ListView.java revision 8f1bfe1a7cef702fd74e5405443e9fdb7c5e7556
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.res.TypedArray; 24import android.graphics.Canvas; 25import android.graphics.Paint; 26import android.graphics.PixelFormat; 27import android.graphics.Rect; 28import android.graphics.drawable.ColorDrawable; 29import android.graphics.drawable.Drawable; 30import android.os.Parcel; 31import android.os.Parcelable; 32import android.util.AttributeSet; 33import android.util.LongSparseArray; 34import android.util.SparseBooleanArray; 35import android.view.FocusFinder; 36import android.view.KeyEvent; 37import android.view.MotionEvent; 38import android.view.SoundEffectConstants; 39import android.view.View; 40import android.view.ViewDebug; 41import android.view.ViewGroup; 42import android.view.ViewParent; 43import android.view.accessibility.AccessibilityEvent; 44 45import java.util.ArrayList; 46 47/* 48 * Implementation Notes: 49 * 50 * Some terminology: 51 * 52 * index - index of the items that are currently visible 53 * position - index of the items in the cursor 54 */ 55 56 57/** 58 * A view that shows items in a vertically scrolling list. The items 59 * come from the {@link ListAdapter} associated with this view. 60 * 61 * @attr ref android.R.styleable#ListView_entries 62 * @attr ref android.R.styleable#ListView_divider 63 * @attr ref android.R.styleable#ListView_dividerHeight 64 * @attr ref android.R.styleable#ListView_choiceMode 65 * @attr ref android.R.styleable#ListView_headerDividersEnabled 66 * @attr ref android.R.styleable#ListView_footerDividersEnabled 67 */ 68public class ListView extends AbsListView { 69 /** 70 * Used to indicate a no preference for a position type. 71 */ 72 static final int NO_POSITION = -1; 73 74 /** 75 * Normal list that does not indicate choices 76 */ 77 public static final int CHOICE_MODE_NONE = 0; 78 79 /** 80 * The list allows up to one choice 81 */ 82 public static final int CHOICE_MODE_SINGLE = 1; 83 84 /** 85 * The list allows multiple choices 86 */ 87 public static final int CHOICE_MODE_MULTIPLE = 2; 88 89 /** 90 * When arrow scrolling, ListView will never scroll more than this factor 91 * times the height of the list. 92 */ 93 private static final float MAX_SCROLL_FACTOR = 0.33f; 94 95 /** 96 * When arrow scrolling, need a certain amount of pixels to preview next 97 * items. This is usually the fading edge, but if that is small enough, 98 * we want to make sure we preview at least this many pixels. 99 */ 100 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 101 102 /** 103 * A class that represents a fixed view in a list, for example a header at the top 104 * or a footer at the bottom. 105 */ 106 public class FixedViewInfo { 107 /** The view to add to the list */ 108 public View view; 109 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 110 public Object data; 111 /** <code>true</code> if the fixed view should be selectable in the list */ 112 public boolean isSelectable; 113 } 114 115 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 116 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 117 118 Drawable mDivider; 119 int mDividerHeight; 120 121 private boolean mIsCacheColorOpaque; 122 private boolean mDividerIsOpaque; 123 private boolean mClipDivider; 124 125 private boolean mHeaderDividersEnabled; 126 private boolean mFooterDividersEnabled; 127 128 private boolean mAreAllItemsSelectable = true; 129 130 private boolean mItemsCanFocus = false; 131 132 private int mChoiceMode = CHOICE_MODE_NONE; 133 134 private SparseBooleanArray mCheckStates; 135 private LongSparseArray<Boolean> mCheckedIdStates; 136 137 // used for temporary calculations. 138 private final Rect mTempRect = new Rect(); 139 private Paint mDividerPaint; 140 141 // the single allocated result per list view; kinda cheesey but avoids 142 // allocating these thingies too often. 143 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 144 145 // Keeps focused children visible through resizes 146 private FocusSelector mFocusSelector; 147 148 public ListView(Context context) { 149 this(context, null); 150 } 151 152 public ListView(Context context, AttributeSet attrs) { 153 this(context, attrs, com.android.internal.R.attr.listViewStyle); 154 } 155 156 public ListView(Context context, AttributeSet attrs, int defStyle) { 157 super(context, attrs, defStyle); 158 159 TypedArray a = context.obtainStyledAttributes(attrs, 160 com.android.internal.R.styleable.ListView, defStyle, 0); 161 162 CharSequence[] entries = a.getTextArray( 163 com.android.internal.R.styleable.ListView_entries); 164 if (entries != null) { 165 setAdapter(new ArrayAdapter<CharSequence>(context, 166 com.android.internal.R.layout.simple_list_item_1, entries)); 167 } 168 169 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 170 if (d != null) { 171 // If a divider is specified use its intrinsic height for divider height 172 setDivider(d); 173 } 174 175 // Use the height specified, zero being the default 176 final int dividerHeight = a.getDimensionPixelSize( 177 com.android.internal.R.styleable.ListView_dividerHeight, 0); 178 if (dividerHeight != 0) { 179 setDividerHeight(dividerHeight); 180 } 181 182 setChoiceMode(a.getInt(R.styleable.ListView_choiceMode, CHOICE_MODE_NONE)); 183 184 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 185 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 186 187 a.recycle(); 188 } 189 190 /** 191 * @return The maximum amount a list view will scroll in response to 192 * an arrow event. 193 */ 194 public int getMaxScrollAmount() { 195 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 196 } 197 198 /** 199 * Make sure views are touching the top or bottom edge, as appropriate for 200 * our gravity 201 */ 202 private void adjustViewsUpOrDown() { 203 final int childCount = getChildCount(); 204 int delta; 205 206 if (childCount > 0) { 207 View child; 208 209 if (!mStackFromBottom) { 210 // Uh-oh -- we came up short. Slide all views up to make them 211 // align with the top 212 child = getChildAt(0); 213 delta = child.getTop() - mListPadding.top; 214 if (mFirstPosition != 0) { 215 // It's OK to have some space above the first item if it is 216 // part of the vertical spacing 217 delta -= mDividerHeight; 218 } 219 if (delta < 0) { 220 // We only are looking to see if we are too low, not too high 221 delta = 0; 222 } 223 } else { 224 // we are too high, slide all views down to align with bottom 225 child = getChildAt(childCount - 1); 226 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 227 228 if (mFirstPosition + childCount < mItemCount) { 229 // It's OK to have some space below the last item if it is 230 // part of the vertical spacing 231 delta += mDividerHeight; 232 } 233 234 if (delta > 0) { 235 delta = 0; 236 } 237 } 238 239 if (delta != 0) { 240 offsetChildrenTopAndBottom(-delta); 241 } 242 } 243 } 244 245 /** 246 * Add a fixed view to appear at the top of the list. If addHeaderView is 247 * called more than once, the views will appear in the order they were 248 * added. Views added using this call can take focus if they want. 249 * <p> 250 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 251 * the supplied cursor with one that will also account for header and footer 252 * views. 253 * 254 * @param v The view to add. 255 * @param data Data to associate with this view 256 * @param isSelectable whether the item is selectable 257 */ 258 public void addHeaderView(View v, Object data, boolean isSelectable) { 259 260 if (mAdapter != null) { 261 throw new IllegalStateException( 262 "Cannot add header view to list -- setAdapter has already been called."); 263 } 264 265 FixedViewInfo info = new FixedViewInfo(); 266 info.view = v; 267 info.data = data; 268 info.isSelectable = isSelectable; 269 mHeaderViewInfos.add(info); 270 } 271 272 /** 273 * Add a fixed view to appear at the top of the list. If addHeaderView is 274 * called more than once, the views will appear in the order they were 275 * added. Views added using this call can take focus if they want. 276 * <p> 277 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 278 * the supplied cursor with one that will also account for header and footer 279 * views. 280 * 281 * @param v The view to add. 282 */ 283 public void addHeaderView(View v) { 284 addHeaderView(v, null, true); 285 } 286 287 @Override 288 public int getHeaderViewsCount() { 289 return mHeaderViewInfos.size(); 290 } 291 292 /** 293 * Removes a previously-added header view. 294 * 295 * @param v The view to remove 296 * @return true if the view was removed, false if the view was not a header 297 * view 298 */ 299 public boolean removeHeaderView(View v) { 300 if (mHeaderViewInfos.size() > 0) { 301 boolean result = false; 302 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 303 mDataSetObserver.onChanged(); 304 result = true; 305 } 306 removeFixedViewInfo(v, mHeaderViewInfos); 307 return result; 308 } 309 return false; 310 } 311 312 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 313 int len = where.size(); 314 for (int i = 0; i < len; ++i) { 315 FixedViewInfo info = where.get(i); 316 if (info.view == v) { 317 where.remove(i); 318 break; 319 } 320 } 321 } 322 323 /** 324 * Add a fixed view to appear at the bottom of the list. If addFooterView is 325 * called more than once, the views will appear in the order they were 326 * added. Views added using this call can take focus if they want. 327 * <p> 328 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 329 * the supplied cursor with one that will also account for header and footer 330 * views. 331 * 332 * @param v The view to add. 333 * @param data Data to associate with this view 334 * @param isSelectable true if the footer view can be selected 335 */ 336 public void addFooterView(View v, Object data, boolean isSelectable) { 337 FixedViewInfo info = new FixedViewInfo(); 338 info.view = v; 339 info.data = data; 340 info.isSelectable = isSelectable; 341 mFooterViewInfos.add(info); 342 343 // in the case of re-adding a footer view, or adding one later on, 344 // we need to notify the observer 345 if (mDataSetObserver != null) { 346 mDataSetObserver.onChanged(); 347 } 348 } 349 350 /** 351 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 352 * than once, the views will appear in the order they were added. Views added using 353 * this call can take focus if they want. 354 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 355 * cursor with one that will also account for header and footer views. 356 * 357 * 358 * @param v The view to add. 359 */ 360 public void addFooterView(View v) { 361 addFooterView(v, null, true); 362 } 363 364 @Override 365 public int getFooterViewsCount() { 366 return mFooterViewInfos.size(); 367 } 368 369 /** 370 * Removes a previously-added footer view. 371 * 372 * @param v The view to remove 373 * @return 374 * true if the view was removed, false if the view was not a footer view 375 */ 376 public boolean removeFooterView(View v) { 377 if (mFooterViewInfos.size() > 0) { 378 boolean result = false; 379 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 380 mDataSetObserver.onChanged(); 381 result = true; 382 } 383 removeFixedViewInfo(v, mFooterViewInfos); 384 return result; 385 } 386 return false; 387 } 388 389 /** 390 * Returns the adapter currently in use in this ListView. The returned adapter 391 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 392 * might be a {@link WrapperListAdapter}. 393 * 394 * @return The adapter currently used to display data in this ListView. 395 * 396 * @see #setAdapter(ListAdapter) 397 */ 398 @Override 399 public ListAdapter getAdapter() { 400 return mAdapter; 401 } 402 403 /** 404 * Sets the data behind this ListView. 405 * 406 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 407 * depending on the ListView features currently in use. For instance, adding 408 * headers and/or footers will cause the adapter to be wrapped. 409 * 410 * @param adapter The ListAdapter which is responsible for maintaining the 411 * data backing this list and for producing a view to represent an 412 * item in that data set. 413 * 414 * @see #getAdapter() 415 */ 416 @Override 417 public void setAdapter(ListAdapter adapter) { 418 if (null != mAdapter) { 419 mAdapter.unregisterDataSetObserver(mDataSetObserver); 420 } 421 422 resetList(); 423 mRecycler.clear(); 424 425 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 426 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 427 } else { 428 mAdapter = adapter; 429 } 430 431 mOldSelectedPosition = INVALID_POSITION; 432 mOldSelectedRowId = INVALID_ROW_ID; 433 if (mAdapter != null) { 434 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 435 mOldItemCount = mItemCount; 436 mItemCount = mAdapter.getCount(); 437 checkFocus(); 438 439 mDataSetObserver = new AdapterDataSetObserver(); 440 mAdapter.registerDataSetObserver(mDataSetObserver); 441 442 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 443 444 int position; 445 if (mStackFromBottom) { 446 position = lookForSelectablePosition(mItemCount - 1, false); 447 } else { 448 position = lookForSelectablePosition(0, true); 449 } 450 setSelectedPositionInt(position); 451 setNextSelectedPositionInt(position); 452 453 if (mItemCount == 0) { 454 // Nothing selected 455 checkSelectionChanged(); 456 } 457 458 } else { 459 mAreAllItemsSelectable = true; 460 checkFocus(); 461 // Nothing selected 462 checkSelectionChanged(); 463 } 464 465 if (mCheckStates != null) { 466 mCheckStates.clear(); 467 } 468 469 if (mCheckedIdStates != null) { 470 mCheckedIdStates.clear(); 471 } 472 473 requestLayout(); 474 } 475 476 477 /** 478 * The list is empty. Clear everything out. 479 */ 480 @Override 481 void resetList() { 482 // The parent's resetList() will remove all views from the layout so we need to 483 // cleanup the state of our footers and headers 484 clearRecycledState(mHeaderViewInfos); 485 clearRecycledState(mFooterViewInfos); 486 487 super.resetList(); 488 489 mLayoutMode = LAYOUT_NORMAL; 490 } 491 492 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 493 if (infos != null) { 494 final int count = infos.size(); 495 496 for (int i = 0; i < count; i++) { 497 final View child = infos.get(i).view; 498 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 499 if (p != null) { 500 p.recycledHeaderFooter = false; 501 } 502 } 503 } 504 } 505 506 /** 507 * @return Whether the list needs to show the top fading edge 508 */ 509 private boolean showingTopFadingEdge() { 510 final int listTop = mScrollY + mListPadding.top; 511 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 512 } 513 514 /** 515 * @return Whether the list needs to show the bottom fading edge 516 */ 517 private boolean showingBottomFadingEdge() { 518 final int childCount = getChildCount(); 519 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 520 final int lastVisiblePosition = mFirstPosition + childCount - 1; 521 522 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 523 524 return (lastVisiblePosition < mItemCount - 1) 525 || (bottomOfBottomChild < listBottom); 526 } 527 528 529 @Override 530 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 531 532 int rectTopWithinChild = rect.top; 533 534 // offset so rect is in coordinates of the this view 535 rect.offset(child.getLeft(), child.getTop()); 536 rect.offset(-child.getScrollX(), -child.getScrollY()); 537 538 final int height = getHeight(); 539 int listUnfadedTop = getScrollY(); 540 int listUnfadedBottom = listUnfadedTop + height; 541 final int fadingEdge = getVerticalFadingEdgeLength(); 542 543 if (showingTopFadingEdge()) { 544 // leave room for top fading edge as long as rect isn't at very top 545 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 546 listUnfadedTop += fadingEdge; 547 } 548 } 549 550 int childCount = getChildCount(); 551 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 552 553 if (showingBottomFadingEdge()) { 554 // leave room for bottom fading edge as long as rect isn't at very bottom 555 if ((mSelectedPosition < mItemCount - 1) 556 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 557 listUnfadedBottom -= fadingEdge; 558 } 559 } 560 561 int scrollYDelta = 0; 562 563 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 564 // need to MOVE DOWN to get it in view: move down just enough so 565 // that the entire rectangle is in view (or at least the first 566 // screen size chunk). 567 568 if (rect.height() > height) { 569 // just enough to get screen size chunk on 570 scrollYDelta += (rect.top - listUnfadedTop); 571 } else { 572 // get entire rect at bottom of screen 573 scrollYDelta += (rect.bottom - listUnfadedBottom); 574 } 575 576 // make sure we aren't scrolling beyond the end of our children 577 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 578 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 579 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 580 // need to MOVE UP to get it in view: move up just enough so that 581 // entire rectangle is in view (or at least the first screen 582 // size chunk of it). 583 584 if (rect.height() > height) { 585 // screen size chunk 586 scrollYDelta -= (listUnfadedBottom - rect.bottom); 587 } else { 588 // entire rect at top 589 scrollYDelta -= (listUnfadedTop - rect.top); 590 } 591 592 // make sure we aren't scrolling any further than the top our children 593 int top = getChildAt(0).getTop(); 594 int deltaToTop = top - listUnfadedTop; 595 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 596 } 597 598 final boolean scroll = scrollYDelta != 0; 599 if (scroll) { 600 scrollListItemsBy(-scrollYDelta); 601 positionSelector(child); 602 mSelectedTop = child.getTop(); 603 invalidate(); 604 } 605 return scroll; 606 } 607 608 /** 609 * {@inheritDoc} 610 */ 611 @Override 612 void fillGap(boolean down) { 613 final int count = getChildCount(); 614 if (down) { 615 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 616 getListPaddingTop(); 617 fillDown(mFirstPosition + count, startOffset); 618 correctTooHigh(getChildCount()); 619 } else { 620 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 621 getHeight() - getListPaddingBottom(); 622 fillUp(mFirstPosition - 1, startOffset); 623 correctTooLow(getChildCount()); 624 } 625 } 626 627 /** 628 * Fills the list from pos down to the end of the list view. 629 * 630 * @param pos The first position to put in the list 631 * 632 * @param nextTop The location where the top of the item associated with pos 633 * should be drawn 634 * 635 * @return The view that is currently selected, if it happens to be in the 636 * range that we draw. 637 */ 638 private View fillDown(int pos, int nextTop) { 639 View selectedView = null; 640 641 int end = (mBottom - mTop) - mListPadding.bottom; 642 643 while (nextTop < end && pos < mItemCount) { 644 // is this the selected item? 645 boolean selected = pos == mSelectedPosition; 646 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 647 648 nextTop = child.getBottom() + mDividerHeight; 649 if (selected) { 650 selectedView = child; 651 } 652 pos++; 653 } 654 655 return selectedView; 656 } 657 658 /** 659 * Fills the list from pos up to the top of the list view. 660 * 661 * @param pos The first position to put in the list 662 * 663 * @param nextBottom The location where the bottom of the item associated 664 * with pos should be drawn 665 * 666 * @return The view that is currently selected 667 */ 668 private View fillUp(int pos, int nextBottom) { 669 View selectedView = null; 670 671 int end = mListPadding.top; 672 673 while (nextBottom > end && pos >= 0) { 674 // is this the selected item? 675 boolean selected = pos == mSelectedPosition; 676 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 677 nextBottom = child.getTop() - mDividerHeight; 678 if (selected) { 679 selectedView = child; 680 } 681 pos--; 682 } 683 684 mFirstPosition = pos + 1; 685 686 return selectedView; 687 } 688 689 /** 690 * Fills the list from top to bottom, starting with mFirstPosition 691 * 692 * @param nextTop The location where the top of the first item should be 693 * drawn 694 * 695 * @return The view that is currently selected 696 */ 697 private View fillFromTop(int nextTop) { 698 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 699 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 700 if (mFirstPosition < 0) { 701 mFirstPosition = 0; 702 } 703 return fillDown(mFirstPosition, nextTop); 704 } 705 706 707 /** 708 * Put mSelectedPosition in the middle of the screen and then build up and 709 * down from there. This method forces mSelectedPosition to the center. 710 * 711 * @param childrenTop Top of the area in which children can be drawn, as 712 * measured in pixels 713 * @param childrenBottom Bottom of the area in which children can be drawn, 714 * as measured in pixels 715 * @return Currently selected view 716 */ 717 private View fillFromMiddle(int childrenTop, int childrenBottom) { 718 int height = childrenBottom - childrenTop; 719 720 int position = reconcileSelectedPosition(); 721 722 View sel = makeAndAddView(position, childrenTop, true, 723 mListPadding.left, true); 724 mFirstPosition = position; 725 726 int selHeight = sel.getMeasuredHeight(); 727 if (selHeight <= height) { 728 sel.offsetTopAndBottom((height - selHeight) / 2); 729 } 730 731 fillAboveAndBelow(sel, position); 732 733 if (!mStackFromBottom) { 734 correctTooHigh(getChildCount()); 735 } else { 736 correctTooLow(getChildCount()); 737 } 738 739 return sel; 740 } 741 742 /** 743 * Once the selected view as been placed, fill up the visible area above and 744 * below it. 745 * 746 * @param sel The selected view 747 * @param position The position corresponding to sel 748 */ 749 private void fillAboveAndBelow(View sel, int position) { 750 final int dividerHeight = mDividerHeight; 751 if (!mStackFromBottom) { 752 fillUp(position - 1, sel.getTop() - dividerHeight); 753 adjustViewsUpOrDown(); 754 fillDown(position + 1, sel.getBottom() + dividerHeight); 755 } else { 756 fillDown(position + 1, sel.getBottom() + dividerHeight); 757 adjustViewsUpOrDown(); 758 fillUp(position - 1, sel.getTop() - dividerHeight); 759 } 760 } 761 762 763 /** 764 * Fills the grid based on positioning the new selection at a specific 765 * location. The selection may be moved so that it does not intersect the 766 * faded edges. The grid is then filled upwards and downwards from there. 767 * 768 * @param selectedTop Where the selected item should be 769 * @param childrenTop Where to start drawing children 770 * @param childrenBottom Last pixel where children can be drawn 771 * @return The view that currently has selection 772 */ 773 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 774 int fadingEdgeLength = getVerticalFadingEdgeLength(); 775 final int selectedPosition = mSelectedPosition; 776 777 View sel; 778 779 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 780 selectedPosition); 781 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 782 selectedPosition); 783 784 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 785 786 787 // Some of the newly selected item extends below the bottom of the list 788 if (sel.getBottom() > bottomSelectionPixel) { 789 // Find space available above the selection into which we can scroll 790 // upwards 791 final int spaceAbove = sel.getTop() - topSelectionPixel; 792 793 // Find space required to bring the bottom of the selected item 794 // fully into view 795 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 796 final int offset = Math.min(spaceAbove, spaceBelow); 797 798 // Now offset the selected item to get it into view 799 sel.offsetTopAndBottom(-offset); 800 } else if (sel.getTop() < topSelectionPixel) { 801 // Find space required to bring the top of the selected item fully 802 // into view 803 final int spaceAbove = topSelectionPixel - sel.getTop(); 804 805 // Find space available below the selection into which we can scroll 806 // downwards 807 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 808 final int offset = Math.min(spaceAbove, spaceBelow); 809 810 // Offset the selected item to get it into view 811 sel.offsetTopAndBottom(offset); 812 } 813 814 // Fill in views above and below 815 fillAboveAndBelow(sel, selectedPosition); 816 817 if (!mStackFromBottom) { 818 correctTooHigh(getChildCount()); 819 } else { 820 correctTooLow(getChildCount()); 821 } 822 823 return sel; 824 } 825 826 /** 827 * Calculate the bottom-most pixel we can draw the selection into 828 * 829 * @param childrenBottom Bottom pixel were children can be drawn 830 * @param fadingEdgeLength Length of the fading edge in pixels, if present 831 * @param selectedPosition The position that will be selected 832 * @return The bottom-most pixel we can draw the selection into 833 */ 834 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 835 int selectedPosition) { 836 int bottomSelectionPixel = childrenBottom; 837 if (selectedPosition != mItemCount - 1) { 838 bottomSelectionPixel -= fadingEdgeLength; 839 } 840 return bottomSelectionPixel; 841 } 842 843 /** 844 * Calculate the top-most pixel we can draw the selection into 845 * 846 * @param childrenTop Top pixel were children can be drawn 847 * @param fadingEdgeLength Length of the fading edge in pixels, if present 848 * @param selectedPosition The position that will be selected 849 * @return The top-most pixel we can draw the selection into 850 */ 851 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 852 // first pixel we can draw the selection into 853 int topSelectionPixel = childrenTop; 854 if (selectedPosition > 0) { 855 topSelectionPixel += fadingEdgeLength; 856 } 857 return topSelectionPixel; 858 } 859 860 861 /** 862 * Fills the list based on positioning the new selection relative to the old 863 * selection. The new selection will be placed at, above, or below the 864 * location of the new selection depending on how the selection is moving. 865 * The selection will then be pinned to the visible part of the screen, 866 * excluding the edges that are faded. The list is then filled upwards and 867 * downwards from there. 