ListView.java revision ad28bed52ccabd252149b5297a2d94bacdb388cc
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.drawable.Drawable; 24import android.graphics.drawable.ColorDrawable; 25import android.os.Parcel; 26import android.os.Parcelable; 27import android.util.AttributeSet; 28import android.util.SparseBooleanArray; 29import android.view.FocusFinder; 30import android.view.KeyEvent; 31import android.view.MotionEvent; 32import android.view.View; 33import android.view.ViewDebug; 34import android.view.ViewGroup; 35import android.view.ViewParent; 36import android.view.SoundEffectConstants; 37 38import com.google.android.collect.Lists; 39import com.android.internal.R; 40 41import java.util.ArrayList; 42 43/* 44 * Implementation Notes: 45 * 46 * Some terminology: 47 * 48 * index - index of the items that are currently visible 49 * position - index of the items in the cursor 50 */ 51 52 53/** 54 * A view that shows items in a vertically scrolling list. The items 55 * come from the {@link ListAdapter} associated with this view. 56 * 57 * @attr ref android.R.styleable#ListView_entries 58 * @attr ref android.R.styleable#ListView_divider 59 * @attr ref android.R.styleable#ListView_dividerHeight 60 * @attr ref android.R.styleable#ListView_choiceMode 61 * @attr ref android.R.styleable#ListView_headerDividersEnabled 62 * @attr ref android.R.styleable#ListView_footerDividersEnabled 63 */ 64public class ListView extends AbsListView { 65 /** 66 * Used to indicate a no preference for a position type. 67 */ 68 static final int NO_POSITION = -1; 69 70 /** 71 * Normal list that does not indicate choices 72 */ 73 public static final int CHOICE_MODE_NONE = 0; 74 75 /** 76 * The list allows up to one choice 77 */ 78 public static final int CHOICE_MODE_SINGLE = 1; 79 80 /** 81 * The list allows multiple choices 82 */ 83 public static final int CHOICE_MODE_MULTIPLE = 2; 84 85 /** 86 * When arrow scrolling, ListView will never scroll more than this factor 87 * times the height of the list. 88 */ 89 private static final float MAX_SCROLL_FACTOR = 0.33f; 90 91 /** 92 * When arrow scrolling, need a certain amount of pixels to preview next 93 * items. This is usually the fading edge, but if that is small enough, 94 * we want to make sure we preview at least this many pixels. 95 */ 96 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 97 98 /** 99 * A class that represents a fixed view in a list, for example a header at the top 100 * or a footer at the bottom. 101 */ 102 public class FixedViewInfo { 103 /** The view to add to the list */ 104 public View view; 105 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 106 public Object data; 107 /** <code>true</code> if the fixed view should be selectable in the list */ 108 public boolean isSelectable; 109 } 110 111 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 112 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 113 114 Drawable mDivider; 115 int mDividerHeight; 116 private boolean mClipDivider; 117 private boolean mHeaderDividersEnabled; 118 private boolean mFooterDividersEnabled; 119 120 private boolean mAreAllItemsSelectable = true; 121 122 private boolean mItemsCanFocus = false; 123 124 private int mChoiceMode = CHOICE_MODE_NONE; 125 126 private SparseBooleanArray mCheckStates; 127 128 // used for temporary calculations. 129 private final Rect mTempRect = new Rect(); 130 131 // the single allocated result per list view; kinda cheesey but avoids 132 // allocating these thingies too often. 133 private ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 134 135 public ListView(Context context) { 136 this(context, null); 137 } 138 139 public ListView(Context context, AttributeSet attrs) { 140 this(context, attrs, com.android.internal.R.attr.listViewStyle); 141 } 142 143 public ListView(Context context, AttributeSet attrs, int defStyle) { 144 super(context, attrs, defStyle); 145 146 TypedArray a = context.obtainStyledAttributes(attrs, 147 com.android.internal.R.styleable.ListView, defStyle, 0); 148 149 CharSequence[] entries = a.getTextArray( 150 com.android.internal.R.styleable.ListView_entries); 151 if (entries != null) { 152 setAdapter(new ArrayAdapter<CharSequence>(context, 153 com.android.internal.R.layout.simple_list_item_1, entries)); 154 } 155 156 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 157 if (d != null) { 158 // If a divider is specified use its intrinsic height for divider height 159 setDivider(d); 160 } 161 162 // Use the height specified, zero being the default 163 final int dividerHeight = a.getDimensionPixelSize( 164 com.android.internal.R.styleable.ListView_dividerHeight, 0); 165 if (dividerHeight != 0) { 166 setDividerHeight(dividerHeight); 167 } 168 169 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 170 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 171 172 a.recycle(); 173 } 174 175 /** 176 * @return The maximum amount a list view will scroll in response to 177 * an arrow event. 178 */ 179 public int getMaxScrollAmount() { 180 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 181 } 182 183 /** 184 * Make sure views are touching the top or bottom edge, as appropriate for 185 * our gravity 186 */ 187 private void adjustViewsUpOrDown() { 188 final int childCount = getChildCount(); 189 int delta; 190 191 if (childCount > 0) { 192 View child; 193 194 if (!mStackFromBottom) { 195 // Uh-oh -- we came up short. Slide all views up to make them 196 // align with the top 197 child = getChildAt(0); 198 delta = child.getTop() - mListPadding.top; 199 if (mFirstPosition != 0) { 200 // It's OK to have some space above the first item if it is 201 // part of the vertical spacing 202 delta -= mDividerHeight; 203 } 204 if (delta < 0) { 205 // We only are looking to see if we are too low, not too high 206 delta = 0; 207 } 208 } else { 209 // we are too high, slide all views down to align with bottom 210 child = getChildAt(childCount - 1); 211 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 212 213 if (mFirstPosition + childCount < mItemCount) { 214 // It's OK to have some space below the last item if it is 215 // part of the vertical spacing 216 delta += mDividerHeight; 217 } 218 219 if (delta > 0) { 220 delta = 0; 221 } 222 } 223 224 if (delta != 0) { 225 offsetChildrenTopAndBottom(-delta); 226 } 227 } 228 } 229 230 /** 231 * Add a fixed view to appear at the top of the list. If addHeaderView is 232 * called more than once, the views will appear in the order they were 233 * added. Views added using this call can take focus if they want. 234 * <p> 235 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 236 * the supplied cursor with one that that will also account for header 237 * views. 238 * 239 * @param v The view to add. 240 * @param data Data to associate with this view 241 * @param isSelectable whether the item is selectable 242 */ 243 public void addHeaderView(View v, Object data, boolean isSelectable) { 244 245 if (mAdapter != null) { 246 throw new IllegalStateException( 247 "Cannot add header view to list -- setAdapter has already been called."); 248 } 249 250 FixedViewInfo info = new FixedViewInfo(); 251 info.view = v; 252 info.data = data; 253 info.isSelectable = isSelectable; 254 mHeaderViewInfos.add(info); 255 } 256 257 /** 258 * Add a fixed view to appear at the top of the list. If addHeaderView is 259 * called more than once, the views will appear in the order they were 260 * added. Views added using this call can take focus if they want. 261 * <p> 262 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 263 * the supplied cursor with one that that will also account for header 264 * views. 265 * 266 * @param v The view to add. 267 */ 268 public void addHeaderView(View v) { 269 addHeaderView(v, null, true); 270 } 271 272 @Override 273 public int getHeaderViewsCount() { 274 return mHeaderViewInfos.size(); 275 } 276 277 /** 278 * Removes a previously-added header view. 279 * 280 * @param v The view to remove 281 * @return true if the view was removed, false if the view was not a header 282 * view 283 */ 284 public boolean removeHeaderView(View v) { 285 if (mHeaderViewInfos.size() > 0) { 286 boolean result = false; 287 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 288 mDataSetObserver.onChanged(); 289 result = true; 290 } 291 removeFixedViewInfo(v, mHeaderViewInfos); 292 return result; 293 } 294 return false; 295 } 296 297 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 298 int len = where.size(); 299 for (int i = 0; i < len; ++i) { 300 FixedViewInfo info = where.get(i); 301 if (info.view == v) { 302 where.remove(i); 303 break; 304 } 305 } 306 } 307 308 /** 309 * Add a fixed view to appear at the bottom of the list. If addFooterView is 310 * called more than once, the views will appear in the order they were 311 * added. Views added using this call can take focus if they want. 312 * <p> 313 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 314 * the supplied cursor with one that that will also account for header 315 * views. 316 * 317 * @param v The view to add. 318 * @param data Data to associate with this view 319 * @param isSelectable true if the footer view can be selected 320 */ 321 public void addFooterView(View v, Object data, boolean isSelectable) { 322 FixedViewInfo info = new FixedViewInfo(); 323 info.view = v; 324 info.data = data; 325 info.isSelectable = isSelectable; 326 mFooterViewInfos.add(info); 327 328 // in the case of re-adding a footer view, or adding one later on, 329 // we need to notify the observer 330 if (mDataSetObserver != null) { 331 mDataSetObserver.onChanged(); 332 } 333 } 334 335 /** 336 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 337 * than once, the views will appear in the order they were added. Views added using 338 * this call can take focus if they want. 339 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 340 * cursor with one that that will also account for header views. 341 * 342 * 343 * @param v The view to add. 344 */ 345 public void addFooterView(View v) { 346 addFooterView(v, null, true); 347 } 348 349 @Override 350 public int getFooterViewsCount() { 351 return mFooterViewInfos.size(); 352 } 353 354 /** 355 * Removes a previously-added footer view. 356 * 357 * @param v The view to remove 358 * @return 359 * true if the view was removed, false if the view was not a footer view 360 */ 361 public boolean removeFooterView(View v) { 362 if (mFooterViewInfos.size() > 0) { 363 boolean result = false; 364 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 365 mDataSetObserver.onChanged(); 366 result = true; 367 } 368 removeFixedViewInfo(v, mFooterViewInfos); 369 return result; 370 } 371 return false; 372 } 373 374 /** 375 * Returns the adapter currently in use in this ListView. The returned adapter 376 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 377 * might be a {@link WrapperListAdapter}. 378 * 379 * @return The adapter currently used to display data in this ListView. 380 * 381 * @see #setAdapter(ListAdapter) 382 */ 383 @Override 384 public ListAdapter getAdapter() { 385 return mAdapter; 386 } 387 388 /** 389 * Sets the data behind this ListView. 390 * 391 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 392 * depending on the ListView features currently in use. For instance, adding 393 * headers and/or footers will cause the adapter to be wrapped. 