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1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package android.support.v4.widget;
18 
19 import android.content.Context;
20 import android.content.res.TypedArray;
21 import android.graphics.Bitmap;
22 import android.graphics.Canvas;
23 import android.graphics.Paint;
24 import android.graphics.PixelFormat;
25 import android.graphics.PorterDuff;
26 import android.graphics.PorterDuffColorFilter;
27 import android.graphics.Rect;
28 import android.graphics.drawable.Drawable;
29 import android.os.Build;
30 import android.os.Parcel;
31 import android.os.Parcelable;
32 import android.support.annotation.ColorInt;
33 import android.support.annotation.DrawableRes;
34 import android.support.v4.view.AccessibilityDelegateCompat;
35 import android.support.v4.view.MotionEventCompat;
36 import android.support.v4.view.ViewCompat;
37 import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
38 import android.util.AttributeSet;
39 import android.util.Log;
40 import android.view.MotionEvent;
41 import android.view.View;
42 import android.view.ViewConfiguration;
43 import android.view.ViewGroup;
44 import android.view.ViewParent;
45 import android.view.accessibility.AccessibilityEvent;
46 
47 import java.lang.reflect.Field;
48 import java.lang.reflect.Method;
49 import java.util.ArrayList;
50 
51 /**
52  * SlidingPaneLayout provides a horizontal, multi-pane layout for use at the top level
53  * of a UI. A left (or first) pane is treated as a content list or browser, subordinate to a
54  * primary detail view for displaying content.
55  *
56  * <p>Child views may overlap if their combined width exceeds the available width
57  * in the SlidingPaneLayout. When this occurs the user may slide the topmost view out of the way
58  * by dragging it, or by navigating in the direction of the overlapped view using a keyboard.
59  * If the content of the dragged child view is itself horizontally scrollable, the user may
60  * grab it by the very edge.</p>
61  *
62  * <p>Thanks to this sliding behavior, SlidingPaneLayout may be suitable for creating layouts
63  * that can smoothly adapt across many different screen sizes, expanding out fully on larger
64  * screens and collapsing on smaller screens.</p>
65  *
66  * <p>SlidingPaneLayout is distinct from a navigation drawer as described in the design
67  * guide and should not be used in the same scenarios. SlidingPaneLayout should be thought
68  * of only as a way to allow a two-pane layout normally used on larger screens to adapt to smaller
69  * screens in a natural way. The interaction patterns expressed by SlidingPaneLayout imply
70  * a physicality and direct information hierarchy between panes that does not necessarily exist
71  * in a scenario where a navigation drawer should be used instead.</p>
72  *
73  * <p>Appropriate uses of SlidingPaneLayout include pairings of panes such as a contact list and
74  * subordinate interactions with those contacts, or an email thread list with the content pane
75  * displaying the contents of the selected thread. Inappropriate uses of SlidingPaneLayout include
76  * switching between disparate functions of your app, such as jumping from a social stream view
77  * to a view of your personal profile - cases such as this should use the navigation drawer
78  * pattern instead. ({@link DrawerLayout DrawerLayout} implements this pattern.)</p>
79  *
80  * <p>Like {@link android.widget.LinearLayout LinearLayout}, SlidingPaneLayout supports
81  * the use of the layout parameter <code>layout_weight</code> on child views to determine
82  * how to divide leftover space after measurement is complete. It is only relevant for width.
83  * When views do not overlap weight behaves as it does in a LinearLayout.</p>
84  *
85  * <p>When views do overlap, weight on a slideable pane indicates that the pane should be
86  * sized to fill all available space in the closed state. Weight on a pane that becomes covered
87  * indicates that the pane should be sized to fill all available space except a small minimum strip
88  * that the user may use to grab the slideable view and pull it back over into a closed state.</p>
89  */
90 public class SlidingPaneLayout extends ViewGroup {
91     private static final String TAG = "SlidingPaneLayout";
92 
93     /**
94      * Default size of the overhang for a pane in the open state.
95      * At least this much of a sliding pane will remain visible.
96      * This indicates that there is more content available and provides
97      * a "physical" edge to grab to pull it closed.
98      */
99     private static final int DEFAULT_OVERHANG_SIZE = 32; // dp;
100 
101     /**
102      * If no fade color is given by default it will fade to 80% gray.
103      */
104     private static final int DEFAULT_FADE_COLOR = 0xcccccccc;
105 
106     /**
107      * The fade color used for the sliding panel. 0 = no fading.
108      */
109     private int mSliderFadeColor = DEFAULT_FADE_COLOR;
110 
111     /**
112      * Minimum velocity that will be detected as a fling
113      */
114     private static final int MIN_FLING_VELOCITY = 400; // dips per second
115 
116     /**
117      * The fade color used for the panel covered by the slider. 0 = no fading.
118      */
119     private int mCoveredFadeColor;
120 
121     /**
122      * Drawable used to draw the shadow between panes by default.
