ListView.java revision 8842f0bd5c97cb39f6912392f34ba7435c275a42
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import android.content.Context; 20import android.content.res.TypedArray; 21import android.graphics.Canvas; 22import android.graphics.Rect; 23import android.graphics.PixelFormat; 24import android.graphics.Paint; 25import android.graphics.drawable.Drawable; 26import android.graphics.drawable.ColorDrawable; 27import android.os.Parcel; 28import android.os.Parcelable; 29import android.util.AttributeSet; 30import android.util.SparseBooleanArray; 31import android.view.FocusFinder; 32import android.view.KeyEvent; 33import android.view.MotionEvent; 34import android.view.View; 35import android.view.ViewDebug; 36import android.view.ViewGroup; 37import android.view.ViewParent; 38import android.view.SoundEffectConstants; 39import android.view.accessibility.AccessibilityEvent; 40 41import com.google.android.collect.Lists; 42import com.android.internal.R; 43 44import java.util.ArrayList; 45 46/* 47 * Implementation Notes: 48 * 49 * Some terminology: 50 * 51 * index - index of the items that are currently visible 52 * position - index of the items in the cursor 53 */ 54 55 56/** 57 * A view that shows items in a vertically scrolling list. The items 58 * come from the {@link ListAdapter} associated with this view. 59 * 60 * @attr ref android.R.styleable#ListView_entries 61 * @attr ref android.R.styleable#ListView_divider 62 * @attr ref android.R.styleable#ListView_dividerHeight 63 * @attr ref android.R.styleable#ListView_choiceMode 64 * @attr ref android.R.styleable#ListView_headerDividersEnabled 65 * @attr ref android.R.styleable#ListView_footerDividersEnabled 66 */ 67public class ListView extends AbsListView { 68 /** 69 * Used to indicate a no preference for a position type. 70 */ 71 static final int NO_POSITION = -1; 72 73 /** 74 * Normal list that does not indicate choices 75 */ 76 public static final int CHOICE_MODE_NONE = 0; 77 78 /** 79 * The list allows up to one choice 80 */ 81 public static final int CHOICE_MODE_SINGLE = 1; 82 83 /** 84 * The list allows multiple choices 85 */ 86 public static final int CHOICE_MODE_MULTIPLE = 2; 87 88 /** 89 * When arrow scrolling, ListView will never scroll more than this factor 90 * times the height of the list. 91 */ 92 private static final float MAX_SCROLL_FACTOR = 0.33f; 93 94 /** 95 * When arrow scrolling, need a certain amount of pixels to preview next 96 * items. This is usually the fading edge, but if that is small enough, 97 * we want to make sure we preview at least this many pixels. 98 */ 99 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 100 101 /** 102 * A class that represents a fixed view in a list, for example a header at the top 103 * or a footer at the bottom. 104 */ 105 public class FixedViewInfo { 106 /** The view to add to the list */ 107 public View view; 108 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 109 public Object data; 110 /** <code>true</code> if the fixed view should be selectable in the list */ 111 public boolean isSelectable; 112 } 113 114 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 115 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 116 117 Drawable mDivider; 118 int mDividerHeight; 119 120 private boolean mIsCacheColorOpaque; 121 private boolean mDividerIsOpaque; 122 private boolean mClipDivider; 123 124 private boolean mHeaderDividersEnabled; 125 private boolean mFooterDividersEnabled; 126 127 private boolean mAreAllItemsSelectable = true; 128 129 private boolean mItemsCanFocus = false; 130 131 private int mChoiceMode = CHOICE_MODE_NONE; 132 133 private SparseBooleanArray mCheckStates; 134 135 // used for temporary calculations. 136 private final Rect mTempRect = new Rect(); 137 private Paint mDividerPaint; 138 139 // the single allocated result per list view; kinda cheesey but avoids 140 // allocating these thingies too often. 141 private ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 142 143 public ListView(Context context) { 144 this(context, null); 145 } 146 147 public ListView(Context context, AttributeSet attrs) { 148 this(context, attrs, com.android.internal.R.attr.listViewStyle); 149 } 150 151 public ListView(Context context, AttributeSet attrs, int defStyle) { 152 super(context, attrs, defStyle); 153 154 TypedArray a = context.obtainStyledAttributes(attrs, 155 com.android.internal.R.styleable.ListView, defStyle, 0); 156 157 CharSequence[] entries = a.getTextArray( 158 com.android.internal.R.styleable.ListView_entries); 159 if (entries != null) { 160 setAdapter(new ArrayAdapter<CharSequence>(context, 161 com.android.internal.R.layout.simple_list_item_1, entries)); 162 } 163 164 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 165 if (d != null) { 166 // If a divider is specified use its intrinsic height for divider height 167 setDivider(d); 168 } 169 170 // Use the height specified, zero being the default 171 final int dividerHeight = a.getDimensionPixelSize( 172 com.android.internal.R.styleable.ListView_dividerHeight, 0); 173 if (dividerHeight != 0) { 174 setDividerHeight(dividerHeight); 175 } 176 177 setChoiceMode(a.getInt(R.styleable.ListView_choiceMode, CHOICE_MODE_NONE)); 178 179 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 180 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 181 182 a.recycle(); 183 } 184 185 /** 186 * @return The maximum amount a list view will scroll in response to 187 * an arrow event. 188 */ 189 public int getMaxScrollAmount() { 190 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 191 } 192 193 /** 194 * Make sure views are touching the top or bottom edge, as appropriate for 195 * our gravity 196 */ 197 private void adjustViewsUpOrDown() { 198 final int childCount = getChildCount(); 199 int delta; 200 201 if (childCount > 0) { 202 View child; 203 204 if (!mStackFromBottom) { 205 // Uh-oh -- we came up short. Slide all views up to make them 206 // align with the top 207 child = getChildAt(0); 208 delta = child.getTop() - mListPadding.top; 209 if (mFirstPosition != 0) { 210 // It's OK to have some space above the first item if it is 211 // part of the vertical spacing 212 delta -= mDividerHeight; 213 } 214 if (delta < 0) { 215 // We only are looking to see if we are too low, not too high 216 delta = 0; 217 } 218 } else { 219 // we are too high, slide all views down to align with bottom 220 child = getChildAt(childCount - 1); 221 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 222 223 if (mFirstPosition + childCount < mItemCount) { 224 // It's OK to have some space below the last item if it is 225 // part of the vertical spacing 226 delta += mDividerHeight; 227 } 228 229 if (delta > 0) { 230 delta = 0; 231 } 232 } 233 234 if (delta != 0) { 235 offsetChildrenTopAndBottom(-delta); 236 } 237 } 238 } 239 240 /** 241 * Add a fixed view to appear at the top of the list. If addHeaderView is 242 * called more than once, the views will appear in the order they were 243 * added. Views added using this call can take focus if they want. 244 * <p> 245 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 246 * the supplied cursor with one that that will also account for header 247 * views. 248 * 249 * @param v The view to add. 250 * @param data Data to associate with this view 251 * @param isSelectable whether the item is selectable 252 */ 253 public void addHeaderView(View v, Object data, boolean isSelectable) { 254 255 if (mAdapter != null) { 256 throw new IllegalStateException( 257 "Cannot add header view to list -- setAdapter has already been called."); 258 } 259 260 FixedViewInfo info = new FixedViewInfo(); 261 info.view = v; 262 info.data = data; 263 info.isSelectable = isSelectable; 264 mHeaderViewInfos.add(info); 265 } 266 267 /** 268 * Add a fixed view to appear at the top of the list. If addHeaderView is 269 * called more than once, the views will appear in the order they were 270 * added. Views added using this call can take focus if they want. 271 * <p> 272 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 273 * the supplied cursor with one that that will also account for header 274 * views. 275 * 276 * @param v The view to add. 277 */ 278 public void addHeaderView(View v) { 279 addHeaderView(v, null, true); 280 } 281 282 @Override 283 public int getHeaderViewsCount() { 284 return mHeaderViewInfos.size(); 285 } 286 287 /** 288 * Removes a previously-added header view. 289 * 290 * @param v The view to remove 291 * @return true if the view was removed, false if the view was not a header 292 * view 293 */ 294 public boolean removeHeaderView(View v) { 295 if (mHeaderViewInfos.size() > 0) { 296 boolean result = false; 297 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 298 mDataSetObserver.onChanged(); 299 result = true; 300 } 301 removeFixedViewInfo(v, mHeaderViewInfos); 302 return result; 303 } 304 return false; 305 } 306 307 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 308 int len = where.size(); 309 for (int i = 0; i < len; ++i) { 310 FixedViewInfo info = where.get(i); 311 if (info.view == v) { 312 where.remove(i); 313 break; 314 } 315 } 316 } 317 318 /** 319 * Add a fixed view to appear at the bottom of the list. If addFooterView is 320 * called more than once, the views will appear in the order they were 321 * added. Views added using this call can take focus if they want. 322 * <p> 323 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 324 * the supplied cursor with one that that will also account for header 325 * views. 326 * 327 * @param v The view to add. 328 * @param data Data to associate with this view 329 * @param isSelectable true if the footer view can be selected 330 */ 331 public void addFooterView(View v, Object data, boolean isSelectable) { 332 FixedViewInfo info = new FixedViewInfo(); 333 info.view = v; 334 info.data = data; 335 info.isSelectable = isSelectable; 336 mFooterViewInfos.add(info); 337 338 // in the case of re-adding a footer view, or adding one later on, 339 // we need to notify the observer 340 if (mDataSetObserver != null) { 341 mDataSetObserver.onChanged(); 342 } 343 } 344 345 /** 346 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 347 * than once, the views will appear in the order they were added. Views added using 348 * this call can take focus if they want. 349 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 350 * cursor with one that that will also account for header views. 351 * 352 * 353 * @param v The view to add. 354 */ 355 public void addFooterView(View v) { 356 addFooterView(v, null, true); 357 } 358 359 @Override 360 public int getFooterViewsCount() { 361 return mFooterViewInfos.size(); 362 } 363 364 /** 365 * Removes a previously-added footer view. 366 * 367 * @param v The view to remove 368 * @return 369 * true if the view was removed, false if the view was not a footer view 370 */ 371 public boolean removeFooterView(View v) { 372 if (mFooterViewInfos.size() > 0) { 373 boolean result = false; 374 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 375 mDataSetObserver.onChanged(); 376 result = true; 377 } 378 removeFixedViewInfo(v, mFooterViewInfos); 379 return result; 380 } 381 return false; 382 } 383 384 /** 385 * Returns the adapter currently in use in this ListView. The returned adapter 386 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 387 * might be a {@link WrapperListAdapter}. 388 * 389 * @return The adapter currently used to display data in this ListView. 390 * 391 * @see #setAdapter(ListAdapter) 392 */ 393 @Override 394 public ListAdapter getAdapter() { 395 return mAdapter; 396 } 397 398 /** 399 * Sets the data behind this ListView. 400 * 401 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 402 * depending on the ListView features currently in use. For instance, adding 403 * headers and/or footers will cause the adapter to be wrapped. 