394 * 395 * @param adapter The ListAdapter which is responsible for maintaining the 396 * data backing this list and for producing a view to represent an 397 * item in that data set. 398 * 399 * @see #getAdapter() 400 */ 401 @Override 402 public void setAdapter(ListAdapter adapter) { 403 if (null != mAdapter) { 404 mAdapter.unregisterDataSetObserver(mDataSetObserver); 405 } 406 407 resetList(); 408 mRecycler.clear(); 409 410 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 411 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 412 } else { 413 mAdapter = adapter; 414 } 415 416 mOldSelectedPosition = INVALID_POSITION; 417 mOldSelectedRowId = INVALID_ROW_ID; 418 if (mAdapter != null) { 419 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 420 mOldItemCount = mItemCount; 421 mItemCount = mAdapter.getCount(); 422 checkFocus(); 423 424 mDataSetObserver = new AdapterDataSetObserver(); 425 mAdapter.registerDataSetObserver(mDataSetObserver); 426 427 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 428 429 int position; 430 if (mStackFromBottom) { 431 position = lookForSelectablePosition(mItemCount - 1, false); 432 } else { 433 position = lookForSelectablePosition(0, true); 434 } 435 setSelectedPositionInt(position); 436 setNextSelectedPositionInt(position); 437 438 if (mItemCount == 0) { 439 // Nothing selected 440 checkSelectionChanged(); 441 } 442 443 } else { 444 mAreAllItemsSelectable = true; 445 checkFocus(); 446 // Nothing selected 447 checkSelectionChanged(); 448 } 449 450 if (mCheckStates != null) { 451 mCheckStates.clear(); 452 } 453 454 requestLayout(); 455 } 456 457 458 /** 459 * The list is empty. Clear everything out. 460 */ 461 @Override 462 void resetList() { 463 super.resetList(); 464 mLayoutMode = LAYOUT_NORMAL; 465 } 466 467 /** 468 * @return Whether the list needs to show the top fading edge 469 */ 470 private boolean showingTopFadingEdge() { 471 final int listTop = mScrollY + mListPadding.top; 472 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 473 } 474 475 /** 476 * @return Whether the list needs to show the bottom fading edge 477 */ 478 private boolean showingBottomFadingEdge() { 479 final int childCount = getChildCount(); 480 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 481 final int lastVisiblePosition = mFirstPosition + childCount - 1; 482 483 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 484 485 return (lastVisiblePosition < mItemCount - 1) 486 || (bottomOfBottomChild < listBottom); 487 } 488 489 490 @Override 491 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 492 493 int rectTopWithinChild = rect.top; 494 495 // offset so rect is in coordinates of the this view 496 rect.offset(child.getLeft(), child.getTop()); 497 rect.offset(-child.getScrollX(), -child.getScrollY()); 498 499 final int height = getHeight(); 500 int listUnfadedTop = getScrollY(); 501 int listUnfadedBottom = listUnfadedTop + height; 502 final int fadingEdge = getVerticalFadingEdgeLength(); 503 504 if (showingTopFadingEdge()) { 505 // leave room for top fading edge as long as rect isn't at very top 506 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 507 listUnfadedTop += fadingEdge; 508 } 509 } 510 511 int childCount = getChildCount(); 512 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 513 514 if (showingBottomFadingEdge()) { 515 // leave room for bottom fading edge as long as rect isn't at very bottom 516 if ((mSelectedPosition < mItemCount - 1) 517 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 518 listUnfadedBottom -= fadingEdge; 519 } 520 } 521 522 int scrollYDelta = 0; 523 524 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 525 // need to MOVE DOWN to get it in view: move down just enough so 526 // that the entire rectangle is in view (or at least the first 527 // screen size chunk). 528 529 if (rect.height() > height) { 530 // just enough to get screen size chunk on 531 scrollYDelta += (rect.top - listUnfadedTop); 532 } else { 533 // get entire rect at bottom of screen 534 scrollYDelta += (rect.bottom - listUnfadedBottom); 535 } 536 537 // make sure we aren't scrolling beyond the end of our children 538 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 539 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 540 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 541 // need to MOVE UP to get it in view: move up just enough so that 542 // entire rectangle is in view (or at least the first screen 543 // size chunk of it). 544 545 if (rect.height() > height) { 546 // screen size chunk 547 scrollYDelta -= (listUnfadedBottom - rect.bottom); 548 } else { 549 // entire rect at top 550 scrollYDelta -= (listUnfadedTop - rect.top); 551 } 552 553 // make sure we aren't scrolling any further than the top our children 554 int top = getChildAt(0).getTop(); 555 int deltaToTop = top - listUnfadedTop; 556 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 557 } 558 559 final boolean scroll = scrollYDelta != 0; 560 if (scroll) { 561 scrollListItemsBy(-scrollYDelta); 562 positionSelector(child); 563 mSelectedTop = child.getTop(); 564 invalidate(); 565 } 566 return scroll; 567 } 568 569 /** 570 * {@inheritDoc} 571 */ 572 @Override 573 void fillGap(boolean down) { 574 final int count = getChildCount(); 575 if (down) { 576 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 577 getListPaddingTop(); 578 fillDown(mFirstPosition + count, startOffset); 579 correctTooHigh(getChildCount()); 580 } else { 581 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 582 getHeight() - getListPaddingBottom(); 583 fillUp(mFirstPosition - 1, startOffset); 584 correctTooLow(getChildCount()); 585 } 586 } 587 588 /** 589 * Fills the list from pos down to the end of the list view. 590 * 591 * @param pos The first position to put in the list 592 * 593 * @param nextTop The location where the top of the item associated with pos 594 * should be drawn 595 * 596 * @return The view that is currently selected, if it happens to be in the 597 * range that we draw. 598 */ 599 private View fillDown(int pos, int nextTop) { 600 View selectedView = null; 601 602 int end = (mBottom - mTop) - mListPadding.bottom; 603 604 while (nextTop < end && pos < mItemCount) { 605 // is this the selected item? 606 boolean selected = pos == mSelectedPosition; 607 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 608 609 nextTop = child.getBottom() + mDividerHeight; 610 if (selected) { 611 selectedView = child; 612 } 613 pos++; 614 } 615 616 return selectedView; 617 } 618 619 /** 620 * Fills the list from pos up to the top of the list view. 621 * 622 * @param pos The first position to put in the list 623 * 624 * @param nextBottom The location where the bottom of the item associated 625 * with pos should be drawn 626 * 627 * @return The view that is currently selected 628 */ 629 private View fillUp(int pos, int nextBottom) { 630 View selectedView = null; 631 632 int end = mListPadding.top; 633 634 while (nextBottom > end && pos >= 0) { 635 // is this the selected item? 636 boolean selected = pos == mSelectedPosition; 637 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 638 nextBottom = child.getTop() - mDividerHeight; 639 if (selected) { 640 selectedView = child; 641 } 642 pos--; 643 } 644 645 mFirstPosition = pos + 1; 646 647 return selectedView; 648 } 649 650 /** 651 * Fills the list from top to bottom, starting with mFirstPosition 652 * 653 * @param nextTop The location where the top of the first item should be 654 * drawn 655 * 656 * @return The view that is currently selected 657 */ 658 private View fillFromTop(int nextTop) { 659 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 660 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 661 if (mFirstPosition < 0) { 662 mFirstPosition = 0; 663 } 664 return fillDown(mFirstPosition, nextTop); 665 } 666 667 668 /** 669 * Put mSelectedPosition in the middle of the screen and then build up and 670 * down from there. This method forces mSelectedPosition to the center. 671 * 672 * @param childrenTop Top of the area in which children can be drawn, as 673 * measured in pixels 674 * @param childrenBottom Bottom of the area in which children can be drawn, 675 * as measured in pixels 676 * @return Currently selected view 677 */ 678 private View fillFromMiddle(int childrenTop, int childrenBottom) { 679 int height = childrenBottom - childrenTop; 680 681 int position = reconcileSelectedPosition(); 682 683 View sel = makeAndAddView(position, childrenTop, true, 684 mListPadding.left, true); 685 mFirstPosition = position; 686 687 int selHeight = sel.getMeasuredHeight(); 688 if (selHeight <= height) { 689 sel.offsetTopAndBottom((height - selHeight) / 2); 690 } 691 692 fillAboveAndBelow(sel, position); 693 694 if (!mStackFromBottom) { 695 correctTooHigh(getChildCount()); 696 } else { 697 correctTooLow(getChildCount()); 698 } 699 700 return sel; 701 } 702 703 /** 704 * Once the selected view as been placed, fill up the visible area above and 705 * below it. 706 * 707 * @param sel The selected view 708 * @param position The position corresponding to sel 709 */ 710 private void fillAboveAndBelow(View sel, int position) { 711 final int dividerHeight = mDividerHeight; 712 if (!mStackFromBottom) { 713 fillUp(position - 1, sel.getTop() - dividerHeight); 714 adjustViewsUpOrDown(); 715 fillDown(position + 1, sel.getBottom() + dividerHeight); 716 } else { 717 fillDown(position + 1, sel.getBottom() + dividerHeight); 718 adjustViewsUpOrDown(); 719 fillUp(position - 1, sel.getTop() - dividerHeight); 720 } 721 } 722 723 724 /** 725 * Fills the grid based on positioning the new selection at a specific 726 * location. The selection may be moved so that it does not intersect the 727 * faded edges. The grid is then filled upwards and downwards from there. 728 * 729 * @param selectedTop Where the selected item should be 730 * @param childrenTop Where to start drawing children 731 * @param childrenBottom Last pixel where children can be drawn 732 * @return The view that currently has selection 733 */ 734 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 735 int fadingEdgeLength = getVerticalFadingEdgeLength(); 736 final int selectedPosition = mSelectedPosition; 737 738 View sel; 739 740 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 741 selectedPosition); 742 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 743 selectedPosition); 744 745 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 746 747 748 // Some of the newly selected item extends below the bottom of the list 749 if (sel.getBottom() > bottomSelectionPixel) { 750 // Find space available above the selection into which we can scroll 751 // upwards 752 final int spaceAbove = sel.getTop() - topSelectionPixel; 753 754 // Find space required to bring the bottom of the selected item 755 // fully into view 756 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 757 final int offset = Math.min(spaceAbove, spaceBelow); 758 759 // Now offset the selected item to get it into view 760 sel.offsetTopAndBottom(-offset); 761 } else if (sel.getTop() < topSelectionPixel) { 762 // Find space required to bring the top of the selected item fully 763 // into view 764 final int spaceAbove = topSelectionPixel - sel.getTop(); 765 766 // Find space available below the selection into which we can scroll 767 // downwards 768 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 769 final int offset = Math.min(spaceAbove, spaceBelow); 770 771 // Offset the selected item to get it into view 772 sel.offsetTopAndBottom(offset); 773 } 774 775 // Fill in views above and below 776 fillAboveAndBelow(sel, selectedPosition); 777 778 if (!mStackFromBottom) { 779 correctTooHigh(getChildCount()); 780 } else { 781 correctTooLow(getChildCount()); 782 } 783 784 return sel; 785 } 786 787 /** 788 * Calculate the bottom-most pixel we can draw the selection into 789 * 790 * @param childrenBottom Bottom pixel were children can be drawn 791 * @param fadingEdgeLength Length of the fading edge in pixels, if present 792 * @param selectedPosition The position that will be selected 793 * @return The bottom-most pixel we can draw the selection into 794 */ 795 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 796 int selectedPosition) { 797 int bottomSelectionPixel = childrenBottom; 798 if (selectedPosition != mItemCount - 1) { 799 bottomSelectionPixel -= fadingEdgeLength; 800 } 801 return bottomSelectionPixel; 802 } 803 804 /** 805 * Calculate the top-most pixel we can draw the selection into 806 * 807 * @param childrenTop Top pixel were children can be drawn 808 * @param fadingEdgeLength Length of the fading edge in pixels, if present 809 * @param selectedPosition The position that will be selected 810 * @return The top-most pixel we can draw the selection into 811 */ 812 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 813 // first pixel we can draw the selection into 814 int topSelectionPixel = childrenTop; 815 if (selectedPosition > 0) { 816 topSelectionPixel += fadingEdgeLength; 817 } 818 return topSelectionPixel; 819 } 820 821 822 /** 823 * Fills the list based on positioning the new selection relative to the old 824 * selection. The new selection will be placed at, above, or below the 825 * location of the new selection depending on how the selection is moving. 826 * The selection will then be pinned to the visible part of the screen, 827 * excluding the edges that are faded. The list is then filled upwards and 828 * downwards from there. 