-
Notifications
You must be signed in to change notification settings - Fork 135
/
OverScrollView.java
1747 lines (1526 loc) · 44.8 KB
/
OverScrollView.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
package me.everything.android.widget;
/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.FocusFinder;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.animation.AnimationUtils;
import android.view.animation.OvershootInterpolator;
import android.widget.FrameLayout;
import android.widget.Scroller;
import android.view.View.OnTouchListener;
import java.lang.reflect.Field;
import java.util.List;
/**
* Layout container for a view hierarchy that can be scrolled by the user,
* allowing it to be larger than the physical display. A ScrollView is a
* {@link FrameLayout}, meaning you should place one child in it containing the
* entire contents to scroll; this child may itself be a layout manager with a
* complex hierarchy of objects. A child that is often used is a
* {@link LinearLayout} in a vertical orientation, presenting a vertical array
* of top-level items that the user can scroll through.
*
* <p>
* The {@link TextView} class also takes care of its own scrolling, so does not
* require a ScrollView, but using the two together is possible to achieve the
* effect of a text view within a larger container.
*
* <p>
* ScrollView only supports vertical scrolling.
*/
public class OverScrollView extends FrameLayout implements OnTouchListener
{
static final int ANIMATED_SCROLL_GAP = 250;
static final float MAX_SCROLL_FACTOR = 0.5f;
static final float OVERSHOOT_TENSION = 0.75f;
private long mLastScroll;
private final Rect mTempRect = new Rect();
private Scroller mScroller;
protected Context mContext;
Field mScrollYField;
Field mScrollXField;
boolean hasFailedObtainingScrollFields;
int prevScrollY;
boolean isInFlingMode = false;
DisplayMetrics metrics;
LayoutInflater inflater;
protected View child;
private Runnable overScrollerSpringbackTask;
/**
* Flag to indicate that we are moving focus ourselves. This is so the code
* that watches for focus changes initiated outside this ScrollView knows
* that it does not have to do anything.
*/
private boolean mScrollViewMovedFocus;
/**
* Position of the last motion event.
*/
private float mLastMotionY;
/**
* True when the layout has changed but the traversal has not come through
* yet. Ideally the view hierarchy would keep track of this for us.
*/
private boolean mIsLayoutDirty = true;
/**
* The child to give focus to in the event that a child has requested focus
* while the layout is dirty. This prevents the scroll from being wrong if
* the child has not been laid out before requesting focus.
*/
private View mChildToScrollTo = null;
/**
* True if the user is currently dragging this ScrollView around. This is
* not the same as 'is being flinged', which can be checked by
* mScroller.isFinished() (flinging begins when the user lifts his finger).
*/
private boolean mIsBeingDragged = false;
/**
* Determines speed during touch scrolling
*/
private VelocityTracker mVelocityTracker;
/**
* When set to true, the scroll view measure its child to make it fill the
* currently visible area.
*/
private boolean mFillViewport;
/**
* Whether arrow scrolling is animated.
*/
private boolean mSmoothScrollingEnabled = true;
private int mTouchSlop;
private int mMinimumVelocity;
private int mMaximumVelocity;
/**
* ID of the active pointer. This is used to retain consistency during
* drags/flings if multiple pointers are used.
*/
private int mActivePointerId = INVALID_POINTER;
/**
* Sentinel value for no current active pointer. Used by
* {@link #mActivePointerId}.