404 * 405 * @param adapter The ListAdapter which is responsible for maintaining the 406 * data backing this list and for producing a view to represent an 407 * item in that data set. 408 * 409 * @see #getAdapter() 410 */ 411 @Override 412 public void setAdapter(ListAdapter adapter) { 413 if (null != mAdapter) { 414 mAdapter.unregisterDataSetObserver(mDataSetObserver); 415 } 416 417 resetList(); 418 mRecycler.clear(); 419 420 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 421 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 422 } else { 423 mAdapter = adapter; 424 } 425 426 mOldSelectedPosition = INVALID_POSITION; 427 mOldSelectedRowId = INVALID_ROW_ID; 428 if (mAdapter != null) { 429 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 430 mOldItemCount = mItemCount; 431 mItemCount = mAdapter.getCount(); 432 checkFocus(); 433 434 mDataSetObserver = new AdapterDataSetObserver(); 435 mAdapter.registerDataSetObserver(mDataSetObserver); 436 437 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 438 439 int position; 440 if (mStackFromBottom) { 441 position = lookForSelectablePosition(mItemCount - 1, false); 442 } else { 443 position = lookForSelectablePosition(0, true); 444 } 445 setSelectedPositionInt(position); 446 setNextSelectedPositionInt(position); 447 448 if (mItemCount == 0) { 449 // Nothing selected 450 checkSelectionChanged(); 451 } 452 453 } else { 454 mAreAllItemsSelectable = true; 455 checkFocus(); 456 // Nothing selected 457 checkSelectionChanged(); 458 } 459 460 if (mCheckStates != null) { 461 mCheckStates.clear(); 462 } 463 464 requestLayout(); 465 } 466 467 468 /** 469 * The list is empty. Clear everything out. 470 */ 471 @Override 472 void resetList() { 473 // The parent's resetList() will remove all views from the layout so we need to 474 // cleanup the state of our footers and headers 475 clearRecycledState(mHeaderViewInfos); 476 clearRecycledState(mFooterViewInfos); 477 478 super.resetList(); 479 480 mLayoutMode = LAYOUT_NORMAL; 481 } 482 483 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 484 if (infos != null) { 485 final int count = infos.size(); 486 487 for (int i = 0; i < count; i++) { 488 final View child = infos.get(i).view; 489 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 490 if (p != null) { 491 p.recycledHeaderFooter = false; 492 } 493 } 494 } 495 } 496 497 /** 498 * @return Whether the list needs to show the top fading edge 499 */ 500 private boolean showingTopFadingEdge() { 501 final int listTop = mScrollY + mListPadding.top; 502 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 503 } 504 505 /** 506 * @return Whether the list needs to show the bottom fading edge 507 */ 508 private boolean showingBottomFadingEdge() { 509 final int childCount = getChildCount(); 510 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 511 final int lastVisiblePosition = mFirstPosition + childCount - 1; 512 513 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 514 515 return (lastVisiblePosition < mItemCount - 1) 516 || (bottomOfBottomChild < listBottom); 517 } 518 519 520 @Override 521 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 522 523 int rectTopWithinChild = rect.top; 524 525 // offset so rect is in coordinates of the this view 526 rect.offset(child.getLeft(), child.getTop()); 527 rect.offset(-child.getScrollX(), -child.getScrollY()); 528 529 final int height = getHeight(); 530 int listUnfadedTop = getScrollY(); 531 int listUnfadedBottom = listUnfadedTop + height; 532 final int fadingEdge = getVerticalFadingEdgeLength(); 533 534 if (showingTopFadingEdge()) { 535 // leave room for top fading edge as long as rect isn't at very top 536 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 537 listUnfadedTop += fadingEdge; 538 } 539 } 540 541 int childCount = getChildCount(); 542 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 543 544 if (showingBottomFadingEdge()) { 545 // leave room for bottom fading edge as long as rect isn't at very bottom 546 if ((mSelectedPosition < mItemCount - 1) 547 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 548 listUnfadedBottom -= fadingEdge; 549 } 550 } 551 552 int scrollYDelta = 0; 553 554 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 555 // need to MOVE DOWN to get it in view: move down just enough so 556 // that the entire rectangle is in view (or at least the first 557 // screen size chunk). 558 559 if (rect.height() > height) { 560 // just enough to get screen size chunk on 561 scrollYDelta += (rect.top - listUnfadedTop); 562 } else { 563 // get entire rect at bottom of screen 564 scrollYDelta += (rect.bottom - listUnfadedBottom); 565 } 566 567 // make sure we aren't scrolling beyond the end of our children 568 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 569 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 570 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 571 // need to MOVE UP to get it in view: move up just enough so that 572 // entire rectangle is in view (or at least the first screen 573 // size chunk of it). 574 575 if (rect.height() > height) { 576 // screen size chunk 577 scrollYDelta -= (listUnfadedBottom - rect.bottom); 578 } else { 579 // entire rect at top 580 scrollYDelta -= (listUnfadedTop - rect.top); 581 } 582 583 // make sure we aren't scrolling any further than the top our children 584 int top = getChildAt(0).getTop(); 585 int deltaToTop = top - listUnfadedTop; 586 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 587 } 588 589 final boolean scroll = scrollYDelta != 0; 590 if (scroll) { 591 scrollListItemsBy(-scrollYDelta); 592 positionSelector(child); 593 mSelectedTop = child.getTop(); 594 invalidate(); 595 } 596 return scroll; 597 } 598 599 /** 600 * {@inheritDoc} 601 */ 602 @Override 603 void fillGap(boolean down) { 604 final int count = getChildCount(); 605 if (down) { 606 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 607 getListPaddingTop(); 608 fillDown(mFirstPosition + count, startOffset); 609 correctTooHigh(getChildCount()); 610 } else { 611 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 612 getHeight() - getListPaddingBottom(); 613 fillUp(mFirstPosition - 1, startOffset); 614 correctTooLow(getChildCount()); 615 } 616 } 617 618 /** 619 * Fills the list from pos down to the end of the list view. 620 * 621 * @param pos The first position to put in the list 622 * 623 * @param nextTop The location where the top of the item associated with pos 624 * should be drawn 625 * 626 * @return The view that is currently selected, if it happens to be in the 627 * range that we draw. 628 */ 629 private View fillDown(int pos, int nextTop) { 630 View selectedView = null; 631 632 int end = (mBottom - mTop) - mListPadding.bottom; 633 634 while (nextTop < end && pos < mItemCount) { 635 // is this the selected item? 636 boolean selected = pos == mSelectedPosition; 637 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 638 639 nextTop = child.getBottom() + mDividerHeight; 640 if (selected) { 641 selectedView = child; 642 } 643 pos++; 644 } 645 646 return selectedView; 647 } 648 649 /** 650 * Fills the list from pos up to the top of the list view. 651 * 652 * @param pos The first position to put in the list 653 * 654 * @param nextBottom The location where the bottom of the item associated 655 * with pos should be drawn 656 * 657 * @return The view that is currently selected 658 */ 659 private View fillUp(int pos, int nextBottom) { 660 View selectedView = null; 661 662 int end = mListPadding.top; 663 664 while (nextBottom > end && pos >= 0) { 665 // is this the selected item? 666 boolean selected = pos == mSelectedPosition; 667 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 668 nextBottom = child.getTop() - mDividerHeight; 669 if (selected) { 670 selectedView = child; 671 } 672 pos--; 673 } 674 675 mFirstPosition = pos + 1; 676 677 return selectedView; 678 } 679 680 /** 681 * Fills the list from top to bottom, starting with mFirstPosition 682 * 683 * @param nextTop The location where the top of the first item should be 684 * drawn 685 * 686 * @return The view that is currently selected 687 */ 688 private View fillFromTop(int nextTop) { 689 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 690 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 691 if (mFirstPosition < 0) { 692 mFirstPosition = 0; 693 } 694 return fillDown(mFirstPosition, nextTop); 695 } 696 697 698 /** 699 * Put mSelectedPosition in the middle of the screen and then build up and 700 * down from there. This method forces mSelectedPosition to the center. 701 * 702 * @param childrenTop Top of the area in which children can be drawn, as 703 * measured in pixels 704 * @param childrenBottom Bottom of the area in which children can be drawn, 705 * as measured in pixels 706 * @return Currently selected view 707 */ 708 private View fillFromMiddle(int childrenTop, int childrenBottom) { 709 int height = childrenBottom - childrenTop; 710 711 int position = reconcileSelectedPosition(); 712 713 View sel = makeAndAddView(position, childrenTop, true, 714 mListPadding.left, true); 715 mFirstPosition = position; 716 717 int selHeight = sel.getMeasuredHeight(); 718 if (selHeight <= height) { 719 sel.offsetTopAndBottom((height - selHeight) / 2); 720 } 721 722 fillAboveAndBelow(sel, position); 723 724 if (!mStackFromBottom) { 725 correctTooHigh(getChildCount()); 726 } else { 727 correctTooLow(getChildCount()); 728 } 729 730 return sel; 731 } 732 733 /** 734 * Once the selected view as been placed, fill up the visible area above and 735 * below it. 736 * 737 * @param sel The selected view 738 * @param position The position corresponding to sel 739 */ 740 private void fillAboveAndBelow(View sel, int position) { 741 final int dividerHeight = mDividerHeight; 742 if (!mStackFromBottom) { 743 fillUp(position - 1, sel.getTop() - dividerHeight); 744 adjustViewsUpOrDown(); 745 fillDown(position + 1, sel.getBottom() + dividerHeight); 746 } else { 747 fillDown(position + 1, sel.getBottom() + dividerHeight); 748 adjustViewsUpOrDown(); 749 fillUp(position - 1, sel.getTop() - dividerHeight); 750 } 751 } 752 753 754 /** 755 * Fills the grid based on positioning the new selection at a specific 756 * location. The selection may be moved so that it does not intersect the 757 * faded edges. The grid is then filled upwards and downwards from there. 758 * 759 * @param selectedTop Where the selected item should be 760 * @param childrenTop Where to start drawing children 761 * @param childrenBottom Last pixel where children can be drawn 762 * @return The view that currently has selection 763 */ 764 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 765 int fadingEdgeLength = getVerticalFadingEdgeLength(); 766 final int selectedPosition = mSelectedPosition; 767 768 View sel; 769 770 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 771 selectedPosition); 772 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 773 selectedPosition); 774 775 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 776 777 778 // Some of the newly selected item extends below the bottom of the list 779 if (sel.getBottom() > bottomSelectionPixel) { 780 // Find space available above the selection into which we can scroll 781 // upwards 782 final int spaceAbove = sel.getTop() - topSelectionPixel; 783 784 // Find space required to bring the bottom of the selected item 785 // fully into view 786 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 787 final int offset = Math.min(spaceAbove, spaceBelow); 788 789 // Now offset the selected item to get it into view 790 sel.offsetTopAndBottom(-offset); 791 } else if (sel.getTop() < topSelectionPixel) { 792 // Find space required to bring the top of the selected item fully 793 // into view 794 final int spaceAbove = topSelectionPixel - sel.getTop(); 795 796 // Find space available below the selection into which we can scroll 797 // downwards 798 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 799 final int offset = Math.min(spaceAbove, spaceBelow); 800 801 // Offset the selected item to get it into view 802 sel.offsetTopAndBottom(offset); 803 } 804 805 // Fill in views above and below 806 fillAboveAndBelow(sel, selectedPosition); 807 808 if (!mStackFromBottom) { 809 correctTooHigh(getChildCount()); 810 } else { 811 correctTooLow(getChildCount()); 812 } 813 814 return sel; 815 } 816 817 /** 818 * Calculate the bottom-most pixel we can draw the selection into 819 * 820 * @param childrenBottom Bottom pixel were children can be drawn 821 * @param fadingEdgeLength Length of the fading edge in pixels, if present 822 * @param selectedPosition The position that will be selected 823 * @return The bottom-most pixel we can draw the selection into 824 */ 825 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 826 int selectedPosition) { 827 int bottomSelectionPixel = childrenBottom; 828 if (selectedPosition != mItemCount - 1) { 829 bottomSelectionPixel -= fadingEdgeLength; 830 } 831 return bottomSelectionPixel; 832 } 833 834 /** 835 * Calculate the top-most pixel we can draw the selection into 836 * 837 * @param childrenTop Top pixel were children can be drawn 838 * @param fadingEdgeLength Length of the fading edge in pixels, if present 839 * @param selectedPosition The position that will be selected 840 * @return The top-most pixel we can draw the selection into 841 */ 842 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 843 // first pixel we can draw the selection into 844 int topSelectionPixel = childrenTop; 845 if (selectedPosition > 0) { 846 topSelectionPixel += fadingEdgeLength; 847 } 848 return topSelectionPixel; 849 } 850 851 852 /** 853 * Fills the list based on positioning the new selection relative to the old 854 * selection. The new selection will be placed at, above, or below the 855 * location of the new selection depending on how the selection is moving. 856 * The selection will then be pinned to the visible part of the screen, 857 * excluding the edges that are faded. The list is then filled upwards and 858 * downwards from there. 