829 * 830 * @param oldSel The old selected view. Useful for trying to put the new 831 * selection in the same place 832 * @param newSel The view that is to become selected. Useful for trying to 833 * put the new selection in the same place 834 * @param delta Which way we are moving 835 * @param childrenTop Where to start drawing children 836 * @param childrenBottom Last pixel where children can be drawn 837 * @return The view that currently has selection 838 */ 839 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 840 int childrenBottom) { 841 int fadingEdgeLength = getVerticalFadingEdgeLength(); 842 final int selectedPosition = mSelectedPosition; 843 844 View sel; 845 846 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 847 selectedPosition); 848 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 849 selectedPosition); 850 851 if (delta > 0) { 852 /* 853 * Case 1: Scrolling down. 854 */ 855 856 /* 857 * Before After 858 * | | | | 859 * +-------+ +-------+ 860 * | A | | A | 861 * | 1 | => +-------+ 862 * +-------+ | B | 863 * | B | | 2 | 864 * +-------+ +-------+ 865 * | | | | 866 * 867 * Try to keep the top of the previously selected item where it was. 868 * oldSel = A 869 * sel = B 870 */ 871 872 // Put oldSel (A) where it belongs 873 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 874 mListPadding.left, false); 875 876 final int dividerHeight = mDividerHeight; 877 878 // Now put the new selection (B) below that 879 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 880 mListPadding.left, true); 881 882 // Some of the newly selected item extends below the bottom of the list 883 if (sel.getBottom() > bottomSelectionPixel) { 884 885 // Find space available above the selection into which we can scroll upwards 886 int spaceAbove = sel.getTop() - topSelectionPixel; 887 888 // Find space required to bring the bottom of the selected item fully into view 889 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 890 891 // Don't scroll more than half the height of the list 892 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 893 int offset = Math.min(spaceAbove, spaceBelow); 894 offset = Math.min(offset, halfVerticalSpace); 895 896 // We placed oldSel, so offset that item 897 oldSel.offsetTopAndBottom(-offset); 898 // Now offset the selected item to get it into view 899 sel.offsetTopAndBottom(-offset); 900 } 901 902 // Fill in views above and below 903 if (!mStackFromBottom) { 904 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 905 adjustViewsUpOrDown(); 906 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 907 } else { 908 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 909 adjustViewsUpOrDown(); 910 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 911 } 912 } else if (delta < 0) { 913 /* 914 * Case 2: Scrolling up. 915 */ 916 917 /* 918 * Before After 919 * | | | | 920 * +-------+ +-------+ 921 * | A | | A | 922 * +-------+ => | 1 | 923 * | B | +-------+ 924 * | 2 | | B | 925 * +-------+ +-------+ 926 * | | | | 927 * 928 * Try to keep the top of the item about to become selected where it was. 929 * newSel = A 930 * olSel = B 931 */ 932 933 if (newSel != null) { 934 // Try to position the top of newSel (A) where it was before it was selected 935 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 936 true); 937 } else { 938 // If (A) was not on screen and so did not have a view, position 939 // it above the oldSel (B) 940 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 941 true); 942 } 943 944 // Some of the newly selected item extends above the top of the list 945 if (sel.getTop() < topSelectionPixel) { 946 // Find space required to bring the top of the selected item fully into view 947 int spaceAbove = topSelectionPixel - sel.getTop(); 948 949 // Find space available below the selection into which we can scroll downwards 950 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 951 952 // Don't scroll more than half the height of the list 953 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 954 int offset = Math.min(spaceAbove, spaceBelow); 955 offset = Math.min(offset, halfVerticalSpace); 956 957 // Offset the selected item to get it into view 958 sel.offsetTopAndBottom(offset); 959 } 960 961 // Fill in views above and below 962 fillAboveAndBelow(sel, selectedPosition); 963 } else { 964 965 int oldTop = oldSel.getTop(); 966 967 /* 968 * Case 3: Staying still 969 */ 970 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 971 972 // We're staying still... 973 if (oldTop < childrenTop) { 974 // ... but the top of the old selection was off screen. 975 // (This can happen if the data changes size out from under us) 976 int newBottom = sel.getBottom(); 977 if (newBottom < childrenTop + 20) { 978 // Not enough visible -- bring it onscreen 979 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 980 } 981 } 982 983 // Fill in views above and below 984 fillAboveAndBelow(sel, selectedPosition); 985 } 986 987 return sel; 988 } 989 990 @Override 991 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 992 // Sets up mListPadding 993 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 994 995 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 996 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 997 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 998 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 999 1000 int childWidth = 0; 1001 int childHeight = 0; 1002 1003 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1004 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1005 heightMode == MeasureSpec.UNSPECIFIED)) { 1006 final View child = obtainView(0); 1007 1008 measureScrapChild(child, 0, widthMeasureSpec); 1009 1010 childWidth = child.getMeasuredWidth(); 1011 childHeight = child.getMeasuredHeight(); 1012 1013 if (recycleOnMeasure()) { 1014 mRecycler.addScrapView(child); 1015 } 1016 } 1017 1018 if (widthMode == MeasureSpec.UNSPECIFIED) { 1019 widthSize = mListPadding.left + mListPadding.right + childWidth + 1020 getVerticalScrollbarWidth(); 1021 } 1022 1023 if (heightMode == MeasureSpec.UNSPECIFIED) { 1024 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1025 getVerticalFadingEdgeLength() * 2; 1026 } 1027 1028 if (heightMode == MeasureSpec.AT_MOST) { 1029 // TODO: after first layout we should maybe start at the first visible position, not 0 1030 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1031 } 1032 1033 setMeasuredDimension(widthSize, heightSize); 1034 mWidthMeasureSpec = widthMeasureSpec; 1035 } 1036 1037 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1038 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1039 if (p == null) { 1040 p = new LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1041 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1042 child.setLayoutParams(p); 1043 } 1044 p.viewType = mAdapter.getItemViewType(position); 1045 1046 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1047 mListPadding.left + mListPadding.right, p.width); 1048 int lpHeight = p.height; 1049 int childHeightSpec; 1050 if (lpHeight > 0) { 1051 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1052 } else { 1053 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1054 } 1055 child.measure(childWidthSpec, childHeightSpec); 1056 } 1057 1058 /** 1059 * @return True to recycle the views used to measure this ListView in 1060 * UNSPECIFIED/AT_MOST modes, false otherwise. 1061 * @hide 1062 */ 1063 @ViewDebug.ExportedProperty 1064 protected boolean recycleOnMeasure() { 1065 return true; 1066 } 1067 1068 /** 1069 * Measures the height of the given range of children (inclusive) and 1070 * returns the height with this ListView's padding and divider heights 1071 * included. If maxHeight is provided, the measuring will stop when the 1072 * current height reaches maxHeight. 1073 * 1074 * @param widthMeasureSpec The width measure spec to be given to a child's 1075 * {@link View#measure(int, int)}. 1076 * @param startPosition The position of the first child to be shown. 1077 * @param endPosition The (inclusive) position of the last child to be 1078 * shown. Specify {@link #NO_POSITION} if the last child should be 1079 * the last available child from the adapter. 1080 * @param maxHeight The maximum height that will be returned (if all the 1081 * children don't fit in this value, this value will be 1082 * returned). 1083 * @param disallowPartialChildPosition In general, whether the returned 1084 * height should only contain entire children. This is more 1085 * powerful--it is the first inclusive position at which partial 1086 * children will not be allowed. Example: it looks nice to have 1087 * at least 3 completely visible children, and in portrait this 1088 * will most likely fit; but in landscape there could be times 1089 * when even 2 children can not be completely shown, so a value 1090 * of 2 (remember, inclusive) would be good (assuming 1091 * startPosition is 0). 1092 * @return The height of this ListView with the given children. 1093 */ 1094 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1095 final int maxHeight, int disallowPartialChildPosition) { 1096 1097 final ListAdapter adapter = mAdapter; 1098 if (adapter == null) { 1099 return mListPadding.top + mListPadding.bottom; 1100 } 1101 1102 // Include the padding of the list 1103 int returnedHeight = mListPadding.top + mListPadding.bottom; 1104 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1105 // The previous height value that was less than maxHeight and contained 1106 // no partial children 1107 int prevHeightWithoutPartialChild = 0; 1108 int i; 1109 View child; 1110 1111 // mItemCount - 1 since endPosition parameter is inclusive 1112 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1113 final AbsListView.RecycleBin recycleBin = mRecycler; 1114 final boolean recyle = recycleOnMeasure(); 1115 1116 for (i = startPosition; i <= endPosition; ++i) { 1117 child = obtainView(i); 1118 1119 measureScrapChild(child, i, widthMeasureSpec); 1120 1121 if (i > 0) { 1122 // Count the divider for all but one child 1123 returnedHeight += dividerHeight; 1124 } 1125 1126 // Recycle the view before we possibly return from the method 1127 if (recyle) { 1128 recycleBin.addScrapView(child); 1129 } 1130 1131 returnedHeight += child.getMeasuredHeight(); 1132 1133 if (returnedHeight >= maxHeight) { 1134 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1135 // then the i'th position did not fit completely. 1136 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1137 && (i > disallowPartialChildPosition) // We've past the min pos 1138 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1139 && (returnedHeight != maxHeight) // i'th child did not fit completely 1140 ? prevHeightWithoutPartialChild 1141 : maxHeight; 1142 } 1143 1144 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1145 prevHeightWithoutPartialChild = returnedHeight; 1146 } 1147 } 1148 1149 // At this point, we went through the range of children, and they each 1150 // completely fit, so return the returnedHeight 1151 return returnedHeight; 1152 } 1153 1154 @Override 1155 int findMotionRow(int y) { 1156 int childCount = getChildCount(); 1157 if (childCount > 0) { 1158 for (int i = 0; i < childCount; i++) { 1159 View v = getChildAt(i); 1160 if (y <= v.getBottom()) { 1161 return mFirstPosition + i; 1162 } 1163 } 1164 return mFirstPosition + childCount - 1; 1165 } 1166 return INVALID_POSITION; 1167 } 1168 1169 /** 1170 * Put a specific item at a specific location on the screen and then build 1171 * up and down from there. 1172 * 1173 * @param position The reference view to use as the starting point 1174 * @param top Pixel offset from the top of this view to the top of the 1175 * reference view. 1176 * 1177 * @return The selected view, or null if the selected view is outside the 1178 * visible area. 1179 */ 1180 private View fillSpecific(int position, int top) { 1181 boolean tempIsSelected = position == mSelectedPosition; 1182 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1183 // Possibly changed again in fillUp if we add rows above this one. 1184 mFirstPosition = position; 1185 1186 View above; 1187 View below; 1188 1189 final int dividerHeight = mDividerHeight; 1190 if (!mStackFromBottom) { 1191 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1192 // This will correct for the top of the first view not touching the top of the list 1193 adjustViewsUpOrDown(); 1194 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1195 int childCount = getChildCount(); 1196 if (childCount > 0) { 1197 correctTooHigh(childCount); 1198 } 1199 } else { 1200 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1201 // This will correct for the bottom of the last view not touching the bottom of the list 1202 adjustViewsUpOrDown(); 1203 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1204 int childCount = getChildCount(); 1205 if (childCount > 0) { 1206 correctTooLow(childCount); 1207 } 1208 } 1209 1210 if (tempIsSelected) { 1211 return temp; 1212 } else if (above != null) { 1213 return above; 1214 } else { 1215 return below; 1216 } 1217 } 1218 1219 /** 1220 * Check if we have dragged the bottom of the list too high (we have pushed the 1221 * top element off the top of the screen when we did not need to). Correct by sliding 1222 * everything back down. 1223 * 1224 * @param childCount Number of children 1225 */ 1226 private void correctTooHigh(int childCount) { 1227 // First see if the last item is visible. If it is not, it is OK for the 1228 // top of the list to be pushed up. 1229 int lastPosition = mFirstPosition + childCount - 1; 1230 if (lastPosition == mItemCount - 1 && childCount > 0) { 1231 1232 // Get the last child ... 