*/
private static final int INVALID_POINTER = -1;
public OverScrollView(Context context)
{
this(context, null);
}
public OverScrollView(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public OverScrollView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
mContext = context;
initScrollView();
setFillViewport(true);
initBounce();
}
private void initBounce()
{
metrics = this.mContext.getResources().getDisplayMetrics();
// init the bouncy scroller, and make sure the layout is being drawn
// after the top padding
mScroller = new Scroller(getContext(), new OvershootInterpolator(OVERSHOOT_TENSION));
overScrollerSpringbackTask = new Runnable()
{
@Override
public void run()
{
// scroll till after the padding
mScroller.computeScrollOffset();
scrollTo(0, mScroller.getCurrY());
if (!mScroller.isFinished())
{
post(this);
}
}
};
prevScrollY = getPaddingTop();
try
{
mScrollXField = View.class.getDeclaredField("mScrollX");
mScrollYField = View.class.getDeclaredField("mScrollY");
} catch (Exception e)
{
hasFailedObtainingScrollFields = true;
}
}
private void SetScrollY(int value)
{
if (mScrollYField != null)
{
try
{
mScrollYField.setInt(this, value);
} catch (Exception e)
{
}
}
}
private void SetScrollX(int value)
{
if (mScrollXField != null)
{
try
{
mScrollXField.setInt(this, value);
} catch (Exception e)
{
}
}
}
public void initChildPointer()
{
child = getChildAt(0);
child.setPadding(0, 1500, 0, 1500);
}
@Override
protected float getTopFadingEdgeStrength()
{
if (getChildCount() == 0)
{
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
if (getScrollY() < length)
{
return getScrollY() / (float) length;
}
return 1.0f;
}
@Override
protected float getBottomFadingEdgeStrength()
{
if (getChildCount() == 0)
{
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
final int bottomEdge = getHeight() - getPaddingBottom();
final int span = getChildAt(0).getBottom() - getScrollY() - bottomEdge;
if (span < length)
{
return span / (float) length;
}
return 1.0f;
}
/**
* @return The maximum amount this scroll view will scroll in response to an
* arrow event.
*/
public int getMaxScrollAmount()
{
return (int) (MAX_SCROLL_FACTOR * (getBottom() - getTop()));
}
private void initScrollView()
{
mScroller = new Scroller(getContext());
setFocusable(true);
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
setWillNotDraw(false);
final ViewConfiguration configuration = ViewConfiguration.get(mContext);
mTouchSlop = configuration.getScaledTouchSlop();
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
setOnTouchListener(this);
post(new Runnable()
{
public void run()
{
scrollTo(0, child.getPaddingTop());
}
});
}
@Override
public void addView(View child)
{
if (getChildCount() > 0)
{
throw new IllegalStateException("ScrollView can host only one direct child");
}
super.addView(child);
initChildPointer();
}
@Override
public void addView(View child, int index)
{
if (getChildCount() > 0)
{
throw new IllegalStateException("ScrollView can host only one direct child");
}
super.addView(child, index);
initChildPointer();
}
@Override
public void addView(View child, ViewGroup.LayoutParams params)
{
if (getChildCount() > 0)
{
throw new IllegalStateException("ScrollView can host only one direct child");
}
super.addView(child, params);
initChildPointer();
}
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params)
{
if (getChildCount() > 0)
{
throw new IllegalStateException("ScrollView can host only one direct child");
}
super.addView(child, index, params);
}
/**
* @return Returns true this ScrollView can be scrolled
*/
private boolean canScroll()
{
View child = getChildAt(0);
if (child != null)
{
int childHeight = child.getHeight();
return getHeight() < childHeight + getPaddingTop() + getPaddingBottom();
}
return false;
}
/**
* Indicates whether this ScrollView's content is stretched to fill the
* viewport.
*
* @return True if the content fills the viewport, false otherwise.
*/
public boolean isFillViewport()
{
return mFillViewport;
}
/**
* Indicates this ScrollView whether it should stretch its content height to
* fill the viewport or not.
*
* @param fillViewport
* True to stretch the content's height to the viewport's
* boundaries, false otherwise.
*/
public void setFillViewport(boolean fillViewport)
{
if (fillViewport != mFillViewport)
{
mFillViewport = fillViewport;
requestLayout();
}
}
/**
* @return Whether arrow scrolling will animate its transition.
*/
public boolean isSmoothScrollingEnabled()
{
return mSmoothScrollingEnabled;
}
/**
* Set whether arrow scrolling will animate its transition.
