051 return false; 2052 } 2053 2054 if (mDataChanged) { 2055 layoutChildren(); 2056 } 2057 2058 boolean handled = false; 2059 int action = event.getAction(); 2060 2061 if (action != KeyEvent.ACTION_UP) { 2062 if (mSelectedPosition < 0) { 2063 switch (keyCode) { 2064 case KeyEvent.KEYCODE_DPAD_UP: 2065 case KeyEvent.KEYCODE_DPAD_DOWN: 2066 case KeyEvent.KEYCODE_DPAD_CENTER: 2067 case KeyEvent.KEYCODE_ENTER: 2068 case KeyEvent.KEYCODE_SPACE: 2069 if (resurrectSelection()) { 2070 return true; 2071 } 2072 } 2073 } 2074 switch (keyCode) { 2075 case KeyEvent.KEYCODE_DPAD_UP: 2076 if (!event.isAltPressed()) { 2077 while (count > 0) { 2078 handled = arrowScroll(FOCUS_UP); 2079 count--; 2080 } 2081 } else { 2082 handled = fullScroll(FOCUS_UP); 2083 } 2084 break; 2085 2086 case KeyEvent.KEYCODE_DPAD_DOWN: 2087 if (!event.isAltPressed()) { 2088 while (count > 0) { 2089 handled = arrowScroll(FOCUS_DOWN); 2090 count--; 2091 } 2092 } else { 2093 handled = fullScroll(FOCUS_DOWN); 2094 } 2095 break; 2096 2097 case KeyEvent.KEYCODE_DPAD_LEFT: 2098 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2099 break; 2100 case KeyEvent.KEYCODE_DPAD_RIGHT: 2101 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2102 break; 2103 2104 case KeyEvent.KEYCODE_DPAD_CENTER: 2105 case KeyEvent.KEYCODE_ENTER: 2106 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2107 keyPressed(); 2108 } 2109 handled = true; 2110 break; 2111 2112 case KeyEvent.KEYCODE_SPACE: 2113 if (mPopup == null || !mPopup.isShowing()) { 2114 if (!event.isShiftPressed()) { 2115 pageScroll(FOCUS_DOWN); 2116 } else { 2117 pageScroll(FOCUS_UP); 2118 } 2119 handled = true; 2120 } 2121 break; 2122 } 2123 } 2124 2125 if (!handled) { 2126 handled = sendToTextFilter(keyCode, count, event); 2127 } 2128 2129 if (handled) { 2130 return true; 2131 } else { 2132 switch (action) { 2133 case KeyEvent.ACTION_DOWN: 2134 return super.onKeyDown(keyCode, event); 2135 2136 case KeyEvent.ACTION_UP: 2137 return super.onKeyUp(keyCode, event); 2138 2139 case KeyEvent.ACTION_MULTIPLE: 2140 return super.onKeyMultiple(keyCode, count, event); 2141 2142 default: // shouldn't happen 2143 return false; 2144 } 2145 } 2146 } 2147 2148 /** 2149 * Scrolls up or down by the number of items currently present on screen. 2150 * 2151 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2152 * @return whether selection was moved 2153 */ 2154 boolean pageScroll(int direction) { 2155 int nextPage = -1; 2156 boolean down = false; 2157 2158 if (direction == FOCUS_UP) { 2159 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2160 } else if (direction == FOCUS_DOWN) { 2161 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2162 down = true; 2163 } 2164 2165 if (nextPage >= 0) { 2166 int position = lookForSelectablePosition(nextPage, down); 2167 if (position >= 0) { 2168 mLayoutMode = LAYOUT_SPECIFIC; 2169 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2170 2171 if (down && position > mItemCount - getChildCount()) { 2172 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2173 } 2174 2175 if (!down && position < getChildCount()) { 2176 mLayoutMode = LAYOUT_FORCE_TOP; 2177 } 2178 2179 setSelectionInt(position); 2180 invokeOnItemScrollListener(); 2181 if (!awakenScrollBars()) { 2182 invalidate(); 2183 } 2184 2185 return true; 2186 } 2187 } 2188 2189 return false; 2190 } 2191 2192 /** 2193 * Go to the last or first item if possible (not worrying about panning across or navigating 2194 * within the internal focus of the currently selected item.) 2195 * 2196 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2197 * 2198 * @return whether selection was moved 2199 */ 2200 boolean fullScroll(int direction) { 2201 boolean moved = false; 2202 if (direction == FOCUS_UP) { 2203 if (mSelectedPosition != 0) { 2204 int position = lookForSelectablePosition(0, true); 2205 if (position >= 0) { 2206 mLayoutMode = LAYOUT_FORCE_TOP; 2207 setSelectionInt(position); 2208 invokeOnItemScrollListener(); 2209 } 2210 moved = true; 2211 } 2212 } else if (direction == FOCUS_DOWN) { 2213 if (mSelectedPosition < mItemCount - 1) { 2214 int position = lookForSelectablePosition(mItemCount - 1, true); 2215 if (position >= 0) { 2216 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2217 setSelectionInt(position); 2218 invokeOnItemScrollListener(); 2219 } 2220 moved = true; 2221 } 2222 } 2223 2224 if (moved && !awakenScrollBars()) { 2225 awakenScrollBars(); 2226 invalidate(); 2227 } 2228 2229 return moved; 2230 } 2231 2232 /** 2233 * To avoid horizontal focus searches changing the selected item, we 2234 * manually focus search within the selected item (as applicable), and 2235 * prevent focus from jumping to something within another item. 2236 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2237 * @return Whether this consumes the key event. 