GridLayoutManager.java revision e0e66a21916f94ebbced0d1ffe3dc652c9c7a15e
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14package android.support.v17.leanback.widget; 15 16import android.content.Context; 17import android.graphics.PointF; 18import android.graphics.Rect; 19import android.os.Bundle; 20import android.os.Parcel; 21import android.os.Parcelable; 22import android.support.v4.view.ViewCompat; 23import android.support.v7.widget.LinearSmoothScroller; 24import android.support.v7.widget.RecyclerView; 25import android.support.v7.widget.RecyclerView.Recycler; 26import android.support.v7.widget.RecyclerView.State; 27 28import static android.support.v7.widget.RecyclerView.NO_ID; 29import static android.support.v7.widget.RecyclerView.NO_POSITION; 30import static android.support.v7.widget.RecyclerView.HORIZONTAL; 31import static android.support.v7.widget.RecyclerView.VERTICAL; 32 33import android.util.AttributeSet; 34import android.util.Log; 35import android.view.FocusFinder; 36import android.view.Gravity; 37import android.view.View; 38import android.view.ViewParent; 39import android.view.View.MeasureSpec; 40import android.view.ViewGroup.MarginLayoutParams; 41import android.view.ViewGroup; 42 43import java.io.PrintWriter; 44import java.io.StringWriter; 45import java.util.ArrayList; 46import java.util.List; 47 48final class GridLayoutManager extends RecyclerView.LayoutManager { 49 50 /* 51 * LayoutParams for {@link HorizontalGridView} and {@link VerticalGridView}. 52 * The class currently does two internal jobs: 53 * - Saves optical bounds insets. 54 * - Caches focus align view center. 55 */ 56 static class LayoutParams extends RecyclerView.LayoutParams { 57 58 // The view is saved only during animation. 59 private View mView; 60 61 // For placement 62 private int mLeftInset; 63 private int mTopInset; 64 private int mRightInset; 65 private int mBottomInset; 66 67 // For alignment 68 private int mAlignX; 69 private int mAlignY; 70 71 public LayoutParams(Context c, AttributeSet attrs) { 72 super(c, attrs); 73 } 74 75 public LayoutParams(int width, int height) { 76 super(width, height); 77 } 78 79 public LayoutParams(MarginLayoutParams source) { 80 super(source); 81 } 82 83 public LayoutParams(ViewGroup.LayoutParams source) { 84 super(source); 85 } 86 87 public LayoutParams(RecyclerView.LayoutParams source) { 88 super(source); 89 } 90 91 public LayoutParams(LayoutParams source) { 92 super(source); 93 } 94 95 int getAlignX() { 96 return mAlignX; 97 } 98 99 int getAlignY() { 100 return mAlignY; 101 } 102 103 int getOpticalLeft(View view) { 104 return view.getLeft() + mLeftInset; 105 } 106 107 int getOpticalTop(View view) { 108 return view.getTop() + mTopInset; 109 } 110 111 int getOpticalRight(View view) { 112 return view.getRight() - mRightInset; 113 } 114 115 int getOpticalBottom(View view) { 116 return view.getBottom() - mBottomInset; 117 } 118 119 int getOpticalWidth(View view) { 120 return view.getWidth() - mLeftInset - mRightInset; 121 } 122 123 int getOpticalHeight(View view) { 124 return view.getHeight() - mTopInset - mBottomInset; 125 } 126 127 int getOpticalLeftInset() { 128 return mLeftInset; 129 } 130 131 int getOpticalRightInset() { 132 return mRightInset; 133 } 134 135 int getOpticalTopInset() { 136 return mTopInset; 137 } 138 139 int getOpticalBottomInset() { 140 return mBottomInset; 141 } 142 143 void setAlignX(int alignX) { 144 mAlignX = alignX; 145 } 146 147 void setAlignY(int alignY) { 148 mAlignY = alignY; 149 } 150 151 void setOpticalInsets(int leftInset, int topInset, int rightInset, int bottomInset) { 152 mLeftInset = leftInset; 153 mTopInset = topInset; 154 mRightInset = rightInset; 155 mBottomInset = bottomInset; 156 } 157 158 private void invalidateItemDecoration() { 159 ViewParent parent = mView.getParent(); 160 if (parent instanceof RecyclerView) { 161 // TODO: we only need invalidate parent if it has ItemDecoration 162 ((RecyclerView) parent).invalidate(); 163 } 164 } 165 } 166 167 private static final String TAG = "GridLayoutManager"; 168 private static final boolean DEBUG = false; 169 170 private String getTag() { 171 return TAG + ":" + mBaseGridView.getId(); 172 } 173 174 private final BaseGridView mBaseGridView; 175 176 /** 177 * Note on conventions in the presence of RTL layout directions: 178 * Many properties and method names reference entities related to the 179 * beginnings and ends of things. In the presence of RTL flows, 180 * it may not be clear whether this is intended to reference a 181 * quantity that changes direction in RTL cases, or a quantity that 182 * does not. Here are the conventions in use: 183 * 184 * start/end: coordinate quantities - do reverse 185 * (optical) left/right: coordinate quantities - do not reverse 186 * low/high: coordinate quantities - do not reverse 187 * min/max: coordinate quantities - do not reverse 188 * scroll offset - coordinate quantities - do not reverse 189 * first/last: positional indices - do not reverse 190 * front/end: positional indices - do not reverse 191 * prepend/append: related to positional indices - do not reverse 192 * 193 * Note that although quantities do not reverse in RTL flows, their 194 * relationship does. In LTR flows, the first positional index is 195 * leftmost; in RTL flows, it is rightmost. Thus, anywhere that 196 * positional quantities are mapped onto coordinate quantities, 197 * the flow must be checked and the logic reversed. 198 */ 199 200 /** 201 * The orientation of a "row". 202 */ 203 private int mOrientation = HORIZONTAL; 204 205 private RecyclerView.State mState; 206 private RecyclerView.Recycler mRecycler; 207 208 private boolean mInLayout = false; 209 private boolean mInSelection = false; 210 211 private OnChildSelectedListener mChildSelectedListener = null; 212 213 /** 214 * The focused position, it's not the currently visually aligned position 215 * but it is the final position that we intend to focus on. If there are 216 * multiple setSelection() called, mFocusPosition saves last value. 217 */ 218 private int mFocusPosition = NO_POSITION; 219 220 /** 221 * The offset to be applied to mFocusPosition, due to adapter change, on the next 222 * layout. Set to Integer.MIN_VALUE means item was removed. 223 * TODO: This is somewhat duplication of RecyclerView getOldPosition() which is 224 * unfortunately cleared after prelayout. 225 */ 226 private int mFocusPositionOffset = 0; 227 228 /** 229 * Force a full layout under certain situations. 230 */ 231 private boolean mForceFullLayout; 232 233 /** 234 * True if layout is enabled. 235 */ 236 private boolean mLayoutEnabled = true; 237 238 /** 239 * override child visibility 240 */ 241 private int mChildVisibility = -1; 242 243 /** 244 * The scroll offsets of the viewport relative to the entire view. 245 */ 246 private int mScrollOffsetPrimary; 247 private int mScrollOffsetSecondary; 248 249 /** 250 * User-specified row height/column width. Can be WRAP_CONTENT. 251 */ 252 private int mRowSizeSecondaryRequested; 253 254 /** 255 * The fixed size of each grid item in the secondary direction. This corresponds to 256 * the row height, equal for all rows. Grid items may have variable length 257 * in the primary direction. 258 */ 259 private int mFixedRowSizeSecondary; 260 261 /** 262 * Tracks the secondary size of each row. 263 */ 264 private int[] mRowSizeSecondary; 265 266 /** 267 * Flag controlling whether the current/next layout should 268 * be updating the secondary size of rows. 269 */ 270 private boolean mRowSecondarySizeRefresh; 271 272 /** 273 * The maximum measured size of the view. 274 */ 275 private int mMaxSizeSecondary; 276 277 /** 278 * Margin between items. 279 */ 280 private int mHorizontalMargin; 281 /** 282 * Margin between items vertically. 283 */ 284 private int mVerticalMargin; 285 /** 286 * Margin in main direction. 287 */ 288 private int mMarginPrimary; 289 /** 290 * Margin in second direction. 291 */ 292 private int mMarginSecondary; 293 /** 294 * How to position child in secondary direction. 295 */ 296 private int mGravity = Gravity.START | Gravity.TOP; 297 /** 298 * The number of rows in the grid. 299 */ 300 private int mNumRows; 301 /** 302 * Number of rows requested, can be 0 to be determined by parent size and 303 * rowHeight. 304 */ 305 private int mNumRowsRequested = 1; 306 307 /** 308 * Tracking start/end position of each row for visible items. 309 */ 310 private StaggeredGrid.Row[] mRows; 311 312 /** 313 * Saves grid information of each view. 314 */ 315 private StaggeredGrid mGrid; 316 /** 317 * Position of first item (included) that has attached views. 318 */ 319 private int mFirstVisiblePos; 320 /** 321 * Position of last item (included) that has attached views. 322 */ 323 private int mLastVisiblePos; 324 325 /** 326 * Focus Scroll strategy. 327 */ 328 private int mFocusScrollStrategy = BaseGridView.FOCUS_SCROLL_ALIGNED; 329 /** 330 * Defines how item view is aligned in the window. 331 */ 332 private final WindowAlignment mWindowAlignment = new WindowAlignment(); 333 334 /** 335 * Defines how item view is aligned. 336 */ 337 private final ItemAlignment mItemAlignment = new ItemAlignment(); 338 339 /** 340 * Dimensions of the view, width or height depending on orientation. 341 */ 342 private int mSizePrimary; 343 344 /** 345 * Allow DPAD key to navigate out at the front of the View (where position = 0), 346 * default is false. 347 */ 348 private boolean mFocusOutFront; 349 350 /** 351 * Allow DPAD key to navigate out at the end of the view, default is false. 352 */ 353 private boolean mFocusOutEnd; 354 355 /** 356 * True if focus search is disabled. 357 */ 358 private boolean mFocusSearchDisabled; 359 360 /** 361 * True if prune child, might be disabled during transition. 362 */ 363 private boolean mPruneChild = true; 364 365 /** 366 * True if scroll content, might be disabled during transition. 367 */ 368 private boolean mScrollEnabled = true; 369 370 private int[] mTempDeltas = new int[2]; 371 372 /** 373 * Set to true for RTL layout in horizontal orientation 374 */ 375 private boolean mReverseFlowPrimary = false; 376 377 /** 378 * Set to true for RTL layout in vertical orientation 379 */ 380 private boolean mReverseFlowSecondary = false; 381 382 /** 383 * Temporaries used for measuring. 