1233 final View lastChild = getChildAt(childCount - 1); 1234 1235 // ... and its bottom edge 1236 final int lastBottom = lastChild.getBottom(); 1237 1238 // This is bottom of our drawable area 1239 final int end = (mBottom - mTop) - mListPadding.bottom; 1240 1241 // This is how far the bottom edge of the last view is from the bottom of the 1242 // drawable area 1243 int bottomOffset = end - lastBottom; 1244 View firstChild = getChildAt(0); 1245 final int firstTop = firstChild.getTop(); 1246 1247 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1248 // first row or the first row is scrolled off the top of the drawable area 1249 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1250 if (mFirstPosition == 0) { 1251 // Don't pull the top too far down 1252 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1253 } 1254 // Move everything down 1255 offsetChildrenTopAndBottom(bottomOffset); 1256 if (mFirstPosition > 0) { 1257 // Fill the gap that was opened above mFirstPosition with more rows, if 1258 // possible 1259 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1260 // Close up the remaining gap 1261 adjustViewsUpOrDown(); 1262 } 1263 1264 } 1265 } 1266 } 1267 1268 /** 1269 * Check if we have dragged the bottom of the list too low (we have pushed the 1270 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1271 * everything back up. 1272 * 1273 * @param childCount Number of children 1274 */ 1275 private void correctTooLow(int childCount) { 1276 // First see if the first item is visible. If it is not, it is OK for the 1277 // bottom of the list to be pushed down. 1278 if (mFirstPosition == 0 && childCount > 0) { 1279 1280 // Get the first child ... 1281 final View firstChild = getChildAt(0); 1282 1283 // ... and its top edge 1284 final int firstTop = firstChild.getTop(); 1285 1286 // This is top of our drawable area 1287 final int start = mListPadding.top; 1288 1289 // This is bottom of our drawable area 1290 final int end = (mBottom - mTop) - mListPadding.bottom; 1291 1292 // This is how far the top edge of the first view is from the top of the 1293 // drawable area 1294 int topOffset = firstTop - start; 1295 View lastChild = getChildAt(childCount - 1); 1296 final int lastBottom = lastChild.getBottom(); 1297 int lastPosition = mFirstPosition + childCount - 1; 1298 1299 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1300 // last row or the last row is scrolled off the bottom of the drawable area 1301 if (topOffset > 0 && (lastPosition < mItemCount - 1 || lastBottom > end)) { 1302 if (lastPosition == mItemCount - 1 ) { 1303 // Don't pull the bottom too far up 1304 topOffset = Math.min(topOffset, lastBottom - end); 1305 } 1306 // Move everything up 1307 offsetChildrenTopAndBottom(-topOffset); 1308 if (lastPosition < mItemCount - 1) { 1309 // Fill the gap that was opened below the last position with more rows, if 1310 // possible 1311 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1312 // Close up the remaining gap 1313 adjustViewsUpOrDown(); 1314 } 1315 } 1316 } 1317 } 1318 1319 @Override 1320 protected void layoutChildren() { 1321 final boolean blockLayoutRequests = mBlockLayoutRequests; 1322 if (!blockLayoutRequests) { 1323 mBlockLayoutRequests = true; 1324 } else { 1325 return; 1326 } 1327 1328 try { 1329 super.layoutChildren(); 1330 1331 invalidate(); 1332 1333 if (mAdapter == null) { 1334 resetList(); 1335 invokeOnItemScrollListener(); 1336 return; 1337 } 1338 1339 int childrenTop = mListPadding.top; 1340 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1341 1342 int childCount = getChildCount(); 1343 int index; 1344 int delta = 0; 1345 1346 View sel; 1347 View oldSel = null; 1348 View oldFirst = null; 1349 View newSel = null; 1350 1351 View focusLayoutRestoreView = null; 1352 1353 // Remember stuff we will need down below 1354 switch (mLayoutMode) { 1355 case LAYOUT_SET_SELECTION: 1356 index = mNextSelectedPosition - mFirstPosition; 1357 if (index >= 0 && index < childCount) { 1358 newSel = getChildAt(index); 1359 } 1360 break; 1361 case LAYOUT_FORCE_TOP: 1362 case LAYOUT_FORCE_BOTTOM: 1363 case LAYOUT_SPECIFIC: 1364 case LAYOUT_SYNC: 1365 break; 1366 case LAYOUT_MOVE_SELECTION: 1367 default: 1368 // Remember the previously selected view 1369 index = mSelectedPosition - mFirstPosition; 1370 if (index >= 0 && index < childCount) { 1371 oldSel = getChildAt(index); 1372 } 1373 1374 // Remember the previous first child 1375 oldFirst = getChildAt(0); 1376 1377 if (mNextSelectedPosition >= 0) { 1378 delta = mNextSelectedPosition - mSelectedPosition; 1379 } 1380 1381 // Caution: newSel might be null 1382 newSel = getChildAt(index + delta); 1383 } 1384 1385 1386 boolean dataChanged = mDataChanged; 1387 if (dataChanged) { 1388 handleDataChanged(); 1389 } 1390 1391 // Handle the empty set by removing all views that are visible 1392 // and calling it a day 1393 if (mItemCount == 0) { 1394 resetList(); 1395 invokeOnItemScrollListener(); 1396 return; 1397 } else if (mItemCount != mAdapter.getCount()) { 1398 throw new IllegalStateException("The content of the adapter has changed but " 1399 + "ListView did not receive a notification. Make sure the content of " 1400 + "your adapter is not modified from a background thread, but only " 1401 + "from the UI thread."); 1402 } 1403 1404 setSelectedPositionInt(mNextSelectedPosition); 1405 1406 // Pull all children into the RecycleBin. 1407 // These views will be reused if possible 1408 final int firstPosition = mFirstPosition; 1409 final RecycleBin recycleBin = mRecycler; 1410 1411 // reset the focus restoration 1412 View focusLayoutRestoreDirectChild = null; 1413 1414 1415 // Don't put header or footer views into the Recycler. Those are 1416 // already cached in mHeaderViews; 1417 if (dataChanged) { 1418 for (int i = 0; i < childCount; i++) { 1419 recycleBin.addScrapView(getChildAt(i)); 1420 if (ViewDebug.TRACE_RECYCLER) { 1421 ViewDebug.trace(getChildAt(i), 1422 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1423 } 1424 } 1425 } else { 1426 recycleBin.fillActiveViews(childCount, firstPosition); 1427 } 1428 1429 // take focus back to us temporarily to avoid the eventual 1430 // call to clear focus when removing the focused child below 1431 // from messing things up when ViewRoot assigns focus back 1432 // to someone else 1433 final View focusedChild = getFocusedChild(); 1434 if (focusedChild != null) { 1435 // TODO: in some cases focusedChild.getParent() == null 1436 1437 // we can remember the focused view to restore after relayout if the 1438 // data hasn't changed, or if the focused position is a header or footer 1439 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1440 focusLayoutRestoreDirectChild = focusedChild; 1441 // remember the specific view that had focus 1442 focusLayoutRestoreView = findFocus(); 1443 if (focusLayoutRestoreView != null) { 1444 // tell it we are going to mess with it 1445 focusLayoutRestoreView.onStartTemporaryDetach(); 1446 } 1447 } 1448 requestFocus(); 1449 } 1450 1451 // Clear out old views 1452 //removeAllViewsInLayout(); 1453 detachAllViewsFromParent(); 1454 1455 switch (mLayoutMode) { 1456 case LAYOUT_SET_SELECTION: 1457 if (newSel != null) { 1458 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1459 } else { 1460 sel = fillFromMiddle(childrenTop, childrenBottom); 1461 } 1462 break; 1463 case LAYOUT_SYNC: 1464 sel = fillSpecific(mSyncPosition, mSpecificTop); 1465 break; 1466 case LAYOUT_FORCE_BOTTOM: 1467 sel = fillUp(mItemCount - 1, childrenBottom); 1468 adjustViewsUpOrDown(); 1469 break; 1470 case LAYOUT_FORCE_TOP: 1471 mFirstPosition = 0; 1472 sel = fillFromTop(childrenTop); 1473 adjustViewsUpOrDown(); 1474 break; 1475 case LAYOUT_SPECIFIC: 1476 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1477 break; 1478 case LAYOUT_MOVE_SELECTION: 1479 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1480 break; 1481 default: 1482 if (childCount == 0) { 1483 if (!mStackFromBottom) { 1484 final int position = lookForSelectablePosition(0, true); 1485 setSelectedPositionInt(position); 1486 sel = fillFromTop(childrenTop); 1487 } else { 1488 final int position = lookForSelectablePosition(mItemCount - 1, false); 1489 setSelectedPositionInt(position); 1490 sel = fillUp(mItemCount - 1, childrenBottom); 1491 } 1492 } else { 1493 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1494 sel = fillSpecific(mSelectedPosition, 1495 oldSel == null ? childrenTop : oldSel.getTop()); 1496 } else if (mFirstPosition < mItemCount) { 1497 sel = fillSpecific(mFirstPosition, 1498 oldFirst == null ? childrenTop : oldFirst.getTop()); 1499 } else { 1500 sel = fillSpecific(0, childrenTop); 1501 } 1502 } 1503 break; 1504 } 1505 1506 // Flush any cached views that did not get reused above 1507 recycleBin.scrapActiveViews(); 1508 1509 if (sel != null) { 1510 // the current selected item should get focus if items 1511 // are focusable 1512 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1513 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1514 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1515 if (!focusWasTaken) { 1516 // selected item didn't take focus, fine, but still want 1517 // to make sure something else outside of the selected view 1518 // has focus 1519 final View focused = getFocusedChild(); 1520 if (focused != null) { 1521 focused.clearFocus(); 1522 } 1523 positionSelector(sel); 1524 } else { 1525 sel.setSelected(false); 1526 mSelectorRect.setEmpty(); 1527 } 1528 } else { 1529 positionSelector(sel); 1530 } 1531 mSelectedTop = sel.getTop(); 1532 } else { 1533 mSelectedTop = 0; 1534 mSelectorRect.setEmpty(); 1535 1536 // even if there is not selected position, we may need to restore 1537 // focus (i.e. something focusable in touch mode) 1538 if (hasFocus() && focusLayoutRestoreView != null) { 1539 focusLayoutRestoreView.requestFocus(); 1540 } 1541 } 1542 1543 // tell focus view we are done mucking with it, if it is still in 1544 // our view hierarchy. 1545 if (focusLayoutRestoreView != null 1546 && focusLayoutRestoreView.getWindowToken() != null) { 1547 focusLayoutRestoreView.onFinishTemporaryDetach(); 1548 } 1549 1550 mLayoutMode = LAYOUT_NORMAL; 1551 mDataChanged = false; 1552 mNeedSync = false; 1553 setNextSelectedPositionInt(mSelectedPosition); 1554 1555 updateScrollIndicators(); 1556 1557 if (mItemCount > 0) { 1558 checkSelectionChanged(); 1559 } 1560 1561 invokeOnItemScrollListener(); 1562 } finally { 1563 if (!blockLayoutRequests) { 1564 mBlockLayoutRequests = false; 1565 } 1566 } 1567 } 1568 1569 /** 1570 * @param child a direct child of this list. 1571 * @return Whether child is a header or footer view. 1572 */ 1573 private boolean isDirectChildHeaderOrFooter(View child) { 1574 1575 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1576 final int numHeaders = headers.size(); 1577 for (int i = 0; i < numHeaders; i++) { 1578 if (child == headers.get(i).view) { 1579 return true; 1580 } 1581 } 1582 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1583 final int numFooters = footers.size(); 1584 for (int i = 0; i < numFooters; i++) { 1585 if (child == footers.get(i).view) { 1586 return true; 1587 } 1588 } 1589 return false; 1590 } 1591 1592 /** 1593 * Obtain the view and add it to our list of children. The view can be made 1594 * fresh, converted from an unused view, or used as is if it was in the 1595 * recycle bin. 1596 * 1597 * @param position Logical position in the list 1598 * @param y Top or bottom edge of the view to add 1599 * @param flow If flow is true, align top edge to y. If false, align bottom 1600 * edge to y. 1601 * @param childrenLeft Left edge where children should be positioned 1602 * @param selected Is this position selected? 1603 * @return View that was added 1604 */ 1605 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1606 boolean selected) { 1607 View child; 1608 1609 1610 if (!mDataChanged) { 1611 // Try to use an exsiting view for this position 1612 child = mRecycler.getActiveView(position); 1613 if (child != null) { 1614 if (ViewDebug.TRACE_RECYCLER) { 1615 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1616 position, getChildCount()); 1617 } 1618 1619 // Found it -- we're using an existing child 1620 // This just needs to be positioned 1621 setupChild(child, position, y, flow, childrenLeft, selected, true); 1622 1623 return child; 1624 } 1625 } 1626 1627 // Make a new view for this position, or convert an unused view if possible 1628 child = obtainView(position); 1629 1630 // This needs to be positioned and measured 1631 setupChild(child, position, y, flow, childrenLeft, selected, false); 1632 1633 return child; 1634 } 1635 1636 /** 1637 * Add a view as a child and make sure it is measured (if necessary) and 1638 * positioned properly. 1639 * 1640 * @param child The view to add 1641 * @param position The position of this child 1642 * @param y The y position relative to which this view will be positioned 1643 * @param flowDown If true, align top edge to y. If false, align bottom 1644 * edge to y. 1645 * @param childrenLeft Left edge where children should be positioned 1646 * @param selected Is this position selected? 1647 * @param recycled Has this view been pulled from the recycle bin? If so it 1648 * does not need to be remeasured. 