868 * 869 * @param oldSel The old selected view. Useful for trying to put the new 870 * selection in the same place 871 * @param newSel The view that is to become selected. Useful for trying to 872 * put the new selection in the same place 873 * @param delta Which way we are moving 874 * @param childrenTop Where to start drawing children 875 * @param childrenBottom Last pixel where children can be drawn 876 * @return The view that currently has selection 877 */ 878 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 879 int childrenBottom) { 880 int fadingEdgeLength = getVerticalFadingEdgeLength(); 881 final int selectedPosition = mSelectedPosition; 882 883 View sel; 884 885 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 886 selectedPosition); 887 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 888 selectedPosition); 889 890 if (delta > 0) { 891 /* 892 * Case 1: Scrolling down. 893 */ 894 895 /* 896 * Before After 897 * | | | | 898 * +-------+ +-------+ 899 * | A | | A | 900 * | 1 | => +-------+ 901 * +-------+ | B | 902 * | B | | 2 | 903 * +-------+ +-------+ 904 * | | | | 905 * 906 * Try to keep the top of the previously selected item where it was. 907 * oldSel = A 908 * sel = B 909 */ 910 911 // Put oldSel (A) where it belongs 912 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 913 mListPadding.left, false); 914 915 final int dividerHeight = mDividerHeight; 916 917 // Now put the new selection (B) below that 918 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 919 mListPadding.left, true); 920 921 // Some of the newly selected item extends below the bottom of the list 922 if (sel.getBottom() > bottomSelectionPixel) { 923 924 // Find space available above the selection into which we can scroll upwards 925 int spaceAbove = sel.getTop() - topSelectionPixel; 926 927 // Find space required to bring the bottom of the selected item fully into view 928 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 929 930 // Don't scroll more than half the height of the list 931 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 932 int offset = Math.min(spaceAbove, spaceBelow); 933 offset = Math.min(offset, halfVerticalSpace); 934 935 // We placed oldSel, so offset that item 936 oldSel.offsetTopAndBottom(-offset); 937 // Now offset the selected item to get it into view 938 sel.offsetTopAndBottom(-offset); 939 } 940 941 // Fill in views above and below 942 if (!mStackFromBottom) { 943 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 944 adjustViewsUpOrDown(); 945 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 946 } else { 947 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 948 adjustViewsUpOrDown(); 949 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 950 } 951 } else if (delta < 0) { 952 /* 953 * Case 2: Scrolling up. 954 */ 955 956 /* 957 * Before After 958 * | | | | 959 * +-------+ +-------+ 960 * | A | | A | 961 * +-------+ => | 1 | 962 * | B | +-------+ 963 * | 2 | | B | 964 * +-------+ +-------+ 965 * | | | | 966 * 967 * Try to keep the top of the item about to become selected where it was. 968 * newSel = A 969 * olSel = B 970 */ 971 972 if (newSel != null) { 973 // Try to position the top of newSel (A) where it was before it was selected 974 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 975 true); 976 } else { 977 // If (A) was not on screen and so did not have a view, position 978 // it above the oldSel (B) 979 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 980 true); 981 } 982 983 // Some of the newly selected item extends above the top of the list 984 if (sel.getTop() < topSelectionPixel) { 985 // Find space required to bring the top of the selected item fully into view 986 int spaceAbove = topSelectionPixel - sel.getTop(); 987 988 // Find space available below the selection into which we can scroll downwards 989 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 990 991 // Don't scroll more than half the height of the list 992 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 993 int offset = Math.min(spaceAbove, spaceBelow); 994 offset = Math.min(offset, halfVerticalSpace); 995 996 // Offset the selected item to get it into view 997 sel.offsetTopAndBottom(offset); 998 } 999 1000 // Fill in views above and below 1001 fillAboveAndBelow(sel, selectedPosition); 1002 } else { 1003 1004 int oldTop = oldSel.getTop(); 1005 1006 /* 1007 * Case 3: Staying still 1008 */ 1009 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1010 1011 // We're staying still... 1012 if (oldTop < childrenTop) { 1013 // ... but the top of the old selection was off screen. 1014 // (This can happen if the data changes size out from under us) 1015 int newBottom = sel.getBottom(); 1016 if (newBottom < childrenTop + 20) { 1017 // Not enough visible -- bring it onscreen 1018 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1019 } 1020 } 1021 1022 // Fill in views above and below 1023 fillAboveAndBelow(sel, selectedPosition); 1024 } 1025 1026 return sel; 1027 } 1028 1029 private class FocusSelector implements Runnable { 1030 private int mPosition; 1031 private int mPositionTop; 1032 1033 public FocusSelector setup(int position, int top) { 1034 mPosition = position; 1035 mPositionTop = top; 1036 return this; 1037 } 1038 1039 public void run() { 1040 setSelectionFromTop(mPosition, mPositionTop); 1041 } 1042 } 1043 1044 @Override 1045 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1046 if (getChildCount() > 0) { 1047 View focusedChild = getFocusedChild(); 1048 if (focusedChild != null) { 1049 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1050 final int childBottom = focusedChild.getBottom(); 1051 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1052 final int top = focusedChild.getTop() - offset; 1053 if (mFocusSelector == null) { 1054 mFocusSelector = new FocusSelector(); 1055 } 1056 post(mFocusSelector.setup(childPosition, top)); 1057 } 1058 } 1059 super.onSizeChanged(w, h, oldw, oldh); 1060 } 1061 1062 @Override 1063 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1064 // Sets up mListPadding 1065 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1066 1067 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1068 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1069 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1070 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1071 1072 int childWidth = 0; 1073 int childHeight = 0; 1074 1075 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1076 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1077 heightMode == MeasureSpec.UNSPECIFIED)) { 1078 final View child = obtainView(0, mIsScrap); 1079 1080 measureScrapChild(child, 0, widthMeasureSpec); 1081 1082 childWidth = child.getMeasuredWidth(); 1083 childHeight = child.getMeasuredHeight(); 1084 1085 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1086 ((LayoutParams) child.getLayoutParams()).viewType)) { 1087 mRecycler.addScrapView(child); 1088 } 1089 } 1090 1091 if (widthMode == MeasureSpec.UNSPECIFIED) { 1092 widthSize = mListPadding.left + mListPadding.right + childWidth + 1093 getVerticalScrollbarWidth(); 1094 } 1095 1096 if (heightMode == MeasureSpec.UNSPECIFIED) { 1097 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1098 getVerticalFadingEdgeLength() * 2; 1099 } 1100 1101 if (heightMode == MeasureSpec.AT_MOST) { 1102 // TODO: after first layout we should maybe start at the first visible position, not 0 1103 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1104 } 1105 1106 setMeasuredDimension(widthSize, heightSize); 1107 mWidthMeasureSpec = widthMeasureSpec; 1108 } 1109 1110 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1111 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1112 if (p == null) { 1113 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1114 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1115 child.setLayoutParams(p); 1116 } 1117 p.viewType = mAdapter.getItemViewType(position); 1118 p.forceAdd = true; 1119 1120 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1121 mListPadding.left + mListPadding.right, p.width); 1122 int lpHeight = p.height; 1123 int childHeightSpec; 1124 if (lpHeight > 0) { 1125 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1126 } else { 1127 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1128 } 1129 child.measure(childWidthSpec, childHeightSpec); 1130 } 1131 1132 /** 1133 * @return True to recycle the views used to measure this ListView in 1134 * UNSPECIFIED/AT_MOST modes, false otherwise. 1135 * @hide 1136 */ 1137 @ViewDebug.ExportedProperty 1138 protected boolean recycleOnMeasure() { 1139 return true; 1140 } 1141 1142 /** 1143 * Measures the height of the given range of children (inclusive) and 1144 * returns the height with this ListView's padding and divider heights 1145 * included. If maxHeight is provided, the measuring will stop when the 1146 * current height reaches maxHeight. 1147 * 1148 * @param widthMeasureSpec The width measure spec to be given to a child's 1149 * {@link View#measure(int, int)}. 1150 * @param startPosition The position of the first child to be shown. 1151 * @param endPosition The (inclusive) position of the last child to be 1152 * shown. Specify {@link #NO_POSITION} if the last child should be 1153 * the last available child from the adapter. 1154 * @param maxHeight The maximum height that will be returned (if all the 1155 * children don't fit in this value, this value will be 1156 * returned). 1157 * @param disallowPartialChildPosition In general, whether the returned 1158 * height should only contain entire children. This is more 1159 * powerful--it is the first inclusive position at which partial 1160 * children will not be allowed. Example: it looks nice to have 1161 * at least 3 completely visible children, and in portrait this 1162 * will most likely fit; but in landscape there could be times 1163 * when even 2 children can not be completely shown, so a value 1164 * of 2 (remember, inclusive) would be good (assuming 1165 * startPosition is 0). 1166 * @return The height of this ListView with the given children. 1167 */ 1168 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1169 final int maxHeight, int disallowPartialChildPosition) { 1170 1171 final ListAdapter adapter = mAdapter; 1172 if (adapter == null) { 1173 return mListPadding.top + mListPadding.bottom; 1174 } 1175 1176 // Include the padding of the list 1177 int returnedHeight = mListPadding.top + mListPadding.bottom; 1178 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1179 // The previous height value that was less than maxHeight and contained 1180 // no partial children 1181 int prevHeightWithoutPartialChild = 0; 1182 int i; 1183 View child; 1184 1185 // mItemCount - 1 since endPosition parameter is inclusive 1186 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1187 final AbsListView.RecycleBin recycleBin = mRecycler; 1188 final boolean recyle = recycleOnMeasure(); 1189 final boolean[] isScrap = mIsScrap; 1190 1191 for (i = startPosition; i <= endPosition; ++i) { 1192 child = obtainView(i, isScrap); 1193 1194 measureScrapChild(child, i, widthMeasureSpec); 1195 1196 if (i > 0) { 1197 // Count the divider for all but one child 1198 returnedHeight += dividerHeight; 1199 } 1200 1201 // Recycle the view before we possibly return from the method 1202 if (recyle && recycleBin.shouldRecycleViewType( 1203 ((LayoutParams) child.getLayoutParams()).viewType)) { 1204 recycleBin.addScrapView(child); 1205 } 1206 1207 returnedHeight += child.getMeasuredHeight(); 1208 1209 if (returnedHeight >= maxHeight) { 1210 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1211 // then the i'th position did not fit completely. 1212 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1213 && (i > disallowPartialChildPosition) // We've past the min pos 1214 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1215 && (returnedHeight != maxHeight) // i'th child did not fit completely 1216 ? prevHeightWithoutPartialChild 1217 : maxHeight; 1218 } 1219 1220 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1221 prevHeightWithoutPartialChild = returnedHeight; 1222 } 1223 } 1224 1225 // At this point, we went through the range of children, and they each 1226 // completely fit, so return the returnedHeight 1227 return returnedHeight; 1228 } 1229 1230 @Override 1231 int findMotionRow(int y) { 1232 int childCount = getChildCount(); 1233 if (childCount > 0) { 1234 for (int i = 0; i < childCount; i++) { 1235 View v = getChildAt(i); 1236 if (y <= v.getBottom()) { 1237 return mFirstPosition + i; 1238 } 1239 } 1240 } 1241 return INVALID_POSITION; 1242 } 1243 1244 /** 1245 * Put a specific item at a specific location on the screen and then build 1246 * up and down from there. 1247 * 1248 * @param position The reference view to use as the starting point 1249 * @param top Pixel offset from the top of this view to the top of the 1250 * reference view. 1251 * 1252 * @return The selected view, or null if the selected view is outside the 1253 * visible area. 1254 */ 1255 private View fillSpecific(int position, int top) { 1256 boolean tempIsSelected = position == mSelectedPosition; 1257 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1258 // Possibly changed again in fillUp if we add rows above this one. 1259 mFirstPosition = position; 1260 1261 View above; 1262 View below; 1263 1264 final int dividerHeight = mDividerHeight; 1265 if (!mStackFromBottom) { 1266 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1267 // This will correct for the top of the first view not touching the top of the list 1268 adjustViewsUpOrDown(); 1269 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1270 int childCount = getChildCount(); 1271 if (childCount > 0) { 1272 correctTooHigh(childCount); 1273 } 1274 } else { 1275 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1276 // This will correct for the bottom of the last view not touching the bottom of the list 1277 adjustViewsUpOrDown(); 1278 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1279 int childCount = getChildCount(); 1280 if (childCount > 0) { 1281 correctTooLow(childCount); 1282 } 1283 } 1284 1285 if (tempIsSelected) { 1286 return temp; 1287 } else if (above != null) { 1288 return above; 1289 } else { 1290 return below; 1291 } 1292 } 1293 1294 /** 1295 * Check if we have dragged the bottom of the list too high (we have pushed the 1296 * top element off the top of the screen when we did not need to). Correct by sliding 1297 * everything back down. 1298 * 1299 * @param childCount Number of children 1300 */ 1301 private void correctTooHigh(int childCount) { 1302 // First see if the last item is visible. If it is not, it is OK for the 1303 // top of the list to be pushed up. 1304 int lastPosition = mFirstPosition + childCount - 1; 1305 if (lastPosition == mItemCount - 1 && childCount > 0) { 1306 1307 // Get the last child ... 1308 final View lastChild = getChildAt(childCount - 1); 1309 1310 // ... and its bottom edge 1311 final int lastBottom = lastChild.getBottom(); 1312 1313 // This is bottom of our drawable area 1314 final int end = (mBottom - mTop) - mListPadding.bottom; 1315 1316 // This is how far the bottom edge of the last view is from the bottom of the 1317 // drawable area 1318 int bottomOffset = end - lastBottom; 1319 View firstChild = getChildAt(0); 1320 final int firstTop = firstChild.getTop(); 1321 1322 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1323 // first row or the first row is scrolled off the top of the drawable area 1324 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1325 if (mFirstPosition == 0) { 1326 // Don't pull the top too far down 1327 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1328 } 1329 // Move everything down 1330 offsetChildrenTopAndBottom(bottomOffset); 1331 if (mFirstPosition > 0) { 1332 // Fill the gap that was opened above mFirstPosition with more rows, if 1333 // possible 1334 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1335 // Close up the remaining gap 1336 adjustViewsUpOrDown(); 1337 } 1338 1339 } 1340 } 1341 } 1342 1343 /** 1344 * Check if we have dragged the bottom of the list too low (we have pushed the 1345 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1346 * everything back up. 1347 * 1348 * @param childCount Number of children 1349 */ 1350 private void correctTooLow(int childCount) { 1351 // First see if the first item is visible. If it is not, it is OK for the 1352 // bottom of the list to be pushed down. 1353 if (mFirstPosition == 0 && childCount > 0) { 1354 1355 // Get the first child ... 