2238 */ 2239 private boolean handleHorizontalFocusWithinListItem(int direction) { 2240 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2241 throw new IllegalArgumentException("direction must be one of" 2242 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2243 } 2244 2245 final int numChildren = getChildCount(); 2246 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2247 final View selectedView = getSelectedView(); 2248 if (selectedView != null && selectedView.hasFocus() && 2249 selectedView instanceof ViewGroup) { 2250 2251 final View currentFocus = selectedView.findFocus(); 2252 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2253 (ViewGroup) selectedView, currentFocus, direction); 2254 if (nextFocus != null) { 2255 // do the math to get interesting rect in next focus' coordinates 2256 currentFocus.getFocusedRect(mTempRect); 2257 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2258 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2259 if (nextFocus.requestFocus(direction, mTempRect)) { 2260 return true; 2261 } 2262 } 2263 // we are blocking the key from being handled (by returning true) 2264 // if the global result is going to be some other view within this 2265 // list. this is to acheive the overall goal of having 2266 // horizontal d-pad navigation remain in the current item. 2267 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2268 (ViewGroup) getRootView(), currentFocus, direction); 2269 if (globalNextFocus != null) { 2270 return isViewAncestorOf(globalNextFocus, this); 2271 } 2272 } 2273 } 2274 return false; 2275 } 2276 2277 /** 2278 * Scrolls to the next or previous item if possible. 2279 * 2280 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2281 * 2282 * @return whether selection was moved 2283 */ 2284 boolean arrowScroll(int direction) { 2285 try { 2286 mInLayout = true; 2287 final boolean handled = arrowScrollImpl(direction); 2288 if (handled) { 2289 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2290 } 2291 return handled; 2292 } finally { 2293 mInLayout = false; 2294 } 2295 } 2296 2297 /** 2298 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2299 * whether there are focusable items etc. 2300 * 2301 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2302 * @return Whether any scrolling, selection or focus change occured. 2303 */ 2304 private boolean arrowScrollImpl(int direction) { 2305 if (getChildCount() <= 0) { 2306 return false; 2307 } 2308 2309 View selectedView = getSelectedView(); 2310 int selectedPos = mSelectedPosition; 2311 2312 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2313 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2314 2315 // if we are moving focus, we may OVERRIDE the default behavior 2316 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2317 if (focusResult != null) { 2318 nextSelectedPosition = focusResult.getSelectedPosition(); 2319 amountToScroll = focusResult.getAmountToScroll(); 2320 } 2321 2322 boolean needToRedraw = focusResult != null; 2323 if (nextSelectedPosition != INVALID_POSITION) { 2324 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2325 setSelectedPositionInt(nextSelectedPosition); 2326 setNextSelectedPositionInt(nextSelectedPosition); 2327 selectedView = getSelectedView(); 2328 selectedPos = nextSelectedPosition; 2329 if (mItemsCanFocus && focusResult == null) { 2330 // there was no new view found to take focus, make sure we 2331 // don't leave focus with the old selection 2332 final View focused = getFocusedChild(); 2333 if (focused != null) { 2334 focused.clearFocus(); 2335 } 2336 } 2337 needToRedraw = true; 2338 checkSelectionChanged(); 2339 } 2340 2341 if (amountToScroll > 0) { 2342 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2343 needToRedraw = true; 2344 } 2345 2346 // if we didn't find a new focusable, make sure any existing focused 2347 // item that was panned off screen gives up focus. 2348 if (mItemsCanFocus && (focusResult == null) 2349 && selectedView != null && selectedView.hasFocus()) { 2350 final View focused = selectedView.findFocus(); 2351 if (distanceToView(focused) > 0) { 2352 focused.clearFocus(); 2353 } 2354 } 2355 2356 // if the current selection is panned off, we need to remove the selection 2357 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2358 && !isViewAncestorOf(selectedView, this)) { 2359 selectedView = null; 2360 hideSelector(); 2361 2362 // but we don't want to set the ressurect position (that would make subsequent 2363 // unhandled key events bring back the item we just scrolled off!) 2364 mResurrectToPosition = INVALID_POSITION; 2365 } 2366 2367 if (needToRedraw) { 2368 if (selectedView != null) { 2369 positionSelector(selectedPos, selectedView); 2370 mSelectedTop = selectedView.getTop(); 2371 } 2372 if (!awakenScrollBars()) { 2373 invalidate(); 2374 } 2375 invokeOnItemScrollListener(); 2376 return true; 2377 } 2378 2379 return false; 2380 } 2381 2382 /** 2383 * When selection changes, it is possible that the previously selected or the 2384 * next selected item will change its size. If so, we need to offset some folks, 2385 * and re-layout the items as appropriate. 2386 * 2387 * @param selectedView The currently selected view (before changing selection). 2388 * should be <code>null</code> if there was no previous selection. 2389 * @param direction Either {@link android.view.View#FOCUS_UP} or 2390 * {@link android.view.View#FOCUS_DOWN}. 2391 * @param newSelectedPosition The position of the next selection. 2392 * @param newFocusAssigned whether new focus was assigned. This matters because 2393 * when something has focus, we don't want to show selection (ugh). 