859 * 860 * @param oldSel The old selected view. Useful for trying to put the new 861 * selection in the same place 862 * @param newSel The view that is to become selected. Useful for trying to 863 * put the new selection in the same place 864 * @param delta Which way we are moving 865 * @param childrenTop Where to start drawing children 866 * @param childrenBottom Last pixel where children can be drawn 867 * @return The view that currently has selection 868 */ 869 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 870 int childrenBottom) { 871 int fadingEdgeLength = getVerticalFadingEdgeLength(); 872 final int selectedPosition = mSelectedPosition; 873 874 View sel; 875 876 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 877 selectedPosition); 878 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 879 selectedPosition); 880 881 if (delta > 0) { 882 /* 883 * Case 1: Scrolling down. 884 */ 885 886 /* 887 * Before After 888 * | | | | 889 * +-------+ +-------+ 890 * | A | | A | 891 * | 1 | => +-------+ 892 * +-------+ | B | 893 * | B | | 2 | 894 * +-------+ +-------+ 895 * | | | | 896 * 897 * Try to keep the top of the previously selected item where it was. 898 * oldSel = A 899 * sel = B 900 */ 901 902 // Put oldSel (A) where it belongs 903 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 904 mListPadding.left, false); 905 906 final int dividerHeight = mDividerHeight; 907 908 // Now put the new selection (B) below that 909 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 910 mListPadding.left, true); 911 912 // Some of the newly selected item extends below the bottom of the list 913 if (sel.getBottom() > bottomSelectionPixel) { 914 915 // Find space available above the selection into which we can scroll upwards 916 int spaceAbove = sel.getTop() - topSelectionPixel; 917 918 // Find space required to bring the bottom of the selected item fully into view 919 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 920 921 // Don't scroll more than half the height of the list 922 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 923 int offset = Math.min(spaceAbove, spaceBelow); 924 offset = Math.min(offset, halfVerticalSpace); 925 926 // We placed oldSel, so offset that item 927 oldSel.offsetTopAndBottom(-offset); 928 // Now offset the selected item to get it into view 929 sel.offsetTopAndBottom(-offset); 930 } 931 932 // Fill in views above and below 933 if (!mStackFromBottom) { 934 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 935 adjustViewsUpOrDown(); 936 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 937 } else { 938 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 939 adjustViewsUpOrDown(); 940 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 941 } 942 } else if (delta < 0) { 943 /* 944 * Case 2: Scrolling up. 945 */ 946 947 /* 948 * Before After 949 * | | | | 950 * +-------+ +-------+ 951 * | A | | A | 952 * +-------+ => | 1 | 953 * | B | +-------+ 954 * | 2 | | B | 955 * +-------+ +-------+ 956 * | | | | 957 * 958 * Try to keep the top of the item about to become selected where it was. 959 * newSel = A 960 * olSel = B 961 */ 962 963 if (newSel != null) { 964 // Try to position the top of newSel (A) where it was before it was selected 965 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 966 true); 967 } else { 968 // If (A) was not on screen and so did not have a view, position 969 // it above the oldSel (B) 970 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 971 true); 972 } 973 974 // Some of the newly selected item extends above the top of the list 975 if (sel.getTop() < topSelectionPixel) { 976 // Find space required to bring the top of the selected item fully into view 977 int spaceAbove = topSelectionPixel - sel.getTop(); 978 979 // Find space available below the selection into which we can scroll downwards 980 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 981 982 // Don't scroll more than half the height of the list 983 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 984 int offset = Math.min(spaceAbove, spaceBelow); 985 offset = Math.min(offset, halfVerticalSpace); 986 987 // Offset the selected item to get it into view 988 sel.offsetTopAndBottom(offset); 989 } 990 991 // Fill in views above and below 992 fillAboveAndBelow(sel, selectedPosition); 993 } else { 994 995 int oldTop = oldSel.getTop(); 996 997 /* 998 * Case 3: Staying still 999 */ 1000 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1001 1002 // We're staying still... 1003 if (oldTop < childrenTop) { 1004 // ... but the top of the old selection was off screen. 1005 // (This can happen if the data changes size out from under us) 1006 int newBottom = sel.getBottom(); 1007 if (newBottom < childrenTop + 20) { 1008 // Not enough visible -- bring it onscreen 1009 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1010 } 1011 } 1012 1013 // Fill in views above and below 1014 fillAboveAndBelow(sel, selectedPosition); 1015 } 1016 1017 return sel; 1018 } 1019 1020 @Override 1021 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1022 // Sets up mListPadding 1023 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1024 1025 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1026 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1027 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1028 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1029 1030 int childWidth = 0; 1031 int childHeight = 0; 1032 1033 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1034 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1035 heightMode == MeasureSpec.UNSPECIFIED)) { 1036 final View child = obtainView(0); 1037 1038 measureScrapChild(child, 0, widthMeasureSpec); 1039 1040 childWidth = child.getMeasuredWidth(); 1041 childHeight = child.getMeasuredHeight(); 1042 1043 if (recycleOnMeasure()) { 1044 mRecycler.addScrapView(child); 1045 } 1046 } 1047 1048 if (widthMode == MeasureSpec.UNSPECIFIED) { 1049 widthSize = mListPadding.left + mListPadding.right + childWidth + 1050 getVerticalScrollbarWidth(); 1051 } 1052 1053 if (heightMode == MeasureSpec.UNSPECIFIED) { 1054 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1055 getVerticalFadingEdgeLength() * 2; 1056 } 1057 1058 if (heightMode == MeasureSpec.AT_MOST) { 1059 // TODO: after first layout we should maybe start at the first visible position, not 0 1060 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1061 } 1062 1063 setMeasuredDimension(widthSize, heightSize); 1064 mWidthMeasureSpec = widthMeasureSpec; 1065 } 1066 1067 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1068 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1069 if (p == null) { 1070 p = new LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1071 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1072 child.setLayoutParams(p); 1073 } 1074 p.viewType = mAdapter.getItemViewType(position); 1075 1076 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1077 mListPadding.left + mListPadding.right, p.width); 1078 int lpHeight = p.height; 1079 int childHeightSpec; 1080 if (lpHeight > 0) { 1081 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1082 } else { 1083 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1084 } 1085 child.measure(childWidthSpec, childHeightSpec); 1086 } 1087 1088 /** 1089 * @return True to recycle the views used to measure this ListView in 1090 * UNSPECIFIED/AT_MOST modes, false otherwise. 1091 * @hide 1092 */ 1093 @ViewDebug.ExportedProperty 1094 protected boolean recycleOnMeasure() { 1095 return true; 1096 } 1097 1098 /** 1099 * Measures the height of the given range of children (inclusive) and 1100 * returns the height with this ListView's padding and divider heights 1101 * included. If maxHeight is provided, the measuring will stop when the 1102 * current height reaches maxHeight. 1103 * 1104 * @param widthMeasureSpec The width measure spec to be given to a child's 1105 * {@link View#measure(int, int)}. 1106 * @param startPosition The position of the first child to be shown. 1107 * @param endPosition The (inclusive) position of the last child to be 1108 * shown. Specify {@link #NO_POSITION} if the last child should be 1109 * the last available child from the adapter. 1110 * @param maxHeight The maximum height that will be returned (if all the 1111 * children don't fit in this value, this value will be 1112 * returned). 1113 * @param disallowPartialChildPosition In general, whether the returned 1114 * height should only contain entire children. This is more 1115 * powerful--it is the first inclusive position at which partial 1116 * children will not be allowed. Example: it looks nice to have 1117 * at least 3 completely visible children, and in portrait this 1118 * will most likely fit; but in landscape there could be times 1119 * when even 2 children can not be completely shown, so a value 1120 * of 2 (remember, inclusive) would be good (assuming 1121 * startPosition is 0). 1122 * @return The height of this ListView with the given children. 1123 */ 1124 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1125 final int maxHeight, int disallowPartialChildPosition) { 1126 1127 final ListAdapter adapter = mAdapter; 1128 if (adapter == null) { 1129 return mListPadding.top + mListPadding.bottom; 1130 } 1131 1132 // Include the padding of the list 1133 int returnedHeight = mListPadding.top + mListPadding.bottom; 1134 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1135 // The previous height value that was less than maxHeight and contained 1136 // no partial children 1137 int prevHeightWithoutPartialChild = 0; 1138 int i; 1139 View child; 1140 1141 // mItemCount - 1 since endPosition parameter is inclusive 1142 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1143 final AbsListView.RecycleBin recycleBin = mRecycler; 1144 final boolean recyle = recycleOnMeasure(); 1145 1146 for (i = startPosition; i <= endPosition; ++i) { 1147 child = obtainView(i); 1148 1149 measureScrapChild(child, i, widthMeasureSpec); 1150 1151 if (i > 0) { 1152 // Count the divider for all but one child 1153 returnedHeight += dividerHeight; 1154 } 1155 1156 // Recycle the view before we possibly return from the method 1157 if (recyle) { 1158 recycleBin.addScrapView(child); 1159 } 1160 1161 returnedHeight += child.getMeasuredHeight(); 1162 1163 if (returnedHeight >= maxHeight) { 1164 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1165 // then the i'th position did not fit completely. 1166 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1167 && (i > disallowPartialChildPosition) // We've past the min pos 1168 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1169 && (returnedHeight != maxHeight) // i'th child did not fit completely 1170 ? prevHeightWithoutPartialChild 1171 : maxHeight; 1172 } 1173 1174 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1175 prevHeightWithoutPartialChild = returnedHeight; 1176 } 1177 } 1178 1179 // At this point, we went through the range of children, and they each 1180 // completely fit, so return the returnedHeight 1181 return returnedHeight; 1182 } 1183 1184 @Override 1185 int findMotionRow(int y) { 1186 int childCount = getChildCount(); 1187 if (childCount > 0) { 1188 for (int i = 0; i < childCount; i++) { 1189 View v = getChildAt(i); 1190 if (y <= v.getBottom()) { 1191 return mFirstPosition + i; 1192 } 1193 } 1194 return mFirstPosition + childCount - 1; 1195 } 1196 return INVALID_POSITION; 1197 } 1198 1199 /** 1200 * Put a specific item at a specific location on the screen and then build 1201 * up and down from there. 1202 * 1203 * @param position The reference view to use as the starting point 1204 * @param top Pixel offset from the top of this view to the top of the 1205 * reference view. 1206 * 1207 * @return The selected view, or null if the selected view is outside the 1208 * visible area. 1209 */ 1210 private View fillSpecific(int position, int top) { 1211 boolean tempIsSelected = position == mSelectedPosition; 1212 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1213 // Possibly changed again in fillUp if we add rows above this one. 1214 mFirstPosition = position; 1215 1216 View above; 1217 View below; 1218 1219 final int dividerHeight = mDividerHeight; 1220 if (!mStackFromBottom) { 1221 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1222 // This will correct for the top of the first view not touching the top of the list 1223 adjustViewsUpOrDown(); 1224 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1225 int childCount = getChildCount(); 1226 if (childCount > 0) { 1227 correctTooHigh(childCount); 1228 } 1229 } else { 1230 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1231 // This will correct for the bottom of the last view not touching the bottom of the list 1232 adjustViewsUpOrDown(); 1233 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1234 int childCount = getChildCount(); 1235 if (childCount > 0) { 1236 correctTooLow(childCount); 1237 } 1238 } 1239 1240 if (tempIsSelected) { 1241 return temp; 1242 } else if (above != null) { 1243 return above; 1244 } else { 1245 return below; 1246 } 1247 } 1248 1249 /** 1250 * Check if we have dragged the bottom of the list too high (we have pushed the 1251 * top element off the top of the screen when we did not need to). Correct by sliding 1252 * everything back down. 1253 * 1254 * @param childCount Number of children 1255 */ 1256 private void correctTooHigh(int childCount) { 1257 // First see if the last item is visible. If it is not, it is OK for the 1258 // top of the list to be pushed up. 1259 int lastPosition = mFirstPosition + childCount - 1; 1260 if (lastPosition == mItemCount - 1 && childCount > 0) { 1261 1262 // Get the last child ... 