1356 final View firstChild = getChildAt(0); 1357 1358 // ... and its top edge 1359 final int firstTop = firstChild.getTop(); 1360 1361 // This is top of our drawable area 1362 final int start = mListPadding.top; 1363 1364 // This is bottom of our drawable area 1365 final int end = (mBottom - mTop) - mListPadding.bottom; 1366 1367 // This is how far the top edge of the first view is from the top of the 1368 // drawable area 1369 int topOffset = firstTop - start; 1370 View lastChild = getChildAt(childCount - 1); 1371 final int lastBottom = lastChild.getBottom(); 1372 int lastPosition = mFirstPosition + childCount - 1; 1373 1374 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1375 // last row or the last row is scrolled off the bottom of the drawable area 1376 if (topOffset > 0) { 1377 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1378 if (lastPosition == mItemCount - 1) { 1379 // Don't pull the bottom too far up 1380 topOffset = Math.min(topOffset, lastBottom - end); 1381 } 1382 // Move everything up 1383 offsetChildrenTopAndBottom(-topOffset); 1384 if (lastPosition < mItemCount - 1) { 1385 // Fill the gap that was opened below the last position with more rows, if 1386 // possible 1387 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1388 // Close up the remaining gap 1389 adjustViewsUpOrDown(); 1390 } 1391 } else if (lastPosition == mItemCount - 1) { 1392 adjustViewsUpOrDown(); 1393 } 1394 } 1395 } 1396 } 1397 1398 @Override 1399 protected void layoutChildren() { 1400 final boolean blockLayoutRequests = mBlockLayoutRequests; 1401 if (!blockLayoutRequests) { 1402 mBlockLayoutRequests = true; 1403 } else { 1404 return; 1405 } 1406 1407 try { 1408 super.layoutChildren(); 1409 1410 invalidate(); 1411 1412 if (mAdapter == null) { 1413 resetList(); 1414 invokeOnItemScrollListener(); 1415 return; 1416 } 1417 1418 int childrenTop = mListPadding.top; 1419 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1420 1421 int childCount = getChildCount(); 1422 int index = 0; 1423 int delta = 0; 1424 1425 View sel; 1426 View oldSel = null; 1427 View oldFirst = null; 1428 View newSel = null; 1429 1430 View focusLayoutRestoreView = null; 1431 1432 // Remember stuff we will need down below 1433 switch (mLayoutMode) { 1434 case LAYOUT_SET_SELECTION: 1435 index = mNextSelectedPosition - mFirstPosition; 1436 if (index >= 0 && index < childCount) { 1437 newSel = getChildAt(index); 1438 } 1439 break; 1440 case LAYOUT_FORCE_TOP: 1441 case LAYOUT_FORCE_BOTTOM: 1442 case LAYOUT_SPECIFIC: 1443 case LAYOUT_SYNC: 1444 break; 1445 case LAYOUT_MOVE_SELECTION: 1446 default: 1447 // Remember the previously selected view 1448 index = mSelectedPosition - mFirstPosition; 1449 if (index >= 0 && index < childCount) { 1450 oldSel = getChildAt(index); 1451 } 1452 1453 // Remember the previous first child 1454 oldFirst = getChildAt(0); 1455 1456 if (mNextSelectedPosition >= 0) { 1457 delta = mNextSelectedPosition - mSelectedPosition; 1458 } 1459 1460 // Caution: newSel might be null 1461 newSel = getChildAt(index + delta); 1462 } 1463 1464 1465 boolean dataChanged = mDataChanged; 1466 if (dataChanged) { 1467 handleDataChanged(); 1468 } 1469 1470 // Handle the empty set by removing all views that are visible 1471 // and calling it a day 1472 if (mItemCount == 0) { 1473 resetList(); 1474 invokeOnItemScrollListener(); 1475 return; 1476 } else if (mItemCount != mAdapter.getCount()) { 1477 throw new IllegalStateException("The content of the adapter has changed but " 1478 + "ListView did not receive a notification. Make sure the content of " 1479 + "your adapter is not modified from a background thread, but only " 1480 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1481 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1482 } 1483 1484 setSelectedPositionInt(mNextSelectedPosition); 1485 1486 // Pull all children into the RecycleBin. 1487 // These views will be reused if possible 1488 final int firstPosition = mFirstPosition; 1489 final RecycleBin recycleBin = mRecycler; 1490 1491 // reset the focus restoration 1492 View focusLayoutRestoreDirectChild = null; 1493 1494 1495 // Don't put header or footer views into the Recycler. Those are 1496 // already cached in mHeaderViews; 1497 if (dataChanged) { 1498 for (int i = 0; i < childCount; i++) { 1499 recycleBin.addScrapView(getChildAt(i)); 1500 if (ViewDebug.TRACE_RECYCLER) { 1501 ViewDebug.trace(getChildAt(i), 1502 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1503 } 1504 } 1505 } else { 1506 recycleBin.fillActiveViews(childCount, firstPosition); 1507 } 1508 1509 // take focus back to us temporarily to avoid the eventual 1510 // call to clear focus when removing the focused child below 1511 // from messing things up when ViewRoot assigns focus back 1512 // to someone else 1513 final View focusedChild = getFocusedChild(); 1514 if (focusedChild != null) { 1515 // TODO: in some cases focusedChild.getParent() == null 1516 1517 // we can remember the focused view to restore after relayout if the 1518 // data hasn't changed, or if the focused position is a header or footer 1519 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1520 focusLayoutRestoreDirectChild = focusedChild; 1521 // remember the specific view that had focus 1522 focusLayoutRestoreView = findFocus(); 1523 if (focusLayoutRestoreView != null) { 1524 // tell it we are going to mess with it 1525 focusLayoutRestoreView.onStartTemporaryDetach(); 1526 } 1527 } 1528 requestFocus(); 1529 } 1530 1531 // Clear out old views 1532 detachAllViewsFromParent(); 1533 1534 switch (mLayoutMode) { 1535 case LAYOUT_SET_SELECTION: 1536 if (newSel != null) { 1537 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1538 } else { 1539 sel = fillFromMiddle(childrenTop, childrenBottom); 1540 } 1541 break; 1542 case LAYOUT_SYNC: 1543 sel = fillSpecific(mSyncPosition, mSpecificTop); 1544 break; 1545 case LAYOUT_FORCE_BOTTOM: 1546 sel = fillUp(mItemCount - 1, childrenBottom); 1547 adjustViewsUpOrDown(); 1548 break; 1549 case LAYOUT_FORCE_TOP: 1550 mFirstPosition = 0; 1551 sel = fillFromTop(childrenTop); 1552 adjustViewsUpOrDown(); 1553 break; 1554 case LAYOUT_SPECIFIC: 1555 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1556 break; 1557 case LAYOUT_MOVE_SELECTION: 1558 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1559 break; 1560 default: 1561 if (childCount == 0) { 1562 if (!mStackFromBottom) { 1563 final int position = lookForSelectablePosition(0, true); 1564 setSelectedPositionInt(position); 1565 sel = fillFromTop(childrenTop); 1566 } else { 1567 final int position = lookForSelectablePosition(mItemCount - 1, false); 1568 setSelectedPositionInt(position); 1569 sel = fillUp(mItemCount - 1, childrenBottom); 1570 } 1571 } else { 1572 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1573 sel = fillSpecific(mSelectedPosition, 1574 oldSel == null ? childrenTop : oldSel.getTop()); 1575 } else if (mFirstPosition < mItemCount) { 1576 sel = fillSpecific(mFirstPosition, 1577 oldFirst == null ? childrenTop : oldFirst.getTop()); 1578 } else { 1579 sel = fillSpecific(0, childrenTop); 1580 } 1581 } 1582 break; 1583 } 1584 1585 // Flush any cached views that did not get reused above 1586 recycleBin.scrapActiveViews(); 1587 1588 if (sel != null) { 1589 // the current selected item should get focus if items 1590 // are focusable 1591 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1592 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1593 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1594 if (!focusWasTaken) { 1595 // selected item didn't take focus, fine, but still want 1596 // to make sure something else outside of the selected view 1597 // has focus 1598 final View focused = getFocusedChild(); 1599 if (focused != null) { 1600 focused.clearFocus(); 1601 } 1602 positionSelector(sel); 1603 } else { 1604 sel.setSelected(false); 1605 mSelectorRect.setEmpty(); 1606 } 1607 } else { 1608 positionSelector(sel); 1609 } 1610 mSelectedTop = sel.getTop(); 1611 } else { 1612 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1613 View child = getChildAt(mMotionPosition - mFirstPosition); 1614 if (child != null) positionSelector(child); 1615 } else { 1616 mSelectedTop = 0; 1617 mSelectorRect.setEmpty(); 1618 } 1619 1620 // even if there is not selected position, we may need to restore 1621 // focus (i.e. something focusable in touch mode) 1622 if (hasFocus() && focusLayoutRestoreView != null) { 1623 focusLayoutRestoreView.requestFocus(); 1624 } 1625 } 1626 1627 // tell focus view we are done mucking with it, if it is still in 1628 // our view hierarchy. 1629 if (focusLayoutRestoreView != null 1630 && focusLayoutRestoreView.getWindowToken() != null) { 1631 focusLayoutRestoreView.onFinishTemporaryDetach(); 1632 } 1633 1634 mLayoutMode = LAYOUT_NORMAL; 1635 mDataChanged = false; 1636 mNeedSync = false; 1637 setNextSelectedPositionInt(mSelectedPosition); 1638 1639 updateScrollIndicators(); 1640 1641 if (mItemCount > 0) { 1642 checkSelectionChanged(); 1643 } 1644 1645 invokeOnItemScrollListener(); 1646 } finally { 1647 if (!blockLayoutRequests) { 1648 mBlockLayoutRequests = false; 1649 } 1650 } 1651 } 1652 1653 /** 1654 * @param child a direct child of this list. 1655 * @return Whether child is a header or footer view. 1656 */ 1657 private boolean isDirectChildHeaderOrFooter(View child) { 1658 1659 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1660 final int numHeaders = headers.size(); 1661 for (int i = 0; i < numHeaders; i++) { 1662 if (child == headers.get(i).view) { 1663 return true; 1664 } 1665 } 1666 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1667 final int numFooters = footers.size(); 1668 for (int i = 0; i < numFooters; i++) { 1669 if (child == footers.get(i).view) { 1670 return true; 1671 } 1672 } 1673 return false; 1674 } 1675 1676 /** 1677 * Obtain the view and add it to our list of children. The view can be made 1678 * fresh, converted from an unused view, or used as is if it was in the 1679 * recycle bin. 1680 * 1681 * @param position Logical position in the list 1682 * @param y Top or bottom edge of the view to add 1683 * @param flow If flow is true, align top edge to y. If false, align bottom 1684 * edge to y. 1685 * @param childrenLeft Left edge where children should be positioned 1686 * @param selected Is this position selected? 1687 * @return View that was added 1688 */ 1689 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1690 boolean selected) { 1691 View child; 1692 1693 1694 if (!mDataChanged) { 1695 // Try to use an exsiting view for this position 1696 child = mRecycler.getActiveView(position); 1697 if (child != null) { 1698 if (ViewDebug.TRACE_RECYCLER) { 1699 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1700 position, getChildCount()); 1701 } 1702 1703 // Found it -- we're using an existing child 1704 // This just needs to be positioned 1705 setupChild(child, position, y, flow, childrenLeft, selected, true); 1706 1707 return child; 1708 } 1709 } 1710 1711 // Make a new view for this position, or convert an unused view if possible 1712 child = obtainView(position, mIsScrap); 1713 1714 // This needs to be positioned and measured 1715 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1716 1717 return child; 1718 } 1719 1720 /** 1721 * Add a view as a child and make sure it is measured (if necessary) and 1722 * positioned properly. 1723 * 1724 * @param child The view to add 1725 * @param position The position of this child 1726 * @param y The y position relative to which this view will be positioned 1727 * @param flowDown If true, align top edge to y. If false, align bottom 1728 * edge to y. 1729 * @param childrenLeft Left edge where children should be positioned 1730 * @param selected Is this position selected? 1731 * @param recycled Has this view been pulled from the recycle bin? If so it 1732 * does not need to be remeasured. 1733 */ 1734 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1735 boolean selected, boolean recycled) { 1736 final boolean isSelected = selected && shouldShowSelector(); 1737 final boolean updateChildSelected = isSelected != child.isSelected(); 1738 final int mode = mTouchMode; 1739 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1740 mMotionPosition == position; 1741 final boolean updateChildPressed = isPressed != child.isPressed(); 1742 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1743 1744 // Respect layout params that are already in the view. Otherwise make some up... 1745 // noinspection unchecked 1746 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1747 if (p == null) { 1748 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1749 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1750 } 1751 p.viewType = mAdapter.getItemViewType(position); 1752 1753 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1754 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1755 attachViewToParent(child, flowDown ? -1 : 0, p); 1756 } else { 1757 p.forceAdd = false; 1758 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1759 p.recycledHeaderFooter = true; 1760 } 1761 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1762 } 1763 1764 if (updateChildSelected) { 1765 child.setSelected(isSelected); 1766 } 1767 1768 if (updateChildPressed) { 1769 child.setPressed(isPressed); 1770 } 1771 1772 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1773 if (child instanceof Checkable) { 1774 ((Checkable) child).setChecked(mCheckStates.get(position)); 1775 } 1776 } 1777 1778 if (needToMeasure) { 1779 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1780 mListPadding.left + mListPadding.right, p.width); 1781 int lpHeight = p.height; 1782 int childHeightSpec; 1783 if (lpHeight > 0) { 1784 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1785 } else { 1786 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1787 } 1788 child.measure(childWidthSpec, childHeightSpec); 1789 } else { 1790 cleanupLayoutState(child); 1791 } 1792 1793 final int w = child.getMeasuredWidth(); 1794 final int h = child.getMeasuredHeight(); 1795 final int childTop = flowDown ? y : y - h; 1796 1797 if (needToMeasure) { 1798 final int childRight = childrenLeft + w; 1799 final int childBottom = childTop + h; 1800 child.layout(childrenLeft, childTop, childRight, childBottom); 1801 } else { 1802 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1803 child.offsetTopAndBottom(childTop - child.getTop()); 1804 } 1805 1806 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1807 child.setDrawingCacheEnabled(true); 1808 } 1809 } 1810 1811 @Override 1812 protected boolean canAnimate() { 1813 return super.canAnimate() && mItemCount > 0; 1814 } 1815 1816 /** 1817 * Sets the currently selected item. If in touch mode, the item will not be selected 1818 * but it will still be positioned appropriately. If the specified selection position 1819 * is less than 0, then the item at position 0 will be selected. 