2394 */ 2395 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2396 boolean newFocusAssigned) { 2397 if (newSelectedPosition == INVALID_POSITION) { 2398 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2399 } 2400 2401 // whether or not we are moving down or up, we want to preserve the 2402 // top of whatever view is on top: 2403 // - moving down: the view that had selection 2404 // - moving up: the view that is getting selection 2405 View topView; 2406 View bottomView; 2407 int topViewIndex, bottomViewIndex; 2408 boolean topSelected = false; 2409 final int selectedIndex = mSelectedPosition - mFirstPosition; 2410 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2411 if (direction == View.FOCUS_UP) { 2412 topViewIndex = nextSelectedIndex; 2413 bottomViewIndex = selectedIndex; 2414 topView = getChildAt(topViewIndex); 2415 bottomView = selectedView; 2416 topSelected = true; 2417 } else { 2418 topViewIndex = selectedIndex; 2419 bottomViewIndex = nextSelectedIndex; 2420 topView = selectedView; 2421 bottomView = getChildAt(bottomViewIndex); 2422 } 2423 2424 final int numChildren = getChildCount(); 2425 2426 // start with top view: is it changing size? 2427 if (topView != null) { 2428 topView.setSelected(!newFocusAssigned && topSelected); 2429 measureAndAdjustDown(topView, topViewIndex, numChildren); 2430 } 2431 2432 // is the bottom view changing size? 2433 if (bottomView != null) { 2434 bottomView.setSelected(!newFocusAssigned && !topSelected); 2435 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2436 } 2437 } 2438 2439 /** 2440 * Re-measure a child, and if its height changes, lay it out preserving its 2441 * top, and adjust the children below it appropriately. 2442 * @param child The child 2443 * @param childIndex The view group index of the child. 2444 * @param numChildren The number of children in the view group. 2445 */ 2446 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2447 int oldHeight = child.getHeight(); 2448 measureItem(child); 2449 if (child.getMeasuredHeight() != oldHeight) { 2450 // lay out the view, preserving its top 2451 relayoutMeasuredItem(child); 2452 2453 // adjust views below appropriately 2454 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2455 for (int i = childIndex + 1; i < numChildren; i++) { 2456 getChildAt(i).offsetTopAndBottom(heightDelta); 2457 } 2458 } 2459 } 2460 2461 /** 2462 * Measure a particular list child. 2463 * TODO: unify with setUpChild. 2464 * @param child The child. 2465 */ 2466 private void measureItem(View child) { 2467 ViewGroup.LayoutParams p = child.getLayoutParams(); 2468 if (p == null) { 2469 p = new ViewGroup.LayoutParams( 2470 ViewGroup.LayoutParams.MATCH_PARENT, 2471 ViewGroup.LayoutParams.WRAP_CONTENT); 2472 } 2473 2474 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2475 mListPadding.left + mListPadding.right, p.width); 2476 int lpHeight = p.height; 2477 int childHeightSpec; 2478 if (lpHeight > 0) { 2479 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2480 } else { 2481 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2482 } 2483 child.measure(childWidthSpec, childHeightSpec); 2484 } 2485 2486 /** 2487 * Layout a child that has been measured, preserving its top position. 2488 * TODO: unify with setUpChild. 2489 * @param child The child. 2490 */ 2491 private void relayoutMeasuredItem(View child) { 2492 final int w = child.getMeasuredWidth(); 2493 final int h = child.getMeasuredHeight(); 2494 final int childLeft = mListPadding.left; 2495 final int childRight = childLeft + w; 2496 final int childTop = child.getTop(); 2497 final int childBottom = childTop + h; 2498 child.layout(childLeft, childTop, childRight, childBottom); 2499 } 2500 2501 /** 2502 * @return The amount to preview next items when arrow srolling. 2503 */ 2504 private int getArrowScrollPreviewLength() { 2505 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2506 } 2507 2508 /** 2509 * Determine how much we need to scroll in order to get the next selected view 2510 * visible, with a fading edge showing below as applicable. The amount is 2511 * capped at {@link #getMaxScrollAmount()} . 2512 * 2513 * @param direction either {@link android.view.View#FOCUS_UP} or 2514 * {@link android.view.View#FOCUS_DOWN}. 2515 * @param nextSelectedPosition The position of the next selection, or 2516 * {@link #INVALID_POSITION} if there is no next selectable position 2517 * @return The amount to scroll. Note: this is always positive! Direction 2518 * needs to be taken into account when actually scrolling. 2519 */ 2520 private int amountToScroll(int direction, int nextSelectedPosition) { 2521 final int listBottom = getHeight() - mListPadding.bottom; 2522 final int listTop = mListPadding.top; 2523 2524 final int numChildren = getChildCount(); 2525 2526 if (direction == View.FOCUS_DOWN) { 2527 int indexToMakeVisible = numChildren - 1; 2528 if (nextSelectedPosition != INVALID_POSITION) { 2529 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2530 } 2531 2532 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2533 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2534 2535 int goalBottom = listBottom; 2536 if (positionToMakeVisible < mItemCount - 1) { 2537 goalBottom -= getArrowScrollPreviewLength(); 2538 } 2539 2540 if (viewToMakeVisible.getBottom() <= goalBottom) { 2541 // item is fully visible. 