1649 */ 1650 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1651 boolean selected, boolean recycled) { 1652 final boolean isSelected = selected && shouldShowSelector(); 1653 final boolean updateChildSelected = isSelected != child.isSelected(); 1654 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1655 1656 // Respect layout params that are already in the view. Otherwise make some up... 1657 // noinspection unchecked 1658 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1659 if (p == null) { 1660 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1661 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1662 } 1663 p.viewType = mAdapter.getItemViewType(position); 1664 1665 if (recycled || (p.recycledHeaderFooter && 1666 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1667 attachViewToParent(child, flowDown ? -1 : 0, p); 1668 } else { 1669 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1670 p.recycledHeaderFooter = true; 1671 } 1672 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1673 } 1674 1675 if (updateChildSelected) { 1676 child.setSelected(isSelected); 1677 } 1678 1679 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1680 if (child instanceof Checkable) { 1681 ((Checkable) child).setChecked(mCheckStates.get(position)); 1682 } 1683 } 1684 1685 if (needToMeasure) { 1686 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1687 mListPadding.left + mListPadding.right, p.width); 1688 int lpHeight = p.height; 1689 int childHeightSpec; 1690 if (lpHeight > 0) { 1691 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1692 } else { 1693 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1694 } 1695 child.measure(childWidthSpec, childHeightSpec); 1696 } else { 1697 cleanupLayoutState(child); 1698 } 1699 1700 final int w = child.getMeasuredWidth(); 1701 final int h = child.getMeasuredHeight(); 1702 final int childTop = flowDown ? y : y - h; 1703 1704 if (needToMeasure) { 1705 final int childRight = childrenLeft + w; 1706 final int childBottom = childTop + h; 1707 child.layout(childrenLeft, childTop, childRight, childBottom); 1708 } else { 1709 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1710 child.offsetTopAndBottom(childTop - child.getTop()); 1711 } 1712 1713 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1714 child.setDrawingCacheEnabled(true); 1715 } 1716 } 1717 1718 @Override 1719 protected boolean canAnimate() { 1720 return super.canAnimate() && mItemCount > 0; 1721 } 1722 1723 /** 1724 * Sets the currently selected item. If in touch mode, the item will not be selected 1725 * but it will still be positioned appropriately. If the specified selection position 1726 * is less than 0, then the item at position 0 will be selected. 1727 * 1728 * @param position Index (starting at 0) of the data item to be selected. 1729 */ 1730 @Override 1731 public void setSelection(int position) { 1732 setSelectionFromTop(position, 0); 1733 } 1734 1735 /** 1736 * Sets the selected item and positions the selection y pixels from the top edge 1737 * of the ListView. (If in touch mode, the item will not be selected but it will 1738 * still be positioned appropriately.) 1739 * 1740 * @param position Index (starting at 0) of the data item to be selected. 1741 * @param y The distance from the top edge of the ListView (plus padding) that the 1742 * item will be positioned. 1743 */ 1744 public void setSelectionFromTop(int position, int y) { 1745 if (mAdapter == null) { 1746 return; 1747 } 1748 1749 if (!isInTouchMode()) { 1750 position = lookForSelectablePosition(position, true); 1751 if (position >= 0) { 1752 setNextSelectedPositionInt(position); 1753 } 1754 } else { 1755 mResurrectToPosition = position; 1756 } 1757 1758 if (position >= 0) { 1759 mLayoutMode = LAYOUT_SPECIFIC; 1760 mSpecificTop = mListPadding.top + y; 1761 1762 if (mNeedSync) { 1763 mSyncPosition = position; 1764 mSyncRowId = mAdapter.getItemId(position); 1765 } 1766 1767 requestLayout(); 1768 } 1769 } 1770 1771 /** 1772 * Makes the item at the supplied position selected. 1773 * 1774 * @param position the position of the item to select 1775 */ 1776 @Override 1777 void setSelectionInt(int position) { 1778 setNextSelectedPositionInt(position); 1779 layoutChildren(); 1780 } 1781 1782 /** 1783 * Find a position that can be selected (i.e., is not a separator). 1784 * 1785 * @param position The starting position to look at. 1786 * @param lookDown Whether to look down for other positions. 1787 * @return The next selectable position starting at position and then searching either up or 1788 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1789 */ 1790 @Override 1791 int lookForSelectablePosition(int position, boolean lookDown) { 1792 final ListAdapter adapter = mAdapter; 1793 if (adapter == null || isInTouchMode()) { 1794 return INVALID_POSITION; 1795 } 1796 1797 final int count = adapter.getCount(); 1798 if (!mAreAllItemsSelectable) { 1799 if (lookDown) { 1800 position = Math.max(0, position); 1801 while (position < count && !adapter.isEnabled(position)) { 1802 position++; 1803 } 1804 } else { 1805 position = Math.min(position, count - 1); 1806 while (position >= 0 && !adapter.isEnabled(position)) { 1807 position--; 1808 } 1809 } 1810 1811 if (position < 0 || position >= count) { 1812 return INVALID_POSITION; 1813 } 1814 return position; 1815 } else { 1816 if (position < 0 || position >= count) { 1817 return INVALID_POSITION; 1818 } 1819 return position; 1820 } 1821 } 1822 1823 /** 1824 * setSelectionAfterHeaderView set the selection to be the first list item 1825 * after the header views. 1826 */ 1827 public void setSelectionAfterHeaderView() { 1828 final int count = mHeaderViewInfos.size(); 1829 if (count > 0) { 1830 mNextSelectedPosition = 0; 1831 return; 1832 } 1833 1834 if (mAdapter != null) { 1835 setSelection(count); 1836 } else { 1837 mNextSelectedPosition = count; 1838 mLayoutMode = LAYOUT_SET_SELECTION; 1839 } 1840 1841 } 1842 1843 @Override 1844 public boolean dispatchKeyEvent(KeyEvent event) { 1845 // Dispatch in the normal way 1846 boolean handled = super.dispatchKeyEvent(event); 1847 if (!handled) { 1848 // If we didn't handle it... 1849 View focused = getFocusedChild(); 1850 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1851 // ... and our focused child didn't handle it 1852 // ... give it to ourselves so we can scroll if necessary 1853 handled = onKeyDown(event.getKeyCode(), event); 1854 } 1855 } 1856 return handled; 1857 } 1858 1859 @Override 1860 public boolean onKeyDown(int keyCode, KeyEvent event) { 1861 return commonKey(keyCode, 1, event); 1862 } 1863 1864 @Override 1865 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 1866 return commonKey(keyCode, repeatCount, event); 1867 } 1868 1869 @Override 1870 public boolean onKeyUp(int keyCode, KeyEvent event) { 1871 return commonKey(keyCode, 1, event); 1872 } 1873 1874 private boolean commonKey(int keyCode, int count, KeyEvent event) { 1875 if (mAdapter == null) { 1876 return false; 1877 } 1878 1879 if (mDataChanged) { 1880 layoutChildren(); 1881 } 1882 1883 boolean handled = false; 1884 int action = event.getAction(); 1885 1886 if (action != KeyEvent.ACTION_UP) { 1887 if (mSelectedPosition < 0) { 1888 switch (keyCode) { 1889 case KeyEvent.KEYCODE_DPAD_UP: 1890 case KeyEvent.KEYCODE_DPAD_DOWN: 1891 case KeyEvent.KEYCODE_DPAD_CENTER: 1892 case KeyEvent.KEYCODE_ENTER: 1893 case KeyEvent.KEYCODE_SPACE: 1894 if (resurrectSelection()) { 1895 return true; 1896 } 1897 } 1898 } 1899 switch (keyCode) { 1900 case KeyEvent.KEYCODE_DPAD_UP: 1901 if (!event.isAltPressed()) { 1902 while (count > 0) { 1903 handled = arrowScroll(FOCUS_UP); 1904 count--; 1905 } 1906 } else { 1907 handled = fullScroll(FOCUS_UP); 1908 } 1909 break; 1910 1911 case KeyEvent.KEYCODE_DPAD_DOWN: 1912 if (!event.isAltPressed()) { 1913 while (count > 0) { 1914 handled = arrowScroll(FOCUS_DOWN); 1915 count--; 1916 } 1917 } else { 1918 handled = fullScroll(FOCUS_DOWN); 1919 } 1920 break; 1921 1922 case KeyEvent.KEYCODE_DPAD_LEFT: 1923 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 1924 break; 1925 case KeyEvent.KEYCODE_DPAD_RIGHT: 1926 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 1927 break; 1928 1929 case KeyEvent.KEYCODE_DPAD_CENTER: 1930 case KeyEvent.KEYCODE_ENTER: 1931 if (mItemCount > 0 && event.getRepeatCount() == 0) { 1932 keyPressed(); 1933 } 1934 handled = true; 1935 break; 1936 1937 case KeyEvent.KEYCODE_SPACE: 1938 if (mPopup == null || !mPopup.isShowing()) { 1939 if (!event.isShiftPressed()) { 1940 pageScroll(FOCUS_DOWN); 1941 } else { 1942 pageScroll(FOCUS_UP); 1943 } 1944 handled = true; 1945 } 1946 break; 1947 } 1948 } 1949 1950 if (!handled) { 1951 handled = sendToTextFilter(keyCode, count, event); 1952 } 1953 1954 if (handled) { 1955 return true; 1956 } else { 1957 switch (action) { 1958 case KeyEvent.ACTION_DOWN: 1959 return super.onKeyDown(keyCode, event); 1960 1961 case KeyEvent.ACTION_UP: 1962 return super.onKeyUp(keyCode, event); 1963 1964 case KeyEvent.ACTION_MULTIPLE: 1965 return super.onKeyMultiple(keyCode, count, event); 1966 1967 default: // shouldn't happen 1968 return false; 1969 } 1970 } 1971 } 1972 1973 /** 1974 * Scrolls up or down by the number of items currently present on screen. 1975 * 1976 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 1977 * @return whether selection was moved 1978 */ 1979 boolean pageScroll(int direction) { 1980 int nextPage = -1; 1981 boolean down = false; 1982 1983 if (direction == FOCUS_UP) { 1984 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 1985 } else if (direction == FOCUS_DOWN) { 1986 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 1987 down = true; 1988 } 1989 1990 if (nextPage >= 0) { 1991 int position = lookForSelectablePosition(nextPage, down); 1992 if (position >= 0) { 1993 mLayoutMode = LAYOUT_SPECIFIC; 1994 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 1995 1996 if (down && position > mItemCount - getChildCount()) { 1997 mLayoutMode = LAYOUT_FORCE_BOTTOM; 1998 } 1999 2000 if (!down && position < getChildCount()) { 2001 mLayoutMode = LAYOUT_FORCE_TOP; 2002 } 2003 2004 setSelectionInt(position); 2005 invokeOnItemScrollListener(); 2006 invalidate(); 2007 2008 return true; 2009 } 2010 } 2011 2012 return false; 2013 } 2014 2015 /** 2016 * Go to the last or first item if possible (not worrying about panning across or navigating 2017 * within the internal focus of the currently selected item.) 2018 * 2019 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2020 * 2021 * @return whether selection was moved 2022 */ 2023 boolean fullScroll(int direction) { 2024 boolean moved = false; 2025 if (direction == FOCUS_UP) { 2026 if (mSelectedPosition != 0) { 2027 int position = lookForSelectablePosition(0, true); 2028 if (position >= 0) { 2029 mLayoutMode = LAYOUT_FORCE_TOP; 2030 setSelectionInt(position); 2031 invokeOnItemScrollListener(); 2032 } 2033 moved = true; 2034 } 2035 } else if (direction == FOCUS_DOWN) { 2036 if (mSelectedPosition < mItemCount - 1) { 2037 int position = lookForSelectablePosition(mItemCount - 1, true); 2038 if (position >= 0) { 2039 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2040 setSelectionInt(position); 2041 invokeOnItemScrollListener(); 2042 } 2043 moved = true; 2044 } 2045 } 2046 2047 if (moved) { 2048 invalidate(); 2049 } 2050 2051 return moved; 2052 } 2053 2054 /** 2055 * To avoid horizontal focus searches changing the selected item, we 2056 * manually focus search within the selected item (as applicable), and 2057 * prevent focus from jumping to something within another item. 2058 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2059 * @return Whether this consumes the key event. 2060 */ 2061 private boolean handleHorizontalFocusWithinListItem(int direction) { 2062 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2063 throw new IllegalArgumentException("direction must be one of" 2064 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2065 } 2066 2067 final int numChildren = getChildCount(); 2068 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2069 final View selectedView = getSelectedView(); 2070 if (selectedView != null && selectedView.hasFocus() && 2071 selectedView instanceof ViewGroup) { 2072 2073 final View currentFocus = selectedView.findFocus(); 2074 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2075 (ViewGroup) selectedView, currentFocus, direction); 2076 if (nextFocus != null) { 2077 // do the math to get interesting rect in next focus' coordinates 2078 currentFocus.getFocusedRect(mTempRect); 2079 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2080 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2081 if (nextFocus.requestFocus(direction, mTempRect)) { 2082 return true; 2083 } 2084 } 2085 // we are blocking the key from being handled (by returning true) 2086 // if the global result is going to be some other view within this 2087 // list. this is to acheive the overall goal of having 2088 // horizontal d-pad navigation remain in the current item. 2089 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2090 (ViewGroup) getRootView(), currentFocus, direction); 2091 if (globalNextFocus != null) { 2092 return isViewAncestorOf(globalNextFocus, this); 2093 } 2094 } 2095 } 2096 return false; 2097 } 2098 2099 /** 2100 * Scrolls to the next or previous item if possible. 