1263 final View lastChild = getChildAt(childCount - 1); 1264 1265 // ... and its bottom edge 1266 final int lastBottom = lastChild.getBottom(); 1267 1268 // This is bottom of our drawable area 1269 final int end = (mBottom - mTop) - mListPadding.bottom; 1270 1271 // This is how far the bottom edge of the last view is from the bottom of the 1272 // drawable area 1273 int bottomOffset = end - lastBottom; 1274 View firstChild = getChildAt(0); 1275 final int firstTop = firstChild.getTop(); 1276 1277 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1278 // first row or the first row is scrolled off the top of the drawable area 1279 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1280 if (mFirstPosition == 0) { 1281 // Don't pull the top too far down 1282 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1283 } 1284 // Move everything down 1285 offsetChildrenTopAndBottom(bottomOffset); 1286 if (mFirstPosition > 0) { 1287 // Fill the gap that was opened above mFirstPosition with more rows, if 1288 // possible 1289 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1290 // Close up the remaining gap 1291 adjustViewsUpOrDown(); 1292 } 1293 1294 } 1295 } 1296 } 1297 1298 /** 1299 * Check if we have dragged the bottom of the list too low (we have pushed the 1300 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1301 * everything back up. 1302 * 1303 * @param childCount Number of children 1304 */ 1305 private void correctTooLow(int childCount) { 1306 // First see if the first item is visible. If it is not, it is OK for the 1307 // bottom of the list to be pushed down. 1308 if (mFirstPosition == 0 && childCount > 0) { 1309 1310 // Get the first child ... 1311 final View firstChild = getChildAt(0); 1312 1313 // ... and its top edge 1314 final int firstTop = firstChild.getTop(); 1315 1316 // This is top of our drawable area 1317 final int start = mListPadding.top; 1318 1319 // This is bottom of our drawable area 1320 final int end = (mBottom - mTop) - mListPadding.bottom; 1321 1322 // This is how far the top edge of the first view is from the top of the 1323 // drawable area 1324 int topOffset = firstTop - start; 1325 View lastChild = getChildAt(childCount - 1); 1326 final int lastBottom = lastChild.getBottom(); 1327 int lastPosition = mFirstPosition + childCount - 1; 1328 1329 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1330 // last row or the last row is scrolled off the bottom of the drawable area 1331 if (topOffset > 0 && (lastPosition < mItemCount - 1 || lastBottom > end)) { 1332 if (lastPosition == mItemCount - 1 ) { 1333 // Don't pull the bottom too far up 1334 topOffset = Math.min(topOffset, lastBottom - end); 1335 } 1336 // Move everything up 1337 offsetChildrenTopAndBottom(-topOffset); 1338 if (lastPosition < mItemCount - 1) { 1339 // Fill the gap that was opened below the last position with more rows, if 1340 // possible 1341 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1342 // Close up the remaining gap 1343 adjustViewsUpOrDown(); 1344 } 1345 } 1346 } 1347 } 1348 1349 @Override 1350 protected void layoutChildren() { 1351 final boolean blockLayoutRequests = mBlockLayoutRequests; 1352 if (!blockLayoutRequests) { 1353 mBlockLayoutRequests = true; 1354 } else { 1355 return; 1356 } 1357 1358 try { 1359 super.layoutChildren(); 1360 1361 invalidate(); 1362 1363 if (mAdapter == null) { 1364 resetList(); 1365 invokeOnItemScrollListener(); 1366 return; 1367 } 1368 1369 int childrenTop = mListPadding.top; 1370 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1371 1372 int childCount = getChildCount(); 1373 int index; 1374 int delta = 0; 1375 1376 View sel; 1377 View oldSel = null; 1378 View oldFirst = null; 1379 View newSel = null; 1380 1381 View focusLayoutRestoreView = null; 1382 1383 // Remember stuff we will need down below 1384 switch (mLayoutMode) { 1385 case LAYOUT_SET_SELECTION: 1386 index = mNextSelectedPosition - mFirstPosition; 1387 if (index >= 0 && index < childCount) { 1388 newSel = getChildAt(index); 1389 } 1390 break; 1391 case LAYOUT_FORCE_TOP: 1392 case LAYOUT_FORCE_BOTTOM: 1393 case LAYOUT_SPECIFIC: 1394 case LAYOUT_SYNC: 1395 break; 1396 case LAYOUT_MOVE_SELECTION: 1397 default: 1398 // Remember the previously selected view 1399 index = mSelectedPosition - mFirstPosition; 1400 if (index >= 0 && index < childCount) { 1401 oldSel = getChildAt(index); 1402 } 1403 1404 // Remember the previous first child 1405 oldFirst = getChildAt(0); 1406 1407 if (mNextSelectedPosition >= 0) { 1408 delta = mNextSelectedPosition - mSelectedPosition; 1409 } 1410 1411 // Caution: newSel might be null 1412 newSel = getChildAt(index + delta); 1413 } 1414 1415 1416 boolean dataChanged = mDataChanged; 1417 if (dataChanged) { 1418 handleDataChanged(); 1419 } 1420 1421 // Handle the empty set by removing all views that are visible 1422 // and calling it a day 1423 if (mItemCount == 0) { 1424 resetList(); 1425 invokeOnItemScrollListener(); 1426 return; 1427 } else if (mItemCount != mAdapter.getCount()) { 1428 throw new IllegalStateException("The content of the adapter has changed but " 1429 + "ListView did not receive a notification. Make sure the content of " 1430 + "your adapter is not modified from a background thread, but only " 1431 + "from the UI thread."); 1432 } 1433 1434 setSelectedPositionInt(mNextSelectedPosition); 1435 1436 // Pull all children into the RecycleBin. 1437 // These views will be reused if possible 1438 final int firstPosition = mFirstPosition; 1439 final RecycleBin recycleBin = mRecycler; 1440 1441 // reset the focus restoration 1442 View focusLayoutRestoreDirectChild = null; 1443 1444 1445 // Don't put header or footer views into the Recycler. Those are 1446 // already cached in mHeaderViews; 1447 if (dataChanged) { 1448 for (int i = 0; i < childCount; i++) { 1449 recycleBin.addScrapView(getChildAt(i)); 1450 if (ViewDebug.TRACE_RECYCLER) { 1451 ViewDebug.trace(getChildAt(i), 1452 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1453 } 1454 } 1455 } else { 1456 recycleBin.fillActiveViews(childCount, firstPosition); 1457 } 1458 1459 // take focus back to us temporarily to avoid the eventual 1460 // call to clear focus when removing the focused child below 1461 // from messing things up when ViewRoot assigns focus back 1462 // to someone else 1463 final View focusedChild = getFocusedChild(); 1464 if (focusedChild != null) { 1465 // TODO: in some cases focusedChild.getParent() == null 1466 1467 // we can remember the focused view to restore after relayout if the 1468 // data hasn't changed, or if the focused position is a header or footer 1469 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1470 focusLayoutRestoreDirectChild = focusedChild; 1471 // remember the specific view that had focus 1472 focusLayoutRestoreView = findFocus(); 1473 if (focusLayoutRestoreView != null) { 1474 // tell it we are going to mess with it 1475 focusLayoutRestoreView.onStartTemporaryDetach(); 1476 } 1477 } 1478 requestFocus(); 1479 } 1480 1481 // Clear out old views 1482 //removeAllViewsInLayout(); 1483 detachAllViewsFromParent(); 1484 1485 switch (mLayoutMode) { 1486 case LAYOUT_SET_SELECTION: 1487 if (newSel != null) { 1488 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1489 } else { 1490 sel = fillFromMiddle(childrenTop, childrenBottom); 1491 } 1492 break; 1493 case LAYOUT_SYNC: 1494 sel = fillSpecific(mSyncPosition, mSpecificTop); 1495 break; 1496 case LAYOUT_FORCE_BOTTOM: 1497 sel = fillUp(mItemCount - 1, childrenBottom); 1498 adjustViewsUpOrDown(); 1499 break; 1500 case LAYOUT_FORCE_TOP: 1501 mFirstPosition = 0; 1502 sel = fillFromTop(childrenTop); 1503 adjustViewsUpOrDown(); 1504 break; 1505 case LAYOUT_SPECIFIC: 1506 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1507 break; 1508 case LAYOUT_MOVE_SELECTION: 1509 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1510 break; 1511 default: 1512 if (childCount == 0) { 1513 if (!mStackFromBottom) { 1514 final int position = lookForSelectablePosition(0, true); 1515 setSelectedPositionInt(position); 1516 sel = fillFromTop(childrenTop); 1517 } else { 1518 final int position = lookForSelectablePosition(mItemCount - 1, false); 1519 setSelectedPositionInt(position); 1520 sel = fillUp(mItemCount - 1, childrenBottom); 1521 } 1522 } else { 1523 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1524 sel = fillSpecific(mSelectedPosition, 1525 oldSel == null ? childrenTop : oldSel.getTop()); 1526 } else if (mFirstPosition < mItemCount) { 1527 sel = fillSpecific(mFirstPosition, 1528 oldFirst == null ? childrenTop : oldFirst.getTop()); 1529 } else { 1530 sel = fillSpecific(0, childrenTop); 1531 } 1532 } 1533 break; 1534 } 1535 1536 // Flush any cached views that did not get reused above 1537 recycleBin.scrapActiveViews(); 1538 1539 if (sel != null) { 1540 // the current selected item should get focus if items 1541 // are focusable 1542 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1543 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1544 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1545 if (!focusWasTaken) { 1546 // selected item didn't take focus, fine, but still want 1547 // to make sure something else outside of the selected view 1548 // has focus 1549 final View focused = getFocusedChild(); 1550 if (focused != null) { 1551 focused.clearFocus(); 1552 } 1553 positionSelector(sel); 1554 } else { 1555 sel.setSelected(false); 1556 mSelectorRect.setEmpty(); 1557 } 1558 } else { 1559 positionSelector(sel); 1560 } 1561 mSelectedTop = sel.getTop(); 1562 } else { 1563 mSelectedTop = 0; 1564 mSelectorRect.setEmpty(); 1565 1566 // even if there is not selected position, we may need to restore 1567 // focus (i.e. something focusable in touch mode) 1568 if (hasFocus() && focusLayoutRestoreView != null) { 1569 focusLayoutRestoreView.requestFocus(); 1570 } 1571 } 1572 1573 // tell focus view we are done mucking with it, if it is still in 1574 // our view hierarchy. 1575 if (focusLayoutRestoreView != null 1576 && focusLayoutRestoreView.getWindowToken() != null) { 1577 focusLayoutRestoreView.onFinishTemporaryDetach(); 1578 } 1579 1580 mLayoutMode = LAYOUT_NORMAL; 1581 mDataChanged = false; 1582 mNeedSync = false; 1583 setNextSelectedPositionInt(mSelectedPosition); 1584 1585 updateScrollIndicators(); 1586 1587 if (mItemCount > 0) { 1588 checkSelectionChanged(); 1589 } 1590 1591 invokeOnItemScrollListener(); 1592 } finally { 1593 if (!blockLayoutRequests) { 1594 mBlockLayoutRequests = false; 1595 } 1596 } 1597 } 1598 1599 /** 1600 * @param child a direct child of this list. 1601 * @return Whether child is a header or footer view. 1602 */ 1603 private boolean isDirectChildHeaderOrFooter(View child) { 1604 1605 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1606 final int numHeaders = headers.size(); 1607 for (int i = 0; i < numHeaders; i++) { 1608 if (child == headers.get(i).view) { 1609 return true; 1610 } 1611 } 1612 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1613 final int numFooters = footers.size(); 1614 for (int i = 0; i < numFooters; i++) { 1615 if (child == footers.get(i).view) { 1616 return true; 1617 } 1618 } 1619 return false; 1620 } 1621 1622 /** 1623 * Obtain the view and add it to our list of children. The view can be made 1624 * fresh, converted from an unused view, or used as is if it was in the 1625 * recycle bin. 1626 * 1627 * @param position Logical position in the list 1628 * @param y Top or bottom edge of the view to add 1629 * @param flow If flow is true, align top edge to y. If false, align bottom 1630 * edge to y. 1631 * @param childrenLeft Left edge where children should be positioned 1632 * @param selected Is this position selected? 1633 * @return View that was added 1634 */ 1635 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1636 boolean selected) { 1637 View child; 1638 1639 1640 if (!mDataChanged) { 1641 // Try to use an exsiting view for this position 1642 child = mRecycler.getActiveView(position); 1643 if (child != null) { 1644 if (ViewDebug.TRACE_RECYCLER) { 1645 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1646 position, getChildCount()); 1647 } 1648 1649 // Found it -- we're using an existing child 1650 // This just needs to be positioned 1651 setupChild(child, position, y, flow, childrenLeft, selected, true); 1652 1653 return child; 1654 } 1655 } 1656 1657 // Make a new view for this position, or convert an unused view if possible 1658 child = obtainView(position); 1659 1660 // This needs to be positioned and measured 1661 setupChild(child, position, y, flow, childrenLeft, selected, false); 1662 1663 return child; 1664 } 1665 1666 /** 1667 * Add a view as a child and make sure it is measured (if necessary) and 1668 * positioned properly. 1669 * 1670 * @param child The view to add 1671 * @param position The position of this child 1672 * @param y The y position relative to which this view will be positioned 1673 * @param flowDown If true, align top edge to y. If false, align bottom 1674 * edge to y. 1675 * @param childrenLeft Left edge where children should be positioned 1676 * @param selected Is this position selected? 1677 * @param recycled Has this view been pulled from the recycle bin? If so it 1678 * does not need to be remeasured. 