2542 return 0; 2543 } 2544 2545 if (nextSelectedPosition != INVALID_POSITION 2546 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2547 // item already has enough of it visible, changing selection is good enough 2548 return 0; 2549 } 2550 2551 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2552 2553 if ((mFirstPosition + numChildren) == mItemCount) { 2554 // last is last in list -> make sure we don't scroll past it 2555 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2556 amountToScroll = Math.min(amountToScroll, max); 2557 } 2558 2559 return Math.min(amountToScroll, getMaxScrollAmount()); 2560 } else { 2561 int indexToMakeVisible = 0; 2562 if (nextSelectedPosition != INVALID_POSITION) { 2563 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2564 } 2565 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2566 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2567 int goalTop = listTop; 2568 if (positionToMakeVisible > 0) { 2569 goalTop += getArrowScrollPreviewLength(); 2570 } 2571 if (viewToMakeVisible.getTop() >= goalTop) { 2572 // item is fully visible. 2573 return 0; 2574 } 2575 2576 if (nextSelectedPosition != INVALID_POSITION && 2577 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2578 // item already has enough of it visible, changing selection is good enough 2579 return 0; 2580 } 2581 2582 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2583 if (mFirstPosition == 0) { 2584 // first is first in list -> make sure we don't scroll past it 2585 final int max = listTop - getChildAt(0).getTop(); 2586 amountToScroll = Math.min(amountToScroll, max); 2587 } 2588 return Math.min(amountToScroll, getMaxScrollAmount()); 2589 } 2590 } 2591 2592 /** 2593 * Holds results of focus aware arrow scrolling. 2594 */ 2595 static private class ArrowScrollFocusResult { 2596 private int mSelectedPosition; 2597 private int mAmountToScroll; 2598 2599 /** 2600 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2601 */ 2602 void populate(int selectedPosition, int amountToScroll) { 2603 mSelectedPosition = selectedPosition; 2604 mAmountToScroll = amountToScroll; 2605 } 2606 2607 public int getSelectedPosition() { 2608 return mSelectedPosition; 2609 } 2610 2611 public int getAmountToScroll() { 2612 return mAmountToScroll; 2613 } 2614 } 2615 2616 /** 2617 * @param direction either {@link android.view.View#FOCUS_UP} or 2618 * {@link android.view.View#FOCUS_DOWN}. 2619 * @return The position of the next selectable position of the views that 2620 * are currently visible, taking into account the fact that there might 2621 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2622 * selectable view on screen in the given direction. 2623 */ 2624 private int lookForSelectablePositionOnScreen(int direction) { 2625 final int firstPosition = mFirstPosition; 2626 if (direction == View.FOCUS_DOWN) { 2627 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2628 mSelectedPosition + 1 : 2629 firstPosition; 2630 if (startPos >= mAdapter.getCount()) { 2631 return INVALID_POSITION; 2632 } 2633 if (startPos < firstPosition) { 2634 startPos = firstPosition; 2635 } 2636 2637 final int lastVisiblePos = getLastVisiblePosition(); 2638 final ListAdapter adapter = getAdapter(); 2639 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2640 if (adapter.isEnabled(pos) 2641 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2642 return pos; 2643 } 2644 } 2645 } else { 2646 int last = firstPosition + getChildCount() - 1; 2647 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2648 mSelectedPosition - 1 : 2649 firstPosition + getChildCount() - 1; 2650 if (startPos < 0) { 2651 return INVALID_POSITION; 2652 } 2653 if (startPos > last) { 2654 startPos = last; 2655 } 2656 2657 final ListAdapter adapter = getAdapter(); 2658 for (int pos = startPos; pos >= firstPosition; pos--) { 2659 if (adapter.isEnabled(pos) 2660 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2661 return pos; 2662 } 2663 } 2664 } 2665 return INVALID_POSITION; 2666 } 2667 2668 /** 2669 * Do an arrow scroll based on focus searching. If a new view is 2670 * given focus, return the selection delta and amount to scroll via 2671 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2672 * 2673 * @param direction either {@link android.view.View#FOCUS_UP} or 2674 * {@link android.view.View#FOCUS_DOWN}. 2675 * @return The result if focus has changed, or <code>null</code>. 2676 */ 2677 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2678 final View selectedView = getSelectedView(); 2679 View newFocus; 2680 if (selectedView != null && selectedView.hasFocus()) { 2681 View oldFocus = selectedView.findFocus(); 2682 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2683 } else { 2684 if (direction == View.FOCUS_DOWN) { 2685 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2686 final int listTop = mListPadding.top + 2687 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2688 final int ySearchPoint = 2689 (selectedView != null && selectedView.getTop() > listTop) ? 