*
* @param smoothScrollingEnabled
* whether arrow scrolling will animate its transition
*/
public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled)
{
mSmoothScrollingEnabled = smoothScrollingEnabled;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (!mFillViewport)
{
return;
}
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode == MeasureSpec.UNSPECIFIED)
{
return;
}
if (getChildCount() > 0)
{
final View child = getChildAt(0);
int height = getMeasuredHeight();
if (child.getMeasuredHeight() < height)
{
final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams();
int childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec, getPaddingLeft() + getPaddingRight(), lp.width);
height -= getPaddingTop();
height -= getPaddingBottom();
int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
}
}
@Override
public boolean dispatchKeyEvent(KeyEvent event)
{
// Let the focused view and/or our descendants get the key first
return super.dispatchKeyEvent(event) || executeKeyEvent(event);
}
/**
* You can call this function yourself to have the scroll view perform
* scrolling from a key event, just as if the event had been dispatched to
* it by the view hierarchy.
*
* @param event
* The key event to execute.
* @return Return true if the event was handled, else false.
*/
public boolean executeKeyEvent(KeyEvent event)
{
mTempRect.setEmpty();
if (!canScroll())
{
if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK)
{
View currentFocused = findFocus();
if (currentFocused == this)
currentFocused = null;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, View.FOCUS_DOWN);
return nextFocused != null && nextFocused != this && nextFocused.requestFocus(View.FOCUS_DOWN);
}
return false;
}
boolean handled = false;
if (event.getAction() == KeyEvent.ACTION_DOWN)
{
switch (event.getKeyCode())
{
case KeyEvent.KEYCODE_DPAD_UP:
if (!event.isAltPressed())
{
handled = arrowScroll(View.FOCUS_UP);
} else
{
handled = fullScroll(View.FOCUS_UP);
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if (!event.isAltPressed())
{
handled = arrowScroll(View.FOCUS_DOWN);
} else
{
handled = fullScroll(View.FOCUS_DOWN);
}
break;
case KeyEvent.KEYCODE_SPACE:
pageScroll(event.isShiftPressed() ? View.FOCUS_UP : View.FOCUS_DOWN);
break;
}
}
return handled;
}
public boolean inChild(int x, int y)
{
if (getChildCount() > 0)
{
final int scrollY = getScrollY();
final View child = getChildAt(0);
return !(y < child.getTop() - scrollY || y >= child.getBottom() - scrollY || x < child.getLeft() || x >= child.getRight());
}
return false;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev)
{
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onMotionEvent will be called and we do the actual
* scrolling there.
*/
/*
* Shortcut the most recurring case: the user is in the dragging state
* and he is moving his finger. We want to intercept this motion.
*/
final int action = ev.getAction();
if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged))
{
return true;
}
switch (action & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_MOVE:
{
/*
* mIsBeingDragged == false, otherwise the shortcut would have
* caught it. Check whether the user has moved far enough from his
* original down touch.
*/
/*
* Locally do absolute value. mLastMotionY is set to the y value of
* the down event.
*/
final int activePointerId = mActivePointerId;
if (activePointerId == INVALID_POINTER)
{
// If we don't have a valid id, the touch down wasn't on
// content.
break;
}
final int pointerIndex = ev.findPointerIndex(activePointerId);
final float y = ev.getY(pointerIndex);
final int yDiff = (int) Math.abs(y - mLastMotionY);
if (yDiff > mTouchSlop)
{
mIsBeingDragged = true;
mLastMotionY = y;
}
break;
}
case MotionEvent.ACTION_DOWN:
{
final float y = ev.getY();
if (!inChild((int) ev.getX(), (int) y))
{
mIsBeingDragged = false;
break;
}
/*
* Remember location of down touch. ACTION_DOWN always refers to
* pointer index 0.
*/
mLastMotionY = y;
mActivePointerId = ev.getPointerId(0);
/*
* If being flinged and user touches the screen, initiate drag;
* otherwise don't. mScroller.isFinished should be false when being
* flinged.
*/
mIsBeingDragged = !mScroller.isFinished();
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
/* Release the drag */
mIsBeingDragged = false;
mActivePointerId = INVALID_POINTER;
break;
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mIsBeingDragged;
}
@Override
public boolean onTouchEvent(MotionEvent ev)
{
if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0)
{
// Don't handle edge touches immediately -- they may actually belong
// to one of our
// descendants.