2101 * 2102 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2103 * 2104 * @return whether selection was moved 2105 */ 2106 boolean arrowScroll(int direction) { 2107 try { 2108 mInLayout = true; 2109 final boolean handled = arrowScrollImpl(direction); 2110 if (handled) { 2111 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2112 } 2113 return handled; 2114 } finally { 2115 mInLayout = false; 2116 } 2117 } 2118 2119 /** 2120 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2121 * whether there are focusable items etc. 2122 * 2123 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2124 * @return Whether any scrolling, selection or focus change occured. 2125 */ 2126 private boolean arrowScrollImpl(int direction) { 2127 if (getChildCount() <= 0) { 2128 return false; 2129 } 2130 2131 View selectedView = getSelectedView(); 2132 2133 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2134 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2135 2136 // if we are moving focus, we may OVERRIDE the default behavior 2137 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2138 if (focusResult != null) { 2139 nextSelectedPosition = focusResult.getSelectedPosition(); 2140 amountToScroll = focusResult.getAmountToScroll(); 2141 } 2142 2143 boolean needToRedraw = focusResult != null; 2144 if (nextSelectedPosition != INVALID_POSITION) { 2145 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2146 setSelectedPositionInt(nextSelectedPosition); 2147 setNextSelectedPositionInt(nextSelectedPosition); 2148 selectedView = getSelectedView(); 2149 if (mItemsCanFocus && focusResult == null) { 2150 // there was no new view found to take focus, make sure we 2151 // don't leave focus with the old selection 2152 final View focused = getFocusedChild(); 2153 if (focused != null) { 2154 focused.clearFocus(); 2155 } 2156 } 2157 needToRedraw = true; 2158 checkSelectionChanged(); 2159 } 2160 2161 if (amountToScroll > 0) { 2162 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2163 needToRedraw = true; 2164 } 2165 2166 // if we didn't find a new focusable, make sure any existing focused 2167 // item that was panned off screen gives up focus. 2168 if (mItemsCanFocus && (focusResult == null) 2169 && selectedView != null && selectedView.hasFocus()) { 2170 final View focused = selectedView.findFocus(); 2171 if (distanceToView(focused) > 0) { 2172 focused.clearFocus(); 2173 } 2174 } 2175 2176 // if the current selection is panned off, we need to remove the selection 2177 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2178 && !isViewAncestorOf(selectedView, this)) { 2179 selectedView = null; 2180 hideSelector(); 2181 2182 // but we don't want to set the ressurect position (that would make subsequent 2183 // unhandled key events bring back the item we just scrolled off!) 2184 mResurrectToPosition = INVALID_POSITION; 2185 } 2186 2187 if (needToRedraw) { 2188 if (selectedView != null) { 2189 positionSelector(selectedView); 2190 mSelectedTop = selectedView.getTop(); 2191 } 2192 invalidate(); 2193 invokeOnItemScrollListener(); 2194 return true; 2195 } 2196 2197 return false; 2198 } 2199 2200 /** 2201 * When selection changes, it is possible that the previously selected or the 2202 * next selected item will change its size. If so, we need to offset some folks, 2203 * and re-layout the items as appropriate. 2204 * 2205 * @param selectedView The currently selected view (before changing selection). 2206 * should be <code>null</code> if there was no previous selection. 2207 * @param direction Either {@link android.view.View#FOCUS_UP} or 2208 * {@link android.view.View#FOCUS_DOWN}. 2209 * @param newSelectedPosition The position of the next selection. 2210 * @param newFocusAssigned whether new focus was assigned. This matters because 2211 * when something has focus, we don't want to show selection (ugh). 2212 */ 2213 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2214 boolean newFocusAssigned) { 2215 if (newSelectedPosition == INVALID_POSITION) { 2216 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2217 } 2218 2219 // whether or not we are moving down or up, we want to preserve the 2220 // top of whatever view is on top: 2221 // - moving down: the view that had selection 2222 // - moving up: the view that is getting selection 2223 View topView; 2224 View bottomView; 2225 int topViewIndex, bottomViewIndex; 2226 boolean topSelected = false; 2227 final int selectedIndex = mSelectedPosition - mFirstPosition; 2228 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2229 if (direction == View.FOCUS_UP) { 2230 topViewIndex = nextSelectedIndex; 2231 bottomViewIndex = selectedIndex; 2232 topView = getChildAt(topViewIndex); 2233 bottomView = selectedView; 2234 topSelected = true; 2235 } else { 2236 topViewIndex = selectedIndex; 2237 bottomViewIndex = nextSelectedIndex; 2238 topView = selectedView; 2239 bottomView = getChildAt(bottomViewIndex); 2240 } 2241 2242 final int numChildren = getChildCount(); 2243 2244 // start with top view: is it changing size? 2245 if (topView != null) { 2246 topView.setSelected(!newFocusAssigned && topSelected); 2247 measureAndAdjustDown(topView, topViewIndex, numChildren); 2248 } 2249 2250 // is the bottom view changing size? 2251 if (bottomView != null) { 2252 bottomView.setSelected(!newFocusAssigned && !topSelected); 2253 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2254 } 2255 } 2256 2257 /** 2258 * Re-measure a child, and if its height changes, lay it out preserving its 2259 * top, and adjust the children below it appropriately. 2260 * @param child The child 2261 * @param childIndex The view group index of the child. 2262 * @param numChildren The number of children in the view group. 2263 */ 2264 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2265 int oldHeight = child.getHeight(); 2266 measureItem(child); 2267 if (child.getMeasuredHeight() != oldHeight) { 2268 // lay out the view, preserving its top 2269 relayoutMeasuredItem(child); 2270 2271 // adjust views below appropriately 2272 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2273 for (int i = childIndex + 1; i < numChildren; i++) { 2274 getChildAt(i).offsetTopAndBottom(heightDelta); 2275 } 2276 } 2277 } 2278 2279 /** 2280 * Measure a particular list child. 2281 * TODO: unify with setUpChild. 2282 * @param child The child. 2283 */ 2284 private void measureItem(View child) { 2285 ViewGroup.LayoutParams p = child.getLayoutParams(); 2286 if (p == null) { 2287 p = new ViewGroup.LayoutParams( 2288 ViewGroup.LayoutParams.FILL_PARENT, 2289 ViewGroup.LayoutParams.WRAP_CONTENT); 2290 } 2291 2292 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2293 mListPadding.left + mListPadding.right, p.width); 2294 int lpHeight = p.height; 2295 int childHeightSpec; 2296 if (lpHeight > 0) { 2297 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2298 } else { 2299 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2300 } 2301 child.measure(childWidthSpec, childHeightSpec); 2302 } 2303 2304 /** 2305 * Layout a child that has been measured, preserving its top position. 2306 * TODO: unify with setUpChild. 2307 * @param child The child. 2308 */ 2309 private void relayoutMeasuredItem(View child) { 2310 final int w = child.getMeasuredWidth(); 2311 final int h = child.getMeasuredHeight(); 2312 final int childLeft = mListPadding.left; 2313 final int childRight = childLeft + w; 2314 final int childTop = child.getTop(); 2315 final int childBottom = childTop + h; 2316 child.layout(childLeft, childTop, childRight, childBottom); 2317 } 2318 2319 /** 2320 * @return The amount to preview next items when arrow srolling. 2321 */ 2322 private int getArrowScrollPreviewLength() { 2323 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2324 } 2325 2326 /** 2327 * Determine how much we need to scroll in order to get the next selected view 2328 * visible, with a fading edge showing below as applicable. The amount is 2329 * capped at {@link #getMaxScrollAmount()} . 2330 * 2331 * @param direction either {@link android.view.View#FOCUS_UP} or 2332 * {@link android.view.View#FOCUS_DOWN}. 2333 * @param nextSelectedPosition The position of the next selection, or 2334 * {@link #INVALID_POSITION} if there is no next selectable position 2335 * @return The amount to scroll. Note: this is always positive! Direction 2336 * needs to be taken into account when actually scrolling. 2337 */ 2338 private int amountToScroll(int direction, int nextSelectedPosition) { 2339 final int listBottom = getHeight() - mListPadding.bottom; 2340 final int listTop = mListPadding.top; 2341 2342 final int numChildren = getChildCount(); 2343 2344 if (direction == View.FOCUS_DOWN) { 2345 int indexToMakeVisible = numChildren - 1; 2346 if (nextSelectedPosition != INVALID_POSITION) { 2347 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2348 } 2349 2350 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2351 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2352 2353 int goalBottom = listBottom; 2354 if (positionToMakeVisible < mItemCount - 1) { 2355 goalBottom -= getArrowScrollPreviewLength(); 2356 } 2357 2358 if (viewToMakeVisible.getBottom() <= goalBottom) { 2359 // item is fully visible. 2360 return 0; 2361 } 2362 2363 if (nextSelectedPosition != INVALID_POSITION 2364 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2365 // item already has enough of it visible, changing selection is good enough 2366 return 0; 2367 } 2368 2369 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2370 2371 if ((mFirstPosition + numChildren) == mItemCount) { 2372 // last is last in list -> make sure we don't scroll past it 2373 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2374 amountToScroll = Math.min(amountToScroll, max); 2375 } 2376 2377 return Math.min(amountToScroll, getMaxScrollAmount()); 2378 } else { 2379 int indexToMakeVisible = 0; 2380 if (nextSelectedPosition != INVALID_POSITION) { 2381 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2382 } 2383 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2384 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2385 int goalTop = listTop; 2386 if (positionToMakeVisible > 0) { 2387 goalTop += getArrowScrollPreviewLength(); 2388 } 2389 if (viewToMakeVisible.getTop() >= goalTop) { 2390 // item is fully visible. 2391 return 0; 2392 } 2393 2394 if (nextSelectedPosition != INVALID_POSITION && 2395 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2396 // item already has enough of it visible, changing selection is good enough 2397 return 0; 2398 } 2399 2400 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2401 if (mFirstPosition == 0) { 2402 // first is first in list -> make sure we don't scroll past it 2403 final int max = listTop - getChildAt(0).getTop(); 2404 amountToScroll = Math.min(amountToScroll, max); 2405 } 2406 return Math.min(amountToScroll, getMaxScrollAmount()); 2407 } 2408 } 2409 2410 /** 2411 * Holds results of focus aware arrow scrolling. 2412 */ 2413 static private class ArrowScrollFocusResult { 2414 private int mSelectedPosition; 2415 private int mAmountToScroll; 2416 2417 /** 2418 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2419 */ 2420 void populate(int selectedPosition, int amountToScroll) { 2421 mSelectedPosition = selectedPosition; 2422 mAmountToScroll = amountToScroll; 2423 } 2424 2425 public int getSelectedPosition() { 2426 return mSelectedPosition; 2427 } 2428 2429 public int getAmountToScroll() { 2430 return mAmountToScroll; 2431 } 2432 } 2433 2434 /** 2435 * @param direction either {@link android.view.View#FOCUS_UP} or 2436 * {@link android.view.View#FOCUS_DOWN}. 2437 * @return The position of the next selectable position of the views that 2438 * are currently visible, taking into account the fact that there might 2439 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2440 * selectable view on screen in the given direction. 2441 */ 2442 private int lookForSelectablePositionOnScreen(int direction) { 2443 final int firstPosition = mFirstPosition; 2444 if (direction == View.FOCUS_DOWN) { 2445 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2446 mSelectedPosition + 1 : 2447 firstPosition; 2448 if (startPos >= mAdapter.getCount()) { 2449 return INVALID_POSITION; 2450 } 2451 if (startPos < firstPosition) { 2452 startPos = firstPosition; 2453 } 2454 2455 final int lastVisiblePos = getLastVisiblePosition(); 2456 final ListAdapter adapter = getAdapter(); 2457 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2458 if (adapter.isEnabled(pos) 2459 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2460 return pos; 2461 } 2462 } 2463 } else { 2464 int last = firstPosition + getChildCount() - 1; 2465 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2466 mSelectedPosition - 1 : 2467 firstPosition + getChildCount() - 1; 2468 if (startPos < 0) { 2469 return INVALID_POSITION; 2470 } 2471 if (startPos > last) { 2472 startPos = last; 2473 } 2474 2475 final ListAdapter adapter = getAdapter(); 2476 for (int pos = startPos; pos >= firstPosition; pos--) { 2477 if (adapter.isEnabled(pos) 2478 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2479 return pos; 2480 } 2481 } 2482 } 2483 return INVALID_POSITION; 2484 } 2485 2486 /** 2487 * Do an arrow scroll based on focus searching. If a new view is 2488 * given focus, return the selection delta and amount to scroll via 2489 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2490 * 2491 * @param direction either {@link android.view.View#FOCUS_UP} or 2492 * {@link android.view.View#FOCUS_DOWN}. 