2690 selectedView.getTop() : 2691 listTop; 2692 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2693 } else { 2694 final boolean bottomFadingEdgeShowing = 2695 (mFirstPosition + getChildCount() - 1) < mItemCount; 2696 final int listBottom = getHeight() - mListPadding.bottom - 2697 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2698 final int ySearchPoint = 2699 (selectedView != null && selectedView.getBottom() < listBottom) ? 2700 selectedView.getBottom() : 2701 listBottom; 2702 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2703 } 2704 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2705 } 2706 2707 if (newFocus != null) { 2708 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2709 2710 // if the focus change is in a different new position, make sure 2711 // we aren't jumping over another selectable position 2712 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2713 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2714 if (selectablePosition != INVALID_POSITION && 2715 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2716 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2717 return null; 2718 } 2719 } 2720 2721 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2722 2723 final int maxScrollAmount = getMaxScrollAmount(); 2724 if (focusScroll < maxScrollAmount) { 2725 // not moving too far, safe to give next view focus 2726 newFocus.requestFocus(direction); 2727 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2728 return mArrowScrollFocusResult; 2729 } else if (distanceToView(newFocus) < maxScrollAmount){ 2730 // Case to consider: 2731 // too far to get entire next focusable on screen, but by going 2732 // max scroll amount, we are getting it at least partially in view, 2733 // so give it focus and scroll the max ammount. 2734 newFocus.requestFocus(direction); 2735 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2736 return mArrowScrollFocusResult; 2737 } 2738 } 2739 return null; 2740 } 2741 2742 /** 2743 * @param newFocus The view that would have focus. 2744 * @return the position that contains newFocus 2745 */ 2746 private int positionOfNewFocus(View newFocus) { 2747 final int numChildren = getChildCount(); 2748 for (int i = 0; i < numChildren; i++) { 2749 final View child = getChildAt(i); 2750 if (isViewAncestorOf(newFocus, child)) { 2751 return mFirstPosition + i; 2752 } 2753 } 2754 throw new IllegalArgumentException("newFocus is not a child of any of the" 2755 + " children of the list!"); 2756 } 2757 2758 /** 2759 * Return true if child is an ancestor of parent, (or equal to the parent). 2760 */ 2761 private boolean isViewAncestorOf(View child, View parent) { 2762 if (child == parent) { 2763 return true; 2764 } 2765 2766 final ViewParent theParent = child.getParent(); 2767 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2768 } 2769 2770 /** 2771 * Determine how much we need to scroll in order to get newFocus in view. 2772 * @param direction either {@link android.view.View#FOCUS_UP} or 2773 * {@link android.view.View#FOCUS_DOWN}. 2774 * @param newFocus The view that would take focus. 2775 * @param positionOfNewFocus The position of the list item containing newFocus 2776 * @return The amount to scroll. Note: this is always positive! Direction 2777 * needs to be taken into account when actually scrolling. 2778 */ 2779 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2780 int amountToScroll = 0; 2781 newFocus.getDrawingRect(mTempRect); 2782 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2783 if (direction == View.FOCUS_UP) { 2784 if (mTempRect.top < mListPadding.top) { 2785 amountToScroll = mListPadding.top - mTempRect.top; 2786 if (positionOfNewFocus > 0) { 2787 amountToScroll += getArrowScrollPreviewLength(); 2788 } 2789 } 2790 } else { 2791 final int listBottom = getHeight() - mListPadding.bottom; 2792 if (mTempRect.bottom > listBottom) { 2793 amountToScroll = mTempRect.bottom - listBottom; 2794 if (positionOfNewFocus < mItemCount - 1) { 2795 amountToScroll += getArrowScrollPreviewLength(); 2796 } 2797 } 2798 } 2799 return amountToScroll; 2800 } 2801 2802 /** 2803 * Determine the distance to the nearest edge of a view in a particular 2804 * direction. 2805 * 2806 * @param descendant A descendant of this list. 2807 * @return The distance, or 0 if the nearest edge is already on screen. 2808 */ 2809 private int distanceToView(View descendant) { 2810 int distance = 0; 2811 descendant.getDrawingRect(mTempRect); 2812 offsetDescendantRectToMyCoords(descendant, mTempRect); 2813 final int listBottom = mBottom - mTop - mListPadding.bottom; 2814 if (mTempRect.bottom < mListPadding.top) { 2815 distance = mListPadding.top - mTempRect.bottom; 2816 } else if (mTempRect.top > listBottom) { 2817 distance = mTempRect.top - listBottom; 2818 } 2819 return distance; 2820 } 2821 2822 2823 /** 2824 * Scroll the children by amount, adding a view at the end and removing 2825 * views that fall off as necessary. 2826 * 2827 * @param amount The amount (positive or negative) to scroll. 