1679 */ 1680 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1681 boolean selected, boolean recycled) { 1682 final boolean isSelected = selected && shouldShowSelector(); 1683 final boolean updateChildSelected = isSelected != child.isSelected(); 1684 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1685 1686 // Respect layout params that are already in the view. Otherwise make some up... 1687 // noinspection unchecked 1688 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1689 if (p == null) { 1690 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1691 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1692 } 1693 p.viewType = mAdapter.getItemViewType(position); 1694 1695 if (recycled || (p.recycledHeaderFooter && 1696 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1697 attachViewToParent(child, flowDown ? -1 : 0, p); 1698 } else { 1699 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1700 p.recycledHeaderFooter = true; 1701 } 1702 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1703 } 1704 1705 if (updateChildSelected) { 1706 child.setSelected(isSelected); 1707 } 1708 1709 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1710 if (child instanceof Checkable) { 1711 ((Checkable) child).setChecked(mCheckStates.get(position)); 1712 } 1713 } 1714 1715 if (needToMeasure) { 1716 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1717 mListPadding.left + mListPadding.right, p.width); 1718 int lpHeight = p.height; 1719 int childHeightSpec; 1720 if (lpHeight > 0) { 1721 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1722 } else { 1723 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1724 } 1725 child.measure(childWidthSpec, childHeightSpec); 1726 } else { 1727 cleanupLayoutState(child); 1728 } 1729 1730 final int w = child.getMeasuredWidth(); 1731 final int h = child.getMeasuredHeight(); 1732 final int childTop = flowDown ? y : y - h; 1733 1734 if (needToMeasure) { 1735 final int childRight = childrenLeft + w; 1736 final int childBottom = childTop + h; 1737 child.layout(childrenLeft, childTop, childRight, childBottom); 1738 } else { 1739 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1740 child.offsetTopAndBottom(childTop - child.getTop()); 1741 } 1742 1743 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1744 child.setDrawingCacheEnabled(true); 1745 } 1746 } 1747 1748 @Override 1749 protected boolean canAnimate() { 1750 return super.canAnimate() && mItemCount > 0; 1751 } 1752 1753 /** 1754 * Sets the currently selected item. If in touch mode, the item will not be selected 1755 * but it will still be positioned appropriately. If the specified selection position 1756 * is less than 0, then the item at position 0 will be selected. 1757 * 1758 * @param position Index (starting at 0) of the data item to be selected. 1759 */ 1760 @Override 1761 public void setSelection(int position) { 1762 setSelectionFromTop(position, 0); 1763 } 1764 1765 /** 1766 * Sets the selected item and positions the selection y pixels from the top edge 1767 * of the ListView. (If in touch mode, the item will not be selected but it will 1768 * still be positioned appropriately.) 1769 * 1770 * @param position Index (starting at 0) of the data item to be selected. 1771 * @param y The distance from the top edge of the ListView (plus padding) that the 1772 * item will be positioned. 1773 */ 1774 public void setSelectionFromTop(int position, int y) { 1775 if (mAdapter == null) { 1776 return; 1777 } 1778 1779 if (!isInTouchMode()) { 1780 position = lookForSelectablePosition(position, true); 1781 if (position >= 0) { 1782 setNextSelectedPositionInt(position); 1783 } 1784 } else { 1785 mResurrectToPosition = position; 1786 } 1787 1788 if (position >= 0) { 1789 mLayoutMode = LAYOUT_SPECIFIC; 1790 mSpecificTop = mListPadding.top + y; 1791 1792 if (mNeedSync) { 1793 mSyncPosition = position; 1794 mSyncRowId = mAdapter.getItemId(position); 1795 } 1796 1797 requestLayout(); 1798 } 1799 } 1800 1801 /** 1802 * Makes the item at the supplied position selected. 1803 * 1804 * @param position the position of the item to select 1805 */ 1806 @Override 1807 void setSelectionInt(int position) { 1808 setNextSelectedPositionInt(position); 1809 layoutChildren(); 1810 } 1811 1812 /** 1813 * Find a position that can be selected (i.e., is not a separator). 1814 * 1815 * @param position The starting position to look at. 1816 * @param lookDown Whether to look down for other positions. 1817 * @return The next selectable position starting at position and then searching either up or 1818 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1819 */ 1820 @Override 1821 int lookForSelectablePosition(int position, boolean lookDown) { 1822 final ListAdapter adapter = mAdapter; 1823 if (adapter == null || isInTouchMode()) { 1824 return INVALID_POSITION; 1825 } 1826 1827 final int count = adapter.getCount(); 1828 if (!mAreAllItemsSelectable) { 1829 if (lookDown) { 1830 position = Math.max(0, position); 1831 while (position < count && !adapter.isEnabled(position)) { 1832 position++; 1833 } 1834 } else { 1835 position = Math.min(position, count - 1); 1836 while (position >= 0 && !adapter.isEnabled(position)) { 1837 position--; 1838 } 1839 } 1840 1841 if (position < 0 || position >= count) { 1842 return INVALID_POSITION; 1843 } 1844 return position; 1845 } else { 1846 if (position < 0 || position >= count) { 1847 return INVALID_POSITION; 1848 } 1849 return position; 1850 } 1851 } 1852 1853 @Override 1854 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1855 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1856 1857 // If the item count is less than 15 then subtract disabled items from the count and 1858 // position. Otherwise ignore disabled items. 1859 if (!populated) { 1860 int itemCount = 0; 1861 int currentItemIndex = getSelectedItemPosition(); 1862 1863 ListAdapter adapter = getAdapter(); 1864 if (adapter != null) { 1865 final int count = adapter.getCount(); 1866 if (count < 15) { 1867 for (int i = 0; i < count; i++) { 1868 if (adapter.isEnabled(i)) { 1869 itemCount++; 1870 } else if (i <= currentItemIndex) { 1871 currentItemIndex--; 1872 } 1873 } 1874 } else { 1875 itemCount = count; 1876 } 1877 } 1878 1879 event.setItemCount(itemCount); 1880 event.setCurrentItemIndex(currentItemIndex); 1881 } 1882 1883 return populated; 1884 } 1885 1886 /** 1887 * setSelectionAfterHeaderView set the selection to be the first list item 1888 * after the header views. 1889 */ 1890 public void setSelectionAfterHeaderView() { 1891 final int count = mHeaderViewInfos.size(); 1892 if (count > 0) { 1893 mNextSelectedPosition = 0; 1894 return; 1895 } 1896 1897 if (mAdapter != null) { 1898 setSelection(count); 1899 } else { 1900 mNextSelectedPosition = count; 1901 mLayoutMode = LAYOUT_SET_SELECTION; 1902 } 1903 1904 } 1905 1906 @Override 1907 public boolean dispatchKeyEvent(KeyEvent event) { 1908 // Dispatch in the normal way 1909 boolean handled = super.dispatchKeyEvent(event); 1910 if (!handled) { 1911 // If we didn't handle it... 1912 View focused = getFocusedChild(); 1913 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1914 // ... and our focused child didn't handle it 1915 // ... give it to ourselves so we can scroll if necessary 1916 handled = onKeyDown(event.getKeyCode(), event); 1917 } 1918 } 1919 return handled; 1920 } 1921 1922 @Override 1923 public boolean onKeyDown(int keyCode, KeyEvent event) { 1924 return commonKey(keyCode, 1, event); 1925 } 1926 1927 @Override 1928 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 1929 return commonKey(keyCode, repeatCount, event); 1930 } 1931 1932 @Override 1933 public boolean onKeyUp(int keyCode, KeyEvent event) { 1934 return commonKey(keyCode, 1, event); 1935 } 1936 1937 private boolean commonKey(int keyCode, int count, KeyEvent event) { 1938 if (mAdapter == null) { 1939 return false; 1940 } 1941 1942 if (mDataChanged) { 1943 layoutChildren(); 1944 } 1945 1946 boolean handled = false; 1947 int action = event.getAction(); 1948 1949 if (action != KeyEvent.ACTION_UP) { 1950 if (mSelectedPosition < 0) { 1951 switch (keyCode) { 1952 case KeyEvent.KEYCODE_DPAD_UP: 1953 case KeyEvent.KEYCODE_DPAD_DOWN: 1954 case KeyEvent.KEYCODE_DPAD_CENTER: 1955 case KeyEvent.KEYCODE_ENTER: 1956 case KeyEvent.KEYCODE_SPACE: 1957 if (resurrectSelection()) { 1958 return true; 1959 } 1960 } 1961 } 1962 switch (keyCode) { 1963 case KeyEvent.KEYCODE_DPAD_UP: 1964 if (!event.isAltPressed()) { 1965 while (count > 0) { 1966 handled = arrowScroll(FOCUS_UP); 1967 count--; 1968 } 1969 } else { 1970 handled = fullScroll(FOCUS_UP); 1971 } 1972 break; 1973 1974 case KeyEvent.KEYCODE_DPAD_DOWN: 1975 if (!event.isAltPressed()) { 1976 while (count > 0) { 1977 handled = arrowScroll(FOCUS_DOWN); 1978 count--; 1979 } 1980 } else { 1981 handled = fullScroll(FOCUS_DOWN); 1982 } 1983 break; 1984 1985 case KeyEvent.KEYCODE_DPAD_LEFT: 1986 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 1987 break; 1988 case KeyEvent.KEYCODE_DPAD_RIGHT: 1989 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 1990 break; 1991 1992 case KeyEvent.KEYCODE_DPAD_CENTER: 1993 case KeyEvent.KEYCODE_ENTER: 1994 if (mItemCount > 0 && event.getRepeatCount() == 0) { 1995 keyPressed(); 1996 } 1997 handled = true; 1998 break; 1999 2000 case KeyEvent.KEYCODE_SPACE: 2001 if (mPopup == null || !mPopup.isShowing()) { 2002 if (!event.isShiftPressed()) { 2003 pageScroll(FOCUS_DOWN); 2004 } else { 2005 pageScroll(FOCUS_UP); 2006 } 2007 handled = true; 2008 } 2009 break; 2010 } 2011 } 2012 2013 if (!handled) { 2014 handled = sendToTextFilter(keyCode, count, event); 2015 } 2016 2017 if (handled) { 2018 return true; 2019 } else { 2020 switch (action) { 2021 case KeyEvent.ACTION_DOWN: 2022 return super.onKeyDown(keyCode, event); 2023 2024 case KeyEvent.ACTION_UP: 2025 return super.onKeyUp(keyCode, event); 2026 2027 case KeyEvent.ACTION_MULTIPLE: 2028 return super.onKeyMultiple(keyCode, count, event); 2029 2030 default: // shouldn't happen 2031 return false; 2032 } 2033 } 2034 } 2035 2036 /** 2037 * Scrolls up or down by the number of items currently present on screen. 2038 * 2039 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2040 * @return whether selection was moved 2041 */ 2042 boolean pageScroll(int direction) { 2043 int nextPage = -1; 2044 boolean down = false; 2045 2046 if (direction == FOCUS_UP) { 2047 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2048 } else if (direction == FOCUS_DOWN) { 2049 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2050 down = true; 2051 } 2052 2053 if (nextPage >= 0) { 2054 int position = lookForSelectablePosition(nextPage, down); 2055 if (position >= 0) { 2056 mLayoutMode = LAYOUT_SPECIFIC; 2057 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2058 2059 if (down && position > mItemCount - getChildCount()) { 2060 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2061 } 2062 2063 if (!down && position < getChildCount()) { 2064 mLayoutMode = LAYOUT_FORCE_TOP; 2065 } 2066 2067 setSelectionInt(position); 2068 invokeOnItemScrollListener(); 2069 invalidate(); 2070 2071 return true; 2072 } 2073 } 2074 2075 return false; 2076 } 2077 2078 /** 2079 * Go to the last or first item if possible (not worrying about panning across or navigating 2080 * within the internal focus of the currently selected item.) 2081 * 2082 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2083 * 2084 * @return whether selection was moved 2085 */ 2086 boolean fullScroll(int direction) { 2087 boolean moved = false; 2088 if (direction == FOCUS_UP) { 2089 if (mSelectedPosition != 0) { 2090 int position = lookForSelectablePosition(0, true); 2091 if (position >= 0) { 2092 mLayoutMode = LAYOUT_FORCE_TOP; 2093 setSelectionInt(position); 2094 invokeOnItemScrollListener(); 2095 } 2096 moved = true; 2097 } 2098 } else if (direction == FOCUS_DOWN) { 2099 if (mSelectedPosition < mItemCount - 1) { 2100 int position = lookForSelectablePosition(mItemCount - 1, true); 2101 if (position >= 0) { 2102 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2103 setSelectionInt(position); 2104 invokeOnItemScrollListener(); 2105 } 2106 moved = true; 2107 } 2108 } 2109 2110 if (moved) { 2111 invalidate(); 2112 } 2113 2114 return moved; 2115 } 2116 2117 /** 2118 * To avoid horizontal focus searches changing the selected item, we 2119 * manually focus search within the selected item (as applicable), and 2120 * prevent focus from jumping to something within another item. 2121 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2122 * @return Whether this consumes the key event. 2123 */ 2124 private boolean handleHorizontalFocusWithinListItem(int direction) { 2125 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2126 throw new IllegalArgumentException("direction must be one of" 2127 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2128 } 2129 2130 final int numChildren = getChildCount(); 2131 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2132 final View selectedView = getSelectedView(); 2133 if (selectedView != null && selectedView.hasFocus() && 2134 selectedView instanceof ViewGroup) { 2135 2136 final View currentFocus = selectedView.findFocus(); 2137 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2138 (ViewGroup) selectedView, currentFocus, direction); 2139 if (nextFocus != null) { 2140 // do the math to get interesting rect in next focus' coordinates 2141 currentFocus.getFocusedRect(mTempRect); 2142 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2143 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2144 if (nextFocus.requestFocus(direction, mTempRect)) { 2145 return true; 2146 } 2147 } 2148 // we are blocking the key from being handled (by returning true) 2149 // if the global result is going to be some other view within this 2150 // list. this is to acheive the overall goal of having 2151 // horizontal d-pad navigation remain in the current item. 2152 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2153 (ViewGroup) getRootView(), currentFocus, direction); 2154 if (globalNextFocus != null) { 2155 return isViewAncestorOf(globalNextFocus, this); 2156 } 2157 } 2158 } 2159 return false; 2160 } 2161 2162 /** 2163 * Scrolls to the next or previous item if possible. 