384 */ 385 private int[] mMeasuredDimension = new int[2]; 386 387 final ViewsStateBundle mChildrenStates = new ViewsStateBundle(); 388 389 public GridLayoutManager(BaseGridView baseGridView) { 390 mBaseGridView = baseGridView; 391 } 392 393 public void setOrientation(int orientation) { 394 if (orientation != HORIZONTAL && orientation != VERTICAL) { 395 if (DEBUG) Log.v(getTag(), "invalid orientation: " + orientation); 396 return; 397 } 398 399 mOrientation = orientation; 400 mWindowAlignment.setOrientation(orientation); 401 mItemAlignment.setOrientation(orientation); 402 mForceFullLayout = true; 403 } 404 405 public void onRtlPropertiesChanged(int layoutDirection) { 406 if (mOrientation == HORIZONTAL) { 407 mReverseFlowPrimary = layoutDirection == View.LAYOUT_DIRECTION_RTL; 408 mReverseFlowSecondary = false; 409 } else { 410 mReverseFlowSecondary = layoutDirection == View.LAYOUT_DIRECTION_RTL; 411 mReverseFlowPrimary = false; 412 } 413 mWindowAlignment.horizontal.setReversedFlow(layoutDirection == View.LAYOUT_DIRECTION_RTL); 414 } 415 416 public int getFocusScrollStrategy() { 417 return mFocusScrollStrategy; 418 } 419 420 public void setFocusScrollStrategy(int focusScrollStrategy) { 421 mFocusScrollStrategy = focusScrollStrategy; 422 } 423 424 public void setWindowAlignment(int windowAlignment) { 425 mWindowAlignment.mainAxis().setWindowAlignment(windowAlignment); 426 } 427 428 public int getWindowAlignment() { 429 return mWindowAlignment.mainAxis().getWindowAlignment(); 430 } 431 432 public void setWindowAlignmentOffset(int alignmentOffset) { 433 mWindowAlignment.mainAxis().setWindowAlignmentOffset(alignmentOffset); 434 } 435 436 public int getWindowAlignmentOffset() { 437 return mWindowAlignment.mainAxis().getWindowAlignmentOffset(); 438 } 439 440 public void setWindowAlignmentOffsetPercent(float offsetPercent) { 441 mWindowAlignment.mainAxis().setWindowAlignmentOffsetPercent(offsetPercent); 442 } 443 444 public float getWindowAlignmentOffsetPercent() { 445 return mWindowAlignment.mainAxis().getWindowAlignmentOffsetPercent(); 446 } 447 448 public void setItemAlignmentOffset(int alignmentOffset) { 449 mItemAlignment.mainAxis().setItemAlignmentOffset(alignmentOffset); 450 updateChildAlignments(); 451 } 452 453 public int getItemAlignmentOffset() { 454 return mItemAlignment.mainAxis().getItemAlignmentOffset(); 455 } 456 457 public void setItemAlignmentOffsetWithPadding(boolean withPadding) { 458 mItemAlignment.mainAxis().setItemAlignmentOffsetWithPadding(withPadding); 459 updateChildAlignments(); 460 } 461 462 public boolean isItemAlignmentOffsetWithPadding() { 463 return mItemAlignment.mainAxis().isItemAlignmentOffsetWithPadding(); 464 } 465 466 public void setItemAlignmentOffsetPercent(float offsetPercent) { 467 mItemAlignment.mainAxis().setItemAlignmentOffsetPercent(offsetPercent); 468 updateChildAlignments(); 469 } 470 471 public float getItemAlignmentOffsetPercent() { 472 return mItemAlignment.mainAxis().getItemAlignmentOffsetPercent(); 473 } 474 475 public void setItemAlignmentViewId(int viewId) { 476 mItemAlignment.mainAxis().setItemAlignmentViewId(viewId); 477 updateChildAlignments(); 478 } 479 480 public int getItemAlignmentViewId() { 481 return mItemAlignment.mainAxis().getItemAlignmentViewId(); 482 } 483 484 public void setFocusOutAllowed(boolean throughFront, boolean throughEnd) { 485 mFocusOutFront = throughFront; 486 mFocusOutEnd = throughEnd; 487 } 488 489 public void setNumRows(int numRows) { 490 if (numRows < 0) throw new IllegalArgumentException(); 491 mNumRowsRequested = numRows; 492 mForceFullLayout = true; 493 } 494 495 /** 496 * Set the row height. May be WRAP_CONTENT, or a size in pixels. 497 */ 498 public void setRowHeight(int height) { 499 if (height >= 0 || height == ViewGroup.LayoutParams.WRAP_CONTENT) { 500 mRowSizeSecondaryRequested = height; 501 } else { 502 throw new IllegalArgumentException("Invalid row height: " + height); 503 } 504 } 505 506 public void setItemMargin(int margin) { 507 mVerticalMargin = mHorizontalMargin = margin; 508 mMarginPrimary = mMarginSecondary = margin; 509 } 510 511 public void setVerticalMargin(int margin) { 512 if (mOrientation == HORIZONTAL) { 513 mMarginSecondary = mVerticalMargin = margin; 514 } else { 515 mMarginPrimary = mVerticalMargin = margin; 516 } 517 } 518 519 public void setHorizontalMargin(int margin) { 520 if (mOrientation == HORIZONTAL) { 521 mMarginPrimary = mHorizontalMargin = margin; 522 } else { 523 mMarginSecondary = mHorizontalMargin = margin; 524 } 525 } 526 527 public int getVerticalMargin() { 528 return mVerticalMargin; 529 } 530 531 public int getHorizontalMargin() { 532 return mHorizontalMargin; 533 } 534 535 public void setGravity(int gravity) { 536 mGravity = gravity; 537 } 538 539 protected boolean hasDoneFirstLayout() { 540 return mGrid != null; 541 } 542 543 public void setOnChildSelectedListener(OnChildSelectedListener listener) { 544 mChildSelectedListener = listener; 545 } 546 547 private int getPositionByView(View view) { 548 if (view == null) { 549 return NO_POSITION; 550 } 551 LayoutParams params = (LayoutParams) view.getLayoutParams(); 552 if (params == null || params.isItemRemoved()) { 553 // when item is removed, the position value can be any value. 554 return NO_POSITION; 555 } 556 return params.getViewPosition(); 557 } 558 559 private int getPositionByIndex(int index) { 560 return getPositionByView(getChildAt(index)); 561 } 562 563 private void dispatchChildSelected() { 564 if (mChildSelectedListener == null) { 565 return; 566 } 567 if (mFocusPosition != NO_POSITION) { 568 View view = findViewByPosition(mFocusPosition); 569 if (view != null) { 570 RecyclerView.ViewHolder vh = mBaseGridView.getChildViewHolder(view); 571 mChildSelectedListener.onChildSelected(mBaseGridView, view, mFocusPosition, 572 vh == null? NO_ID: vh.getItemId()); 573 return; 574 } 575 } 576 mChildSelectedListener.onChildSelected(mBaseGridView, null, NO_POSITION, NO_ID); 577 } 578 579 @Override 580 public boolean canScrollHorizontally() { 581 // We can scroll horizontally if we have horizontal orientation, or if 582 // we are vertical and have more than one column. 583 return mOrientation == HORIZONTAL || mNumRows > 1; 584 } 585 586 @Override 587 public boolean canScrollVertically() { 588 // We can scroll vertically if we have vertical orientation, or if we 589 // are horizontal and have more than one row. 590 return mOrientation == VERTICAL || mNumRows > 1; 591 } 592 593 @Override 594 public RecyclerView.LayoutParams generateDefaultLayoutParams() { 595 return new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, 596 ViewGroup.LayoutParams.WRAP_CONTENT); 597 } 598 599 @Override 600 public RecyclerView.LayoutParams generateLayoutParams(Context context, AttributeSet attrs) { 601 return new LayoutParams(context, attrs); 602 } 603 604 @Override 605 public RecyclerView.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) { 606 if (lp instanceof LayoutParams) { 607 return new LayoutParams((LayoutParams) lp); 608 } else if (lp instanceof RecyclerView.LayoutParams) { 609 return new LayoutParams((RecyclerView.LayoutParams) lp); 610 } else if (lp instanceof MarginLayoutParams) { 611 return new LayoutParams((MarginLayoutParams) lp); 612 } else { 613 return new LayoutParams(lp); 614 } 615 } 616 617 protected View getViewForPosition(int position) { 618 return mRecycler.getViewForPosition(position); 619 } 620 621 final int getOpticalLeft(View v) { 622 return ((LayoutParams) v.getLayoutParams()).getOpticalLeft(v); 623 } 624 625 final int getOpticalRight(View v) { 626 return ((LayoutParams) v.getLayoutParams()).getOpticalRight(v); 627 } 628 629 final int getOpticalTop(View v) { 630 return ((LayoutParams) v.getLayoutParams()).getOpticalTop(v); 631 } 632 633 final int getOpticalBottom(View v) { 634 return ((LayoutParams) v.getLayoutParams()).getOpticalBottom(v); 635 } 636 637 private int getViewMin(View v) { 638 return (mOrientation == HORIZONTAL) ? getOpticalLeft(v) : getOpticalTop(v); 639 } 640 641 private int getViewMax(View v) { 642 return (mOrientation == HORIZONTAL) ? getOpticalRight(v) : getOpticalBottom(v); 643 } 644 645 private int getViewCenter(View view) { 646 return (mOrientation == HORIZONTAL) ? getViewCenterX(view) : getViewCenterY(view); 647 } 648 649 private int getViewCenterSecondary(View view) { 650 return (mOrientation == HORIZONTAL) ? getViewCenterY(view) : getViewCenterX(view); 651 } 652 653 private int getViewCenterX(View v) { 654 LayoutParams p = (LayoutParams) v.getLayoutParams(); 655 return p.getOpticalLeft(v) + p.getAlignX(); 656 } 657 658 private int getViewCenterY(View v) { 659 LayoutParams p = (LayoutParams) v.getLayoutParams(); 660 return p.getOpticalTop(v) + p.getAlignY(); 661 } 662 663 /** 664 * Save Recycler and State for convenience. Must be paired with leaveContext(). 665 */ 666 private void saveContext(Recycler recycler, State state) { 667 if (mRecycler != null || mState != null) { 668 Log.e(TAG, "Recycler information was not released, bug!"); 669 } 670 mRecycler = recycler; 671 mState = state; 672 } 673 674 /** 675 * Discard saved Recycler and State. 676 */ 677 private void leaveContext() { 678 mRecycler = null; 679 mState = null; 680 } 681 682 /** 683 * Re-initialize data structures for a data change or handling invisible 684 * selection. The method tries its best to preserve position information so 685 * that staggered grid looks same before and after re-initialize. 686 * @param focusPosition The initial focusPosition that we would like to 687 * focus on. 688 * @return Actual position that can be focused on. 689 */ 690 private int init(int focusPosition) { 691 692 final int newItemCount = mState.getItemCount(); 693 694 // Force the re-init path in the following conditional 695 if (newItemCount == 0) { 696 focusPosition = NO_POSITION; 697 } else if (focusPosition == NO_POSITION && newItemCount > 0) { 698 // if focus position is never set before, initialize it to 0 699 focusPosition = 0; 700 } 701 702 // If adapter has changed then caches are invalid; otherwise, 703 // we try to maintain each row's position if number of rows keeps the same 704 // and existing mGrid contains the focusPosition. 705 if (mRows != null && mNumRows == mRows.length && 706 mGrid != null && mGrid.getSize() > 0 && focusPosition >= 0 && 707 focusPosition >= mGrid.getFirstIndex() && 708 focusPosition <= mGrid.getLastIndex()) { 709 // strip mGrid to a subset (like a column) that contains focusPosition 710 mGrid.stripDownTo(focusPosition); 711 // make sure that remaining items do not exceed new adapter size 712 int firstIndex = mGrid.getFirstIndex(); 713 int lastIndex = mGrid.getLastIndex(); 714 if (DEBUG) { 715 Log .v(getTag(), "mGrid firstIndex " + firstIndex + " lastIndex " + lastIndex); 716 } 717 for (int i = lastIndex; i >=firstIndex; i--) { 718 if (i >= newItemCount) { 719 mGrid.removeLast(); 720 } 721 } 722 if (mGrid.getSize() == 0) { 723 focusPosition = newItemCount - 1; 724 // initialize row start locations 725 for (int i = 0; i < mNumRows; i++) { 726 mRows[i].low = 0; 727 mRows[i].high = 0; 728 } 729 if (DEBUG) Log.v(getTag(), "mGrid zero size"); 730 } else { 731 // initialize row start locations 732 for (int i = 0; i < mNumRows; i++) { 733 mRows[i].low = Integer.MAX_VALUE; 734 mRows[i].high = Integer.MIN_VALUE; 735 } 736 firstIndex = mGrid.getFirstIndex(); 737 lastIndex = mGrid.getLastIndex(); 738 if (focusPosition > lastIndex) { 739 focusPosition = mGrid.getLastIndex(); 740 } 741 if (DEBUG) { 742 Log.v(getTag(), "mGrid firstIndex " + firstIndex + " lastIndex " 743 + lastIndex + " focusPosition " + focusPosition); 744 } 745 // fill rows with minimal view positions of the subset 746 for (int i = firstIndex; i <= lastIndex; i++) { 747 View v = findViewByPosition(i); 748 if (v == null) { 749 continue; 750 } 751 int row = mGrid.getLocation(i).row; 752 int low = getViewMin(v) + mScrollOffsetPrimary; 753 if (low < mRows[row].low) { 754 mRows[row].low = mRows[row].high = low; 755 } 756 } 757 int firstItemRowPosition = mRows[mGrid.getLocation(firstIndex).row].low; 758 if (firstItemRowPosition == Integer.MAX_VALUE) { 759 firstItemRowPosition = 0; 760 } 761 if (mState.didStructureChange()) { 762 // if there is structure change, the removed item might be in the 763 // subset, so it is meaningless to maintain the low locations. 