2828 */ 2829 private void scrollListItemsBy(int amount) { 2830 offsetChildrenTopAndBottom(amount); 2831 2832 final int listBottom = getHeight() - mListPadding.bottom; 2833 final int listTop = mListPadding.top; 2834 final AbsListView.RecycleBin recycleBin = mRecycler; 2835 2836 if (amount < 0) { 2837 // shifted items up 2838 2839 // may need to pan views into the bottom space 2840 int numChildren = getChildCount(); 2841 View last = getChildAt(numChildren - 1); 2842 while (last.getBottom() < listBottom) { 2843 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2844 if (lastVisiblePosition < mItemCount - 1) { 2845 last = addViewBelow(last, lastVisiblePosition); 2846 numChildren++; 2847 } else { 2848 break; 2849 } 2850 } 2851 2852 // may have brought in the last child of the list that is skinnier 2853 // than the fading edge, thereby leaving space at the end. need 2854 // to shift back 2855 if (last.getBottom() < listBottom) { 2856 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2857 } 2858 2859 // top views may be panned off screen 2860 View first = getChildAt(0); 2861 while (first.getBottom() < listTop) { 2862 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2863 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2864 detachViewFromParent(first); 2865 recycleBin.addScrapView(first, mFirstPosition); 2866 } else { 2867 removeViewInLayout(first); 2868 } 2869 first = getChildAt(0); 2870 mFirstPosition++; 2871 } 2872 } else { 2873 // shifted items down 2874 View first = getChildAt(0); 2875 2876 // may need to pan views into top 2877 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2878 first = addViewAbove(first, mFirstPosition); 2879 mFirstPosition--; 2880 } 2881 2882 // may have brought the very first child of the list in too far and 2883 // need to shift it back 2884 if (first.getTop() > listTop) { 2885 offsetChildrenTopAndBottom(listTop - first.getTop()); 2886 } 2887 2888 int lastIndex = getChildCount() - 1; 2889 View last = getChildAt(lastIndex); 2890 2891 // bottom view may be panned off screen 2892 while (last.getTop() > listBottom) { 2893 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2894 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2895 detachViewFromParent(last); 2896 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 2897 } else { 2898 removeViewInLayout(last); 2899 } 2900 last = getChildAt(--lastIndex); 2901 } 2902 } 2903 } 2904 2905 private View addViewAbove(View theView, int position) { 2906 int abovePosition = position - 1; 2907 View view = obtainView(abovePosition, mIsScrap); 2908 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2909 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2910 false, mIsScrap[0]); 2911 return view; 2912 } 2913 2914 private View addViewBelow(View theView, int position) { 2915 int belowPosition = position + 1; 2916 View view = obtainView(belowPosition, mIsScrap); 2917 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2918 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2919 false, mIsScrap[0]); 2920 return view; 2921 } 2922 2923 /** 2924 * Indicates that the views created by the ListAdapter can contain focusable 2925 * items. 2926 * 2927 * @param itemsCanFocus true if items can get focus, false otherwise 2928 */ 2929 public void setItemsCanFocus(boolean itemsCanFocus) { 2930 mItemsCanFocus = itemsCanFocus; 2931 if (!itemsCanFocus) { 2932 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2933 } 2934 } 2935 2936 /** 2937 * @return Whether the views created by the ListAdapter can contain focusable 2938 * items. 2939 */ 2940 public boolean getItemsCanFocus() { 2941 return mItemsCanFocus; 2942 } 2943 2944 /** 2945 * @hide Pending API council approval. 2946 */ 2947 @Override 2948 public boolean isOpaque() { 2949 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2950 hasOpaqueScrollbars()) || super.isOpaque(); 2951 } 2952 2953 @Override 2954 public void setCacheColorHint(int color) { 2955 final boolean opaque = (color >>> 24) == 0xFF; 2956 mIsCacheColorOpaque = opaque; 2957 if (opaque) { 2958 if (mDividerPaint == null) { 2959 mDividerPaint = new Paint(); 2960 } 2961 mDividerPaint.setColor(color); 2962 } 2963 super.setCacheColorHint(color); 2964 } 2965 2966 @Override 2967 protected void dispatchDraw(Canvas canvas) { 2968 // Draw the dividers 2969 final int dividerHeight = mDividerHeight; 2970 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 2971 2972 if (drawDividers) { 2973 // Only modify the top and bottom in the loop, we set the left and right here 2974 final Rect bounds = mTempRect; 2975 bounds.left = mPaddingLeft; 2976 bounds.right = mRight - mLeft - mPaddingRight; 2977 2978 final int count = getChildCount(); 2979 final int headerCount = mHeaderViewInfos.size(); 2980 final int itemCount = mItemCount; 2981 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 2982 final boolean headerDividers = mHeaderDividersEnabled; 2983 final boolean footerDividers = mFooterDividersEnabled; 2984 final int first = mFirstPosition; 2985 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2986 final ListAdapter adapter = mAdapter; 2987 // If the list is opaque *and* the background is not, we want to 2988 // fill a rect where the dividers would be for non-selectable items 2989 // If the list is opaque and the background is also opaque, we don't 2990 // need to draw anything since the background will do it for us 2991 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2992 2993 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2994 mDividerPaint = new Paint(); 2995 mDividerPaint.setColor(getCacheColorHint()); 2996 } 2997 final Paint paint = mDividerPaint; 2998 2999 final int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY; 