2493 * @return The result if focus has changed, or <code>null</code>. 2494 */ 2495 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2496 final View selectedView = getSelectedView(); 2497 View newFocus; 2498 if (selectedView != null && selectedView.hasFocus()) { 2499 View oldFocus = selectedView.findFocus(); 2500 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2501 } else { 2502 if (direction == View.FOCUS_DOWN) { 2503 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2504 final int listTop = mListPadding.top + 2505 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2506 final int ySearchPoint = 2507 (selectedView != null && selectedView.getTop() > listTop) ? 2508 selectedView.getTop() : 2509 listTop; 2510 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2511 } else { 2512 final boolean bottomFadingEdgeShowing = 2513 (mFirstPosition + getChildCount() - 1) < mItemCount; 2514 final int listBottom = getHeight() - mListPadding.bottom - 2515 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2516 final int ySearchPoint = 2517 (selectedView != null && selectedView.getBottom() < listBottom) ? 2518 selectedView.getBottom() : 2519 listBottom; 2520 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2521 } 2522 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2523 } 2524 2525 if (newFocus != null) { 2526 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2527 2528 // if the focus change is in a different new position, make sure 2529 // we aren't jumping over another selectable position 2530 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2531 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2532 if (selectablePosition != INVALID_POSITION && 2533 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2534 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2535 return null; 2536 } 2537 } 2538 2539 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2540 2541 final int maxScrollAmount = getMaxScrollAmount(); 2542 if (focusScroll < maxScrollAmount) { 2543 // not moving too far, safe to give next view focus 2544 newFocus.requestFocus(direction); 2545 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2546 return mArrowScrollFocusResult; 2547 } else if (distanceToView(newFocus) < maxScrollAmount){ 2548 // Case to consider: 2549 // too far to get entire next focusable on screen, but by going 2550 // max scroll amount, we are getting it at least partially in view, 2551 // so give it focus and scroll the max ammount. 2552 newFocus.requestFocus(direction); 2553 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2554 return mArrowScrollFocusResult; 2555 } 2556 } 2557 return null; 2558 } 2559 2560 /** 2561 * @param newFocus The view that would have focus. 2562 * @return the position that contains newFocus 2563 */ 2564 private int positionOfNewFocus(View newFocus) { 2565 final int numChildren = getChildCount(); 2566 for (int i = 0; i < numChildren; i++) { 2567 final View child = getChildAt(i); 2568 if (isViewAncestorOf(newFocus, child)) { 2569 return mFirstPosition + i; 2570 } 2571 } 2572 throw new IllegalArgumentException("newFocus is not a child of any of the" 2573 + " children of the list!"); 2574 } 2575 2576 /** 2577 * Return true if child is an ancestor of parent, (or equal to the parent). 2578 */ 2579 private boolean isViewAncestorOf(View child, View parent) { 2580 if (child == parent) { 2581 return true; 2582 } 2583 2584 final ViewParent theParent = child.getParent(); 2585 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2586 } 2587 2588 /** 2589 * Determine how much we need to scroll in order to get newFocus in view. 2590 * @param direction either {@link android.view.View#FOCUS_UP} or 2591 * {@link android.view.View#FOCUS_DOWN}. 2592 * @param newFocus The view that would take focus. 2593 * @param positionOfNewFocus The position of the list item containing newFocus 2594 * @return The amount to scroll. Note: this is always positive! Direction 2595 * needs to be taken into account when actually scrolling. 2596 */ 2597 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2598 int amountToScroll = 0; 2599 newFocus.getDrawingRect(mTempRect); 2600 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2601 if (direction == View.FOCUS_UP) { 2602 if (mTempRect.top < mListPadding.top) { 2603 amountToScroll = mListPadding.top - mTempRect.top; 2604 if (positionOfNewFocus > 0) { 2605 amountToScroll += getArrowScrollPreviewLength(); 2606 } 2607 } 2608 } else { 2609 final int listBottom = getHeight() - mListPadding.bottom; 2610 if (mTempRect.bottom > listBottom) { 2611 amountToScroll = mTempRect.bottom - listBottom; 2612 if (positionOfNewFocus < mItemCount - 1) { 2613 amountToScroll += getArrowScrollPreviewLength(); 2614 } 2615 } 2616 } 2617 return amountToScroll; 2618 } 2619 2620 /** 2621 * Determine the distance to the nearest edge of a view in a particular 2622 * direciton. 2623 * @param descendant A descendant of this list. 2624 * @return The distance, or 0 if the nearest edge is already on screen. 2625 */ 2626 private int distanceToView(View descendant) { 2627 int distance = 0; 2628 descendant.getDrawingRect(mTempRect); 2629 offsetDescendantRectToMyCoords(descendant, mTempRect); 2630 final int listBottom = mBottom - mTop - mListPadding.bottom; 2631 if (mTempRect.bottom < mListPadding.top) { 2632 distance = mListPadding.top - mTempRect.bottom; 2633 } else if (mTempRect.top > listBottom) { 2634 distance = mTempRect.top - listBottom; 2635 } 2636 return distance; 2637 } 2638 2639 2640 /** 2641 * Scroll the children by amount, adding a view at the end and removing 2642 * views that fall off as necessary. 2643 * 2644 * @param amount The amount (positive or negative) to scroll. 2645 */ 2646 private void scrollListItemsBy(int amount) { 2647 offsetChildrenTopAndBottom(amount); 2648 2649 final int listBottom = getHeight() - mListPadding.bottom; 2650 final int listTop = mListPadding.top; 2651 final AbsListView.RecycleBin recycleBin = mRecycler; 2652 2653 if (amount < 0) { 2654 // shifted items up 2655 2656 // may need to pan views into the bottom space 2657 int numChildren = getChildCount(); 2658 View last = getChildAt(numChildren - 1); 2659 while (last.getBottom() < listBottom) { 2660 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2661 if (lastVisiblePosition < mItemCount - 1) { 2662 last = addViewBelow(last, lastVisiblePosition); 2663 numChildren++; 2664 } else { 2665 break; 2666 } 2667 } 2668 2669 // may have brought in the last child of the list that is skinnier 2670 // than the fading edge, thereby leaving space at the end. need 2671 // to shift back 2672 if (last.getBottom() < listBottom) { 2673 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2674 } 2675 2676 // top views may be panned off screen 2677 View first = getChildAt(0); 2678 while (first.getBottom() < listTop) { 2679 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2680 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2681 removeViewInLayout(first); 2682 recycleBin.addScrapView(first); 2683 } else { 2684 detachViewFromParent(first); 2685 } 2686 first = getChildAt(0); 2687 mFirstPosition++; 2688 } 2689 } else { 2690 // shifted items down 2691 View first = getChildAt(0); 2692 2693 // may need to pan views into top 2694 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2695 first = addViewAbove(first, mFirstPosition); 2696 mFirstPosition--; 2697 } 2698 2699 // may have brought the very first child of the list in too far and 2700 // need to shift it back 2701 if (first.getTop() > listTop) { 2702 offsetChildrenTopAndBottom(listTop - first.getTop()); 2703 } 2704 2705 int lastIndex = getChildCount() - 1; 2706 View last = getChildAt(lastIndex); 2707 2708 // bottom view may be panned off screen 2709 while (last.getTop() > listBottom) { 2710 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2711 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2712 removeViewInLayout(last); 2713 recycleBin.addScrapView(last); 2714 } else { 2715 detachViewFromParent(last); 2716 } 2717 last = getChildAt(--lastIndex); 2718 } 2719 } 2720 } 2721 2722 private View addViewAbove(View theView, int position) { 2723 int abovePosition = position - 1; 2724 View view = obtainView(abovePosition); 2725 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2726 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, false, false); 2727 return view; 2728 } 2729 2730 private View addViewBelow(View theView, int position) { 2731 int belowPosition = position + 1; 2732 View view = obtainView(belowPosition); 2733 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2734 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, false, false); 2735 return view; 2736 } 2737 2738 /** 2739 * Indicates that the views created by the ListAdapter can contain focusable 2740 * items. 2741 * 2742 * @param itemsCanFocus true if items can get focus, false otherwise 2743 */ 2744 public void setItemsCanFocus(boolean itemsCanFocus) { 2745 mItemsCanFocus = itemsCanFocus; 2746 if (!itemsCanFocus) { 2747 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2748 } 2749 } 2750 2751 /** 2752 * @return Whether the views created by the ListAdapter can contain focusable 2753 * items. 2754 */ 2755 public boolean getItemsCanFocus() { 2756 return mItemsCanFocus; 2757 } 2758 2759 @Override 2760 protected void dispatchDraw(Canvas canvas) { 2761 // Draw the dividers 2762 final int dividerHeight = mDividerHeight; 2763 2764 if (dividerHeight > 0 && mDivider != null) { 2765 // Only modify the top and bottom in the loop, we set the left and right here 2766 final Rect bounds = mTempRect; 2767 bounds.left = mPaddingLeft; 2768 bounds.right = mRight - mLeft - mPaddingRight; 2769 2770 final int count = getChildCount(); 2771 final int headerCount = mHeaderViewInfos.size(); 2772 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2773 final boolean headerDividers = mHeaderDividersEnabled; 2774 final boolean footerDividers = mFooterDividersEnabled; 2775 final int first = mFirstPosition; 2776 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2777 final ListAdapter adapter = mAdapter; 2778 2779 if (!mStackFromBottom) { 2780 int bottom; 2781 int listBottom = mBottom - mTop - mListPadding.bottom; 2782 2783 for (int i = 0; i < count; i++) { 2784 if ((headerDividers || first + i >= headerCount) && 2785 (footerDividers || first + i < footerLimit)) { 2786 View child = getChildAt(i); 2787 bottom = child.getBottom(); 2788 // Don't draw dividers next to items that are not enabled 2789 if (bottom < listBottom && (areAllItemsSelectable || 2790 (adapter.isEnabled(first + i) && (i == count - 1 || 2791 adapter.isEnabled(first + i + 1))))) { 2792 bounds.top = bottom; 2793 bounds.bottom = bottom + dividerHeight; 2794 drawDivider(canvas, bounds, i); 2795 } 2796 } 2797 } 2798 } else { 2799 int top; 2800 int listTop = mListPadding.top; 2801 2802 for (int i = 0; i < count; i++) { 2803 if ((headerDividers || first + i >= headerCount) && 2804 (footerDividers || first + i < footerLimit)) { 2805 View child = getChildAt(i); 2806 top = child.getTop(); 2807 // Don't draw dividers next to items that are not enabled 2808 if (top > listTop && (areAllItemsSelectable || 2809 (adapter.isEnabled(first + i) && (i == count - 1 || 2810 adapter.isEnabled(first + i + 1))))) { 2811 bounds.top = top - dividerHeight; 2812 bounds.bottom = top; 2813 // Give the method the child ABOVE the divider, so we 2814 // subtract one from our child 2815 // position. Give -1 when there is no child above the 2816 // divider. 2817 drawDivider(canvas, bounds, i - 1); 2818 } 2819 } 2820 } 2821 } 2822 } 2823 2824 // Draw the indicators (these should be drawn above the dividers) and children 2825 super.dispatchDraw(canvas); 2826 } 2827 2828 /** 2829 * Draws a divider for the given child in the given bounds. 2830 * 2831 * @param canvas The canvas to draw to. 2832 * @param bounds The bounds of the divider. 2833 * @param childIndex The index of child (of the View) above the divider. 2834 * This will be -1 if there is no child above the divider to be 2835 * drawn. 