764 for (int i = 0; i < mNumRows; i++) { 765 mRows[i].low = firstItemRowPosition; 766 mRows[i].high = firstItemRowPosition; 767 } 768 } else { 769 // fill other rows that does not include the subset using first item 770 for (int i = 0; i < mNumRows; i++) { 771 if (mRows[i].low == Integer.MAX_VALUE) { 772 mRows[i].low = mRows[i].high = firstItemRowPosition; 773 } 774 } 775 } 776 } 777 778 // Same adapter, we can reuse any attached views 779 detachAndScrapAttachedViews(mRecycler); 780 781 } else { 782 // otherwise recreate data structure 783 mRows = new StaggeredGrid.Row[mNumRows]; 784 785 for (int i = 0; i < mNumRows; i++) { 786 mRows[i] = new StaggeredGrid.Row(); 787 } 788 mGrid = new StaggeredGridDefault(); 789 mGrid.setReversedFlow(mOrientation == HORIZONTAL && mReverseFlowPrimary); 790 if (newItemCount == 0) { 791 focusPosition = NO_POSITION; 792 } else if (focusPosition >= newItemCount) { 793 focusPosition = newItemCount - 1; 794 } 795 796 // Adapter may have changed so remove all attached views permanently 797 removeAndRecycleAllViews(mRecycler); 798 799 mScrollOffsetPrimary = 0; 800 mScrollOffsetSecondary = 0; 801 mWindowAlignment.reset(); 802 } 803 804 mGrid.setProvider(mGridProvider); 805 // mGrid share the same Row array information 806 mGrid.setRows(mRows); 807 mFirstVisiblePos = mLastVisiblePos = NO_POSITION; 808 809 initScrollController(); 810 updateScrollSecondAxis(); 811 812 return focusPosition; 813 } 814 815 private int getRowSizeSecondary(int rowIndex) { 816 if (mFixedRowSizeSecondary != 0) { 817 return mFixedRowSizeSecondary; 818 } 819 if (mRowSizeSecondary == null) { 820 return 0; 821 } 822 return mRowSizeSecondary[rowIndex]; 823 } 824 825 private int getRowStartSecondary(int rowIndex) { 826 int start = 0; 827 // Iterate from left to right, which is a different index traversal 828 // in RTL flow 829 if (mReverseFlowSecondary) { 830 for (int i = mNumRows-1; i > rowIndex; i--) { 831 start += getRowSizeSecondary(i) + mMarginSecondary; 832 } 833 } else { 834 for (int i = 0; i < rowIndex; i++) { 835 start += getRowSizeSecondary(i) + mMarginSecondary; 836 } 837 } 838 return start; 839 } 840 841 private int getSizeSecondary() { 842 int rightmostIndex = mReverseFlowSecondary ? 0 : mNumRows - 1; 843 return getRowStartSecondary(rightmostIndex) + getRowSizeSecondary(rightmostIndex); 844 } 845 846 private void measureScrapChild(int position, int widthSpec, int heightSpec, 847 int[] measuredDimension) { 848 View view = mRecycler.getViewForPosition(position); 849 if (view != null) { 850 LayoutParams p = (LayoutParams) view.getLayoutParams(); 851 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec, 852 getPaddingLeft() + getPaddingRight(), p.width); 853 int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec, 854 getPaddingTop() + getPaddingBottom(), p.height); 855 view.measure(childWidthSpec, childHeightSpec); 856 measuredDimension[0] = view.getMeasuredWidth(); 857 measuredDimension[1] = view.getMeasuredHeight(); 858 mRecycler.recycleView(view); 859 } 860 } 861 862 private boolean processRowSizeSecondary(boolean measure) { 863 if (mFixedRowSizeSecondary != 0) { 864 return false; 865 } 866 867 List<Integer>[] rows = mGrid == null ? null : 868 mGrid.getItemPositionsInRows(mFirstVisiblePos, mLastVisiblePos); 869 boolean changed = false; 870 int scrapChildWidth = -1; 871 int scrapChildHeight = -1; 872 873 for (int rowIndex = 0; rowIndex < mNumRows; rowIndex++) { 874 final int rowItemCount = rows == null ? 0 : rows[rowIndex].size(); 875 if (DEBUG) Log.v(getTag(), "processRowSizeSecondary row " + rowIndex + 876 " rowItemCount " + rowItemCount); 877 878 int rowSize = -1; 879 for (int i = 0; i < rowItemCount; i++) { 880 final View view = findViewByPosition(rows[rowIndex].get(i)); 881 if (view == null) { 882 continue; 883 } 884 if (measure && view.isLayoutRequested()) { 885 measureChild(view); 886 } 887 final int secondarySize = mOrientation == HORIZONTAL ? 888 view.getMeasuredHeight() : view.getMeasuredWidth(); 889 if (secondarySize > rowSize) { 890 rowSize = secondarySize; 891 } 892 } 893 894 final int itemCount = mState.getItemCount(); 895 if (measure && rowSize < 0 && itemCount > 0) { 896 if (scrapChildWidth < 0 && scrapChildHeight < 0) { 897 int position; 898 if (mFocusPosition == NO_POSITION) { 899 position = 0; 900 } else if (mFocusPosition >= itemCount) { 901 position = itemCount - 1; 902 } else { 903 position = mFocusPosition; 904 } 905 measureScrapChild(position, 906 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 907 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 908 mMeasuredDimension); 909 scrapChildWidth = mMeasuredDimension[0]; 910 scrapChildHeight = mMeasuredDimension[1]; 911 if (DEBUG) Log.v(TAG, "measured scrap child: " + scrapChildWidth + 912 " " + scrapChildHeight); 913 } 914 rowSize = mOrientation == HORIZONTAL ? scrapChildHeight : scrapChildWidth; 915 } 916 917 if (rowSize < 0) { 918 rowSize = 0; 919 } 920 921 if (DEBUG) Log.v(getTag(), "row " + rowIndex + " rowItemCount " + rowItemCount + 922 " rowSize " + rowSize); 923 924 if (mRowSizeSecondary[rowIndex] != rowSize) { 925 if (DEBUG) Log.v(getTag(), "row size secondary changed: " + mRowSizeSecondary[rowIndex] + 926 ", " + rowSize); 927 928 mRowSizeSecondary[rowIndex] = rowSize; 929 changed = true; 930 } 931 } 932 933 return changed; 934 } 935 936 /** 937 * Checks if we need to update row secondary sizes. 938 */ 939 private void updateRowSecondarySizeRefresh() { 940 mRowSecondarySizeRefresh = processRowSizeSecondary(false); 941 if (mRowSecondarySizeRefresh) { 942 if (DEBUG) Log.v(getTag(), "mRowSecondarySizeRefresh now set"); 943 forceRequestLayout(); 944 } 945 } 946 947 private void forceRequestLayout() { 948 if (DEBUG) Log.v(getTag(), "forceRequestLayout"); 949 // RecyclerView prevents us from requesting layout in many cases 950 // (during layout, during scroll, etc.) 951 // For secondary row size wrap_content support we currently need a 952 // second layout pass to update the measured size after having measured 953 // and added child views in layoutChildren. 954 // Force the second layout by posting a delayed runnable. 955 // TODO: investigate allowing a second layout pass, 956 // or move child add/measure logic to the measure phase. 957 ViewCompat.postOnAnimation(mBaseGridView, mRequestLayoutRunnable); 958 } 959 960 private final Runnable mRequestLayoutRunnable = new Runnable() { 961 @Override 962 public void run() { 963 if (DEBUG) Log.v(getTag(), "request Layout from runnable"); 964 requestLayout(); 965 } 966 }; 967 968 @Override 969 public void onMeasure(Recycler recycler, State state, int widthSpec, int heightSpec) { 970 saveContext(recycler, state); 971 972 int sizePrimary, sizeSecondary, modeSecondary, paddingSecondary; 973 int measuredSizeSecondary; 974 if (mOrientation == HORIZONTAL) { 975 sizePrimary = MeasureSpec.getSize(widthSpec); 976 sizeSecondary = MeasureSpec.getSize(heightSpec); 977 modeSecondary = MeasureSpec.getMode(heightSpec); 978 paddingSecondary = getPaddingTop() + getPaddingBottom(); 979 } else { 980 sizeSecondary = MeasureSpec.getSize(widthSpec); 981 sizePrimary = MeasureSpec.getSize(heightSpec); 982 modeSecondary = MeasureSpec.getMode(widthSpec); 983 paddingSecondary = getPaddingLeft() + getPaddingRight(); 984 } 985 if (DEBUG) Log.v(getTag(), "onMeasure widthSpec " + Integer.toHexString(widthSpec) + 986 " heightSpec " + Integer.toHexString(heightSpec) + 987 " modeSecondary " + Integer.toHexString(modeSecondary) + 988 " sizeSecondary " + sizeSecondary + " " + this); 989 990 mMaxSizeSecondary = sizeSecondary; 991 992 if (mRowSizeSecondaryRequested == ViewGroup.LayoutParams.WRAP_CONTENT) { 993 mNumRows = mNumRowsRequested == 0 ? 1 : mNumRowsRequested; 994 mFixedRowSizeSecondary = 0; 995 996 if (mRowSizeSecondary == null || mRowSizeSecondary.length != mNumRows) { 997 mRowSizeSecondary = new int[mNumRows]; 998 } 999 1000 // Measure all current children and update cached row heights 1001 processRowSizeSecondary(true); 1002 1003 switch (modeSecondary) { 1004 case MeasureSpec.UNSPECIFIED: 1005 measuredSizeSecondary = getSizeSecondary() + paddingSecondary; 1006 break; 1007 case MeasureSpec.AT_MOST: 1008 measuredSizeSecondary = Math.min(getSizeSecondary() + paddingSecondary, 1009 mMaxSizeSecondary); 1010 break; 1011 case MeasureSpec.EXACTLY: 1012 measuredSizeSecondary = mMaxSizeSecondary; 1013 break; 1014 default: 1015 throw new IllegalStateException("wrong spec"); 1016 } 1017 1018 } else { 1019 switch (modeSecondary) { 1020 case MeasureSpec.UNSPECIFIED: 1021 if (mRowSizeSecondaryRequested == 0) { 1022 if (mOrientation == HORIZONTAL) { 1023 throw new IllegalStateException("Must specify rowHeight or view height"); 1024 } else { 1025 throw new IllegalStateException("Must specify columnWidth or view width"); 1026 } 1027 } 1028 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1029 mNumRows = mNumRowsRequested == 0 ? 1 : mNumRowsRequested; 1030 measuredSizeSecondary = mFixedRowSizeSecondary * mNumRows + mMarginSecondary 1031 * (mNumRows - 1) + paddingSecondary; 1032 break; 1033 case MeasureSpec.AT_MOST: 1034 case MeasureSpec.EXACTLY: 1035 if (mNumRowsRequested == 0 && mRowSizeSecondaryRequested == 0) { 1036 mNumRows = 1; 1037 mFixedRowSizeSecondary = sizeSecondary - paddingSecondary; 1038 } else if (mNumRowsRequested == 0) { 1039 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1040 mNumRows = (sizeSecondary + mMarginSecondary) 1041 / (mRowSizeSecondaryRequested + mMarginSecondary); 1042 } else if (mRowSizeSecondaryRequested == 0) { 1043 mNumRows = mNumRowsRequested; 1044 mFixedRowSizeSecondary = (sizeSecondary - paddingSecondary - mMarginSecondary 1045 * (mNumRows - 1)) / mNumRows; 1046 } else { 1047 mNumRows = mNumRowsRequested; 1048 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1049 } 1050 measuredSizeSecondary = sizeSecondary; 1051 if (modeSecondary == MeasureSpec.AT_MOST) { 1052 int childrenSize = mFixedRowSizeSecondary * mNumRows + mMarginSecondary 1053 * (mNumRows - 1) + paddingSecondary; 1054 if (childrenSize < measuredSizeSecondary) { 1055 measuredSizeSecondary = childrenSize; 1056 } 1057 } 1058 break; 1059 default: 1060 throw new IllegalStateException("wrong spec"); 1061 } 1062 } 1063 if (mOrientation == HORIZONTAL) { 1064 setMeasuredDimension(sizePrimary, measuredSizeSecondary); 1065 } else { 1066 setMeasuredDimension(measuredSizeSecondary, sizePrimary); 1067 } 1068 if (DEBUG) { 1069 Log.v(getTag(), "onMeasure sizePrimary " + sizePrimary + 1070 " measuredSizeSecondary " + measuredSizeSecondary + 1071 " mFixedRowSizeSecondary " + mFixedRowSizeSecondary + 1072 " mNumRows " + mNumRows); 1073 } 1074 1075 leaveContext(); 1076 } 1077 1078 private void measureChild(View child) { 1079 final ViewGroup.LayoutParams lp = child.getLayoutParams(); 1080 final int secondarySpec = (mRowSizeSecondaryRequested == ViewGroup.LayoutParams.WRAP_CONTENT) ? 1081 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED) : 1082 MeasureSpec.makeMeasureSpec(mFixedRowSizeSecondary, MeasureSpec.EXACTLY); 1083 int widthSpec, heightSpec; 1084 1085 if (mOrientation == HORIZONTAL) { 1086 widthSpec = ViewGroup.getChildMeasureSpec( 1087 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 1088 0, lp.width); 1089 heightSpec = ViewGroup.getChildMeasureSpec(secondarySpec, 0, lp.height); 1090 } else { 1091 heightSpec = ViewGroup.getChildMeasureSpec( 1092 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 1093 0, lp.height); 1094 widthSpec = ViewGroup.getChildMeasureSpec(secondarySpec, 0, lp.width); 1095 } 1096 1097 child.measure(widthSpec, heightSpec); 1098 1099 if (DEBUG) Log.v(getTag(), "measureChild secondarySpec " + Integer.toHexString(secondarySpec) + 1100 " widthSpec " + Integer.toHexString(widthSpec) + 1101 " heightSpec " + Integer.toHexString(heightSpec) + 1102 " measuredWidth " + child.getMeasuredWidth() + 1103 " measuredHeight " + child.getMeasuredHeight()); 1104 if (DEBUG) Log.v(getTag(), "child lp width " + lp.width + " height " + lp.height); 1105 } 1106 1107 private StaggeredGrid.Provider mGridProvider = new StaggeredGrid.Provider() { 1108 1109 @Override 1110 public int getCount() { 1111 return mState.getItemCount(); 1112 } 1113 1114 @Override 1115 public void createItem(int index, int rowIndex, boolean append) { 1116 View v = getViewForPosition(index); 1117 if (mFirstVisiblePos >= 0) { 1118 // when StaggeredGrid append or prepend item, we must guarantee 1119 // that sibling item has created views already. 