2164 * 2165 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2166 * 2167 * @return whether selection was moved 2168 */ 2169 boolean arrowScroll(int direction) { 2170 try { 2171 mInLayout = true; 2172 final boolean handled = arrowScrollImpl(direction); 2173 if (handled) { 2174 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2175 } 2176 return handled; 2177 } finally { 2178 mInLayout = false; 2179 } 2180 } 2181 2182 /** 2183 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2184 * whether there are focusable items etc. 2185 * 2186 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2187 * @return Whether any scrolling, selection or focus change occured. 2188 */ 2189 private boolean arrowScrollImpl(int direction) { 2190 if (getChildCount() <= 0) { 2191 return false; 2192 } 2193 2194 View selectedView = getSelectedView(); 2195 2196 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2197 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2198 2199 // if we are moving focus, we may OVERRIDE the default behavior 2200 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2201 if (focusResult != null) { 2202 nextSelectedPosition = focusResult.getSelectedPosition(); 2203 amountToScroll = focusResult.getAmountToScroll(); 2204 } 2205 2206 boolean needToRedraw = focusResult != null; 2207 if (nextSelectedPosition != INVALID_POSITION) { 2208 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2209 setSelectedPositionInt(nextSelectedPosition); 2210 setNextSelectedPositionInt(nextSelectedPosition); 2211 selectedView = getSelectedView(); 2212 if (mItemsCanFocus && focusResult == null) { 2213 // there was no new view found to take focus, make sure we 2214 // don't leave focus with the old selection 2215 final View focused = getFocusedChild(); 2216 if (focused != null) { 2217 focused.clearFocus(); 2218 } 2219 } 2220 needToRedraw = true; 2221 checkSelectionChanged(); 2222 } 2223 2224 if (amountToScroll > 0) { 2225 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2226 needToRedraw = true; 2227 } 2228 2229 // if we didn't find a new focusable, make sure any existing focused 2230 // item that was panned off screen gives up focus. 2231 if (mItemsCanFocus && (focusResult == null) 2232 && selectedView != null && selectedView.hasFocus()) { 2233 final View focused = selectedView.findFocus(); 2234 if (distanceToView(focused) > 0) { 2235 focused.clearFocus(); 2236 } 2237 } 2238 2239 // if the current selection is panned off, we need to remove the selection 2240 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2241 && !isViewAncestorOf(selectedView, this)) { 2242 selectedView = null; 2243 hideSelector(); 2244 2245 // but we don't want to set the ressurect position (that would make subsequent 2246 // unhandled key events bring back the item we just scrolled off!) 2247 mResurrectToPosition = INVALID_POSITION; 2248 } 2249 2250 if (needToRedraw) { 2251 if (selectedView != null) { 2252 positionSelector(selectedView); 2253 mSelectedTop = selectedView.getTop(); 2254 } 2255 invalidate(); 2256 invokeOnItemScrollListener(); 2257 return true; 2258 } 2259 2260 return false; 2261 } 2262 2263 /** 2264 * When selection changes, it is possible that the previously selected or the 2265 * next selected item will change its size. If so, we need to offset some folks, 2266 * and re-layout the items as appropriate. 2267 * 2268 * @param selectedView The currently selected view (before changing selection). 2269 * should be <code>null</code> if there was no previous selection. 2270 * @param direction Either {@link android.view.View#FOCUS_UP} or 2271 * {@link android.view.View#FOCUS_DOWN}. 2272 * @param newSelectedPosition The position of the next selection. 2273 * @param newFocusAssigned whether new focus was assigned. This matters because 2274 * when something has focus, we don't want to show selection (ugh). 2275 */ 2276 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2277 boolean newFocusAssigned) { 2278 if (newSelectedPosition == INVALID_POSITION) { 2279 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2280 } 2281 2282 // whether or not we are moving down or up, we want to preserve the 2283 // top of whatever view is on top: 2284 // - moving down: the view that had selection 2285 // - moving up: the view that is getting selection 2286 View topView; 2287 View bottomView; 2288 int topViewIndex, bottomViewIndex; 2289 boolean topSelected = false; 2290 final int selectedIndex = mSelectedPosition - mFirstPosition; 2291 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2292 if (direction == View.FOCUS_UP) { 2293 topViewIndex = nextSelectedIndex; 2294 bottomViewIndex = selectedIndex; 2295 topView = getChildAt(topViewIndex); 2296 bottomView = selectedView; 2297 topSelected = true; 2298 } else { 2299 topViewIndex = selectedIndex; 2300 bottomViewIndex = nextSelectedIndex; 2301 topView = selectedView; 2302 bottomView = getChildAt(bottomViewIndex); 2303 } 2304 2305 final int numChildren = getChildCount(); 2306 2307 // start with top view: is it changing size? 2308 if (topView != null) { 2309 topView.setSelected(!newFocusAssigned && topSelected); 2310 measureAndAdjustDown(topView, topViewIndex, numChildren); 2311 } 2312 2313 // is the bottom view changing size? 2314 if (bottomView != null) { 2315 bottomView.setSelected(!newFocusAssigned && !topSelected); 2316 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2317 } 2318 } 2319 2320 /** 2321 * Re-measure a child, and if its height changes, lay it out preserving its 2322 * top, and adjust the children below it appropriately. 2323 * @param child The child 2324 * @param childIndex The view group index of the child. 2325 * @param numChildren The number of children in the view group. 2326 */ 2327 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2328 int oldHeight = child.getHeight(); 2329 measureItem(child); 2330 if (child.getMeasuredHeight() != oldHeight) { 2331 // lay out the view, preserving its top 2332 relayoutMeasuredItem(child); 2333 2334 // adjust views below appropriately 2335 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2336 for (int i = childIndex + 1; i < numChildren; i++) { 2337 getChildAt(i).offsetTopAndBottom(heightDelta); 2338 } 2339 } 2340 } 2341 2342 /** 2343 * Measure a particular list child. 2344 * TODO: unify with setUpChild. 2345 * @param child The child. 2346 */ 2347 private void measureItem(View child) { 2348 ViewGroup.LayoutParams p = child.getLayoutParams(); 2349 if (p == null) { 2350 p = new ViewGroup.LayoutParams( 2351 ViewGroup.LayoutParams.FILL_PARENT, 2352 ViewGroup.LayoutParams.WRAP_CONTENT); 2353 } 2354 2355 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2356 mListPadding.left + mListPadding.right, p.width); 2357 int lpHeight = p.height; 2358 int childHeightSpec; 2359 if (lpHeight > 0) { 2360 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2361 } else { 2362 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2363 } 2364 child.measure(childWidthSpec, childHeightSpec); 2365 } 2366 2367 /** 2368 * Layout a child that has been measured, preserving its top position. 2369 * TODO: unify with setUpChild. 2370 * @param child The child. 2371 */ 2372 private void relayoutMeasuredItem(View child) { 2373 final int w = child.getMeasuredWidth(); 2374 final int h = child.getMeasuredHeight(); 2375 final int childLeft = mListPadding.left; 2376 final int childRight = childLeft + w; 2377 final int childTop = child.getTop(); 2378 final int childBottom = childTop + h; 2379 child.layout(childLeft, childTop, childRight, childBottom); 2380 } 2381 2382 /** 2383 * @return The amount to preview next items when arrow srolling. 2384 */ 2385 private int getArrowScrollPreviewLength() { 2386 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2387 } 2388 2389 /** 2390 * Determine how much we need to scroll in order to get the next selected view 2391 * visible, with a fading edge showing below as applicable. The amount is 2392 * capped at {@link #getMaxScrollAmount()} . 2393 * 2394 * @param direction either {@link android.view.View#FOCUS_UP} or 2395 * {@link android.view.View#FOCUS_DOWN}. 2396 * @param nextSelectedPosition The position of the next selection, or 2397 * {@link #INVALID_POSITION} if there is no next selectable position 2398 * @return The amount to scroll. Note: this is always positive! Direction 2399 * needs to be taken into account when actually scrolling. 2400 */ 2401 private int amountToScroll(int direction, int nextSelectedPosition) { 2402 final int listBottom = getHeight() - mListPadding.bottom; 2403 final int listTop = mListPadding.top; 2404 2405 final int numChildren = getChildCount(); 2406 2407 if (direction == View.FOCUS_DOWN) { 2408 int indexToMakeVisible = numChildren - 1; 2409 if (nextSelectedPosition != INVALID_POSITION) { 2410 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2411 } 2412 2413 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2414 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2415 2416 int goalBottom = listBottom; 2417 if (positionToMakeVisible < mItemCount - 1) { 2418 goalBottom -= getArrowScrollPreviewLength(); 2419 } 2420 2421 if (viewToMakeVisible.getBottom() <= goalBottom) { 2422 // item is fully visible. 2423 return 0; 2424 } 2425 2426 if (nextSelectedPosition != INVALID_POSITION 2427 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2428 // item already has enough of it visible, changing selection is good enough 2429 return 0; 2430 } 2431 2432 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2433 2434 if ((mFirstPosition + numChildren) == mItemCount) { 2435 // last is last in list -> make sure we don't scroll past it 2436 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2437 amountToScroll = Math.min(amountToScroll, max); 2438 } 2439 2440 return Math.min(amountToScroll, getMaxScrollAmount()); 2441 } else { 2442 int indexToMakeVisible = 0; 2443 if (nextSelectedPosition != INVALID_POSITION) { 2444 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2445 } 2446 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2447 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2448 int goalTop = listTop; 2449 if (positionToMakeVisible > 0) { 2450 goalTop += getArrowScrollPreviewLength(); 2451 } 2452 if (viewToMakeVisible.getTop() >= goalTop) { 2453 // item is fully visible. 2454 return 0; 2455 } 2456 2457 if (nextSelectedPosition != INVALID_POSITION && 2458 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2459 // item already has enough of it visible, changing selection is good enough 2460 return 0; 2461 } 2462 2463 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2464 if (mFirstPosition == 0) { 2465 // first is first in list -> make sure we don't scroll past it 2466 final int max = listTop - getChildAt(0).getTop(); 2467 amountToScroll = Math.min(amountToScroll, max); 2468 } 2469 return Math.min(amountToScroll, getMaxScrollAmount()); 2470 } 2471 } 2472 2473 /** 2474 * Holds results of focus aware arrow scrolling. 2475 */ 2476 static private class ArrowScrollFocusResult { 2477 private int mSelectedPosition; 2478 private int mAmountToScroll; 2479 2480 /** 2481 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2482 */ 2483 void populate(int selectedPosition, int amountToScroll) { 2484 mSelectedPosition = selectedPosition; 2485 mAmountToScroll = amountToScroll; 2486 } 2487 2488 public int getSelectedPosition() { 2489 return mSelectedPosition; 2490 } 2491 2492 public int getAmountToScroll() { 2493 return mAmountToScroll; 2494 } 2495 } 2496 2497 /** 2498 * @param direction either {@link android.view.View#FOCUS_UP} or 2499 * {@link android.view.View#FOCUS_DOWN}. 2500 * @return The position of the next selectable position of the views that 2501 * are currently visible, taking into account the fact that there might 2502 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2503 * selectable view on screen in the given direction. 2504 */ 2505 private int lookForSelectablePositionOnScreen(int direction) { 2506 final int firstPosition = mFirstPosition; 2507 if (direction == View.FOCUS_DOWN) { 2508 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2509 mSelectedPosition + 1 : 2510 firstPosition; 2511 if (startPos >= mAdapter.getCount()) { 2512 return INVALID_POSITION; 2513 } 2514 if (startPos < firstPosition) { 2515 startPos = firstPosition; 2516 } 2517 2518 final int lastVisiblePos = getLastVisiblePosition(); 2519 final ListAdapter adapter = getAdapter(); 2520 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2521 if (adapter.isEnabled(pos) 2522 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2523 return pos; 2524 } 2525 } 2526 } else { 2527 int last = firstPosition + getChildCount() - 1; 2528 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2529 mSelectedPosition - 1 : 2530 firstPosition + getChildCount() - 1; 2531 if (startPos < 0) { 2532 return INVALID_POSITION; 2533 } 2534 if (startPos > last) { 2535 startPos = last; 2536 } 2537 2538 final ListAdapter adapter = getAdapter(); 2539 for (int pos = startPos; pos >= firstPosition; pos--) { 2540 if (adapter.isEnabled(pos) 2541 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2542 return pos; 2543 } 2544 } 2545 } 2546 return INVALID_POSITION; 2547 } 2548 2549 /** 2550 * Do an arrow scroll based on focus searching. If a new view is 2551 * given focus, return the selection delta and amount to scroll via 2552 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2553 * 2554 * @param direction either {@link android.view.View#FOCUS_UP} or 2555 * {@link android.view.View#FOCUS_DOWN}. 