3000 if (!mStackFromBottom) { 3001 int bottom; 3002 3003 for (int i = 0; i < count; i++) { 3004 if ((headerDividers || first + i >= headerCount) && 3005 (footerDividers || first + i < footerLimit)) { 3006 View child = getChildAt(i); 3007 bottom = child.getBottom(); 3008 // Don't draw dividers next to items that are not enabled 3009 if ((areAllItemsSelectable || 3010 (adapter.isEnabled(first + i) && (i == count - 1 || 3011 adapter.isEnabled(first + i + 1))))) { 3012 bounds.top = bottom; 3013 bounds.bottom = bottom + dividerHeight; 3014 drawDivider(canvas, bounds, i); 3015 } else if (fillForMissingDividers) { 3016 bounds.top = bottom; 3017 bounds.bottom = bottom + dividerHeight; 3018 canvas.drawRect(bounds, paint); 3019 } 3020 } 3021 } 3022 } else { 3023 int top; 3024 int listTop = mListPadding.top; 3025 3026 final int scrollY = mScrollY; 3027 3028 for (int i = 0; i < count; i++) { 3029 if ((headerDividers || first + i >= headerCount) && 3030 (footerDividers || first + i < footerLimit)) { 3031 View child = getChildAt(i); 3032 top = child.getTop(); 3033 // Don't draw dividers next to items that are not enabled 3034 if (top > listTop) { 3035 if ((areAllItemsSelectable || 3036 (adapter.isEnabled(first + i) && (i == count - 1 || 3037 adapter.isEnabled(first + i + 1))))) { 3038 bounds.top = top - dividerHeight; 3039 bounds.bottom = top; 3040 // Give the method the child ABOVE the divider, so we 3041 // subtract one from our child 3042 // position. Give -1 when there is no child above the 3043 // divider. 3044 drawDivider(canvas, bounds, i - 1); 3045 } else if (fillForMissingDividers) { 3046 bounds.top = top - dividerHeight; 3047 bounds.bottom = top; 3048 canvas.drawRect(bounds, paint); 3049 } 3050 } 3051 } 3052 } 3053 3054 if (count > 0 && scrollY > 0) { 3055 bounds.top = listBottom; 3056 bounds.bottom = listBottom + dividerHeight; 3057 drawDivider(canvas, bounds, -1); 3058 } 3059 } 3060 } 3061 3062 // Draw the indicators (these should be drawn above the dividers) and children 3063 super.dispatchDraw(canvas); 3064 } 3065 3066 /** 3067 * Draws a divider for the given child in the given bounds. 3068 * 3069 * @param canvas The canvas to draw to. 3070 * @param bounds The bounds of the divider. 3071 * @param childIndex The index of child (of the View) above the divider. 3072 * This will be -1 if there is no child above the divider to be 3073 * drawn. 3074 */ 3075 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3076 // This widget draws the same divider for all children 3077 final Drawable divider = mDivider; 3078 3079 divider.setBounds(bounds); 3080 divider.draw(canvas); 3081 } 3082 3083 /** 3084 * Returns the drawable that will be drawn between each item in the list. 3085 * 3086 * @return the current drawable drawn between list elements 3087 */ 3088 public Drawable getDivider() { 3089 return mDivider; 3090 } 3091 3092 /** 3093 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3094 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3095 * 3096 * @param divider The drawable to use. 3097 */ 3098 public void setDivider(Drawable divider) { 3099 if (divider != null) { 3100 mDividerHeight = divider.getIntrinsicHeight(); 3101 } else { 3102 mDividerHeight = 0; 3103 } 3104 mDivider = divider; 3105 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3106 requestLayoutIfNecessary(); 3107 } 3108 3109 /** 3110 * @return Returns the height of the divider that will be drawn between each item in the list. 3111 */ 3112 public int getDividerHeight() { 3113 return mDividerHeight; 3114 } 3115 3116 /** 3117 * Sets the height of the divider that will be drawn between each item in the list. Calling 3118 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3119 * 3120 * @param height The new height of the divider in pixels. 3121 */ 3122 public void setDividerHeight(int height) { 3123 mDividerHeight = height; 3124 requestLayoutIfNecessary(); 3125 } 3126 3127 /** 3128 * Enables or disables the drawing of the divider for header views. 3129 * 3130 * @param headerDividersEnabled True to draw the headers, false otherwise. 3131 * 3132 * @see #setFooterDividersEnabled(boolean) 3133 * @see #addHeaderView(android.view.View) 3134 */ 3135 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3136 mHeaderDividersEnabled = headerDividersEnabled; 3137 invalidate(); 3138 } 3139 3140 /** 3141 * Enables or disables the drawing of the divider for footer views. 3142 * 3143 * @param footerDividersEnabled True to draw the footers, false otherwise. 3144 * 3145 * @see #setHeaderDividersEnabled(boolean) 3146 * @see #addFooterView(android.view.View) 3147 */ 3148 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3149 mFooterDividersEnabled = footerDividersEnabled; 3150 invalidate(); 3151 } 3152 3153 @Override 3154 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3155 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3156 3157 int closetChildIndex = -1; 3158 if (gainFocus && previouslyFocusedRect != null) { 3159 previouslyFocusedRect.offset(mScrollX, mScrollY); 3160 3161 final ListAdapter adapter = mAdapter; 3162 // Don't cache the result of getChildCount or mFirstPosition here, 3163 // it could change in layoutChildren. 