1120 if (append && index != mLastVisiblePos + 1) { 1121 throw new RuntimeException(); 1122 } else if (!append && index != mFirstVisiblePos - 1) { 1123 throw new RuntimeException(); 1124 } 1125 } 1126 1127 // See recyclerView docs: we don't need re-add scraped view if it was removed. 1128 if (!((RecyclerView.LayoutParams) v.getLayoutParams()).isItemRemoved()) { 1129 if (append) { 1130 addView(v); 1131 } else { 1132 addView(v, 0); 1133 } 1134 if (mChildVisibility != -1) { 1135 v.setVisibility(mChildVisibility); 1136 } 1137 1138 // View is added first or it won't be found by dispatchChildSelected. 1139 if (mInLayout && index == mFocusPosition) { 1140 dispatchChildSelected(); 1141 } 1142 1143 measureChild(v); 1144 } 1145 1146 int length = mOrientation == HORIZONTAL ? v.getMeasuredWidth() : v.getMeasuredHeight(); 1147 int start, end; 1148 final boolean rowIsEmpty = mRows[rowIndex].high == mRows[rowIndex].low; 1149 boolean addHigh = (!mReverseFlowPrimary) ? append : !append; 1150 int lowVisiblePos = (!mReverseFlowPrimary) ? mFirstVisiblePos : mLastVisiblePos; 1151 int highVisiblePos = (!mReverseFlowPrimary) ? mLastVisiblePos : mFirstVisiblePos; 1152 if (addHigh) { 1153 if (!rowIsEmpty) { 1154 // if there are existing item in the row, add margin between 1155 start = mRows[rowIndex].high + mMarginPrimary; 1156 } else { 1157 if (highVisiblePos >= 0) { 1158 int lastRow = mGrid.getLocation(highVisiblePos).row; 1159 // if the last visible item is not last row, align to beginning, 1160 // otherwise start a new column after. 1161 if (lastRow < mNumRows - 1) { 1162 start = mRows[lastRow].low; 1163 } else { 1164 start = mRows[lastRow].high + mMarginPrimary; 1165 } 1166 } else { 1167 start = 0; 1168 } 1169 mRows[rowIndex].low = start; 1170 } 1171 end = start + length; 1172 mRows[rowIndex].high = end; 1173 } else { 1174 if (!rowIsEmpty) { 1175 // if there are existing item in the row, add margin between 1176 end = mRows[rowIndex].low - mMarginPrimary; 1177 start = end - length; 1178 } else { 1179 if (lowVisiblePos >= 0) { 1180 int firstRow = mGrid.getLocation(lowVisiblePos).row; 1181 // if the first visible item is not first row, align to end, 1182 // otherwise start a new column before. 1183 if (firstRow < mNumRows - 1) { 1184 end = mRows[firstRow].high; 1185 } else { 1186 end = mRows[firstRow].low - mMarginPrimary; 1187 } 1188 start = end - length; 1189 } else { 1190 end = 0; 1191 start = -length; 1192 } 1193 mRows[rowIndex].high = end; 1194 } 1195 mRows[rowIndex].low = start; 1196 } 1197 if (mFirstVisiblePos < 0) { 1198 mFirstVisiblePos = mLastVisiblePos = index; 1199 } else { 1200 if (append) { 1201 mLastVisiblePos++; 1202 } else { 1203 mFirstVisiblePos--; 1204 } 1205 } 1206 if (DEBUG) Log.v(getTag(), "start " + start + " end " + end); 1207 int startSecondary = getRowStartSecondary(rowIndex) - mScrollOffsetSecondary; 1208 mChildrenStates.loadView(v, index); 1209 layoutChild(rowIndex, v, start - mScrollOffsetPrimary, end - mScrollOffsetPrimary, 1210 startSecondary); 1211 if (DEBUG) { 1212 Log.d(getTag(), "addView " + index + " " + v); 1213 } 1214 if (index == mFirstVisiblePos) { 1215 if (!mReverseFlowPrimary) { 1216 updateScrollMin(); 1217 } else { 1218 updateScrollMax(); 1219 } 1220 } 1221 if (index == mLastVisiblePos) { 1222 if (!mReverseFlowPrimary) { 1223 updateScrollMax(); 1224 } else { 1225 updateScrollMin(); 1226 } 1227 } 1228 } 1229 }; 1230 1231 private void layoutChild(int rowIndex, View v, int start, int end, int startSecondary) { 1232 int sizeSecondary = mOrientation == HORIZONTAL ? v.getMeasuredHeight() 1233 : v.getMeasuredWidth(); 1234 if (mFixedRowSizeSecondary > 0) { 1235 sizeSecondary = Math.min(sizeSecondary, mFixedRowSizeSecondary); 1236 } 1237 final int verticalGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK; 1238 final int horizontalGravity = (mReverseFlowPrimary || mReverseFlowSecondary) ? 1239 Gravity.getAbsoluteGravity(mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK, View.LAYOUT_DIRECTION_RTL) : 1240 mGravity & Gravity.HORIZONTAL_GRAVITY_MASK; 1241 if (mOrientation == HORIZONTAL && verticalGravity == Gravity.TOP 1242 || mOrientation == VERTICAL && horizontalGravity == Gravity.LEFT) { 1243 // do nothing 1244 } else if (mOrientation == HORIZONTAL && verticalGravity == Gravity.BOTTOM 1245 || mOrientation == VERTICAL && horizontalGravity == Gravity.RIGHT) { 1246 startSecondary += getRowSizeSecondary(rowIndex) - sizeSecondary; 1247 } else if (mOrientation == HORIZONTAL && verticalGravity == Gravity.CENTER_VERTICAL 1248 || mOrientation == VERTICAL && horizontalGravity == Gravity.CENTER_HORIZONTAL) { 1249 startSecondary += (getRowSizeSecondary(rowIndex) - sizeSecondary) / 2; 1250 } 1251 int left, top, right, bottom; 1252 if (mOrientation == HORIZONTAL) { 1253 left = start; 1254 top = startSecondary; 1255 right = end; 1256 bottom = startSecondary + sizeSecondary; 1257 } else { 1258 top = start; 1259 left = startSecondary; 1260 bottom = end; 1261 right = startSecondary + sizeSecondary; 1262 } 1263 v.layout(left, top, right, bottom); 1264 updateChildOpticalInsets(v, left, top, right, bottom); 1265 updateChildAlignments(v); 1266 } 1267 1268 private void updateChildOpticalInsets(View v, int left, int top, int right, int bottom) { 1269 LayoutParams p = (LayoutParams) v.getLayoutParams(); 1270 p.setOpticalInsets(left - v.getLeft(), top - v.getTop(), 1271 v.getRight() - right, v.getBottom() - bottom); 1272 } 1273 1274 private void updateChildAlignments(View v) { 1275 LayoutParams p = (LayoutParams) v.getLayoutParams(); 1276 p.setAlignX(mItemAlignment.horizontal.getAlignmentPosition(v)); 1277 p.setAlignY(mItemAlignment.vertical.getAlignmentPosition(v)); 1278 } 1279 1280 private void updateChildAlignments() { 1281 for (int i = 0, c = getChildCount(); i < c; i++) { 1282 updateChildAlignments(getChildAt(i)); 1283 } 1284 } 1285 1286 private boolean needsAppendVisibleItem() { 1287 if (mLastVisiblePos < mFocusPosition) { 1288 return true; 1289 } 1290 if (mReverseFlowPrimary) { 1291 for (int i = 0; i < mNumRows; i++) { 1292 if (mRows[i].low == mRows[i].high) { 1293 if (mRows[i].low > mScrollOffsetPrimary) { 1294 return true; 1295 } 1296 } else if (mRows[i].low - mMarginPrimary > mScrollOffsetPrimary) { 1297 return true; 1298 } 1299 } 1300 } else { 1301 int right = mScrollOffsetPrimary + mSizePrimary; 1302 for (int i = 0; i < mNumRows; i++) { 1303 if (mRows[i].low == mRows[i].high) { 1304 if (mRows[i].high < right) { 1305 return true; 1306 } 1307 } else if (mRows[i].high < right - mMarginPrimary) { 1308 return true; 1309 } 1310 } 1311 } 1312 return false; 1313 } 1314 1315 private boolean needsPrependVisibleItem() { 1316 if (mFirstVisiblePos > mFocusPosition) { 1317 return true; 1318 } 1319 if (mReverseFlowPrimary) { 1320 int right = mScrollOffsetPrimary + mSizePrimary; 1321 for (int i = 0; i < mNumRows; i++) { 1322 if (mRows[i].low == mRows[i].high) { 1323 if (mRows[i].high < right) { 1324 return true; 1325 } 1326 } else if (mRows[i].high < right - mMarginPrimary) { 1327 return true; 1328 } 1329 } 1330 } else { 1331 for (int i = 0; i < mNumRows; i++) { 1332 if (mRows[i].low == mRows[i].high) { 1333 if (mRows[i].low > mScrollOffsetPrimary) { 1334 return true; 1335 } 1336 } else if (mRows[i].low - mMarginPrimary > mScrollOffsetPrimary) { 1337 return true; 1338 } 1339 } 1340 } 1341 return false; 1342 } 1343 1344 // Append one column if possible and return true if reach end. 1345 private boolean appendOneVisibleItem() { 1346 while (true) { 1347 if (mLastVisiblePos != NO_POSITION && mLastVisiblePos < mState.getItemCount() -1 && 1348 mLastVisiblePos < mGrid.getLastIndex()) { 1349 // append invisible view of saved location till last row 1350 final int index = mLastVisiblePos + 1; 1351 final int row = mGrid.getLocation(index).row; 1352 mGridProvider.createItem(index, row, true); 1353 if (row == mNumRows - 1) { 1354 return false; 1355 } 1356 } else if ((mLastVisiblePos == NO_POSITION && mState.getItemCount() > 0) || 1357 (mLastVisiblePos != NO_POSITION && 1358 mLastVisiblePos < mState.getItemCount() - 1)) { 1359 if (mReverseFlowPrimary) { 1360 mGrid.appendItems(mScrollOffsetPrimary); 1361 } else { 1362 mGrid.appendItems(mScrollOffsetPrimary + mSizePrimary); 1363 } 1364 return false; 1365 } else { 1366 return true; 1367 } 1368 } 1369 } 1370 1371 private void appendVisibleItems() { 1372 while (needsAppendVisibleItem()) { 1373 if (appendOneVisibleItem()) { 1374 break; 1375 } 1376 } 1377 } 1378 1379 // Prepend one column if possible and return true if reach end. 1380 private boolean prependOneVisibleItem() { 1381 while (true) { 1382 if (mFirstVisiblePos > 0) { 1383 if (mFirstVisiblePos > mGrid.getFirstIndex()) { 1384 // prepend invisible view of saved location till first row 1385 final int index = mFirstVisiblePos - 1; 1386 final int row = mGrid.getLocation(index).row; 1387 mGridProvider.createItem(index, row, false); 1388 if (row == 0) { 1389 return false; 1390 } 1391 } else { 1392 if (mReverseFlowPrimary) { 1393 mGrid.prependItems(mScrollOffsetPrimary + mSizePrimary); 1394 } else { 1395 mGrid.prependItems(mScrollOffsetPrimary); 1396 } 1397 return false; 1398 } 1399 } else { 1400 return true; 1401 } 1402 } 1403 } 1404 1405 private void prependVisibleItems() { 1406 while (needsPrependVisibleItem()) { 1407 if (prependOneVisibleItem()) { 1408 break; 1409 } 1410 } 1411 } 1412 1413 private void removeChildAt(int position) { 1414 View v = findViewByPosition(position); 1415 if (v != null) { 1416 if (DEBUG) { 1417 Log.d(getTag(), "removeAndRecycleViewAt " + position + " " + v); 1418 } 1419 mChildrenStates.saveOffscreenView(v, position); 1420 removeAndRecycleView(v, mRecycler); 1421 } 1422 } 1423 1424 private void removeInvisibleViewsAtEnd() { 1425 if (!mPruneChild) { 1426 return; 1427 } 1428 boolean update = false; 1429 while(mLastVisiblePos > mFirstVisiblePos && mLastVisiblePos > mFocusPosition) { 1430 View view = findViewByPosition(mLastVisiblePos); 1431 boolean offEnd = (!mReverseFlowPrimary) ? getViewMin(view) > mSizePrimary : 1432 getViewMax(view) < 0; 1433 if (offEnd) { 1434 removeChildAt(mLastVisiblePos); 1435 mLastVisiblePos--; 1436 update = true; 1437 } else { 1438 break; 1439 } 1440 } 1441 if (update) { 1442 updateRowsMinMax(); 1443 } 1444 } 1445 1446 private void removeInvisibleViewsAtFront() { 1447 if (!mPruneChild) { 1448 return; 1449 } 1450 boolean update = false; 1451 while(mLastVisiblePos > mFirstVisiblePos && mFirstVisiblePos < mFocusPosition) { 1452 View view = findViewByPosition(mFirstVisiblePos); 1453 boolean offFront = (!mReverseFlowPrimary) ? getViewMax(view) < 0: 1454 getViewMin(view) > mSizePrimary; 1455 if (offFront) { 1456 removeChildAt(mFirstVisiblePos); 1457 mFirstVisiblePos++; 1458 update = true; 1459 } else { 1460 break; 1461 } 1462 } 1463 if (update) { 1464 updateRowsMinMax(); 1465 } 1466 } 1467 1468 private void updateRowsMinMax() { 1469 if (mFirstVisiblePos < 0) { 1470 return; 1471 } 1472 for (int i = 0; i < mNumRows; i++) { 1473 mRows[i].low = Integer.MAX_VALUE; 1474 mRows[i].high = Integer.MIN_VALUE; 1475 } 1476 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1477 View view = findViewByPosition(i); 1478 int row = mGrid.getLocation(i).row; 1479 int low = getViewMin(view) + mScrollOffsetPrimary; 1480 if (low < mRows[row].low) { 1481 mRows[row].low = low; 1482 } 1483 int high = getViewMax(view) + mScrollOffsetPrimary; 1484 if (high > mRows[row].high) { 1485 mRows[row].high = high; 1486 } 1487 } 1488 } 1489 1490 // Fast layout when there is no structure change, adapter change, etc. 1491 protected void fastRelayout(boolean scrollToFocus) { 1492 initScrollController(); 1493 1494 List<Integer>[] rows = mGrid.getItemPositionsInRows(mFirstVisiblePos, mLastVisiblePos); 1495 1496 // relayout and repositioning views on each row 1497 for (int i = 0; i < mNumRows; i++) { 1498 List<Integer> row = rows[i]; 1499 final int startSecondary = getRowStartSecondary(i) - mScrollOffsetSecondary; 1500 for (int j = 0, size = row.size(); j < size; j++) { 1501 final int position = row.get(j); 1502 View view = findViewByPosition(position); 1503 int primaryDelta, end; 1504 1505 int start = getViewMin(view); 1506 int oldPrimarySize = (mOrientation == HORIZONTAL) ? 