2556 * @return The result if focus has changed, or <code>null</code>. 2557 */ 2558 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2559 final View selectedView = getSelectedView(); 2560 View newFocus; 2561 if (selectedView != null && selectedView.hasFocus()) { 2562 View oldFocus = selectedView.findFocus(); 2563 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2564 } else { 2565 if (direction == View.FOCUS_DOWN) { 2566 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2567 final int listTop = mListPadding.top + 2568 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2569 final int ySearchPoint = 2570 (selectedView != null && selectedView.getTop() > listTop) ? 2571 selectedView.getTop() : 2572 listTop; 2573 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2574 } else { 2575 final boolean bottomFadingEdgeShowing = 2576 (mFirstPosition + getChildCount() - 1) < mItemCount; 2577 final int listBottom = getHeight() - mListPadding.bottom - 2578 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2579 final int ySearchPoint = 2580 (selectedView != null && selectedView.getBottom() < listBottom) ? 2581 selectedView.getBottom() : 2582 listBottom; 2583 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2584 } 2585 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2586 } 2587 2588 if (newFocus != null) { 2589 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2590 2591 // if the focus change is in a different new position, make sure 2592 // we aren't jumping over another selectable position 2593 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2594 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2595 if (selectablePosition != INVALID_POSITION && 2596 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2597 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2598 return null; 2599 } 2600 } 2601 2602 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2603 2604 final int maxScrollAmount = getMaxScrollAmount(); 2605 if (focusScroll < maxScrollAmount) { 2606 // not moving too far, safe to give next view focus 2607 newFocus.requestFocus(direction); 2608 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2609 return mArrowScrollFocusResult; 2610 } else if (distanceToView(newFocus) < maxScrollAmount){ 2611 // Case to consider: 2612 // too far to get entire next focusable on screen, but by going 2613 // max scroll amount, we are getting it at least partially in view, 2614 // so give it focus and scroll the max ammount. 2615 newFocus.requestFocus(direction); 2616 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2617 return mArrowScrollFocusResult; 2618 } 2619 } 2620 return null; 2621 } 2622 2623 /** 2624 * @param newFocus The view that would have focus. 2625 * @return the position that contains newFocus 2626 */ 2627 private int positionOfNewFocus(View newFocus) { 2628 final int numChildren = getChildCount(); 2629 for (int i = 0; i < numChildren; i++) { 2630 final View child = getChildAt(i); 2631 if (isViewAncestorOf(newFocus, child)) { 2632 return mFirstPosition + i; 2633 } 2634 } 2635 throw new IllegalArgumentException("newFocus is not a child of any of the" 2636 + " children of the list!"); 2637 } 2638 2639 /** 2640 * Return true if child is an ancestor of parent, (or equal to the parent). 2641 */ 2642 private boolean isViewAncestorOf(View child, View parent) { 2643 if (child == parent) { 2644 return true; 2645 } 2646 2647 final ViewParent theParent = child.getParent(); 2648 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2649 } 2650 2651 /** 2652 * Determine how much we need to scroll in order to get newFocus in view. 2653 * @param direction either {@link android.view.View#FOCUS_UP} or 2654 * {@link android.view.View#FOCUS_DOWN}. 2655 * @param newFocus The view that would take focus. 2656 * @param positionOfNewFocus The position of the list item containing newFocus 2657 * @return The amount to scroll. Note: this is always positive! Direction 2658 * needs to be taken into account when actually scrolling. 2659 */ 2660 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2661 int amountToScroll = 0; 2662 newFocus.getDrawingRect(mTempRect); 2663 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2664 if (direction == View.FOCUS_UP) { 2665 if (mTempRect.top < mListPadding.top) { 2666 amountToScroll = mListPadding.top - mTempRect.top; 2667 if (positionOfNewFocus > 0) { 2668 amountToScroll += getArrowScrollPreviewLength(); 2669 } 2670 } 2671 } else { 2672 final int listBottom = getHeight() - mListPadding.bottom; 2673 if (mTempRect.bottom > listBottom) { 2674 amountToScroll = mTempRect.bottom - listBottom; 2675 if (positionOfNewFocus < mItemCount - 1) { 2676 amountToScroll += getArrowScrollPreviewLength(); 2677 } 2678 } 2679 } 2680 return amountToScroll; 2681 } 2682 2683 /** 2684 * Determine the distance to the nearest edge of a view in a particular 2685 * direciton. 2686 * @param descendant A descendant of this list. 2687 * @return The distance, or 0 if the nearest edge is already on screen. 2688 */ 2689 private int distanceToView(View descendant) { 2690 int distance = 0; 2691 descendant.getDrawingRect(mTempRect); 2692 offsetDescendantRectToMyCoords(descendant, mTempRect); 2693 final int listBottom = mBottom - mTop - mListPadding.bottom; 2694 if (mTempRect.bottom < mListPadding.top) { 2695 distance = mListPadding.top - mTempRect.bottom; 2696 } else if (mTempRect.top > listBottom) { 2697 distance = mTempRect.top - listBottom; 2698 } 2699 return distance; 2700 } 2701 2702 2703 /** 2704 * Scroll the children by amount, adding a view at the end and removing 2705 * views that fall off as necessary. 2706 * 2707 * @param amount The amount (positive or negative) to scroll. 2708 */ 2709 private void scrollListItemsBy(int amount) { 2710 offsetChildrenTopAndBottom(amount); 2711 2712 final int listBottom = getHeight() - mListPadding.bottom; 2713 final int listTop = mListPadding.top; 2714 final AbsListView.RecycleBin recycleBin = mRecycler; 2715 2716 if (amount < 0) { 2717 // shifted items up 2718 2719 // may need to pan views into the bottom space 2720 int numChildren = getChildCount(); 2721 View last = getChildAt(numChildren - 1); 2722 while (last.getBottom() < listBottom) { 2723 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2724 if (lastVisiblePosition < mItemCount - 1) { 2725 last = addViewBelow(last, lastVisiblePosition); 2726 numChildren++; 2727 } else { 2728 break; 2729 } 2730 } 2731 2732 // may have brought in the last child of the list that is skinnier 2733 // than the fading edge, thereby leaving space at the end. need 2734 // to shift back 2735 if (last.getBottom() < listBottom) { 2736 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2737 } 2738 2739 // top views may be panned off screen 2740 View first = getChildAt(0); 2741 while (first.getBottom() < listTop) { 2742 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2743 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2744 removeViewInLayout(first); 2745 recycleBin.addScrapView(first); 2746 } else { 2747 detachViewFromParent(first); 2748 } 2749 first = getChildAt(0); 2750 mFirstPosition++; 2751 } 2752 } else { 2753 // shifted items down 2754 View first = getChildAt(0); 2755 2756 // may need to pan views into top 2757 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2758 first = addViewAbove(first, mFirstPosition); 2759 mFirstPosition--; 2760 } 2761 2762 // may have brought the very first child of the list in too far and 2763 // need to shift it back 2764 if (first.getTop() > listTop) { 2765 offsetChildrenTopAndBottom(listTop - first.getTop()); 2766 } 2767 2768 int lastIndex = getChildCount() - 1; 2769 View last = getChildAt(lastIndex); 2770 2771 // bottom view may be panned off screen 2772 while (last.getTop() > listBottom) { 2773 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2774 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2775 removeViewInLayout(last); 2776 recycleBin.addScrapView(last); 2777 } else { 2778 detachViewFromParent(last); 2779 } 2780 last = getChildAt(--lastIndex); 2781 } 2782 } 2783 } 2784 2785 private View addViewAbove(View theView, int position) { 2786 int abovePosition = position - 1; 2787 View view = obtainView(abovePosition); 2788 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2789 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, false, false); 2790 return view; 2791 } 2792 2793 private View addViewBelow(View theView, int position) { 2794 int belowPosition = position + 1; 2795 View view = obtainView(belowPosition); 2796 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2797 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, false, false); 2798 return view; 2799 } 2800 2801 /** 2802 * Indicates that the views created by the ListAdapter can contain focusable 2803 * items. 2804 * 2805 * @param itemsCanFocus true if items can get focus, false otherwise 2806 */ 2807 public void setItemsCanFocus(boolean itemsCanFocus) { 2808 mItemsCanFocus = itemsCanFocus; 2809 if (!itemsCanFocus) { 2810 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2811 } 2812 } 2813 2814 /** 2815 * @return Whether the views created by the ListAdapter can contain focusable 2816 * items. 2817 */ 2818 public boolean getItemsCanFocus() { 2819 return mItemsCanFocus; 2820 } 2821 2822 /** 2823 * @hide Pending API council approval. 2824 */ 2825 @Override 2826 public boolean isOpaque() { 2827 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2828 hasOpaqueScrollbars()) || super.isOpaque(); 2829 } 2830 2831 @Override 2832 public void setCacheColorHint(int color) { 2833 final boolean opaque = (color >>> 24) == 0xFF; 2834 mIsCacheColorOpaque = opaque; 2835 if (opaque) { 2836 if (mDividerPaint == null) { 2837 mDividerPaint = new Paint(); 2838 } 2839 mDividerPaint.setColor(color); 2840 } 2841 super.setCacheColorHint(color); 2842 } 2843 2844 @Override 2845 protected void dispatchDraw(Canvas canvas) { 2846 // Draw the dividers 2847 final int dividerHeight = mDividerHeight; 2848 2849 if (dividerHeight > 0 && mDivider != null) { 2850 // Only modify the top and bottom in the loop, we set the left and right here 2851 final Rect bounds = mTempRect; 2852 bounds.left = mPaddingLeft; 2853 bounds.right = mRight - mLeft - mPaddingRight; 2854 2855 final int count = getChildCount(); 2856 final int headerCount = mHeaderViewInfos.size(); 2857 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2858 final boolean headerDividers = mHeaderDividersEnabled; 2859 final boolean footerDividers = mFooterDividersEnabled; 2860 final int first = mFirstPosition; 2861 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2862 final ListAdapter adapter = mAdapter; 2863 // If the list is opaque *and* the background is not, we want to 2864 // fill a rect where the dividers would be for non-selectable items 2865 // If the list is opaque and the background is also opaque, we don't 2866 // need to draw anything since the background will do it for us 2867 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2868 2869 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2870 mDividerPaint = new Paint(); 2871 mDividerPaint.setColor(getCacheColorHint()); 2872 } 2873 final Paint paint = mDividerPaint; 2874 2875 if (!mStackFromBottom) { 2876 int bottom; 2877 int listBottom = mBottom - mTop - mListPadding.bottom; 2878 2879 for (int i = 0; i < count; i++) { 2880 if ((headerDividers || first + i >= headerCount) && 2881 (footerDividers || first + i < footerLimit)) { 2882 View child = getChildAt(i); 2883 bottom = child.getBottom(); 2884 // Don't draw dividers next to items that are not enabled 2885 if (bottom < listBottom) { 2886 if ((areAllItemsSelectable || 2887 (adapter.isEnabled(first + i) && (i == count - 1 || 2888 adapter.isEnabled(first + i + 1))))) { 2889 bounds.top = bottom; 2890 bounds.bottom = bottom + dividerHeight; 2891 drawDivider(canvas, bounds, i); 2892 } else if (fillForMissingDividers) { 2893 bounds.top = bottom; 2894 bounds.bottom = bottom + dividerHeight; 2895 canvas.drawRect(bounds, paint); 2896 } 2897 } 2898 } 2899 } 2900 } else { 2901 int top; 2902 int listTop = mListPadding.top; 2903 2904 for (int i = 0; i < count; i++) { 2905 if ((headerDividers || first + i >= headerCount) && 2906 (footerDividers || first + i < footerLimit)) { 2907 View child = getChildAt(i); 2908 top = child.getTop(); 2909 // Don't draw dividers next to items that are not enabled 2910 if (top > listTop) { 2911 if ((areAllItemsSelectable || 2912 (adapter.isEnabled(first + i) && (i == count - 1 || 2913 adapter.isEnabled(first + i + 1))))) { 2914 bounds.top = top - dividerHeight; 2915 bounds.bottom = top; 2916 // Give the method the child ABOVE the divider, so we 2917 // subtract one from our child 2918 // position. Give -1 when there is no child above the 2919 // divider. 2920 drawDivider(canvas, bounds, i - 1); 2921 } else if (fillForMissingDividers) { 2922 bounds.top = top - dividerHeight; 2923 bounds.bottom = top; 2924 canvas.drawRect(bounds, paint); 2925 } 2926 } 2927 } 2928 } 2929 } 2930 } 2931 2932 // Draw the indicators (these should be drawn above the dividers) and children 2933 super.dispatchDraw(canvas); 2934 } 2935 2936 /** 2937 * Draws a divider for the given child in the given bounds. 2938 * 2939 * @param canvas The canvas to draw to. 2940 * @param bounds The bounds of the divider. 2941 * @param childIndex The index of child (of the View) above the divider. 2942 * This will be -1 if there is no child above the divider to be 2943 * drawn. 