return false;
}
if (mVelocityTracker == null)
{
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN:
{
final float y = ev.getY();
if (!(mIsBeingDragged = inChild((int) ev.getX(), (int) y)))
{
return false;
}
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished())
{
mScroller.abortAnimation();
}
// Remember where the motion event started
mLastMotionY = y;
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE:
if (mIsBeingDragged)
{
// Scroll to follow the motion event
final int activePointerIndex = ev.findPointerIndex(mActivePointerId);
final float y = ev.getY(activePointerIndex);
final int deltaY = (int) (mLastMotionY - y);
mLastMotionY = y;
if (isOverScrolled())
{
// when overscrolling, move the scroller just half of the
// finger movement, to make it feel like a spring...
scrollBy(0, deltaY / 2);
} else
{
scrollBy(0, deltaY);
}
}
break;
case MotionEvent.ACTION_UP:
if (mIsBeingDragged)
{
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int initialVelocity = (int) velocityTracker.getYVelocity(mActivePointerId);
if (getChildCount() > 0 && Math.abs(initialVelocity) > mMinimumVelocity)
{
fling(-initialVelocity);
}
mActivePointerId = INVALID_POINTER;
mIsBeingDragged = false;
if (mVelocityTracker != null)
{
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
break;
case MotionEvent.ACTION_CANCEL:
if (mIsBeingDragged && getChildCount() > 0)
{
mActivePointerId = INVALID_POINTER;
mIsBeingDragged = false;
if (mVelocityTracker != null)
{
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
break;
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
break;
}
return true;
}
public boolean isOverScrolled()
{
return (getScrollY() < child.getPaddingTop() || getScrollY() > child.getBottom() - child.getPaddingBottom() - getHeight());
}
private void onSecondaryPointerUp(MotionEvent ev)
{
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId)
{
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
// TODO: Make this decision more intelligent.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastMotionY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
if (mVelocityTracker != null)
{
mVelocityTracker.clear();
}
}
}
/**
* <p>
* Finds the next focusable component that fits in this View's bounds
* (excluding fading edges) pretending that this View's top is located at
* the parameter top.
* </p>
*
* @param topFocus
* look for a candidate is the one at the top of the bounds if
* topFocus is true, or at the bottom of the bounds if topFocus
* is false
* @param top
* the top offset of the bounds in which a focusable must be
* found (the fading edge is assumed to start at this position)
* @param preferredFocusable
* the View that has highest priority and will be returned if it
* is within my bounds (null is valid)
* @return the next focusable component in the bounds or null if none can be
* found
*/
private View findFocusableViewInMyBounds(final boolean topFocus, final int top, View preferredFocusable)
{
/*
* The fading edge's transparent side should be considered for focus
* since it's mostly visible, so we divide the actual fading edge length
* by 2.
*/
final int fadingEdgeLength = getVerticalFadingEdgeLength() / 2;
final int topWithoutFadingEdge = top + fadingEdgeLength;
final int bottomWithoutFadingEdge = top + getHeight() - fadingEdgeLength;
if ((preferredFocusable != null) && (preferredFocusable.getTop() < bottomWithoutFadingEdge)
&& (preferredFocusable.getBottom() > topWithoutFadingEdge))
{
return preferredFocusable;
}
return findFocusableViewInBounds(topFocus, topWithoutFadingEdge, bottomWithoutFadingEdge);
}
/**
* <p>
* Finds the next focusable component that fits in the specified bounds.
* </p>
*
* @param topFocus
* look for a candidate is the one at the top of the bounds if
* topFocus is true, or at the bottom of the bounds if topFocus
* is false
* @param top
* the top offset of the bounds in which a focusable must be
* found
* @param bottom
* the bottom offset of the bounds in which a focusable must be
* found
* @return the next focusable component in the bounds or null if none can be
* found
*/
private View findFocusableViewInBounds(boolean topFocus, int top, int bottom)
{
List<View> focusables = getFocusables(View.FOCUS_FORWARD);
View focusCandidate = null;
/*
* A fully contained focusable is one where its top is below the bound's
* top, and its bottom is above the bound's bottom. A partially
* contained focusable is one where some part of it is within the
* bounds, but it also has some part that is not within bounds. A fully
* contained focusable is preferred to a partially contained focusable.