1820 * 1821 * @param position Index (starting at 0) of the data item to be selected. 1822 */ 1823 @Override 1824 public void setSelection(int position) { 1825 setSelectionFromTop(position, 0); 1826 } 1827 1828 /** 1829 * Sets the selected item and positions the selection y pixels from the top edge 1830 * of the ListView. (If in touch mode, the item will not be selected but it will 1831 * still be positioned appropriately.) 1832 * 1833 * @param position Index (starting at 0) of the data item to be selected. 1834 * @param y The distance from the top edge of the ListView (plus padding) that the 1835 * item will be positioned. 1836 */ 1837 public void setSelectionFromTop(int position, int y) { 1838 if (mAdapter == null) { 1839 return; 1840 } 1841 1842 if (!isInTouchMode()) { 1843 position = lookForSelectablePosition(position, true); 1844 if (position >= 0) { 1845 setNextSelectedPositionInt(position); 1846 } 1847 } else { 1848 mResurrectToPosition = position; 1849 } 1850 1851 if (position >= 0) { 1852 mLayoutMode = LAYOUT_SPECIFIC; 1853 mSpecificTop = mListPadding.top + y; 1854 1855 if (mNeedSync) { 1856 mSyncPosition = position; 1857 mSyncRowId = mAdapter.getItemId(position); 1858 } 1859 1860 requestLayout(); 1861 } 1862 } 1863 1864 /** 1865 * Makes the item at the supplied position selected. 1866 * 1867 * @param position the position of the item to select 1868 */ 1869 @Override 1870 void setSelectionInt(int position) { 1871 setNextSelectedPositionInt(position); 1872 boolean awakeScrollbars = false; 1873 1874 final int selectedPosition = mSelectedPosition; 1875 1876 if (selectedPosition >= 0) { 1877 if (position == selectedPosition - 1) { 1878 awakeScrollbars = true; 1879 } else if (position == selectedPosition + 1) { 1880 awakeScrollbars = true; 1881 } 1882 } 1883 1884 layoutChildren(); 1885 1886 if (awakeScrollbars) { 1887 awakenScrollBars(); 1888 } 1889 } 1890 1891 /** 1892 * Find a position that can be selected (i.e., is not a separator). 1893 * 1894 * @param position The starting position to look at. 1895 * @param lookDown Whether to look down for other positions. 1896 * @return The next selectable position starting at position and then searching either up or 1897 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1898 */ 1899 @Override 1900 int lookForSelectablePosition(int position, boolean lookDown) { 1901 final ListAdapter adapter = mAdapter; 1902 if (adapter == null || isInTouchMode()) { 1903 return INVALID_POSITION; 1904 } 1905 1906 final int count = adapter.getCount(); 1907 if (!mAreAllItemsSelectable) { 1908 if (lookDown) { 1909 position = Math.max(0, position); 1910 while (position < count && !adapter.isEnabled(position)) { 1911 position++; 1912 } 1913 } else { 1914 position = Math.min(position, count - 1); 1915 while (position >= 0 && !adapter.isEnabled(position)) { 1916 position--; 1917 } 1918 } 1919 1920 if (position < 0 || position >= count) { 1921 return INVALID_POSITION; 1922 } 1923 return position; 1924 } else { 1925 if (position < 0 || position >= count) { 1926 return INVALID_POSITION; 1927 } 1928 return position; 1929 } 1930 } 1931 1932 @Override 1933 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1934 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1935 1936 // If the item count is less than 15 then subtract disabled items from the count and 1937 // position. Otherwise ignore disabled items. 1938 if (!populated) { 1939 int itemCount = 0; 1940 int currentItemIndex = getSelectedItemPosition(); 1941 1942 ListAdapter adapter = getAdapter(); 1943 if (adapter != null) { 1944 final int count = adapter.getCount(); 1945 if (count < 15) { 1946 for (int i = 0; i < count; i++) { 1947 if (adapter.isEnabled(i)) { 1948 itemCount++; 1949 } else if (i <= currentItemIndex) { 1950 currentItemIndex--; 1951 } 1952 } 1953 } else { 1954 itemCount = count; 1955 } 1956 } 1957 1958 event.setItemCount(itemCount); 1959 event.setCurrentItemIndex(currentItemIndex); 1960 } 1961 1962 return populated; 1963 } 1964 1965 /** 1966 * setSelectionAfterHeaderView set the selection to be the first list item 1967 * after the header views. 1968 */ 1969 public void setSelectionAfterHeaderView() { 1970 final int count = mHeaderViewInfos.size(); 1971 if (count > 0) { 1972 mNextSelectedPosition = 0; 1973 return; 1974 } 1975 1976 if (mAdapter != null) { 1977 setSelection(count); 1978 } else { 1979 mNextSelectedPosition = count; 1980 mLayoutMode = LAYOUT_SET_SELECTION; 1981 } 1982 1983 } 1984 1985 @Override 1986 public boolean dispatchKeyEvent(KeyEvent event) { 1987 // Dispatch in the normal way 1988 boolean handled = super.dispatchKeyEvent(event); 1989 if (!handled) { 1990 // If we didn't handle it... 1991 View focused = getFocusedChild(); 1992 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1993 // ... and our focused child didn't handle it 1994 // ... give it to ourselves so we can scroll if necessary 1995 handled = onKeyDown(event.getKeyCode(), event); 1996 } 1997 } 1998 return handled; 1999 } 2000 2001 @Override 2002 public boolean onKeyDown(int keyCode, KeyEvent event) { 2003 return commonKey(keyCode, 1, event); 2004 } 2005 2006 @Override 2007 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2008 return commonKey(keyCode, repeatCount, event); 2009 } 2010 2011 @Override 2012 public boolean onKeyUp(int keyCode, KeyEvent event) { 2013 return commonKey(keyCode, 1, event); 2014 } 2015 2016 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2017 if (mAdapter == null) { 2018 return false; 2019 } 2020 2021 if (mDataChanged) { 2022 layoutChildren(); 2023 } 2024 2025 boolean handled = false; 2026 int action = event.getAction(); 2027 2028 if (action != KeyEvent.ACTION_UP) { 2029 if (mSelectedPosition < 0) { 2030 switch (keyCode) { 2031 case KeyEvent.KEYCODE_DPAD_UP: 2032 case KeyEvent.KEYCODE_DPAD_DOWN: 2033 case KeyEvent.KEYCODE_DPAD_CENTER: 2034 case KeyEvent.KEYCODE_ENTER: 2035 case KeyEvent.KEYCODE_SPACE: 2036 if (resurrectSelection()) { 2037 return true; 2038 } 2039 } 2040 } 2041 switch (keyCode) { 2042 case KeyEvent.KEYCODE_DPAD_UP: 2043 if (!event.isAltPressed()) { 2044 while (count > 0) { 2045 handled = arrowScroll(FOCUS_UP); 2046 count--; 2047 } 2048 } else { 2049 handled = fullScroll(FOCUS_UP); 2050 } 2051 break; 2052 2053 case KeyEvent.KEYCODE_DPAD_DOWN: 2054 if (!event.isAltPressed()) { 2055 while (count > 0) { 2056 handled = arrowScroll(FOCUS_DOWN); 2057 count--; 2058 } 2059 } else { 2060 handled = fullScroll(FOCUS_DOWN); 2061 } 2062 break; 2063 2064 case KeyEvent.KEYCODE_DPAD_LEFT: 2065 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2066 break; 2067 case KeyEvent.KEYCODE_DPAD_RIGHT: 2068 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2069 break; 2070 2071 case KeyEvent.KEYCODE_DPAD_CENTER: 2072 case KeyEvent.KEYCODE_ENTER: 2073 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2074 keyPressed(); 2075 } 2076 handled = true; 2077 break; 2078 2079 case KeyEvent.KEYCODE_SPACE: 2080 if (mPopup == null || !mPopup.isShowing()) { 2081 if (!event.isShiftPressed()) { 2082 pageScroll(FOCUS_DOWN); 2083 } else { 2084 pageScroll(FOCUS_UP); 2085 } 2086 handled = true; 2087 } 2088 break; 2089 } 2090 } 2091 2092 if (!handled) { 2093 handled = sendToTextFilter(keyCode, count, event); 2094 } 2095 2096 if (handled) { 2097 return true; 2098 } else { 2099 switch (action) { 2100 case KeyEvent.ACTION_DOWN: 2101 return super.onKeyDown(keyCode, event); 2102 2103 case KeyEvent.ACTION_UP: 2104 return super.onKeyUp(keyCode, event); 2105 2106 case KeyEvent.ACTION_MULTIPLE: 2107 return super.onKeyMultiple(keyCode, count, event); 2108 2109 default: // shouldn't happen 2110 return false; 2111 } 2112 } 2113 } 2114 2115 /** 2116 * Scrolls up or down by the number of items currently present on screen. 2117 * 2118 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2119 * @return whether selection was moved 2120 */ 2121 boolean pageScroll(int direction) { 2122 int nextPage = -1; 2123 boolean down = false; 2124 2125 if (direction == FOCUS_UP) { 2126 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2127 } else if (direction == FOCUS_DOWN) { 2128 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2129 down = true; 2130 } 2131 2132 if (nextPage >= 0) { 2133 int position = lookForSelectablePosition(nextPage, down); 2134 if (position >= 0) { 2135 mLayoutMode = LAYOUT_SPECIFIC; 2136 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2137 2138 if (down && position > mItemCount - getChildCount()) { 2139 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2140 } 2141 2142 if (!down && position < getChildCount()) { 2143 mLayoutMode = LAYOUT_FORCE_TOP; 2144 } 2145 2146 setSelectionInt(position); 2147 invokeOnItemScrollListener(); 2148 if (!awakenScrollBars()) { 2149 invalidate(); 2150 } 2151 2152 return true; 2153 } 2154 } 2155 2156 return false; 2157 } 2158 2159 /** 2160 * Go to the last or first item if possible (not worrying about panning across or navigating 2161 * within the internal focus of the currently selected item.) 2162 * 2163 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2164 * 2165 * @return whether selection was moved 2166 */ 2167 boolean fullScroll(int direction) { 2168 boolean moved = false; 2169 if (direction == FOCUS_UP) { 2170 if (mSelectedPosition != 0) { 2171 int position = lookForSelectablePosition(0, true); 2172 if (position >= 0) { 2173 mLayoutMode = LAYOUT_FORCE_TOP; 2174 setSelectionInt(position); 2175 invokeOnItemScrollListener(); 2176 } 2177 moved = true; 2178 } 2179 } else if (direction == FOCUS_DOWN) { 2180 if (mSelectedPosition < mItemCount - 1) { 2181 int position = lookForSelectablePosition(mItemCount - 1, true); 2182 if (position >= 0) { 2183 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2184 setSelectionInt(position); 2185 invokeOnItemScrollListener(); 2186 } 2187 moved = true; 2188 } 2189 } 2190 2191 if (moved && !awakenScrollBars()) { 2192 awakenScrollBars(); 2193 invalidate(); 2194 } 2195 2196 return moved; 2197 } 2198 2199 /** 2200 * To avoid horizontal focus searches changing the selected item, we 2201 * manually focus search within the selected item (as applicable), and 2202 * prevent focus from jumping to something within another item. 2203 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2204 * @return Whether this consumes the key event. 2205 */ 2206 private boolean handleHorizontalFocusWithinListItem(int direction) { 2207 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2208 throw new IllegalArgumentException("direction must be one of" 2209 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2210 } 2211 2212 final int numChildren = getChildCount(); 2213 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2214 final View selectedView = getSelectedView(); 2215 if (selectedView != null && selectedView.hasFocus() && 2216 selectedView instanceof ViewGroup) { 2217 2218 final View currentFocus = selectedView.findFocus(); 2219 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2220 (ViewGroup) selectedView, currentFocus, direction); 2221 if (nextFocus != null) { 2222 // do the math to get interesting rect in next focus' coordinates 2223 currentFocus.getFocusedRect(mTempRect); 2224 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2225 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2226 if (nextFocus.requestFocus(direction, mTempRect)) { 2227 return true; 2228 } 2229 } 2230 // we are blocking the key from being handled (by returning true) 2231 // if the global result is going to be some other view within this 2232 // list. this is to acheive the overall goal of having 2233 // horizontal d-pad navigation remain in the current item. 2234 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2235 (ViewGroup) getRootView(), currentFocus, direction); 2236 if (globalNextFocus != null) { 2237 return isViewAncestorOf(globalNextFocus, this); 2238 } 2239 } 2240 } 2241 return false; 2242 } 2243 2244 /** 2245 * Scrolls to the next or previous item if possible. 2246 * 2247 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2248 * 2249 * @return whether selection was moved 2250 */ 2251 boolean arrowScroll(int direction) { 2252 try { 2253 mInLayout = true; 2254 final boolean handled = arrowScrollImpl(direction); 2255 if (handled) { 2256 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2257 } 2258 return handled; 2259 } finally { 2260 mInLayout = false; 2261 } 2262 } 2263 2264 /** 2265 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2266 * whether there are focusable items etc. 2267 * 2268 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2269 * @return Whether any scrolling, selection or focus change occured. 