3164 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3165 mLayoutMode = LAYOUT_NORMAL; 3166 layoutChildren(); 3167 } 3168 3169 // figure out which item should be selected based on previously 3170 // focused rect 3171 Rect otherRect = mTempRect; 3172 int minDistance = Integer.MAX_VALUE; 3173 final int childCount = getChildCount(); 3174 final int firstPosition = mFirstPosition; 3175 3176 for (int i = 0; i < childCount; i++) { 3177 // only consider selectable views 3178 if (!adapter.isEnabled(firstPosition + i)) { 3179 continue; 3180 } 3181 3182 View other = getChildAt(i); 3183 other.getDrawingRect(otherRect); 3184 offsetDescendantRectToMyCoords(other, otherRect); 3185 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3186 3187 if (distance < minDistance) { 3188 minDistance = distance; 3189 closetChildIndex = i; 3190 } 3191 } 3192 } 3193 3194 if (closetChildIndex >= 0) { 3195 setSelection(closetChildIndex + mFirstPosition); 3196 } else { 3197 requestLayout(); 3198 } 3199 } 3200 3201 3202 /* 3203 * (non-Javadoc) 3204 * 3205 * Children specified in XML are assumed to be header views. After we have 3206 * parsed them move them out of the children list and into mHeaderViews. 3207 */ 3208 @Override 3209 protected void onFinishInflate() { 3210 super.onFinishInflate(); 3211 3212 int count = getChildCount(); 3213 if (count > 0) { 3214 for (int i = 0; i < count; ++i) { 3215 addHeaderView(getChildAt(i)); 3216 } 3217 removeAllViews(); 3218 } 3219 } 3220 3221 /* (non-Javadoc) 3222 * @see android.view.View#findViewById(int) 3223 * First look in our children, then in any header and footer views that may be scrolled off. 3224 */ 3225 @Override 3226 protected View findViewTraversal(int id) { 3227 View v; 3228 v = super.findViewTraversal(id); 3229 if (v == null) { 3230 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3231 if (v != null) { 3232 return v; 3233 } 3234 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3235 if (v != null) { 3236 return v; 3237 } 3238 } 3239 return v; 3240 } 3241 3242 /* (non-Javadoc) 3243 * 3244 * Look in the passed in list of headers or footers for the view. 3245 */ 3246 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3247 if (where != null) { 3248 int len = where.size(); 3249 View v; 3250 3251 for (int i = 0; i < len; i++) { 3252 v = where.get(i).view; 3253 3254 if (!v.isRootNamespace()) { 3255 v = v.findViewById(id); 3256 3257 if (v != null) { 3258 return v; 3259 } 3260 } 3261 } 3262 } 3263 return null; 3264 } 3265 3266 /* (non-Javadoc) 3267 * @see android.view.View#findViewWithTag(String) 3268 * First look in our children, then in any header and footer views that may be scrolled off. 3269 */ 3270 @Override 3271 protected View findViewWithTagTraversal(Object tag) { 3272 View v; 3273 v = super.findViewWithTagTraversal(tag); 3274 if (v == null) { 3275 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3276 if (v != null) { 3277 return v; 3278 } 3279 3280 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3281 if (v != null) { 3282 return v; 3283 } 3284 } 3285 return v; 3286 } 3287 3288 /* (non-Javadoc) 3289 * 3290 * Look in the passed in list of headers or footers for the view with the tag. 3291 */ 3292 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3293 if (where != null) { 3294 int len = where.size(); 3295 View v; 3296 3297 for (int i = 0; i < len; i++) { 3298 v = where.get(i).view; 3299 3300 if (!v.isRootNamespace()) { 3301 v = v.findViewWithTag(tag); 3302 3303 if (v != null) { 3304 return v; 3305 } 3306 } 3307 } 3308 } 3309 return null; 3310 } 3311 3312 @Override 3313 public boolean onTouchEvent(MotionEvent ev) { 3314 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3315 // Don't handle edge touches immediately -- they may actually belong to one of our 3316 // descendants. 3317 return false; 3318 } 3319 return super.onTouchEvent(ev); 3320 } 3321 3322 /** 3323 * Returns the set of checked items ids. The result is only valid if the 3324 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3325 * 3326 * @return A new array which contains the id of each checked item in the 3327 * list. 3328 * 3329 * @deprecated Use {@link #getCheckedItemIds()} instead. 3330 */ 3331 @Deprecated 3332 public long[] getCheckItemIds() { 3333 // Use new behavior that correctly handles stable ID mapping. 3334 if (mAdapter != null && mAdapter.hasStableIds()) { 3335 return getCheckedItemIds(); 3336 } 3337 3338 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3339 // Fall back to it to support legacy apps. 3340 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3341 final SparseBooleanArray states = mCheckStates; 3342 final int count = states.size(); 3343 final long[] ids = new long[count]; 3344 final ListAdapter adapter = mAdapter; 3345 3346 int checkedCount = 0; 3347 for (int i = 0; i < count; i++) { 3348 if (states.valueAt(i)) { 3349 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3350 } 3351 } 3352 3353 // Trim array if needed. mCheckStates may contain false values 3354 // resulting in checkedCount being smaller than count. 3355 if (checkedCount == count) { 3356 return ids; 3357 } else { 3358 final long[] result = new long[checkedCount]; 3359 System.arraycopy(ids, 0, result, 0, checkedCount); 3360 3361 return result; 3362 } 3363 } 3364 return new long[0]; 3365 } 3366} 3367