2836 */ 2837 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 2838 // This widget draws the same divider for all children 2839 final Drawable divider = mDivider; 2840 final boolean clipDivider = mClipDivider; 2841 2842 if (!clipDivider) { 2843 divider.setBounds(bounds); 2844 } else { 2845 canvas.save(); 2846 canvas.clipRect(bounds); 2847 } 2848 2849 divider.draw(canvas); 2850 2851 if (clipDivider) { 2852 canvas.restore(); 2853 } 2854 } 2855 2856 /** 2857 * Returns the drawable that will be drawn between each item in the list. 2858 * 2859 * @return the current drawable drawn between list elements 2860 */ 2861 public Drawable getDivider() { 2862 return mDivider; 2863 } 2864 2865 /** 2866 * Sets the drawable that will be drawn between each item in the list. If the drawable does 2867 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 2868 * 2869 * @param divider The drawable to use. 2870 */ 2871 public void setDivider(Drawable divider) { 2872 if (divider != null) { 2873 mDividerHeight = divider.getIntrinsicHeight(); 2874 mClipDivider = divider instanceof ColorDrawable; 2875 } else { 2876 mDividerHeight = 0; 2877 mClipDivider = false; 2878 } 2879 mDivider = divider; 2880 requestLayoutIfNecessary(); 2881 } 2882 2883 /** 2884 * @return Returns the height of the divider that will be drawn between each item in the list. 2885 */ 2886 public int getDividerHeight() { 2887 return mDividerHeight; 2888 } 2889 2890 /** 2891 * Sets the height of the divider that will be drawn between each item in the list. Calling 2892 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 2893 * 2894 * @param height The new height of the divider in pixels. 2895 */ 2896 public void setDividerHeight(int height) { 2897 mDividerHeight = height; 2898 requestLayoutIfNecessary(); 2899 } 2900 2901 /** 2902 * Enables or disables the drawing of the divider for header views. 2903 * 2904 * @param headerDividersEnabled True to draw the headers, false otherwise. 2905 * 2906 * @see #setFooterDividersEnabled(boolean) 2907 * @see #addHeaderView(android.view.View) 2908 */ 2909 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 2910 mHeaderDividersEnabled = headerDividersEnabled; 2911 invalidate(); 2912 } 2913 2914 /** 2915 * Enables or disables the drawing of the divider for footer views. 2916 * 2917 * @param footerDividersEnabled True to draw the footers, false otherwise. 2918 * 2919 * @see #setHeaderDividersEnabled(boolean) 2920 * @see #addFooterView(android.view.View) 2921 */ 2922 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 2923 mFooterDividersEnabled = footerDividersEnabled; 2924 invalidate(); 2925 } 2926 2927 @Override 2928 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 2929 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 2930 2931 int closetChildIndex = -1; 2932 if (gainFocus && previouslyFocusedRect != null) { 2933 previouslyFocusedRect.offset(mScrollX, mScrollY); 2934 2935 // figure out which item should be selected based on previously 2936 // focused rect 2937 Rect otherRect = mTempRect; 2938 int minDistance = Integer.MAX_VALUE; 2939 final int childCount = getChildCount(); 2940 final int firstPosition = mFirstPosition; 2941 final ListAdapter adapter = mAdapter; 2942 2943 for (int i = 0; i < childCount; i++) { 2944 // only consider selectable views 2945 if (!adapter.isEnabled(firstPosition + i)) { 2946 continue; 2947 } 2948 2949 View other = getChildAt(i); 2950 other.getDrawingRect(otherRect); 2951 offsetDescendantRectToMyCoords(other, otherRect); 2952 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 2953 2954 if (distance < minDistance) { 2955 minDistance = distance; 2956 closetChildIndex = i; 2957 } 2958 } 2959 } 2960 2961 if (closetChildIndex >= 0) { 2962 setSelection(closetChildIndex + mFirstPosition); 2963 } else { 2964 requestLayout(); 2965 } 2966 } 2967 2968 2969 /* 2970 * (non-Javadoc) 2971 * 2972 * Children specified in XML are assumed to be header views. After we have 2973 * parsed them move them out of the children list and into mHeaderViews. 2974 */ 2975 @Override 2976 protected void onFinishInflate() { 2977 super.onFinishInflate(); 2978 2979 int count = getChildCount(); 2980 if (count > 0) { 2981 for (int i = 0; i < count; ++i) { 2982 addHeaderView(getChildAt(i)); 2983 } 2984 removeAllViews(); 2985 } 2986 } 2987 2988 /* (non-Javadoc) 2989 * @see android.view.View#findViewById(int) 2990 * First look in our children, then in any header and footer views that may be scrolled off. 2991 */ 2992 @Override 2993 protected View findViewTraversal(int id) { 2994 View v; 2995 v = super.findViewTraversal(id); 2996 if (v == null) { 2997 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 2998 if (v != null) { 2999 return v; 3000 } 3001 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3002 if (v != null) { 3003 return v; 3004 } 3005 } 3006 return v; 3007 } 3008 3009 /* (non-Javadoc) 3010 * 3011 * Look in the passed in list of headers or footers for the view. 3012 */ 3013 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3014 if (where != null) { 3015 int len = where.size(); 3016 View v; 3017 3018 for (int i = 0; i < len; i++) { 3019 v = where.get(i).view; 3020 3021 if (!v.isRootNamespace()) { 3022 v = v.findViewById(id); 3023 3024 if (v != null) { 3025 return v; 3026 } 3027 } 3028 } 3029 } 3030 return null; 3031 } 3032 3033 /* (non-Javadoc) 3034 * @see android.view.View#findViewWithTag(String) 3035 * First look in our children, then in any header and footer views that may be scrolled off. 3036 */ 3037 @Override 3038 protected View findViewWithTagTraversal(Object tag) { 3039 View v; 3040 v = super.findViewWithTagTraversal(tag); 3041 if (v == null) { 3042 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3043 if (v != null) { 3044 return v; 3045 } 3046 3047 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3048 if (v != null) { 3049 return v; 3050 } 3051 } 3052 return v; 3053 } 3054 3055 /* (non-Javadoc) 3056 * 3057 * Look in the passed in list of headers or footers for the view with the tag. 3058 */ 3059 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3060 if (where != null) { 3061 int len = where.size(); 3062 View v; 3063 3064 for (int i = 0; i < len; i++) { 3065 v = where.get(i).view; 3066 3067 if (!v.isRootNamespace()) { 3068 v = v.findViewWithTag(tag); 3069 3070 if (v != null) { 3071 return v; 3072 } 3073 } 3074 } 3075 } 3076 return null; 3077 } 3078 3079 @Override 3080 public boolean onTouchEvent(MotionEvent ev) { 3081 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3082 // Don't handle edge touches immediately -- they may actually belong to one of our 3083 // descendants. 3084 return false; 3085 } 3086 return super.onTouchEvent(ev); 3087 } 3088 3089 /** 3090 * @see #setChoiceMode(int) 3091 * 3092 * @return The current choice mode 3093 */ 3094 public int getChoiceMode() { 3095 return mChoiceMode; 3096 } 3097 3098 /** 3099 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3100 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3101 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3102 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3103 * 3104 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3105 * {@link #CHOICE_MODE_MULTIPLE} 3106 */ 3107 public void setChoiceMode(int choiceMode) { 3108 mChoiceMode = choiceMode; 3109 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { 3110 mCheckStates = new SparseBooleanArray(); 3111 } 3112 } 3113 3114 @Override 3115 public boolean performItemClick(View view, int position, long id) { 3116 boolean handled = false; 3117 3118 if (mChoiceMode != CHOICE_MODE_NONE) { 3119 handled = true; 3120 3121 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3122 boolean oldValue = mCheckStates.get(position, false); 3123 mCheckStates.put(position, !oldValue); 3124 } else { 3125 boolean oldValue = mCheckStates.get(position, false); 3126 if (!oldValue) { 3127 mCheckStates.clear(); 3128 mCheckStates.put(position, true); 3129 } 3130 } 3131 3132 mDataChanged = true; 3133 rememberSyncState(); 3134 requestLayout(); 3135 } 3136 3137 handled |= super.performItemClick(view, position, id); 3138 3139 return handled; 3140 } 3141 3142 /** 3143 * Sets the checked state of the specified position. The is only valid if 3144 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3145 * {@link #CHOICE_MODE_MULTIPLE}. 3146 * 3147 * @param position The item whose checked state is to be checked 3148 * @param value The new checked sate for the item 3149 */ 3150 public void setItemChecked(int position, boolean value) { 3151 if (mChoiceMode == CHOICE_MODE_NONE) { 3152 return; 3153 } 3154 3155 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3156 mCheckStates.put(position, value); 3157 } else { 3158 boolean oldValue = mCheckStates.get(position, false); 3159 mCheckStates.clear(); 3160 if (!oldValue) { 3161 mCheckStates.put(position, true); 3162 } 3163 } 3164 3165 // Do not generate a data change while we are in the layout phase 3166 if (!mInLayout && !mBlockLayoutRequests) { 3167 mDataChanged = true; 3168 rememberSyncState(); 3169 requestLayout(); 3170 } 3171 } 3172 3173 /** 3174 * Returns the checked state of the specified position. The result is only 3175 * valid if the choice mode has not been set to {@link #CHOICE_MODE_SINGLE} 3176 * or {@link #CHOICE_MODE_MULTIPLE}. 3177 * 3178 * @param position The item whose checked state to return 3179 * @return The item's checked state 3180 * 3181 * @see #setChoiceMode(int) 3182 */ 3183 public boolean isItemChecked(int position) { 3184 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3185 return mCheckStates.get(position); 3186 } 3187 3188 return false; 3189 } 3190 3191 /** 3192 * Returns the currently checked item. The result is only valid if the choice 3193 * mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3194 * 3195 * @return The position of the currently checked item or 3196 * {@link #INVALID_POSITION} if nothing is selected 3197 * 3198 * @see #setChoiceMode(int) 3199 */ 3200 public int getCheckedItemPosition() { 3201 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3202 return mCheckStates.keyAt(0); 3203 } 3204 3205 return INVALID_POSITION; 3206 } 3207 3208 /** 3209 * Returns the set of checked items in the list. The result is only valid if 3210 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3211 * 3212 * @return A SparseBooleanArray which will return true for each call to 3213 * get(int position) where position is a position in the list. 3214 */ 3215 public SparseBooleanArray getCheckedItemPositions() { 3216 if (mChoiceMode != CHOICE_MODE_NONE) { 3217 return mCheckStates; 3218 } 3219 return null; 3220 } 3221 3222 /** 3223 * Returns the set of checked items ids. The result is only valid if 3224 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3225 * 3226 * @return A new array which contains the id of each checked item in the list. 3227 */ 3228 public long[] getCheckItemIds() { 3229 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3230 final SparseBooleanArray states = mCheckStates; 3231 final int count = states.size(); 3232 final long[] ids = new long[count]; 3233 final ListAdapter adapter = mAdapter; 3234 3235 for (int i = 0; i < count; i++) { 3236 ids[i]= adapter.getItemId(states.keyAt(i)); 3237 } 3238 3239 return ids; 3240 } 3241 3242 return new long[0]; 3243 } 3244 3245 /** 3246 * Clear any choices previously set 3247 */ 3248 public void clearChoices() { 3249 if (mCheckStates != null) { 3250 mCheckStates.clear(); 3251 } 3252 } 3253 3254 static class SavedState extends BaseSavedState { 3255 SparseBooleanArray checkState; 3256 3257 /** 3258 * Constructor called from {@link ListView#onSaveInstanceState()} 3259 */ 3260 SavedState(Parcelable superState, SparseBooleanArray checkState) { 3261 super(superState); 3262 this.checkState = checkState; 3263 } 3264 3265 /** 3266 * Constructor called from {@link #CREATOR} 3267 */ 3268 private SavedState(Parcel in) { 3269 super(in); 3270 checkState = in.readSparseBooleanArray(); 3271 } 3272 3273 @Override 3274 public void writeToParcel(Parcel out, int flags) { 3275 super.writeToParcel(out, flags); 3276 out.writeSparseBooleanArray(checkState); 3277 } 3278 3279 @Override 3280 public String toString() { 3281 return "ListView.SavedState{" 3282 + Integer.toHexString(System.identityHashCode(this)) 3283 + " checkState=" + checkState + "}"; 3284 } 3285 3286 public static final Parcelable.Creator<SavedState> CREATOR 3287 = new Parcelable.Creator<SavedState>() { 3288 public SavedState createFromParcel(Parcel in) { 3289 return new SavedState(in); 3290 } 3291 3292 public SavedState[] newArray(int size) { 3293 return new SavedState[size]; 3294 } 3295 }; 3296 } 3297 3298 @Override 3299 public Parcelable onSaveInstanceState() { 3300 Parcelable superState = super.onSaveInstanceState(); 3301 return new SavedState(superState, mCheckStates); 3302 } 3303 3304 @Override 3305 public void onRestoreInstanceState(Parcelable state) { 3306 SavedState ss = (SavedState) state; 3307 3308 super.onRestoreInstanceState(ss.getSuperState()); 3309 3310 if (ss.checkState != null) { 3311 mCheckStates = ss.checkState; 3312 } 3313 3314 } 3315} 3316