2270 */ 2271 private boolean arrowScrollImpl(int direction) { 2272 if (getChildCount() <= 0) { 2273 return false; 2274 } 2275 2276 View selectedView = getSelectedView(); 2277 2278 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2279 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2280 2281 // if we are moving focus, we may OVERRIDE the default behavior 2282 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2283 if (focusResult != null) { 2284 nextSelectedPosition = focusResult.getSelectedPosition(); 2285 amountToScroll = focusResult.getAmountToScroll(); 2286 } 2287 2288 boolean needToRedraw = focusResult != null; 2289 if (nextSelectedPosition != INVALID_POSITION) { 2290 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2291 setSelectedPositionInt(nextSelectedPosition); 2292 setNextSelectedPositionInt(nextSelectedPosition); 2293 selectedView = getSelectedView(); 2294 if (mItemsCanFocus && focusResult == null) { 2295 // there was no new view found to take focus, make sure we 2296 // don't leave focus with the old selection 2297 final View focused = getFocusedChild(); 2298 if (focused != null) { 2299 focused.clearFocus(); 2300 } 2301 } 2302 needToRedraw = true; 2303 checkSelectionChanged(); 2304 } 2305 2306 if (amountToScroll > 0) { 2307 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2308 needToRedraw = true; 2309 } 2310 2311 // if we didn't find a new focusable, make sure any existing focused 2312 // item that was panned off screen gives up focus. 2313 if (mItemsCanFocus && (focusResult == null) 2314 && selectedView != null && selectedView.hasFocus()) { 2315 final View focused = selectedView.findFocus(); 2316 if (distanceToView(focused) > 0) { 2317 focused.clearFocus(); 2318 } 2319 } 2320 2321 // if the current selection is panned off, we need to remove the selection 2322 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2323 && !isViewAncestorOf(selectedView, this)) { 2324 selectedView = null; 2325 hideSelector(); 2326 2327 // but we don't want to set the ressurect position (that would make subsequent 2328 // unhandled key events bring back the item we just scrolled off!) 2329 mResurrectToPosition = INVALID_POSITION; 2330 } 2331 2332 if (needToRedraw) { 2333 if (selectedView != null) { 2334 positionSelector(selectedView); 2335 mSelectedTop = selectedView.getTop(); 2336 } 2337 if (!awakenScrollBars()) { 2338 invalidate(); 2339 } 2340 invokeOnItemScrollListener(); 2341 return true; 2342 } 2343 2344 return false; 2345 } 2346 2347 /** 2348 * When selection changes, it is possible that the previously selected or the 2349 * next selected item will change its size. If so, we need to offset some folks, 2350 * and re-layout the items as appropriate. 2351 * 2352 * @param selectedView The currently selected view (before changing selection). 2353 * should be <code>null</code> if there was no previous selection. 2354 * @param direction Either {@link android.view.View#FOCUS_UP} or 2355 * {@link android.view.View#FOCUS_DOWN}. 2356 * @param newSelectedPosition The position of the next selection. 2357 * @param newFocusAssigned whether new focus was assigned. This matters because 2358 * when something has focus, we don't want to show selection (ugh). 2359 */ 2360 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2361 boolean newFocusAssigned) { 2362 if (newSelectedPosition == INVALID_POSITION) { 2363 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2364 } 2365 2366 // whether or not we are moving down or up, we want to preserve the 2367 // top of whatever view is on top: 2368 // - moving down: the view that had selection 2369 // - moving up: the view that is getting selection 2370 View topView; 2371 View bottomView; 2372 int topViewIndex, bottomViewIndex; 2373 boolean topSelected = false; 2374 final int selectedIndex = mSelectedPosition - mFirstPosition; 2375 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2376 if (direction == View.FOCUS_UP) { 2377 topViewIndex = nextSelectedIndex; 2378 bottomViewIndex = selectedIndex; 2379 topView = getChildAt(topViewIndex); 2380 bottomView = selectedView; 2381 topSelected = true; 2382 } else { 2383 topViewIndex = selectedIndex; 2384 bottomViewIndex = nextSelectedIndex; 2385 topView = selectedView; 2386 bottomView = getChildAt(bottomViewIndex); 2387 } 2388 2389 final int numChildren = getChildCount(); 2390 2391 // start with top view: is it changing size? 2392 if (topView != null) { 2393 topView.setSelected(!newFocusAssigned && topSelected); 2394 measureAndAdjustDown(topView, topViewIndex, numChildren); 2395 } 2396 2397 // is the bottom view changing size? 2398 if (bottomView != null) { 2399 bottomView.setSelected(!newFocusAssigned && !topSelected); 2400 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2401 } 2402 } 2403 2404 /** 2405 * Re-measure a child, and if its height changes, lay it out preserving its 2406 * top, and adjust the children below it appropriately. 2407 * @param child The child 2408 * @param childIndex The view group index of the child. 2409 * @param numChildren The number of children in the view group. 2410 */ 2411 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2412 int oldHeight = child.getHeight(); 2413 measureItem(child); 2414 if (child.getMeasuredHeight() != oldHeight) { 2415 // lay out the view, preserving its top 2416 relayoutMeasuredItem(child); 2417 2418 // adjust views below appropriately 2419 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2420 for (int i = childIndex + 1; i < numChildren; i++) { 2421 getChildAt(i).offsetTopAndBottom(heightDelta); 2422 } 2423 } 2424 } 2425 2426 /** 2427 * Measure a particular list child. 2428 * TODO: unify with setUpChild. 2429 * @param child The child. 2430 */ 2431 private void measureItem(View child) { 2432 ViewGroup.LayoutParams p = child.getLayoutParams(); 2433 if (p == null) { 2434 p = new ViewGroup.LayoutParams( 2435 ViewGroup.LayoutParams.MATCH_PARENT, 2436 ViewGroup.LayoutParams.WRAP_CONTENT); 2437 } 2438 2439 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2440 mListPadding.left + mListPadding.right, p.width); 2441 int lpHeight = p.height; 2442 int childHeightSpec; 2443 if (lpHeight > 0) { 2444 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2445 } else { 2446 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2447 } 2448 child.measure(childWidthSpec, childHeightSpec); 2449 } 2450 2451 /** 2452 * Layout a child that has been measured, preserving its top position. 2453 * TODO: unify with setUpChild. 2454 * @param child The child. 2455 */ 2456 private void relayoutMeasuredItem(View child) { 2457 final int w = child.getMeasuredWidth(); 2458 final int h = child.getMeasuredHeight(); 2459 final int childLeft = mListPadding.left; 2460 final int childRight = childLeft + w; 2461 final int childTop = child.getTop(); 2462 final int childBottom = childTop + h; 2463 child.layout(childLeft, childTop, childRight, childBottom); 2464 } 2465 2466 /** 2467 * @return The amount to preview next items when arrow srolling. 2468 */ 2469 private int getArrowScrollPreviewLength() { 2470 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2471 } 2472 2473 /** 2474 * Determine how much we need to scroll in order to get the next selected view 2475 * visible, with a fading edge showing below as applicable. The amount is 2476 * capped at {@link #getMaxScrollAmount()} . 2477 * 2478 * @param direction either {@link android.view.View#FOCUS_UP} or 2479 * {@link android.view.View#FOCUS_DOWN}. 2480 * @param nextSelectedPosition The position of the next selection, or 2481 * {@link #INVALID_POSITION} if there is no next selectable position 2482 * @return The amount to scroll. Note: this is always positive! Direction 2483 * needs to be taken into account when actually scrolling. 2484 */ 2485 private int amountToScroll(int direction, int nextSelectedPosition) { 2486 final int listBottom = getHeight() - mListPadding.bottom; 2487 final int listTop = mListPadding.top; 2488 2489 final int numChildren = getChildCount(); 2490 2491 if (direction == View.FOCUS_DOWN) { 2492 int indexToMakeVisible = numChildren - 1; 2493 if (nextSelectedPosition != INVALID_POSITION) { 2494 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2495 } 2496 2497 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2498 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2499 2500 int goalBottom = listBottom; 2501 if (positionToMakeVisible < mItemCount - 1) { 2502 goalBottom -= getArrowScrollPreviewLength(); 2503 } 2504 2505 if (viewToMakeVisible.getBottom() <= goalBottom) { 2506 // item is fully visible. 2507 return 0; 2508 } 2509 2510 if (nextSelectedPosition != INVALID_POSITION 2511 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2512 // item already has enough of it visible, changing selection is good enough 2513 return 0; 2514 } 2515 2516 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2517 2518 if ((mFirstPosition + numChildren) == mItemCount) { 2519 // last is last in list -> make sure we don't scroll past it 2520 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2521 amountToScroll = Math.min(amountToScroll, max); 2522 } 2523 2524 return Math.min(amountToScroll, getMaxScrollAmount()); 2525 } else { 2526 int indexToMakeVisible = 0; 2527 if (nextSelectedPosition != INVALID_POSITION) { 2528 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2529 } 2530 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2531 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2532 int goalTop = listTop; 2533 if (positionToMakeVisible > 0) { 2534 goalTop += getArrowScrollPreviewLength(); 2535 } 2536 if (viewToMakeVisible.getTop() >= goalTop) { 2537 // item is fully visible. 2538 return 0; 2539 } 2540 2541 if (nextSelectedPosition != INVALID_POSITION && 2542 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2543 // item already has enough of it visible, changing selection is good enough 2544 return 0; 2545 } 2546 2547 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2548 if (mFirstPosition == 0) { 2549 // first is first in list -> make sure we don't scroll past it 2550 final int max = listTop - getChildAt(0).getTop(); 2551 amountToScroll = Math.min(amountToScroll, max); 2552 } 2553 return Math.min(amountToScroll, getMaxScrollAmount()); 2554 } 2555 } 2556 2557 /** 2558 * Holds results of focus aware arrow scrolling. 2559 */ 2560 static private class ArrowScrollFocusResult { 2561 private int mSelectedPosition; 2562 private int mAmountToScroll; 2563 2564 /** 2565 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2566 */ 2567 void populate(int selectedPosition, int amountToScroll) { 2568 mSelectedPosition = selectedPosition; 2569 mAmountToScroll = amountToScroll; 2570 } 2571 2572 public int getSelectedPosition() { 2573 return mSelectedPosition; 2574 } 2575 2576 public int getAmountToScroll() { 2577 return mAmountToScroll; 2578 } 2579 } 2580 2581 /** 2582 * @param direction either {@link android.view.View#FOCUS_UP} or 2583 * {@link android.view.View#FOCUS_DOWN}. 2584 * @return The position of the next selectable position of the views that 2585 * are currently visible, taking into account the fact that there might 2586 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2587 * selectable view on screen in the given direction. 2588 */ 2589 private int lookForSelectablePositionOnScreen(int direction) { 2590 final int firstPosition = mFirstPosition; 2591 if (direction == View.FOCUS_DOWN) { 2592 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2593 mSelectedPosition + 1 : 2594 firstPosition; 2595 if (startPos >= mAdapter.getCount()) { 2596 return INVALID_POSITION; 2597 } 2598 if (startPos < firstPosition) { 2599 startPos = firstPosition; 2600 } 2601 2602 final int lastVisiblePos = getLastVisiblePosition(); 2603 final ListAdapter adapter = getAdapter(); 2604 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2605 if (adapter.isEnabled(pos) 2606 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2607 return pos; 2608 } 2609 } 2610 } else { 2611 int last = firstPosition + getChildCount() - 1; 2612 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2613 mSelectedPosition - 1 : 2614 firstPosition + getChildCount() - 1; 2615 if (startPos < 0) { 2616 return INVALID_POSITION; 2617 } 2618 if (startPos > last) { 2619 startPos = last; 2620 } 2621 2622 final ListAdapter adapter = getAdapter(); 2623 for (int pos = startPos; pos >= firstPosition; pos--) { 2624 if (adapter.isEnabled(pos) 2625 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2626 return pos; 2627 } 2628 } 2629 } 2630 return INVALID_POSITION; 2631 } 2632 2633 /** 2634 * Do an arrow scroll based on focus searching. If a new view is 2635 * given focus, return the selection delta and amount to scroll via 2636 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2637 * 2638 * @param direction either {@link android.view.View#FOCUS_UP} or 2639 * {@link android.view.View#FOCUS_DOWN}. 2640 * @return The result if focus has changed, or <code>null</code>. 2641 */ 2642 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2643 final View selectedView = getSelectedView(); 2644 View newFocus; 2645 if (selectedView != null && selectedView.hasFocus()) { 2646 View oldFocus = selectedView.findFocus(); 2647 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2648 } else { 2649 if (direction == View.FOCUS_DOWN) { 2650 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2651 final int listTop = mListPadding.top + 2652 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2653 final int ySearchPoint = 2654 (selectedView != null && selectedView.getTop() > listTop) ? 2655 selectedView.getTop() : 2656 listTop; 2657 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2658 } else { 2659 final boolean bottomFadingEdgeShowing = 2660 (mFirstPosition + getChildCount() - 1) < mItemCount; 2661 final int listBottom = getHeight() - mListPadding.bottom - 2662 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2663 final int ySearchPoint = 2664 (selectedView != null && selectedView.getBottom() < listBottom) ? 