1507 view.getMeasuredWidth() : 1508 view.getMeasuredHeight(); 1509 1510 LayoutParams lp = (LayoutParams) view.getLayoutParams(); 1511 if (lp.viewNeedsUpdate()) { 1512 int index = mBaseGridView.indexOfChild(view); 1513 detachAndScrapView(view, mRecycler); 1514 view = getViewForPosition(position); 1515 addView(view, index); 1516 } 1517 1518 if (view.isLayoutRequested()) { 1519 measureChild(view); 1520 } 1521 1522 if (mOrientation == HORIZONTAL) { 1523 end = start + view.getMeasuredWidth(); 1524 primaryDelta = view.getMeasuredWidth() - oldPrimarySize; 1525 if (primaryDelta != 0) { 1526 for (int k = j + 1; k < size; k++) { 1527 findViewByPosition(row.get(k)).offsetLeftAndRight(primaryDelta); 1528 } 1529 } 1530 } else { 1531 end = start + view.getMeasuredHeight(); 1532 primaryDelta = view.getMeasuredHeight() - oldPrimarySize; 1533 if (primaryDelta != 0) { 1534 for (int k = j + 1; k < size; k++) { 1535 findViewByPosition(row.get(k)).offsetTopAndBottom(primaryDelta); 1536 } 1537 } 1538 } 1539 layoutChild(i, view, start, end, startSecondary); 1540 } 1541 } 1542 1543 updateRowsMinMax(); 1544 appendVisibleItems(); 1545 prependVisibleItems(); 1546 1547 updateRowsMinMax(); 1548 updateScrollMin(); 1549 updateScrollMax(); 1550 updateScrollSecondAxis(); 1551 1552 if (scrollToFocus) { 1553 View focusView = findViewByPosition(mFocusPosition == NO_POSITION ? 0 : mFocusPosition); 1554 scrollToView(focusView, false); 1555 } 1556 } 1557 1558 public void removeAndRecycleAllViews(RecyclerView.Recycler recycler) { 1559 if (DEBUG) Log.v(TAG, "removeAndRecycleAllViews " + getChildCount()); 1560 for (int i = getChildCount() - 1; i >= 0; i--) { 1561 removeAndRecycleViewAt(i, recycler); 1562 } 1563 } 1564 1565 // Lays out items based on the current scroll position 1566 @Override 1567 public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) { 1568 if (DEBUG) { 1569 Log.v(getTag(), "layoutChildren start numRows " + mNumRows + " mScrollOffsetSecondary " 1570 + mScrollOffsetSecondary + " mScrollOffsetPrimary " + mScrollOffsetPrimary 1571 + " inPreLayout " + state.isPreLayout() 1572 + " didStructureChange " + state.didStructureChange() 1573 + " mForceFullLayout " + mForceFullLayout); 1574 Log.v(getTag(), "width " + getWidth() + " height " + getHeight()); 1575 } 1576 1577 if (mNumRows == 0) { 1578 // haven't done measure yet 1579 return; 1580 } 1581 final int itemCount = state.getItemCount(); 1582 if (itemCount < 0) { 1583 return; 1584 } 1585 1586 if (!mLayoutEnabled) { 1587 discardLayoutInfo(); 1588 removeAndRecycleAllViews(recycler); 1589 return; 1590 } 1591 mInLayout = true; 1592 1593 final boolean scrollToFocus = !isSmoothScrolling() 1594 && mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_ALIGNED; 1595 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE) { 1596 mFocusPosition = mFocusPosition + mFocusPositionOffset; 1597 mFocusPositionOffset = 0; 1598 } 1599 saveContext(recycler, state); 1600 1601 // Track the old focus view so we can adjust our system scroll position 1602 // so that any scroll animations happening now will remain valid. 1603 // We must use same delta in Pre Layout (if prelayout exists) and second layout. 1604 // So we cache the deltas in PreLayout and use it in second layout. 1605 int delta = 0, deltaSecondary = 0; 1606 if (mFocusPosition != NO_POSITION && scrollToFocus 1607 && mBaseGridView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) { 1608 // FIXME: we should get the remaining scroll animation offset from RecyclerView 1609 View focusView = findViewByPosition(mFocusPosition); 1610 if (focusView != null) { 1611 delta = mWindowAlignment.mainAxis().getSystemScrollPos(mScrollOffsetPrimary 1612 + getViewCenter(focusView), false, false) - mScrollOffsetPrimary; 1613 deltaSecondary = mWindowAlignment.secondAxis().getSystemScrollPos( 1614 mScrollOffsetSecondary + getViewCenterSecondary(focusView), 1615 false, false) - mScrollOffsetSecondary; 1616 } 1617 } 1618 1619 final boolean hasDoneFirstLayout = hasDoneFirstLayout(); 1620 int savedFocusPos = mFocusPosition; 1621 boolean fastRelayout = false; 1622 if (!mState.didStructureChange() && !mForceFullLayout && hasDoneFirstLayout) { 1623 fastRelayout = true; 1624 fastRelayout(scrollToFocus); 1625 } else { 1626 boolean hadFocus = mBaseGridView.hasFocus(); 1627 1628 mFocusPosition = init(mFocusPosition); 1629 if (mFocusPosition != savedFocusPos) { 1630 if (DEBUG) Log.v(getTag(), "savedFocusPos " + savedFocusPos + 1631 " mFocusPosition " + mFocusPosition); 1632 } 1633 if (mFocusPosition == NO_POSITION) { 1634 mBaseGridView.clearFocus(); 1635 } 1636 1637 mWindowAlignment.mainAxis().invalidateScrollMin(); 1638 mWindowAlignment.mainAxis().invalidateScrollMax(); 1639 // depending on result of init(), either recreating everything 1640 // or try to reuse the row start positions near mFocusPosition 1641 if (mGrid.getSize() == 0) { 1642 // this is a fresh creating all items, starting from 1643 // mFocusPosition with a estimated row index. 1644 mGrid.setStart(mFocusPosition, StaggeredGrid.START_DEFAULT); 1645 1646 // Can't track the old focus view 1647 delta = deltaSecondary = 0; 1648 1649 } else { 1650 // mGrid remembers Locations for the column that 1651 // contains mFocusePosition and also mRows remembers start 1652 // positions of each row. 1653 // Manually re-create child views for that column 1654 int firstIndex = mGrid.getFirstIndex(); 1655 int lastIndex = mGrid.getLastIndex(); 1656 for (int i = firstIndex; i <= lastIndex; i++) { 1657 mGridProvider.createItem(i, mGrid.getLocation(i).row, true); 1658 } 1659 } 1660 1661 // add visible views at end until reach the end of window 1662 appendVisibleItems(); 1663 // add visible views at front until reach the start of window 1664 prependVisibleItems(); 1665 // multiple rounds: scrollToView of first round may drag first/last child into 1666 // "visible window" and we update scrollMin/scrollMax then run second scrollToView 1667 int oldFirstVisible; 1668 int oldLastVisible; 1669 do { 1670 updateScrollMin(); 1671 updateScrollMax(); 1672 oldFirstVisible = mFirstVisiblePos; 1673 oldLastVisible = mLastVisiblePos; 1674 View focusView = findViewByPosition(mFocusPosition); 1675 // we need force to initialize the child view's position 1676 scrollToView(focusView, false); 1677 if (focusView != null && hadFocus) { 1678 focusView.requestFocus(); 1679 } 1680 appendVisibleItems(); 1681 prependVisibleItems(); 1682 removeInvisibleViewsAtFront(); 1683 removeInvisibleViewsAtEnd(); 1684 } while (mFirstVisiblePos != oldFirstVisible || mLastVisiblePos != oldLastVisible); 1685 } 1686 mForceFullLayout = false; 1687 1688 if (scrollToFocus) { 1689 scrollDirectionPrimary(-delta); 1690 scrollDirectionSecondary(-deltaSecondary); 1691 } 1692 appendVisibleItems(); 1693 prependVisibleItems(); 1694 removeInvisibleViewsAtFront(); 1695 removeInvisibleViewsAtEnd(); 1696 1697 if (DEBUG) { 1698 StringWriter sw = new StringWriter(); 1699 PrintWriter pw = new PrintWriter(sw); 1700 mGrid.debugPrint(pw); 1701 Log.d(getTag(), sw.toString()); 1702 } 1703 1704 if (mRowSecondarySizeRefresh) { 1705 mRowSecondarySizeRefresh = false; 1706 } else { 1707 updateRowSecondarySizeRefresh(); 1708 } 1709 1710 if (fastRelayout && mFocusPosition != savedFocusPos) { 1711 dispatchChildSelected(); 1712 } 1713 mInLayout = false; 1714 leaveContext(); 1715 if (DEBUG) Log.v(getTag(), "layoutChildren end"); 1716 } 1717 1718 private void offsetChildrenSecondary(int increment) { 1719 final int childCount = getChildCount(); 1720 if (mOrientation == HORIZONTAL) { 1721 for (int i = 0; i < childCount; i++) { 1722 getChildAt(i).offsetTopAndBottom(increment); 1723 } 1724 } else { 1725 for (int i = 0; i < childCount; i++) { 1726 getChildAt(i).offsetLeftAndRight(increment); 1727 } 1728 } 1729 } 1730 1731 private void offsetChildrenPrimary(int increment) { 1732 final int childCount = getChildCount(); 1733 if (mOrientation == VERTICAL) { 1734 for (int i = 0; i < childCount; i++) { 1735 getChildAt(i).offsetTopAndBottom(increment); 1736 } 1737 } else { 1738 for (int i = 0; i < childCount; i++) { 1739 getChildAt(i).offsetLeftAndRight(increment); 1740 } 1741 } 1742 } 1743 1744 @Override 1745 public int scrollHorizontallyBy(int dx, Recycler recycler, RecyclerView.State state) { 1746 if (DEBUG) Log.v(getTag(), "scrollHorizontallyBy " + dx); 1747 if (!mLayoutEnabled || !hasDoneFirstLayout()) { 1748 return 0; 1749 } 1750 saveContext(recycler, state); 1751 int result; 1752 if (mOrientation == HORIZONTAL) { 1753 result = scrollDirectionPrimary(dx); 1754 } else { 1755 result = scrollDirectionSecondary(dx); 1756 } 1757 leaveContext(); 1758 return result; 1759 } 1760 1761 @Override 1762 public int scrollVerticallyBy(int dy, Recycler recycler, RecyclerView.State state) { 1763 if (DEBUG) Log.v(getTag(), "scrollVerticallyBy " + dy); 1764 if (!mLayoutEnabled || !hasDoneFirstLayout()) { 1765 return 0; 1766 } 1767 saveContext(recycler, state); 1768 int result; 1769 if (mOrientation == VERTICAL) { 1770 result = scrollDirectionPrimary(dy); 1771 } else { 1772 result = scrollDirectionSecondary(dy); 1773 } 1774 leaveContext(); 1775 return result; 1776 } 1777 1778 // scroll in main direction may add/prune views 1779 private int scrollDirectionPrimary(int da) { 1780 boolean isMaxUnknown = false, isMinUnknown = false; 1781 int minScroll = 0, maxScroll = 0; 1782 if (da > 0) { 1783 isMaxUnknown = mWindowAlignment.mainAxis().isMaxUnknown(); 1784 if (!isMaxUnknown) { 1785 maxScroll = mWindowAlignment.mainAxis().getMaxScroll(); 1786 if (mScrollOffsetPrimary + da > maxScroll) { 1787 da = maxScroll - mScrollOffsetPrimary; 1788 } 1789 } 1790 } else if (da < 0) { 1791 isMinUnknown = mWindowAlignment.mainAxis().isMinUnknown(); 1792 if (!isMinUnknown) { 1793 minScroll = mWindowAlignment.mainAxis().getMinScroll(); 1794 if (mScrollOffsetPrimary + da < minScroll) { 1795 da = minScroll - mScrollOffsetPrimary; 1796 } 1797 } 1798 } 1799 if (da == 0) { 1800 return 0; 1801 } 1802 offsetChildrenPrimary(-da); 1803 mScrollOffsetPrimary += da; 1804 if (mInLayout) { 1805 return da; 1806 } 1807 1808 int childCount = getChildCount(); 1809 boolean updated; 1810 1811 if (da > 0) { 1812 if (mReverseFlowPrimary) { 1813 prependVisibleItems(); 1814 } else { 1815 appendVisibleItems(); 1816 } 