*/
boolean foundFullyContainedFocusable = false;
int count = focusables.size();
for (int i = 0; i < count; i++)
{
View view = focusables.get(i);
int viewTop = view.getTop();
int viewBottom = view.getBottom();
if (top < viewBottom && viewTop < bottom)
{
/*
* the focusable is in the target area, it is a candidate for
* focusing
*/
final boolean viewIsFullyContained = (top < viewTop) && (viewBottom < bottom);
if (focusCandidate == null)
{
/* No candidate, take this one */
focusCandidate = view;
foundFullyContainedFocusable = viewIsFullyContained;
} else
{
final boolean viewIsCloserToBoundary = (topFocus && viewTop < focusCandidate.getTop())
|| (!topFocus && viewBottom > focusCandidate.getBottom());
if (foundFullyContainedFocusable)
{
if (viewIsFullyContained && viewIsCloserToBoundary)
{
/*
* We're dealing with only fully contained views, so
* it has to be closer to the boundary to beat our
* candidate
*/
focusCandidate = view;
}
} else
{
if (viewIsFullyContained)
{
/*
* Any fully contained view beats a partially
* contained view
*/
focusCandidate = view;
foundFullyContainedFocusable = true;
} else if (viewIsCloserToBoundary)
{
/*
* Partially contained view beats another partially
* contained view if it's closer
*/
focusCandidate = view;
}
}
}
}
}
return focusCandidate;
}
/**
* <p>
* Handles scrolling in response to a "page up/down" shortcut press. This
* method will scroll the view by one page up or down and give the focus to
* the topmost/bottommost component in the new visible area. If no component
* is a good candidate for focus, this scrollview reclaims the focus.
* </p>
*
* @param direction
* the scroll direction: {@link android.view.View#FOCUS_UP} to go
* one page up or {@link android.view.View#FOCUS_DOWN} to go one
* page down
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean pageScroll(int direction)
{
boolean down = direction == View.FOCUS_DOWN;
int height = getHeight();
if (down)
{
mTempRect.top = getScrollY() + height;
int count = getChildCount();
if (count > 0)
{
View view = getChildAt(count - 1);
if (mTempRect.top + height > view.getBottom())
{
mTempRect.top = view.getBottom() - height;
}
}
} else
{
mTempRect.top = getScrollY() - height;
if (mTempRect.top < 0)
{
mTempRect.top = 0;
}
}
mTempRect.bottom = mTempRect.top + height;
return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
}
/**
* <p>
* Handles scrolling in response to a "home/end" shortcut press. This method
* will scroll the view to the top or bottom and give the focus to the
* topmost/bottommost component in the new visible area. If no component is
* a good candidate for focus, this scrollview reclaims the focus.
* </p>
*
* @param direction
* the scroll direction: {@link android.view.View#FOCUS_UP} to go
* the top of the view or {@link android.view.View#FOCUS_DOWN} to
* go the bottom
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean fullScroll(int direction)
{
boolean down = direction == View.FOCUS_DOWN;
int height = getHeight();
mTempRect.top = 0;
mTempRect.bottom = height;
if (down)
{
int count = getChildCount();
if (count > 0)
{
View view = getChildAt(count - 1);
mTempRect.bottom = view.getBottom();
mTempRect.top = mTempRect.bottom - height;
}
}
return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
}
/**
* <p>
* Scrolls the view to make the area defined by <code>top</code> and
* <code>bottom</code> visible. This method attempts to give the focus to a
* component visible in this area. If no component can be focused in the new
* visible area, the focus is reclaimed by this scrollview.
* </p>
*
* @param direction
* the scroll direction: {@link android.view.View#FOCUS_UP} to go
* upward {@link android.view.View#FOCUS_DOWN} to downward
* @param top
* the top offset of the new area to be made visible
* @param bottom
* the bottom offset of the new area to be made visible
* @return true if the key event is consumed by this method, false otherwise
*/
private boolean scrollAndFocus(int direction, int top, int bottom)
{
boolean handled = true;
int height = getHeight();
int containerTop = getScrollY();
int containerBottom = containerTop + height;
boolean up = direction == View.FOCUS_UP;
View newFocused = findFocusableViewInBounds(up, top, bottom);
if (newFocused == null)
{
newFocused = this;
}
if (top >= containerTop && bottom <= containerBottom)
{
handled = false;