2665 selectedView.getBottom() : 2666 listBottom; 2667 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2668 } 2669 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2670 } 2671 2672 if (newFocus != null) { 2673 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2674 2675 // if the focus change is in a different new position, make sure 2676 // we aren't jumping over another selectable position 2677 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2678 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2679 if (selectablePosition != INVALID_POSITION && 2680 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2681 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2682 return null; 2683 } 2684 } 2685 2686 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2687 2688 final int maxScrollAmount = getMaxScrollAmount(); 2689 if (focusScroll < maxScrollAmount) { 2690 // not moving too far, safe to give next view focus 2691 newFocus.requestFocus(direction); 2692 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2693 return mArrowScrollFocusResult; 2694 } else if (distanceToView(newFocus) < maxScrollAmount){ 2695 // Case to consider: 2696 // too far to get entire next focusable on screen, but by going 2697 // max scroll amount, we are getting it at least partially in view, 2698 // so give it focus and scroll the max ammount. 2699 newFocus.requestFocus(direction); 2700 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2701 return mArrowScrollFocusResult; 2702 } 2703 } 2704 return null; 2705 } 2706 2707 /** 2708 * @param newFocus The view that would have focus. 2709 * @return the position that contains newFocus 2710 */ 2711 private int positionOfNewFocus(View newFocus) { 2712 final int numChildren = getChildCount(); 2713 for (int i = 0; i < numChildren; i++) { 2714 final View child = getChildAt(i); 2715 if (isViewAncestorOf(newFocus, child)) { 2716 return mFirstPosition + i; 2717 } 2718 } 2719 throw new IllegalArgumentException("newFocus is not a child of any of the" 2720 + " children of the list!"); 2721 } 2722 2723 /** 2724 * Return true if child is an ancestor of parent, (or equal to the parent). 2725 */ 2726 private boolean isViewAncestorOf(View child, View parent) { 2727 if (child == parent) { 2728 return true; 2729 } 2730 2731 final ViewParent theParent = child.getParent(); 2732 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2733 } 2734 2735 /** 2736 * Determine how much we need to scroll in order to get newFocus in view. 2737 * @param direction either {@link android.view.View#FOCUS_UP} or 2738 * {@link android.view.View#FOCUS_DOWN}. 2739 * @param newFocus The view that would take focus. 2740 * @param positionOfNewFocus The position of the list item containing newFocus 2741 * @return The amount to scroll. Note: this is always positive! Direction 2742 * needs to be taken into account when actually scrolling. 2743 */ 2744 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2745 int amountToScroll = 0; 2746 newFocus.getDrawingRect(mTempRect); 2747 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2748 if (direction == View.FOCUS_UP) { 2749 if (mTempRect.top < mListPadding.top) { 2750 amountToScroll = mListPadding.top - mTempRect.top; 2751 if (positionOfNewFocus > 0) { 2752 amountToScroll += getArrowScrollPreviewLength(); 2753 } 2754 } 2755 } else { 2756 final int listBottom = getHeight() - mListPadding.bottom; 2757 if (mTempRect.bottom > listBottom) { 2758 amountToScroll = mTempRect.bottom - listBottom; 2759 if (positionOfNewFocus < mItemCount - 1) { 2760 amountToScroll += getArrowScrollPreviewLength(); 2761 } 2762 } 2763 } 2764 return amountToScroll; 2765 } 2766 2767 /** 2768 * Determine the distance to the nearest edge of a view in a particular 2769 * direction. 2770 * 2771 * @param descendant A descendant of this list. 2772 * @return The distance, or 0 if the nearest edge is already on screen. 2773 */ 2774 private int distanceToView(View descendant) { 2775 int distance = 0; 2776 descendant.getDrawingRect(mTempRect); 2777 offsetDescendantRectToMyCoords(descendant, mTempRect); 2778 final int listBottom = mBottom - mTop - mListPadding.bottom; 2779 if (mTempRect.bottom < mListPadding.top) { 2780 distance = mListPadding.top - mTempRect.bottom; 2781 } else if (mTempRect.top > listBottom) { 2782 distance = mTempRect.top - listBottom; 2783 } 2784 return distance; 2785 } 2786 2787 2788 /** 2789 * Scroll the children by amount, adding a view at the end and removing 2790 * views that fall off as necessary. 2791 * 2792 * @param amount The amount (positive or negative) to scroll. 2793 */ 2794 private void scrollListItemsBy(int amount) { 2795 offsetChildrenTopAndBottom(amount); 2796 2797 final int listBottom = getHeight() - mListPadding.bottom; 2798 final int listTop = mListPadding.top; 2799 final AbsListView.RecycleBin recycleBin = mRecycler; 2800 2801 if (amount < 0) { 2802 // shifted items up 2803 2804 // may need to pan views into the bottom space 2805 int numChildren = getChildCount(); 2806 View last = getChildAt(numChildren - 1); 2807 while (last.getBottom() < listBottom) { 2808 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2809 if (lastVisiblePosition < mItemCount - 1) { 2810 last = addViewBelow(last, lastVisiblePosition); 2811 numChildren++; 2812 } else { 2813 break; 2814 } 2815 } 2816 2817 // may have brought in the last child of the list that is skinnier 2818 // than the fading edge, thereby leaving space at the end. need 2819 // to shift back 2820 if (last.getBottom() < listBottom) { 2821 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2822 } 2823 2824 // top views may be panned off screen 2825 View first = getChildAt(0); 2826 while (first.getBottom() < listTop) { 2827 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2828 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2829 detachViewFromParent(first); 2830 recycleBin.addScrapView(first); 2831 } else { 2832 removeViewInLayout(first); 2833 } 2834 first = getChildAt(0); 2835 mFirstPosition++; 2836 } 2837 } else { 2838 // shifted items down 2839 View first = getChildAt(0); 2840 2841 // may need to pan views into top 2842 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2843 first = addViewAbove(first, mFirstPosition); 2844 mFirstPosition--; 2845 } 2846 2847 // may have brought the very first child of the list in too far and 2848 // need to shift it back 2849 if (first.getTop() > listTop) { 2850 offsetChildrenTopAndBottom(listTop - first.getTop()); 2851 } 2852 2853 int lastIndex = getChildCount() - 1; 2854 View last = getChildAt(lastIndex); 2855 2856 // bottom view may be panned off screen 2857 while (last.getTop() > listBottom) { 2858 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2859 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2860 detachViewFromParent(last); 2861 recycleBin.addScrapView(last); 2862 } else { 2863 removeViewInLayout(last); 2864 } 2865 last = getChildAt(--lastIndex); 2866 } 2867 } 2868 } 2869 2870 private View addViewAbove(View theView, int position) { 2871 int abovePosition = position - 1; 2872 View view = obtainView(abovePosition, mIsScrap); 2873 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2874 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2875 false, mIsScrap[0]); 2876 return view; 2877 } 2878 2879 private View addViewBelow(View theView, int position) { 2880 int belowPosition = position + 1; 2881 View view = obtainView(belowPosition, mIsScrap); 2882 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2883 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2884 false, mIsScrap[0]); 2885 return view; 2886 } 2887 2888 /** 2889 * Indicates that the views created by the ListAdapter can contain focusable 2890 * items. 2891 * 2892 * @param itemsCanFocus true if items can get focus, false otherwise 2893 */ 2894 public void setItemsCanFocus(boolean itemsCanFocus) { 2895 mItemsCanFocus = itemsCanFocus; 2896 if (!itemsCanFocus) { 2897 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2898 } 2899 } 2900 2901 /** 2902 * @return Whether the views created by the ListAdapter can contain focusable 2903 * items. 2904 */ 2905 public boolean getItemsCanFocus() { 2906 return mItemsCanFocus; 2907 } 2908 2909 /** 2910 * @hide Pending API council approval. 2911 */ 2912 @Override 2913 public boolean isOpaque() { 2914 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2915 hasOpaqueScrollbars()) || super.isOpaque(); 2916 } 2917 2918 @Override 2919 public void setCacheColorHint(int color) { 2920 final boolean opaque = (color >>> 24) == 0xFF; 2921 mIsCacheColorOpaque = opaque; 2922 if (opaque) { 2923 if (mDividerPaint == null) { 2924 mDividerPaint = new Paint(); 2925 } 2926 mDividerPaint.setColor(color); 2927 } 2928 super.setCacheColorHint(color); 2929 } 2930 2931 @Override 2932 protected void dispatchDraw(Canvas canvas) { 2933 // Draw the dividers 2934 final int dividerHeight = mDividerHeight; 2935 2936 if (dividerHeight > 0 && mDivider != null) { 2937 // Only modify the top and bottom in the loop, we set the left and right here 2938 final Rect bounds = mTempRect; 2939 bounds.left = mPaddingLeft; 2940 bounds.right = mRight - mLeft - mPaddingRight; 2941 2942 final int count = getChildCount(); 2943 final int headerCount = mHeaderViewInfos.size(); 2944 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2945 final boolean headerDividers = mHeaderDividersEnabled; 2946 final boolean footerDividers = mFooterDividersEnabled; 2947 final int first = mFirstPosition; 2948 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2949 final ListAdapter adapter = mAdapter; 2950 // If the list is opaque *and* the background is not, we want to 2951 // fill a rect where the dividers would be for non-selectable items 2952 // If the list is opaque and the background is also opaque, we don't 2953 // need to draw anything since the background will do it for us 2954 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2955 2956 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2957 mDividerPaint = new Paint(); 2958 mDividerPaint.setColor(getCacheColorHint()); 2959 } 2960 final Paint paint = mDividerPaint; 2961 2962 if (!mStackFromBottom) { 2963 int bottom; 2964 int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY; 2965 2966 // Draw top divider for overscroll 2967 if (count > 0 && mScrollY < 0) { 2968 bounds.bottom = 0; 2969 bounds.top = -dividerHeight; 2970 drawDivider(canvas, bounds, -1); 2971 } 2972 2973 for (int i = 0; i < count; i++) { 2974 if ((headerDividers || first + i >= headerCount) && 2975 (footerDividers || first + i < footerLimit)) { 2976 View child = getChildAt(i); 2977 bottom = child.getBottom(); 2978 // Don't draw dividers next to items that are not enabled 2979 if (bottom < listBottom) { 2980 if ((areAllItemsSelectable || 2981 (adapter.isEnabled(first + i) && (i == count - 1 || 2982 adapter.isEnabled(first + i + 1))))) { 2983 bounds.top = bottom; 2984 bounds.bottom = bottom + dividerHeight; 2985 drawDivider(canvas, bounds, i); 2986 } else if (fillForMissingDividers) { 2987 bounds.top = bottom; 2988 bounds.bottom = bottom + dividerHeight; 2989 canvas.drawRect(bounds, paint); 2990 } 2991 } 2992 } 2993 } 2994 } else { 2995 int top; 2996 int listTop = mListPadding.top; 2997 2998 for (int i = 0; i < count; i++) { 2999 if ((headerDividers || first + i >= headerCount) && 3000 (footerDividers || first + i < footerLimit)) { 3001 View child = getChildAt(i); 3002 top = child.getTop(); 3003 // Don't draw dividers next to items that are not enabled 3004 if (top > listTop) { 3005 if ((areAllItemsSelectable || 3006 (adapter.isEnabled(first + i) && (i == count - 1 || 3007 adapter.isEnabled(first + i + 1))))) { 3008 bounds.top = top - dividerHeight; 3009 bounds.bottom = top; 3010 // Give the method the child ABOVE the divider, so we 3011 // subtract one from our child 3012 // position. Give -1 when there is no child above the 3013 // divider. 3014 drawDivider(canvas, bounds, i - 1); 3015 } else if (fillForMissingDividers) { 3016 bounds.top = top - dividerHeight; 3017 bounds.bottom = top; 3018 canvas.drawRect(bounds, paint); 3019 } 3020 } 3021 } 3022 } 3023 } 3024 } 3025 3026 // Draw the indicators (these should be drawn above the dividers) and children 3027 super.dispatchDraw(canvas); 3028 } 3029 3030 /** 3031 * Draws a divider for the given child in the given bounds. 3032 * 3033 * @param canvas The canvas to draw to. 3034 * @param bounds The bounds of the divider. 3035 * @param childIndex The index of child (of the View) above the divider. 3036 * This will be -1 if there is no child above the divider to be 3037 * drawn. 3038 */ 3039 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3040 // This widget draws the same divider for all children 3041 final Drawable divider = mDivider; 3042 final boolean clipDivider = mClipDivider; 3043 3044 if (!clipDivider) { 3045 divider.setBounds(bounds); 3046 } else { 3047 canvas.save(); 3048 canvas.clipRect(bounds); 3049 } 3050 3051 divider.draw(canvas); 3052 3053 if (clipDivider) { 3054 canvas.restore(); 3055 } 3056 } 3057 3058 /** 3059 * Returns the drawable that will be drawn between each item in the list. 3060 * 3061 * @return the current drawable drawn between list elements 3062 */ 3063 public Drawable getDivider() { 3064 return mDivider; 3065 } 3066 3067 /** 3068 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3069 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3070 * 3071 * @param divider The drawable to use. 3072 */ 3073 public void setDivider(Drawable divider) { 3074 if (divider != null) { 3075 mDividerHeight = divider.getIntrinsicHeight(); 3076 mClipDivider = divider instanceof ColorDrawable; 3077 } else { 3078 mDividerHeight = 0; 3079 mClipDivider = false; 3080 } 3081 mDivider = divider; 3082 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3083 requestLayoutIfNecessary(); 3084 } 3085 3086 /** 3087 * @return Returns the height of the divider that will be drawn between each item in the list. 3088 */ 3089 public int getDividerHeight() { 3090 return mDividerHeight; 3091 } 3092 3093 /** 3094 * Sets the height of the divider that will be drawn between each item in the list. Calling 3095 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3096 * 3097 * @param height The new height of the divider in pixels. 3098 */ 3099 public void setDividerHeight(int height) { 3100 mDividerHeight = height; 3101 requestLayoutIfNecessary(); 3102 } 3103 3104 /** 3105 * Enables or disables the drawing of the divider for header views. 