1817 } else if (da < 0) { 1818 if (mReverseFlowPrimary) { 1819 appendVisibleItems(); 1820 } else { 1821 prependVisibleItems(); 1822 } 1823 } 1824 updated = getChildCount() > childCount; 1825 childCount = getChildCount(); 1826 1827 if (da > 0) { 1828 if (mReverseFlowPrimary) { 1829 removeInvisibleViewsAtEnd(); 1830 } else { 1831 removeInvisibleViewsAtFront(); 1832 } 1833 } else if (da < 0) { 1834 if (mReverseFlowPrimary) { 1835 removeInvisibleViewsAtFront(); 1836 } else { 1837 removeInvisibleViewsAtEnd(); 1838 } 1839 } 1840 updated |= getChildCount() < childCount; 1841 1842 if (updated) { 1843 updateRowSecondarySizeRefresh(); 1844 } 1845 1846 mBaseGridView.invalidate(); 1847 return da; 1848 } 1849 1850 // scroll in second direction will not add/prune views 1851 private int scrollDirectionSecondary(int dy) { 1852 if (dy == 0) { 1853 return 0; 1854 } 1855 offsetChildrenSecondary(-dy); 1856 mScrollOffsetSecondary += dy; 1857 mBaseGridView.invalidate(); 1858 return dy; 1859 } 1860 1861 private void updateScrollMax() { 1862 int highVisiblePos = (!mReverseFlowPrimary) ? mLastVisiblePos : mFirstVisiblePos; 1863 int highMaxPos = (!mReverseFlowPrimary) ? mState.getItemCount() - 1 : 0; 1864 if (highVisiblePos < 0) { 1865 return; 1866 } 1867 final boolean highAvailable = highVisiblePos == highMaxPos; 1868 final boolean maxUnknown = mWindowAlignment.mainAxis().isMaxUnknown(); 1869 if (!highAvailable && maxUnknown) { 1870 return; 1871 } 1872 int maxEdge = Integer.MIN_VALUE; 1873 int rowIndex = -1; 1874 for (int i = 0; i < mRows.length; i++) { 1875 if (mRows[i].high > maxEdge) { 1876 maxEdge = mRows[i].high; 1877 rowIndex = i; 1878 } 1879 } 1880 int maxScroll = Integer.MAX_VALUE; 1881 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1882 int pos = mReverseFlowPrimary ? i : mLastVisiblePos-i+mFirstVisiblePos; 1883 StaggeredGrid.Location location = mGrid.getLocation(pos); 1884 if (location != null && location.row == rowIndex) { 1885 int savedMaxEdge = mWindowAlignment.mainAxis().getMaxEdge(); 1886 mWindowAlignment.mainAxis().setMaxEdge(maxEdge); 1887 maxScroll = getPrimarySystemScrollPosition(findViewByPosition(pos)); 1888 mWindowAlignment.mainAxis().setMaxEdge(savedMaxEdge); 1889 break; 1890 } 1891 } 1892 if (highAvailable) { 1893 mWindowAlignment.mainAxis().setMaxEdge(maxEdge); 1894 mWindowAlignment.mainAxis().setMaxScroll(maxScroll); 1895 if (DEBUG) Log.v(getTag(), "updating scroll maxEdge to " + maxEdge + 1896 " scrollMax to " + maxScroll); 1897 } else { 1898 // the maxScroll for currently last visible item is larger, 1899 // so we must invalidate the max scroll value. 1900 if (maxScroll > mWindowAlignment.mainAxis().getMaxScroll()) { 1901 mWindowAlignment.mainAxis().invalidateScrollMax(); 1902 if (DEBUG) Log.v(getTag(), "Invalidate scrollMax since it should be " 1903 + "greater than " + maxScroll); 1904 } 1905 } 1906 } 1907 1908 private void updateScrollMin() { 1909 int lowVisiblePos = (!mReverseFlowPrimary) ? mFirstVisiblePos : mLastVisiblePos; 1910 int lowMinPos = (!mReverseFlowPrimary) ? 0 : mState.getItemCount() - 1; 1911 if (lowVisiblePos < 0) { 1912 return; 1913 } 1914 final boolean lowAvailable = lowVisiblePos == lowMinPos; 1915 final boolean minUnknown = mWindowAlignment.mainAxis().isMinUnknown(); 1916 if (!lowAvailable && minUnknown) { 1917 return; 1918 } 1919 int minEdge = Integer.MAX_VALUE; 1920 int rowIndex = -1; 1921 for (int i = 0; i < mRows.length; i++) { 1922 if (mRows[i].low < minEdge) { 1923 minEdge = mRows[i].low; 1924 rowIndex = i; 1925 } 1926 } 1927 int minScroll = Integer.MIN_VALUE; 1928 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1929 int pos = mReverseFlowPrimary ? mLastVisiblePos-i+mFirstVisiblePos : i; 1930 StaggeredGrid.Location location = mGrid.getLocation(pos); 1931 if (location != null && location.row == rowIndex) { 1932 int savedMinEdge = mWindowAlignment.mainAxis().getMinEdge(); 1933 mWindowAlignment.mainAxis().setMinEdge(minEdge); 1934 minScroll = getPrimarySystemScrollPosition(findViewByPosition(pos)); 1935 mWindowAlignment.mainAxis().setMinEdge(savedMinEdge); 1936 break; 1937 } 1938 } 1939 if (lowAvailable) { 1940 mWindowAlignment.mainAxis().setMinEdge(minEdge); 1941 mWindowAlignment.mainAxis().setMinScroll(minScroll); 1942 if (DEBUG) Log.v(getTag(), "updating scroll minEdge to " + minEdge + 1943 " scrollMin to " + minScroll); 1944 } else { 1945 // the minScroll for currently first visible item is smaller, 1946 // so we must invalidate the min scroll value. 1947 if (minScroll < mWindowAlignment.mainAxis().getMinScroll()) { 1948 mWindowAlignment.mainAxis().invalidateScrollMin(); 1949 if (DEBUG) Log.v(getTag(), "Invalidate scrollMin, since it should be " 1950 + "less than " + minScroll); 1951 } 1952 } 1953 } 1954 1955 private void updateScrollSecondAxis() { 1956 mWindowAlignment.secondAxis().setMinEdge(0); 1957 mWindowAlignment.secondAxis().setMaxEdge(getSizeSecondary()); 1958 } 1959 1960 private void initScrollController() { 1961 // mScrollOffsetPrimary and mScrollOffsetSecondary includes the padding. 1962 // e.g. when topPadding is 16 for horizontal grid view, the initial 1963 // mScrollOffsetSecondary is -16. fastLayout() put views based on offsets(not padding), 1964 // when padding changes to 20, we also need update mScrollOffsetSecondary to -20 before 1965 // fastLayout() is performed 1966 int paddingPrimaryDiff, paddingSecondaryDiff; 1967 if (mOrientation == HORIZONTAL) { 1968 paddingPrimaryDiff = getPaddingLeft() - mWindowAlignment.horizontal.getPaddingLow(); 1969 paddingSecondaryDiff = getPaddingTop() - mWindowAlignment.vertical.getPaddingLow(); 1970 } else { 1971 paddingPrimaryDiff = getPaddingTop() - mWindowAlignment.vertical.getPaddingLow(); 1972 paddingSecondaryDiff = getPaddingLeft() - mWindowAlignment.horizontal.getPaddingLow(); 1973 } 1974 mScrollOffsetPrimary -= paddingPrimaryDiff; 1975 mScrollOffsetSecondary -= paddingSecondaryDiff; 1976 1977 mWindowAlignment.horizontal.setSize(getWidth()); 1978 mWindowAlignment.vertical.setSize(getHeight()); 1979 mWindowAlignment.horizontal.setPadding(getPaddingLeft(), getPaddingRight()); 1980 mWindowAlignment.vertical.setPadding(getPaddingTop(), getPaddingBottom()); 1981 mSizePrimary = mWindowAlignment.mainAxis().getSize(); 1982 1983 if (DEBUG) { 1984 Log.v(getTag(), "initScrollController mSizePrimary " + mSizePrimary 1985 + " mWindowAlignment " + mWindowAlignment); 1986 } 1987 } 1988 1989 public void setSelection(RecyclerView parent, int position) { 1990 setSelection(parent, position, false); 1991 } 1992 1993 public void setSelectionSmooth(RecyclerView parent, int position) { 1994 setSelection(parent, position, true); 1995 } 1996 1997 public int getSelection() { 1998 return mFocusPosition; 1999 } 2000 2001 public void setSelection(RecyclerView parent, int position, boolean smooth) { 2002 if (mFocusPosition != position && position != NO_POSITION) { 2003 scrollToSelection(parent, position, smooth); 2004 } 2005 } 2006 2007 private void scrollToSelection(RecyclerView parent, int position, boolean smooth) { 2008 View view = findViewByPosition(position); 2009 if (view != null) { 2010 mInSelection = true; 2011 scrollToView(view, smooth); 2012 mInSelection = false; 2013 } else { 2014 mFocusPosition = position; 2015 mFocusPositionOffset = 0; 2016 if (!mLayoutEnabled) { 2017 return; 2018 } 2019 if (smooth) { 2020 if (!hasDoneFirstLayout()) { 2021 Log.w(getTag(), "setSelectionSmooth should " + 2022 "not be called before first layout pass"); 2023 return; 2024 } 2025 LinearSmoothScroller linearSmoothScroller = 2026 new LinearSmoothScroller(parent.getContext()) { 2027 @Override 2028 public PointF computeScrollVectorForPosition(int targetPosition) { 2029 if (getChildCount() == 0) { 2030 return null; 2031 } 2032 final int firstChildPos = getPosition(getChildAt(0)); 2033 // TODO We should be able to deduce direction from bounds of current and target focus, 2034 // rather than making assumptions about positions and directionality 2035 final boolean isStart = mReverseFlowPrimary ? targetPosition > firstChildPos : targetPosition < firstChildPos; 2036 final int direction = isStart ? -1 : 1; 2037 if (mOrientation == HORIZONTAL) { 2038 return new PointF(direction, 0); 2039 } else { 2040 return new PointF(0, direction); 2041 } 2042 } 2043 @Override 2044 protected void onTargetFound(View targetView, 2045 RecyclerView.State state, Action action) { 2046 if (hasFocus()) { 2047 targetView.requestFocus(); 2048 } 2049 dispatchChildSelected(); 2050 if (getScrollPosition(targetView, mTempDeltas)) { 2051 int dx, dy; 2052 if (mOrientation == HORIZONTAL) { 2053 dx = mTempDeltas[0]; 2054 dy = mTempDeltas[1]; 2055 } else { 2056 dx = mTempDeltas[1]; 2057 dy = mTempDeltas[0]; 2058 } 2059 final int distance = (int) Math.sqrt(dx * dx + dy * dy); 2060 final int time = calculateTimeForDeceleration(distance); 2061 action.update(dx, dy, time, mDecelerateInterpolator); 2062 } 2063 } 2064 }; 2065 linearSmoothScroller.setTargetPosition(position); 2066 startSmoothScroll(linearSmoothScroller); 2067 } else { 2068 mForceFullLayout = true; 2069 parent.requestLayout(); 2070 } 2071 } 2072 } 2073 2074 @Override 2075 public void onItemsAdded(RecyclerView recyclerView, int positionStart, int itemCount) { 2076 if (DEBUG) Log.v(getTag(), "onItemsAdded positionStart " 2077 + positionStart + " itemCount " + itemCount); 2078 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2079 && getChildAt(mFocusPosition) != null) { 2080 int pos = mFocusPosition + mFocusPositionOffset; 2081 if (positionStart <= pos) { 2082 mFocusPositionOffset += itemCount; 2083 } 2084 } 2085 mChildrenStates.clear(); 2086 } 2087 2088 @Override 2089 public void onItemsChanged(RecyclerView recyclerView) { 2090 if (DEBUG) Log.v(getTag(), "onItemsChanged"); 2091 mFocusPositionOffset = 0; 2092 mChildrenStates.clear(); 2093 } 2094 2095 @Override 2096 public void onItemsRemoved(RecyclerView recyclerView, int positionStart, int itemCount) { 2097 if (DEBUG) Log.v(getTag(), "onItemsRemoved positionStart " 2098 + positionStart + " itemCount " + itemCount); 2099 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2100 && getChildAt(mFocusPosition) != null) { 2101 int pos = mFocusPosition + mFocusPositionOffset; 2102 if (positionStart <= pos) { 2103 if (positionStart + itemCount > pos) { 2104 // stop updating offset after the focus item was removed 2105 mFocusPositionOffset = Integer.MIN_VALUE; 2106 } else { 2107 mFocusPositionOffset -= itemCount; 2108 } 2109 } 2110 } 2111 mChildrenStates.clear(); 2112 } 2113 2114 @Override 2115 public void onItemsMoved(RecyclerView recyclerView, int fromPosition, int toPosition, 2116 int itemCount) { 2117 if (DEBUG) Log.v(getTag(), "onItemsMoved fromPosition " 2118 + fromPosition + " toPosition " + toPosition); 2119 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2120 && getChildAt(mFocusPosition) != null) { 2121 int pos = mFocusPosition + mFocusPositionOffset; 2122 if (fromPosition <= pos && pos < fromPosition + itemCount) { 2123 // moved items include focused position 2124 mFocusPositionOffset += toPosition - fromPosition; 2125 } else if (fromPosition < pos && toPosition > pos - itemCount) { 2126 // move items before focus position to after focused position 2127 mFocusPositionOffset -= itemCount; 2128 } else if (fromPosition > pos && toPosition < pos) { 2129 // move items after focus position to before focused position 2130 mFocusPositionOffset += itemCount; 2131 } 2132 } 2133 mChildrenStates.clear(); 2134 } 2135 2136 @Override 2137 public void onItemsUpdated(RecyclerView recyclerView, int positionStart, int itemCount) { 2138 if (DEBUG) Log.v(getTag(), "onItemsUpdated positionStart " 2139 + positionStart + " itemCount " + itemCount); 2140 for (int i = positionStart, end = positionStart + itemCount; i < end; i++) { 2141 mChildrenStates.remove(i); 2142 } 2143 } 2144 2145 @Override 2146 public boolean onRequestChildFocus(RecyclerView parent, View child, View focused) { 2147 if (mFocusSearchDisabled) { 2148 return true; 2149 } 2150 if (getPositionByView(child) == NO_POSITION) { 2151 // This shouldn't happen, but in case it does be sure not to attempt a 2152 // scroll to a view whose item has been removed. 