2944 */ 2945 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 2946 // This widget draws the same divider for all children 2947 final Drawable divider = mDivider; 2948 final boolean clipDivider = mClipDivider; 2949 2950 if (!clipDivider) { 2951 divider.setBounds(bounds); 2952 } else { 2953 canvas.save(); 2954 canvas.clipRect(bounds); 2955 } 2956 2957 divider.draw(canvas); 2958 2959 if (clipDivider) { 2960 canvas.restore(); 2961 } 2962 } 2963 2964 /** 2965 * Returns the drawable that will be drawn between each item in the list. 2966 * 2967 * @return the current drawable drawn between list elements 2968 */ 2969 public Drawable getDivider() { 2970 return mDivider; 2971 } 2972 2973 /** 2974 * Sets the drawable that will be drawn between each item in the list. If the drawable does 2975 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 2976 * 2977 * @param divider The drawable to use. 2978 */ 2979 public void setDivider(Drawable divider) { 2980 if (divider != null) { 2981 mDividerHeight = divider.getIntrinsicHeight(); 2982 mClipDivider = divider instanceof ColorDrawable; 2983 } else { 2984 mDividerHeight = 0; 2985 mClipDivider = false; 2986 } 2987 mDivider = divider; 2988 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 2989 requestLayoutIfNecessary(); 2990 } 2991 2992 /** 2993 * @return Returns the height of the divider that will be drawn between each item in the list. 2994 */ 2995 public int getDividerHeight() { 2996 return mDividerHeight; 2997 } 2998 2999 /** 3000 * Sets the height of the divider that will be drawn between each item in the list. Calling 3001 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3002 * 3003 * @param height The new height of the divider in pixels. 3004 */ 3005 public void setDividerHeight(int height) { 3006 mDividerHeight = height; 3007 requestLayoutIfNecessary(); 3008 } 3009 3010 /** 3011 * Enables or disables the drawing of the divider for header views. 3012 * 3013 * @param headerDividersEnabled True to draw the headers, false otherwise. 3014 * 3015 * @see #setFooterDividersEnabled(boolean) 3016 * @see #addHeaderView(android.view.View) 3017 */ 3018 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3019 mHeaderDividersEnabled = headerDividersEnabled; 3020 invalidate(); 3021 } 3022 3023 /** 3024 * Enables or disables the drawing of the divider for footer views. 3025 * 3026 * @param footerDividersEnabled True to draw the footers, false otherwise. 3027 * 3028 * @see #setHeaderDividersEnabled(boolean) 3029 * @see #addFooterView(android.view.View) 3030 */ 3031 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3032 mFooterDividersEnabled = footerDividersEnabled; 3033 invalidate(); 3034 } 3035 3036 @Override 3037 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3038 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3039 3040 int closetChildIndex = -1; 3041 if (gainFocus && previouslyFocusedRect != null) { 3042 previouslyFocusedRect.offset(mScrollX, mScrollY); 3043 3044 // figure out which item should be selected based on previously 3045 // focused rect 3046 Rect otherRect = mTempRect; 3047 int minDistance = Integer.MAX_VALUE; 3048 final int childCount = getChildCount(); 3049 final int firstPosition = mFirstPosition; 3050 final ListAdapter adapter = mAdapter; 3051 3052 for (int i = 0; i < childCount; i++) { 3053 // only consider selectable views 3054 if (!adapter.isEnabled(firstPosition + i)) { 3055 continue; 3056 } 3057 3058 View other = getChildAt(i); 3059 other.getDrawingRect(otherRect); 3060 offsetDescendantRectToMyCoords(other, otherRect); 3061 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3062 3063 if (distance < minDistance) { 3064 minDistance = distance; 3065 closetChildIndex = i; 3066 } 3067 } 3068 } 3069 3070 if (closetChildIndex >= 0) { 3071 setSelection(closetChildIndex + mFirstPosition); 3072 } else { 3073 requestLayout(); 3074 } 3075 } 3076 3077 3078 /* 3079 * (non-Javadoc) 3080 * 3081 * Children specified in XML are assumed to be header views. After we have 3082 * parsed them move them out of the children list and into mHeaderViews. 3083 */ 3084 @Override 3085 protected void onFinishInflate() { 3086 super.onFinishInflate(); 3087 3088 int count = getChildCount(); 3089 if (count > 0) { 3090 for (int i = 0; i < count; ++i) { 3091 addHeaderView(getChildAt(i)); 3092 } 3093 removeAllViews(); 3094 } 3095 } 3096 3097 /* (non-Javadoc) 3098 * @see android.view.View#findViewById(int) 3099 * First look in our children, then in any header and footer views that may be scrolled off. 3100 */ 3101 @Override 3102 protected View findViewTraversal(int id) { 3103 View v; 3104 v = super.findViewTraversal(id); 3105 if (v == null) { 3106 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3107 if (v != null) { 3108 return v; 3109 } 3110 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3111 if (v != null) { 3112 return v; 3113 } 3114 } 3115 return v; 3116 } 3117 3118 /* (non-Javadoc) 3119 * 3120 * Look in the passed in list of headers or footers for the view. 3121 */ 3122 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3123 if (where != null) { 3124 int len = where.size(); 3125 View v; 3126 3127 for (int i = 0; i < len; i++) { 3128 v = where.get(i).view; 3129 3130 if (!v.isRootNamespace()) { 3131 v = v.findViewById(id); 3132 3133 if (v != null) { 3134 return v; 3135 } 3136 } 3137 } 3138 } 3139 return null; 3140 } 3141 3142 /* (non-Javadoc) 3143 * @see android.view.View#findViewWithTag(String) 3144 * First look in our children, then in any header and footer views that may be scrolled off. 3145 */ 3146 @Override 3147 protected View findViewWithTagTraversal(Object tag) { 3148 View v; 3149 v = super.findViewWithTagTraversal(tag); 3150 if (v == null) { 3151 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3152 if (v != null) { 3153 return v; 3154 } 3155 3156 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3157 if (v != null) { 3158 return v; 3159 } 3160 } 3161 return v; 3162 } 3163 3164 /* (non-Javadoc) 3165 * 3166 * Look in the passed in list of headers or footers for the view with the tag. 3167 */ 3168 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3169 if (where != null) { 3170 int len = where.size(); 3171 View v; 3172 3173 for (int i = 0; i < len; i++) { 3174 v = where.get(i).view; 3175 3176 if (!v.isRootNamespace()) { 3177 v = v.findViewWithTag(tag); 3178 3179 if (v != null) { 3180 return v; 3181 } 3182 } 3183 } 3184 } 3185 return null; 3186 } 3187 3188 @Override 3189 public boolean onTouchEvent(MotionEvent ev) { 3190 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3191 // Don't handle edge touches immediately -- they may actually belong to one of our 3192 // descendants. 3193 return false; 3194 } 3195 return super.onTouchEvent(ev); 3196 } 3197 3198 /** 3199 * @see #setChoiceMode(int) 3200 * 3201 * @return The current choice mode 3202 */ 3203 public int getChoiceMode() { 3204 return mChoiceMode; 3205 } 3206 3207 /** 3208 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3209 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3210 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3211 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3212 * 3213 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3214 * {@link #CHOICE_MODE_MULTIPLE} 3215 */ 3216 public void setChoiceMode(int choiceMode) { 3217 mChoiceMode = choiceMode; 3218 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { 3219 mCheckStates = new SparseBooleanArray(); 3220 } 3221 } 3222 3223 @Override 3224 public boolean performItemClick(View view, int position, long id) { 3225 boolean handled = false; 3226 3227 if (mChoiceMode != CHOICE_MODE_NONE) { 3228 handled = true; 3229 3230 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3231 boolean oldValue = mCheckStates.get(position, false); 3232 mCheckStates.put(position, !oldValue); 3233 } else { 3234 boolean oldValue = mCheckStates.get(position, false); 3235 if (!oldValue) { 3236 mCheckStates.clear(); 3237 mCheckStates.put(position, true); 3238 } 3239 } 3240 3241 mDataChanged = true; 3242 rememberSyncState(); 3243 requestLayout(); 3244 } 3245 3246 handled |= super.performItemClick(view, position, id); 3247 3248 return handled; 3249 } 3250 3251 /** 3252 * Sets the checked state of the specified position. The is only valid if 3253 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3254 * {@link #CHOICE_MODE_MULTIPLE}. 3255 * 3256 * @param position The item whose checked state is to be checked 3257 * @param value The new checked sate for the item 3258 */ 3259 public void setItemChecked(int position, boolean value) { 3260 if (mChoiceMode == CHOICE_MODE_NONE) { 3261 return; 3262 } 3263 3264 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3265 mCheckStates.put(position, value); 3266 } else { 3267 // Clear the old value: if something was selected and value == false 3268 // then it is unselected 3269 mCheckStates.clear(); 3270 // If value == true, select the appropriate position 3271 // this may end up selecting the value we just cleared but this way 3272 // we don't have to first to a get(position) 3273 if (value) { 3274 mCheckStates.put(position, true); 3275 } 3276 } 3277 3278 // Do not generate a data change while we are in the layout phase 3279 if (!mInLayout && !mBlockLayoutRequests) { 3280 mDataChanged = true; 3281 rememberSyncState(); 3282 requestLayout(); 3283 } 3284 } 3285 3286 /** 3287 * Returns the checked state of the specified position. The result is only 3288 * valid if the choice mode has not been set to {@link #CHOICE_MODE_SINGLE} 3289 * or {@link #CHOICE_MODE_MULTIPLE}. 3290 * 3291 * @param position The item whose checked state to return 3292 * @return The item's checked state 3293 * 3294 * @see #setChoiceMode(int) 3295 */ 3296 public boolean isItemChecked(int position) { 3297 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3298 return mCheckStates.get(position); 3299 } 3300 3301 return false; 3302 } 3303 3304 /** 3305 * Returns the currently checked item. The result is only valid if the choice 3306 * mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3307 * 3308 * @return The position of the currently checked item or 3309 * {@link #INVALID_POSITION} if nothing is selected 3310 * 3311 * @see #setChoiceMode(int) 3312 */ 3313 public int getCheckedItemPosition() { 3314 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3315 return mCheckStates.keyAt(0); 3316 } 3317 3318 return INVALID_POSITION; 3319 } 3320 3321 /** 3322 * Returns the set of checked items in the list. The result is only valid if 3323 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3324 * 3325 * @return A SparseBooleanArray which will return true for each call to 3326 * get(int position) where position is a position in the list. 3327 */ 3328 public SparseBooleanArray getCheckedItemPositions() { 3329 if (mChoiceMode != CHOICE_MODE_NONE) { 3330 return mCheckStates; 3331 } 3332 return null; 3333 } 3334 3335 /** 3336 * Returns the set of checked items ids. The result is only valid if 3337 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3338 * 3339 * @return A new array which contains the id of each checked item in the list. 3340 */ 3341 public long[] getCheckItemIds() { 3342 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3343 final SparseBooleanArray states = mCheckStates; 3344 final int count = states.size(); 3345 final long[] ids = new long[count]; 3346 final ListAdapter adapter = mAdapter; 3347 3348 for (int i = 0; i < count; i++) { 3349 ids[i]= adapter.getItemId(states.keyAt(i)); 3350 } 3351 3352 return ids; 3353 } 3354 3355 return new long[0]; 3356 } 3357 3358 /** 3359 * Clear any choices previously set 3360 */ 3361 public void clearChoices() { 3362 if (mCheckStates != null) { 3363 mCheckStates.clear(); 3364 } 3365 } 3366 3367 static class SavedState extends BaseSavedState { 3368 SparseBooleanArray checkState; 3369 3370 /** 3371 * Constructor called from {@link ListView#onSaveInstanceState()} 3372 */ 3373 SavedState(Parcelable superState, SparseBooleanArray checkState) { 3374 super(superState); 3375 this.checkState = checkState; 3376 } 3377 3378 /** 3379 * Constructor called from {@link #CREATOR} 3380 */ 3381 private SavedState(Parcel in) { 3382 super(in); 3383 checkState = in.readSparseBooleanArray(); 3384 } 3385 3386 @Override 3387 public void writeToParcel(Parcel out, int flags) { 3388 super.writeToParcel(out, flags); 3389 out.writeSparseBooleanArray(checkState); 3390 } 3391 3392 @Override 3393 public String toString() { 3394 return "ListView.SavedState{" 3395 + Integer.toHexString(System.identityHashCode(this)) 3396 + " checkState=" + checkState + "}"; 3397 } 3398 3399 public static final Parcelable.Creator<SavedState> CREATOR 3400 = new Parcelable.Creator<SavedState>() { 3401 public SavedState createFromParcel(Parcel in) { 3402 return new SavedState(in); 3403 } 3404 3405 public SavedState[] newArray(int size) { 3406 return new SavedState[size]; 3407 } 3408 }; 3409 } 3410 3411 @Override 3412 public Parcelable onSaveInstanceState() { 3413 Parcelable superState = super.onSaveInstanceState(); 3414 return new SavedState(superState, mCheckStates); 3415 } 3416 3417 @Override 3418 public void onRestoreInstanceState(Parcelable state) { 3419 SavedState ss = (SavedState) state; 3420 3421 super.onRestoreInstanceState(ss.getSuperState()); 3422 3423 if (ss.checkState != null) { 3424 mCheckStates = ss.checkState; 3425 } 3426 3427 } 3428} 3429