3106 * 3107 * @param headerDividersEnabled True to draw the headers, false otherwise. 3108 * 3109 * @see #setFooterDividersEnabled(boolean) 3110 * @see #addHeaderView(android.view.View) 3111 */ 3112 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3113 mHeaderDividersEnabled = headerDividersEnabled; 3114 invalidate(); 3115 } 3116 3117 /** 3118 * Enables or disables the drawing of the divider for footer views. 3119 * 3120 * @param footerDividersEnabled True to draw the footers, false otherwise. 3121 * 3122 * @see #setHeaderDividersEnabled(boolean) 3123 * @see #addFooterView(android.view.View) 3124 */ 3125 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3126 mFooterDividersEnabled = footerDividersEnabled; 3127 invalidate(); 3128 } 3129 3130 @Override 3131 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3132 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3133 3134 int closetChildIndex = -1; 3135 if (gainFocus && previouslyFocusedRect != null) { 3136 previouslyFocusedRect.offset(mScrollX, mScrollY); 3137 3138 final ListAdapter adapter = mAdapter; 3139 // Don't cache the result of getChildCount or mFirstPosition here, 3140 // it could change in layoutChildren. 3141 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3142 mLayoutMode = LAYOUT_NORMAL; 3143 layoutChildren(); 3144 } 3145 3146 // figure out which item should be selected based on previously 3147 // focused rect 3148 Rect otherRect = mTempRect; 3149 int minDistance = Integer.MAX_VALUE; 3150 final int childCount = getChildCount(); 3151 final int firstPosition = mFirstPosition; 3152 3153 for (int i = 0; i < childCount; i++) { 3154 // only consider selectable views 3155 if (!adapter.isEnabled(firstPosition + i)) { 3156 continue; 3157 } 3158 3159 View other = getChildAt(i); 3160 other.getDrawingRect(otherRect); 3161 offsetDescendantRectToMyCoords(other, otherRect); 3162 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3163 3164 if (distance < minDistance) { 3165 minDistance = distance; 3166 closetChildIndex = i; 3167 } 3168 } 3169 } 3170 3171 if (closetChildIndex >= 0) { 3172 setSelection(closetChildIndex + mFirstPosition); 3173 } else { 3174 requestLayout(); 3175 } 3176 } 3177 3178 3179 /* 3180 * (non-Javadoc) 3181 * 3182 * Children specified in XML are assumed to be header views. After we have 3183 * parsed them move them out of the children list and into mHeaderViews. 3184 */ 3185 @Override 3186 protected void onFinishInflate() { 3187 super.onFinishInflate(); 3188 3189 int count = getChildCount(); 3190 if (count > 0) { 3191 for (int i = 0; i < count; ++i) { 3192 addHeaderView(getChildAt(i)); 3193 } 3194 removeAllViews(); 3195 } 3196 } 3197 3198 /* (non-Javadoc) 3199 * @see android.view.View#findViewById(int) 3200 * First look in our children, then in any header and footer views that may be scrolled off. 3201 */ 3202 @Override 3203 protected View findViewTraversal(int id) { 3204 View v; 3205 v = super.findViewTraversal(id); 3206 if (v == null) { 3207 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3208 if (v != null) { 3209 return v; 3210 } 3211 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3212 if (v != null) { 3213 return v; 3214 } 3215 } 3216 return v; 3217 } 3218 3219 /* (non-Javadoc) 3220 * 3221 * Look in the passed in list of headers or footers for the view. 3222 */ 3223 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3224 if (where != null) { 3225 int len = where.size(); 3226 View v; 3227 3228 for (int i = 0; i < len; i++) { 3229 v = where.get(i).view; 3230 3231 if (!v.isRootNamespace()) { 3232 v = v.findViewById(id); 3233 3234 if (v != null) { 3235 return v; 3236 } 3237 } 3238 } 3239 } 3240 return null; 3241 } 3242 3243 /* (non-Javadoc) 3244 * @see android.view.View#findViewWithTag(String) 3245 * First look in our children, then in any header and footer views that may be scrolled off. 3246 */ 3247 @Override 3248 protected View findViewWithTagTraversal(Object tag) { 3249 View v; 3250 v = super.findViewWithTagTraversal(tag); 3251 if (v == null) { 3252 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3253 if (v != null) { 3254 return v; 3255 } 3256 3257 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3258 if (v != null) { 3259 return v; 3260 } 3261 } 3262 return v; 3263 } 3264 3265 /* (non-Javadoc) 3266 * 3267 * Look in the passed in list of headers or footers for the view with the tag. 3268 */ 3269 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3270 if (where != null) { 3271 int len = where.size(); 3272 View v; 3273 3274 for (int i = 0; i < len; i++) { 3275 v = where.get(i).view; 3276 3277 if (!v.isRootNamespace()) { 3278 v = v.findViewWithTag(tag); 3279 3280 if (v != null) { 3281 return v; 3282 } 3283 } 3284 } 3285 } 3286 return null; 3287 } 3288 3289 @Override 3290 public boolean onTouchEvent(MotionEvent ev) { 3291 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3292 // Don't handle edge touches immediately -- they may actually belong to one of our 3293 // descendants. 3294 return false; 3295 } 3296 return super.onTouchEvent(ev); 3297 } 3298 3299 /** 3300 * @see #setChoiceMode(int) 3301 * 3302 * @return The current choice mode 3303 */ 3304 public int getChoiceMode() { 3305 return mChoiceMode; 3306 } 3307 3308 /** 3309 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3310 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3311 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3312 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3313 * 3314 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3315 * {@link #CHOICE_MODE_MULTIPLE} 3316 */ 3317 public void setChoiceMode(int choiceMode) { 3318 mChoiceMode = choiceMode; 3319 if (mChoiceMode != CHOICE_MODE_NONE) { 3320 if (mCheckStates == null) { 3321 mCheckStates = new SparseBooleanArray(); 3322 } 3323 if (mCheckedIdStates == null && mAdapter.hasStableIds()) { 3324 mCheckedIdStates = new LongSparseArray<Boolean>(); 3325 } 3326 } 3327 } 3328 3329 @Override 3330 public boolean performItemClick(View view, int position, long id) { 3331 boolean handled = false; 3332 3333 if (mChoiceMode != CHOICE_MODE_NONE) { 3334 handled = true; 3335 3336 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3337 boolean newValue = !mCheckStates.get(position, false); 3338 mCheckStates.put(position, newValue); 3339 if (mCheckedIdStates != null && mAdapter.hasStableIds()) { 3340 if (newValue) { 3341 mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE); 3342 } else { 3343 mCheckedIdStates.delete(mAdapter.getItemId(position)); 3344 } 3345 } 3346 } else { 3347 boolean newValue = !mCheckStates.get(position, false); 3348 if (newValue) { 3349 mCheckStates.clear(); 3350 mCheckStates.put(position, true); 3351 if (mCheckedIdStates != null && mAdapter.hasStableIds()) { 3352 mCheckedIdStates.clear(); 3353 mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE); 3354 } 3355 } 3356 } 3357 3358 mDataChanged = true; 3359 rememberSyncState(); 3360 requestLayout(); 3361 } 3362 3363 handled |= super.performItemClick(view, position, id); 3364 3365 return handled; 3366 } 3367 3368 /** 3369 * Sets the checked state of the specified position. The is only valid if 3370 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3371 * {@link #CHOICE_MODE_MULTIPLE}. 3372 * 3373 * @param position The item whose checked state is to be checked 3374 * @param value The new checked state for the item 3375 */ 3376 public void setItemChecked(int position, boolean value) { 3377 if (mChoiceMode == CHOICE_MODE_NONE) { 3378 return; 3379 } 3380 3381 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3382 mCheckStates.put(position, value); 3383 if (mCheckedIdStates != null && mAdapter.hasStableIds()) { 3384 if (value) { 3385 mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE); 3386 } else { 3387 mCheckedIdStates.delete(mAdapter.getItemId(position)); 3388 } 3389 } 3390 } else { 3391 boolean updateIds = mCheckedIdStates != null && mAdapter.hasStableIds(); 3392 // Clear all values if we're checking something, or unchecking the currently 3393 // selected item 3394 if (value || isItemChecked(position)) { 3395 mCheckStates.clear(); 3396 if (updateIds) { 3397 mCheckedIdStates.clear(); 3398 } 3399 } 3400 // this may end up selecting the value we just cleared but this way 3401 // we ensure length of mCheckStates is 1, a fact getCheckedItemPosition relies on 3402 if (value) { 3403 mCheckStates.put(position, true); 3404 if (updateIds) { 3405 mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE); 3406 } 3407 } 3408 } 3409 3410 // Do not generate a data change while we are in the layout phase 3411 if (!mInLayout && !mBlockLayoutRequests) { 3412 mDataChanged = true; 3413 rememberSyncState(); 3414 requestLayout(); 3415 } 3416 } 3417 3418 /** 3419 * Returns the checked state of the specified position. The result is only 3420 * valid if the choice mode has been set to {@link #CHOICE_MODE_SINGLE} 3421 * or {@link #CHOICE_MODE_MULTIPLE}. 3422 * 3423 * @param position The item whose checked state to return 3424 * @return The item's checked state or <code>false</code> if choice mode 3425 * is invalid 3426 * 3427 * @see #setChoiceMode(int) 3428 */ 3429 public boolean isItemChecked(int position) { 3430 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3431 return mCheckStates.get(position); 3432 } 3433 3434 return false; 3435 } 3436 3437 /** 3438 * Returns the currently checked item. The result is only valid if the choice 3439 * mode has been set to {@link #CHOICE_MODE_SINGLE}. 3440 * 3441 * @return The position of the currently checked item or 3442 * {@link #INVALID_POSITION} if nothing is selected 3443 * 3444 * @see #setChoiceMode(int) 3445 */ 3446 public int getCheckedItemPosition() { 3447 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3448 return mCheckStates.keyAt(0); 3449 } 3450 3451 return INVALID_POSITION; 3452 } 3453 3454 /** 3455 * Returns the set of checked items in the list. The result is only valid if 3456 * the choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3457 * 3458 * @return A SparseBooleanArray which will return true for each call to 3459 * get(int position) where position is a position in the list, 3460 * or <code>null</code> if the choice mode is set to 3461 * {@link #CHOICE_MODE_NONE}. 3462 */ 3463 public SparseBooleanArray getCheckedItemPositions() { 3464 if (mChoiceMode != CHOICE_MODE_NONE) { 3465 return mCheckStates; 3466 } 3467 return null; 3468 } 3469 3470 /** 3471 * Returns the set of checked items ids. The result is only valid if the 3472 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3473 * 3474 * @return A new array which contains the id of each checked item in the 3475 * list. 3476 * 3477 * @deprecated Use {@link #getCheckedItemIds()} instead. 3478 */ 3479 public long[] getCheckItemIds() { 3480 return getCheckedItemIds(); 3481 } 3482 3483 /** 3484 * Returns the set of checked items ids. The result is only valid if the 3485 * choice mode has not been set to {@link #CHOICE_MODE_NONE} and the adapter 3486 * has stable IDs. ({@link ListAdapter#hasStableIds()} == {@code true}) 3487 * 3488 * @return A new array which contains the id of each checked item in the 3489 * list. 3490 */ 3491 public long[] getCheckedItemIds() { 3492 if (mChoiceMode == CHOICE_MODE_NONE || mCheckedIdStates == null || mAdapter == null) { 3493 return new long[0]; 3494 } 3495 3496 final LongSparseArray<Boolean> idStates = mCheckedIdStates; 3497 final int count = idStates.size(); 3498 final long[] ids = new long[count]; 3499 3500 for (int i = 0; i < count; i++) { 3501 ids[i] = idStates.keyAt(i); 3502 } 3503 3504 return ids; 3505 } 3506 3507 /** 3508 * Clear any choices previously set 3509 */ 3510 public void clearChoices() { 3511 if (mCheckStates != null) { 3512 mCheckStates.clear(); 3513 } 3514 if (mCheckedIdStates != null) { 3515 mCheckedIdStates.clear(); 3516 } 3517 } 3518 3519 static class SavedState extends BaseSavedState { 3520 SparseBooleanArray checkState; 3521 LongSparseArray<Boolean> checkIdState; 3522 3523 /** 3524 * Constructor called from {@link ListView#onSaveInstanceState()} 3525 */ 3526 SavedState(Parcelable superState, SparseBooleanArray checkState, 3527 LongSparseArray<Boolean> checkIdState) { 3528 super(superState); 3529 this.checkState = checkState; 3530 this.checkIdState = checkIdState; 3531 } 3532 3533 /** 3534 * Constructor called from {@link #CREATOR} 3535 */ 3536 private SavedState(Parcel in) { 3537 super(in); 3538 checkState = in.readSparseBooleanArray(); 3539 long[] idState = in.createLongArray(); 3540 3541 if (idState.length > 0) { 3542 checkIdState = new LongSparseArray<Boolean>(); 3543 checkIdState.setValues(idState, Boolean.TRUE); 3544 } 3545 } 3546 3547 @Override 3548 public void writeToParcel(Parcel out, int flags) { 3549 super.writeToParcel(out, flags); 3550 out.writeSparseBooleanArray(checkState); 3551 out.writeLongArray(checkIdState != null ? checkIdState.getKeys() : new long[0]); 3552 } 3553 3554 @Override 3555 public String toString() { 3556 return "ListView.SavedState{" 3557 + Integer.toHexString(System.identityHashCode(this)) 3558 + " checkState=" + checkState + "}"; 3559 } 3560 3561 public static final Parcelable.Creator<SavedState> CREATOR 3562 = new Parcelable.Creator<SavedState>() { 3563 public SavedState createFromParcel(Parcel in) { 3564 return new SavedState(in); 3565 } 3566 3567 public SavedState[] newArray(int size) { 3568 return new SavedState[size]; 3569 } 3570 }; 3571 } 3572 3573 @Override 3574 public Parcelable onSaveInstanceState() { 3575 Parcelable superState = super.onSaveInstanceState(); 3576 return new SavedState(superState, mCheckStates, mCheckedIdStates); 3577 } 3578 3579 @Override 3580 public void onRestoreInstanceState(Parcelable state) { 3581 SavedState ss = (SavedState) state; 3582 3583 super.onRestoreInstanceState(ss.getSuperState()); 3584 3585 if (ss.checkState != null) { 3586 mCheckStates = ss.checkState; 3587 } 3588 3589 if (ss.checkIdState != null) { 3590 mCheckedIdStates = ss.checkIdState; 3591 } 3592 } 3593} 3594