2153 return true; 2154 } 2155 if (!mInLayout && !mInSelection) { 2156 scrollToView(child, true); 2157 } 2158 return true; 2159 } 2160 2161 @Override 2162 public boolean requestChildRectangleOnScreen(RecyclerView parent, View view, Rect rect, 2163 boolean immediate) { 2164 if (DEBUG) Log.v(getTag(), "requestChildRectangleOnScreen " + view + " " + rect); 2165 return false; 2166 } 2167 2168 int getScrollOffsetX() { 2169 return mOrientation == HORIZONTAL ? mScrollOffsetPrimary : mScrollOffsetSecondary; 2170 } 2171 2172 int getScrollOffsetY() { 2173 return mOrientation == HORIZONTAL ? mScrollOffsetSecondary : mScrollOffsetPrimary; 2174 } 2175 2176 public void getViewSelectedOffsets(View view, int[] offsets) { 2177 if (mOrientation == HORIZONTAL) { 2178 offsets[0] = getPrimarySystemScrollPosition(view) - mScrollOffsetPrimary; 2179 offsets[1] = getSecondarySystemScrollPosition(view) - mScrollOffsetSecondary; 2180 } else { 2181 offsets[1] = getPrimarySystemScrollPosition(view) - mScrollOffsetPrimary; 2182 offsets[0] = getSecondarySystemScrollPosition(view) - mScrollOffsetSecondary; 2183 } 2184 } 2185 2186 private int getPrimarySystemScrollPosition(View view) { 2187 final int viewCenterPrimary = mScrollOffsetPrimary + getViewCenter(view); 2188 final int viewMin = getViewMin(view); 2189 final int viewMax = getViewMax(view); 2190 // TODO: change to use State object in onRequestChildFocus() 2191 boolean isMin, isMax; 2192 if (!mReverseFlowPrimary) { 2193 isMin = mFirstVisiblePos == 0; 2194 isMax = mLastVisiblePos == (mState == null ? 2195 getItemCount() : mState.getItemCount()) - 1; 2196 } else { 2197 isMax = mFirstVisiblePos == 0; 2198 isMin = mLastVisiblePos == (mState == null ? 2199 getItemCount() : mState.getItemCount()) - 1; 2200 } 2201 for (int i = getChildCount() - 1; (isMin || isMax) && i >= 0; i--) { 2202 View v = getChildAt(i); 2203 if (v == view || v == null) { 2204 continue; 2205 } 2206 if (isMin && getViewMin(v) < viewMin) { 2207 isMin = false; 2208 } 2209 if (isMax && getViewMax(v) > viewMax) { 2210 isMax = false; 2211 } 2212 } 2213 return mWindowAlignment.mainAxis().getSystemScrollPos(viewCenterPrimary, isMin, isMax); 2214 } 2215 2216 private int getSecondarySystemScrollPosition(View view) { 2217 int viewCenterSecondary = mScrollOffsetSecondary + getViewCenterSecondary(view); 2218 int pos = getPositionByView(view); 2219 StaggeredGrid.Location location = mGrid.getLocation(pos); 2220 final int row = location.row; 2221 final boolean isMin, isMax; 2222 if (!mReverseFlowSecondary) { 2223 isMin = row == 0; 2224 isMax = row == mGrid.getNumRows() - 1; 2225 } else { 2226 isMax = row == 0; 2227 isMin = row == mGrid.getNumRows() - 1; 2228 } 2229 return mWindowAlignment.secondAxis().getSystemScrollPos(viewCenterSecondary, isMin, isMax); 2230 } 2231 2232 /** 2233 * Scroll to a given child view and change mFocusPosition. 2234 */ 2235 private void scrollToView(View view, boolean smooth) { 2236 int newFocusPosition = getPositionByView(view); 2237 if (newFocusPosition != mFocusPosition) { 2238 mFocusPosition = newFocusPosition; 2239 mFocusPositionOffset = 0; 2240 if (!mInLayout) { 2241 dispatchChildSelected(); 2242 } 2243 } 2244 if (mBaseGridView.isChildrenDrawingOrderEnabledInternal()) { 2245 mBaseGridView.invalidate(); 2246 } 2247 if (view == null) { 2248 return; 2249 } 2250 if (!view.hasFocus() && mBaseGridView.hasFocus()) { 2251 // transfer focus to the child if it does not have focus yet (e.g. triggered 2252 // by setSelection()) 2253 view.requestFocus(); 2254 } 2255 if (!mScrollEnabled) { 2256 return; 2257 } 2258 if (getScrollPosition(view, mTempDeltas)) { 2259 scrollGrid(mTempDeltas[0], mTempDeltas[1], smooth); 2260 } 2261 } 2262 2263 private boolean getScrollPosition(View view, int[] deltas) { 2264 switch (mFocusScrollStrategy) { 2265 case BaseGridView.FOCUS_SCROLL_ALIGNED: 2266 default: 2267 return getAlignedPosition(view, deltas); 2268 case BaseGridView.FOCUS_SCROLL_ITEM: 2269 case BaseGridView.FOCUS_SCROLL_PAGE: 2270 return getNoneAlignedPosition(view, deltas); 2271 } 2272 } 2273 2274 private boolean getNoneAlignedPosition(View view, int[] deltas) { 2275 int pos = getPositionByView(view); 2276 int viewMin = getViewMin(view); 2277 int viewMax = getViewMax(view); 2278 // we either align "firstView" to left/top padding edge 2279 // or align "lastView" to right/bottom padding edge 2280 View firstView = null; 2281 View lastView = null; 2282 int paddingLow = mWindowAlignment.mainAxis().getPaddingLow(); 2283 int clientSize = mWindowAlignment.mainAxis().getClientSize(); 2284 final int row = mGrid.getLocation(pos).row; 2285 if (viewMin < paddingLow) { 2286 // view enters low padding area: 2287 firstView = view; 2288 if (mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_PAGE) { 2289 // scroll one "page" left/top, 2290 // align first visible item of the "page" at the low padding edge. 2291 while (!prependOneVisibleItem()) { 2292 List<Integer> positions = 2293 mGrid.getItemPositionsInRows(mFirstVisiblePos, pos)[row]; 2294 firstView = findViewByPosition(positions.get(0)); 2295 if (viewMax - getViewMin(firstView) > clientSize) { 2296 if (positions.size() > 1) { 2297 firstView = findViewByPosition(positions.get(1)); 2298 } 2299 break; 2300 } 2301 } 2302 } 2303 } else if (viewMax > clientSize + paddingLow) { 2304 // view enters high padding area: 2305 if (mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_PAGE) { 2306 // scroll whole one page right/bottom, align view at the low padding edge. 2307 firstView = view; 2308 do { 2309 List<Integer> positions = 2310 mGrid.getItemPositionsInRows(pos, mLastVisiblePos)[row]; 2311 lastView = findViewByPosition(positions.get(positions.size() - 1)); 2312 if (getViewMax(lastView) - viewMin > clientSize) { 2313 lastView = null; 2314 break; 2315 } 2316 } while (!appendOneVisibleItem()); 2317 if (lastView != null) { 2318 // however if we reached end, we should align last view. 2319 firstView = null; 2320 } 2321 } else { 2322 lastView = view; 2323 } 2324 } 2325 int scrollPrimary = 0; 2326 int scrollSecondary = 0; 2327 if (firstView != null) { 2328 scrollPrimary = getViewMin(firstView) - paddingLow; 2329 } else if (lastView != null) { 2330 scrollPrimary = getViewMax(lastView) - (paddingLow + clientSize); 2331 } 2332 View secondaryAlignedView; 2333 if (firstView != null) { 2334 secondaryAlignedView = firstView; 2335 } else if (lastView != null) { 2336 secondaryAlignedView = lastView; 2337 } else { 2338 secondaryAlignedView = view; 2339 } 2340 scrollSecondary = getSecondarySystemScrollPosition(secondaryAlignedView); 2341 scrollSecondary -= mScrollOffsetSecondary; 2342 if (scrollPrimary != 0 || scrollSecondary != 0) { 2343 deltas[0] = scrollPrimary; 2344 deltas[1] = scrollSecondary; 2345 return true; 2346 } 2347 return false; 2348 } 2349 2350 private boolean getAlignedPosition(View view, int[] deltas) { 2351 int scrollPrimary = getPrimarySystemScrollPosition(view); 2352 int scrollSecondary = getSecondarySystemScrollPosition(view); 2353 if (DEBUG) { 2354 Log.v(getTag(), "getAlignedPosition " + scrollPrimary + " " + scrollSecondary 2355 + " " + mWindowAlignment); 2356 Log.v(getTag(), "getAlignedPosition " + mScrollOffsetPrimary + " " + mScrollOffsetSecondary); 2357 } 2358 scrollPrimary -= mScrollOffsetPrimary; 2359 scrollSecondary -= mScrollOffsetSecondary; 2360 if (scrollPrimary != 0 || scrollSecondary != 0) { 2361 deltas[0] = scrollPrimary; 2362 deltas[1] = scrollSecondary; 2363 return true; 2364 } 2365 return false; 2366 } 2367 2368 private void scrollGrid(int scrollPrimary, int scrollSecondary, boolean smooth) { 2369 if (mInLayout) { 2370 scrollDirectionPrimary(scrollPrimary); 2371 scrollDirectionSecondary(scrollSecondary); 2372 } else { 2373 int scrollX; 2374 int scrollY; 2375 if (mOrientation == HORIZONTAL) { 2376 scrollX = scrollPrimary; 2377 scrollY = scrollSecondary; 2378 } else { 2379 scrollX = scrollSecondary; 2380 scrollY = scrollPrimary; 2381 } 2382 if (smooth) { 2383 mBaseGridView.smoothScrollBy(scrollX, scrollY); 2384 } else { 2385 mBaseGridView.scrollBy(scrollX, scrollY); 2386 } 2387 } 2388 } 2389 2390 public void setPruneChild(boolean pruneChild) { 2391 if (mPruneChild != pruneChild) { 2392 mPruneChild = pruneChild; 2393 if (mPruneChild) { 2394 requestLayout(); 2395 } 2396 } 2397 } 2398 2399 public boolean getPruneChild() { 2400 return mPruneChild; 2401 } 2402 2403 public void setScrollEnabled(boolean scrollEnabled) { 2404 if (mScrollEnabled != scrollEnabled) { 2405 mScrollEnabled = scrollEnabled; 2406 if (mScrollEnabled && mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_ALIGNED 2407 && mFocusPosition != NO_POSITION) { 2408 scrollToSelection(mBaseGridView, mFocusPosition, true); 2409 } 2410 } 2411 } 2412 2413 public boolean isScrollEnabled() { 2414 return mScrollEnabled; 2415 } 2416 2417 private int findImmediateChildIndex(View view) { 2418 while (view != null && view != mBaseGridView) { 2419 int index = mBaseGridView.indexOfChild(view); 2420 if (index >= 0) { 2421 return index; 2422 } 2423 view = (View) view.getParent(); 2424 } 2425 return NO_POSITION; 2426 } 2427 2428 void setFocusSearchDisabled(boolean disabled) { 2429 mFocusSearchDisabled = disabled; 2430 } 2431 2432 boolean isFocusSearchDisabled() { 2433 return mFocusSearchDisabled; 2434 } 2435 2436 @Override 2437 public View onInterceptFocusSearch(View focused, int direction) { 2438 if (mFocusSearchDisabled) { 2439 return focused; 2440 } 2441 return null; 2442 } 2443 2444 boolean hasPreviousViewInSameRow(int pos) { 2445 if (mGrid == null || pos == NO_POSITION) { 2446 return false; 2447 } 2448 if (mFirstVisiblePos > 0) { 2449 return true; 2450 } 2451 final int focusedRow = mGrid.getLocation(pos).row; 2452 for (int i = getChildCount() - 1; i >= 0; i--) { 2453 int position = getPositionByIndex(i); 2454 StaggeredGrid.Location loc = mGrid.getLocation(position); 2455 if (loc != null && loc.row == focusedRow) { 2456 if (position < pos) { 2457 return true; 2458 } 2459 } 2460 } 2461 return false; 2462 } 2463 2464 @Override 2465 public boolean onAddFocusables(RecyclerView recyclerView, 2466 ArrayList<View> views, int direction, int focusableMode) { 2467 if (mFocusSearchDisabled) { 2468 return true; 2469 } 2470 // If this viewgroup or one of its children currently has focus then we 2471 // consider our children for focus searching in main direction on the same row. 2472 // If this viewgroup has no focus and using focus align, we want the system 2473 // to ignore our children and pass focus to the viewgroup, which will pass 2474 // focus on to its children appropriately. 2475 // If this viewgroup has no focus and not using focus align, we want to 2476 // consider the child that does not overlap with padding area. 2477 if (recyclerView.hasFocus()) { 2478 final int movement = getMovement(direction); 2479 if (movement != PREV_ITEM && movement != NEXT_ITEM) { 2480 // Move on secondary direction uses default addFocusables(). 2481 return false; 2482 } 2483 final View focused = recyclerView.findFocus(); 2484 final int focusedPos = getPositionByIndex(findImmediateChildIndex(focused)); 2485 // Add focusables of focused item. 2486 if (focusedPos != NO_POSITION) { 2487 findViewByPosition(focusedPos).addFocusables(views, direction, focusableMode); 2488 } 2489 final int focusedRow = mGrid != null && focusedPos != NO_POSITION ? 2490 mGrid.getLocation(focusedPos).row : NO_POSITION; 2491 // Add focusables of next neighbor of same row on the focus search direction. 2492 if (mGrid != null) { 2493 final int focusableCount = views.size(); 2494 for (int i = 0, count = getChildCount(); i < count; i++) { 2495 int index = movement == NEXT_ITEM ? i : count - 1 - i; 2496 final View child = getChildAt(index); 2497 if (child.getVisibility() != View.VISIBLE) { 2498 continue; 2499 } 2500 int position = getPositionByIndex(index); 2501 StaggeredGrid.Location loc = mGrid.getLocation(position); 2502 if (focusedRow == NO_POSITION || (loc != null && loc.row == focusedRow)) { 2503 if (focusedPos == NO_POSITION || 2504 (movement == NEXT_ITEM && position > focusedPos) 2505 || (movement == PREV_ITEM && position < focusedPos)) { 2506 child.addFocusables(views, direction, focusableMode); 2507 if (views.size() > focusableCount) { 2508 break; 2509 } 2510 } 2511 } 2512 } 2513 } 2514 } else { 2515 if (mFocusScrollStrategy != BaseGridView.FOCUS_SCROLL_ALIGNED) { 2516 // adding views not overlapping padding area to avoid scrolling in gaining focus 2517 int left = mWindowAlignment.mainAxis().getPaddingLow(); 2518 int right = mWindowAlignment.mainAxis().getClientSize() + left; 2519 int focusableCount = views.size(); 2520 for (int i = 0, count = getChildCount(); i < count; i++) { 2521 View child = getChildAt(i); 2522 if (child.getVisibility() == View.VISIBLE) { 2523 if (getViewMin(child) >= left && getViewMax(child) <= right) { 2524 child.addFocusables(views, direction, focusableMode); 2525 } 2526 } 2527 } 2528 // if we cannot find any, then just add all children. 2529 if (views.size() == focusableCount) { 2530 for (int i = 0, count = getChildCount(); i < count; i++) { 2531 View child = getChildAt(i); 2532 if (child.getVisibility() == View.VISIBLE) { 2533 child.addFocusables(views, direction, focusableMode); 2534 } 2535 } 2536 if (views.size() != focusableCount) { 2537 return true; 2538 } 2539 } else { 2540 return true; 2541 } 2542 // if still cannot find any, fall through and add itself 2543 } 2544 if (recyclerView.isFocusable()) { 2545 views.add(recyclerView); 2546 } 2547 } 2548 return true; 2549 } 2550 2551 @Override 2552 public View onFocusSearchFailed(View focused, int direction, Recycler recycler, 2553 RecyclerView.State state) { 2554 if (DEBUG) Log.v(getTag(), "onFocusSearchFailed direction " + direction); 2555 2556 View view = null; 2557 int movement = getMovement(direction); 2558 final boolean isScroll = mBaseGridView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE; 2559 if (mNumRows == 1) { 2560 // for simple row, use LinearSmoothScroller to smooth animation. 2561 // It will stay at a fixed cap speed in continuous scroll. 2562 if (movement == NEXT_ITEM) { 2563 int newPos = mFocusPosition + mNumRows; 2564 if (newPos < getItemCount() && mScrollEnabled) { 2565 setSelectionSmooth(mBaseGridView, newPos); 2566 view = focused; 2567 } else { 2568 if (isScroll || !mFocusOutEnd) { 2569 view = focused; 2570 } 2571 } 2572 } else if (movement == PREV_ITEM){ 2573 int newPos = mFocusPosition - mNumRows; 2574 if (newPos >= 0 && mScrollEnabled) { 2575 setSelectionSmooth(mBaseGridView, newPos); 2576 view = focused; 2577 } else { 2578 if (isScroll || !mFocusOutFront) { 2579 view = focused; 2580 } 2581 } 2582 } 2583 } else if (mNumRows > 1) { 2584 // for possible staggered grid, we need guarantee focus to same row/column. 2585 // TODO: we may also use LinearSmoothScroller. 2586 saveContext(recycler, state); 2587 final FocusFinder ff = FocusFinder.getInstance(); 2588 if (movement == NEXT_ITEM) { 2589 while (view == null && !appendOneVisibleItem()) { 2590 view = ff.findNextFocus(mBaseGridView, focused, direction); 2591 } 2592 } else if (movement == PREV_ITEM){ 2593 while (view == null && !prependOneVisibleItem()) { 2594 view = ff.findNextFocus(mBaseGridView, focused, direction); 2595 } 2596 } 2597 if (view == null) { 2598 // returning the same view to prevent focus lost when scrolling past the end of the list 2599 if (movement == PREV_ITEM) { 2600 view = mFocusOutFront && !isScroll ? null : focused; 2601 } else if (movement == NEXT_ITEM){ 2602 view = mFocusOutEnd && !isScroll ? null : focused; 2603 } 2604 } 2605 leaveContext(); 2606 } 2607 if (DEBUG) Log.v(getTag(), "returning view " + view); 2608 return view; 2609 } 2610 2611 boolean gridOnRequestFocusInDescendants(RecyclerView recyclerView, int direction, 2612 Rect previouslyFocusedRect) { 2613 switch (mFocusScrollStrategy) { 2614 case BaseGridView.FOCUS_SCROLL_ALIGNED: 2615 default: 2616 return gridOnRequestFocusInDescendantsAligned(recyclerView, 2617 direction, previouslyFocusedRect); 2618 case BaseGridView.FOCUS_SCROLL_PAGE: 2619 case BaseGridView.FOCUS_SCROLL_ITEM: 2620 return gridOnRequestFocusInDescendantsUnaligned(recyclerView, 2621 direction, previouslyFocusedRect); 2622 } 2623 } 2624 2625 private boolean gridOnRequestFocusInDescendantsAligned(RecyclerView recyclerView, 2626 int direction, Rect previouslyFocusedRect) { 2627 View view = findViewByPosition(mFocusPosition); 2628 if (view != null) { 2629 boolean result = view.requestFocus(direction, previouslyFocusedRect); 2630 if (!result && DEBUG) { 2631 Log.w(getTag(), "failed to request focus on " + view); 2632 } 2633 return result; 2634 } 2635 return false; 2636 } 2637 2638 private boolean gridOnRequestFocusInDescendantsUnaligned(RecyclerView recyclerView, 2639 int direction, Rect previouslyFocusedRect) { 2640 // focus to view not overlapping padding area to avoid scrolling in gaining focus 2641 int index; 2642 int increment; 2643 int end; 2644 int count = getChildCount(); 2645 if ((direction & View.FOCUS_FORWARD) != 0) { 2646 index = 0; 2647 increment = 1; 2648 end = count; 2649 } else { 2650 index = count - 1; 2651 increment = -1; 2652 end = -1; 2653 } 2654 int left = mWindowAlignment.mainAxis().getPaddingLow(); 2655 int right = mWindowAlignment.mainAxis().getClientSize() + left; 2656 for (int i = index; i != end; i += increment) { 2657 View child = getChildAt(i); 2658 if (child.getVisibility() == View.VISIBLE) { 2659 if (getViewMin(child) >= left && getViewMax(child) <= right) { 2660 if (child.requestFocus(direction, previouslyFocusedRect)) { 2661 return true; 2662 } 2663 } 2664 } 2665 } 2666 return false; 2667 } 2668 2669 private final static int PREV_ITEM = 0; 2670 private final static int NEXT_ITEM = 1; 2671 private final static int PREV_ROW = 2; 2672 private final static int NEXT_ROW = 3; 2673 2674 private int getMovement(int direction) { 2675 int movement = View.FOCUS_LEFT; 2676 2677 if (mOrientation == HORIZONTAL) { 2678 switch(direction) { 2679 case View.FOCUS_LEFT: 2680 movement = (!mReverseFlowPrimary) ? PREV_ITEM : NEXT_ITEM; 2681 break; 2682 case View.FOCUS_RIGHT: 2683 movement = (!mReverseFlowPrimary) ? NEXT_ITEM : PREV_ITEM; 2684 break; 2685 case View.FOCUS_UP: 2686 movement = PREV_ROW; 2687 break; 2688 case View.FOCUS_DOWN: 2689 movement = NEXT_ROW; 2690 break; 2691 } 2692 } else if (mOrientation == VERTICAL) { 2693 switch(direction) { 2694 case View.FOCUS_LEFT: 2695 movement = (!mReverseFlowPrimary) ? PREV_ROW : NEXT_ROW; 2696 break; 2697 case View.FOCUS_RIGHT: 2698 movement = (!mReverseFlowPrimary) ? NEXT_ROW : PREV_ROW; 2699 break; 2700 case View.FOCUS_UP: 2701 movement = PREV_ITEM; 2702 break; 2703 case View.FOCUS_DOWN: 2704 movement = NEXT_ITEM; 2705 break; 2706 } 2707 } 2708 2709 return movement; 2710 } 2711 2712 int getChildDrawingOrder(RecyclerView recyclerView, int childCount, int i) { 2713 View view = findViewByPosition(mFocusPosition); 2714 if (view == null) { 2715 return i; 2716 } 2717 int focusIndex = recyclerView.indexOfChild(view); 2718 // supposely 0 1 2 3 4 5 6 7 8 9, 4 is the center item 2719 // drawing order is 0 1 2 3 9 8 7 6 5 4 2720 if (i < focusIndex) { 2721 return i; 2722 } else if (i < childCount - 1) { 2723 return focusIndex + childCount - 1 - i; 2724 } else { 2725 return focusIndex; 2726 } 2727 } 2728 2729 @Override 2730 public void onAdapterChanged(RecyclerView.Adapter oldAdapter, 2731 RecyclerView.Adapter newAdapter) { 2732 if (DEBUG) Log.v(getTag(), "onAdapterChanged to " + newAdapter); 2733 if (oldAdapter != null) { 2734 discardLayoutInfo(); 2735 mFocusPosition = NO_POSITION; 2736 mFocusPositionOffset = 0; 2737 mChildrenStates.clear(); 2738 } 2739 super.onAdapterChanged(oldAdapter, newAdapter); 2740 } 2741 2742 private void discardLayoutInfo() { 2743 mGrid = null; 2744 mRows = null; 2745 mRowSizeSecondary = null; 2746 mFirstVisiblePos = -1; 2747 mLastVisiblePos = -1; 2748 mRowSecondarySizeRefresh = false; 2749 } 2750 2751 public void setLayoutEnabled(boolean layoutEnabled) { 2752 if (mLayoutEnabled != layoutEnabled) { 2753 mLayoutEnabled = layoutEnabled; 2754 requestLayout(); 2755 } 2756 } 2757 2758 void setChildrenVisibility(int visiblity) { 2759 mChildVisibility = visiblity; 2760 if (mChildVisibility != -1) { 2761 int count = getChildCount(); 2762 for (int i= 0; i < count; i++) { 2763 getChildAt(i).setVisibility(mChildVisibility); 2764 } 2765 } 2766 } 2767 2768 final static class SavedState implements Parcelable { 2769 2770 int index; // index inside adapter of the current view 2771 Bundle childStates = Bundle.EMPTY; 2772 2773 @Override 2774 public void writeToParcel(Parcel out, int flags) { 2775 out.writeInt(index); 2776 out.writeBundle(childStates); 2777 } 2778 2779 @SuppressWarnings("hiding") 2780 public static final Parcelable.Creator<SavedState> CREATOR = 2781 new Parcelable.Creator<SavedState>() { 2782 @Override 2783 public SavedState createFromParcel(Parcel in) { 2784 return new SavedState(in); 2785 } 2786 2787 @Override 2788 public SavedState[] newArray(int size) { 2789 return new SavedState[size]; 2790 } 2791 }; 2792 2793 @Override 2794 public int describeContents() { 2795 return 0; 2796 } 2797 2798 SavedState(Parcel in) { 2799 index = in.readInt(); 2800 childStates = in.readBundle(GridLayoutManager.class.getClassLoader()); 2801 } 2802 2803 SavedState() { 2804 } 2805 } 2806 2807 @Override 2808 public Parcelable onSaveInstanceState() { 2809 if (DEBUG) Log.v(getTag(), "onSaveInstanceState getSelection() " + getSelection()); 2810 SavedState ss = new SavedState(); 2811 for (int i = 0, count = getChildCount(); i < count; i++) { 2812 View view = getChildAt(i); 2813 int position = getPositionByView(view); 2814 if (position != NO_POSITION) { 2815 mChildrenStates.saveOnScreenView(view, position); 2816 } 2817 } 2818 ss.index = getSelection(); 2819 ss.childStates = mChildrenStates.saveAsBundle(); 2820 return ss; 2821 } 2822 2823 @Override 2824 public void onRestoreInstanceState(Parcelable state) { 2825 if (!(state instanceof SavedState)) { 2826 return; 2827 } 2828 SavedState loadingState = (SavedState)state; 2829 mFocusPosition = loadingState.index; 2830 mFocusPositionOffset = 0; 2831 mChildrenStates.loadFromBundle(loadingState.childStates); 2832 mForceFullLayout = true; 2833 requestLayout(); 2834 if (DEBUG) Log.v(getTag(), "onRestoreInstanceState mFocusPosition " + mFocusPosition); 2835 } 2836} 2837