123      */
124     private Drawable mShadowDrawableLeft;
125 
126     /**
127      * Drawable used to draw the shadow between panes to support RTL (right to left language).
128      */
129     private Drawable mShadowDrawableRight;
130 
131     /**
132      * The size of the overhang in pixels.
133      * This is the minimum section of the sliding panel that will
134      * be visible in the open state to allow for a closing drag.
135      */
136     private final int mOverhangSize;
137 
138     /**
139      * True if a panel can slide with the current measurements
140      */
141     private boolean mCanSlide;
142 
143     /**
144      * The child view that can slide, if any.
145      */
146     private View mSlideableView;
147 
148     /**
149      * How far the panel is offset from its closed position.
150      * range [0, 1] where 0 = closed, 1 = open.
151      */
152     private float mSlideOffset;
153 
154     /**
155      * How far the non-sliding panel is parallaxed from its usual position when open.
156      * range [0, 1]
157      */
158     private float mParallaxOffset;
159 
160     /**
161      * How far in pixels the slideable panel may move.
162      */
163     private int mSlideRange;
164 
165     /**
166      * A panel view is locked into internal scrolling or another condition that
167      * is preventing a drag.
168      */
169     private boolean mIsUnableToDrag;
170 
171     /**
172      * Distance in pixels to parallax the fixed pane by when fully closed
173      */
174     private int mParallaxBy;
175 
176     private float mInitialMotionX;
177     private float mInitialMotionY;
178 
179     private PanelSlideListener mPanelSlideListener;
180 
181     private final ViewDragHelper mDragHelper;
182 
183     /**
184      * Stores whether or not the pane was open the last time it was slideable.
185      * If open/close operations are invoked this state is modified. Used by
186      * instance state save/restore.
187      */
188     private boolean mPreservedOpenState;
189     private boolean mFirstLayout = true;
190 
191     private final Rect mTmpRect = new Rect();
192 
193     private final ArrayList<DisableLayerRunnable> mPostedRunnables =
194             new ArrayList<DisableLayerRunnable>();
195 
196     static final SlidingPanelLayoutImpl IMPL;
197 
198     static {
199         final int deviceVersion = Build.VERSION.SDK_INT;
200         if (deviceVersion >= 17) {
201             IMPL = new SlidingPanelLayoutImplJBMR1();
202         } else if (deviceVersion >= 16) {
203             IMPL = new SlidingPanelLayoutImplJB();
204         } else {
205             IMPL = new SlidingPanelLayoutImplBase();
206         }
207     }
208 
209     /**
210      * Listener for monitoring events about sliding panes.
211      */
212     public interface PanelSlideListener {
213         /**
214          * Called when a sliding pane's position changes.
215          * @param panel The child view that was moved
216          * @param slideOffset The new offset of this sliding pane within its range, from 0-1
217          */
onPanelSlide(View panel, float slideOffset)218         public void onPanelSlide(View panel, float slideOffset);
219         /**
220          * Called when a sliding pane becomes slid completely open. The pane may or may not
221          * be interactive at this point depending on how much of the pane is visible.
222          * @param panel The child view that was slid to an open position, revealing other panes
223          */
onPanelOpened(View panel)224         public void onPanelOpened(View panel);
225 
226         /**
227          * Called when a sliding pane becomes slid completely closed. The pane is now guaranteed
228          * to be interactive. It may now obscure other views in the layout.
229          * @param panel The child view that was slid to a closed position
230          */
onPanelClosed(View panel)231         public void onPanelClosed(View panel);
232     }
233 
234     /**
235      * No-op stubs for {@link PanelSlideListener}. If you only want to implement a subset
236      * of the listener methods you can extend this instead of implement the full interface.
237      */
238     public static class SimplePanelSlideListener implements PanelSlideListener {
239         @Override
onPanelSlide(View panel, float slideOffset)240         public void onPanelSlide(View panel, float slideOffset) {
241         }
242         @Override
onPanelOpened(View panel)243         public void onPanelOpened(View panel) {
244         }
245         @Override
onPanelClosed(View panel)246         public void onPanelClosed(View panel) {
247         }
248     }
249 
SlidingPaneLayout(Context context)250     public SlidingPaneLayout(Context context) {
251         this(context, null);
252     }
253 
SlidingPaneLayout(Context context, AttributeSet attrs)254     public SlidingPaneLayout(Context context, AttributeSet attrs) {
255         this(context, attrs, 0);
256     }
257 
SlidingPaneLayout(Context context, AttributeSet attrs, int defStyle)258     public SlidingPaneLayout(Context context, AttributeSet attrs, int defStyle) {
259         super(context, attrs, defStyle);
260 
261         final float density = context.getResources().getDisplayMetrics().density;
262         mOverhangSize = (int) (DEFAULT_OVERHANG_SIZE * density + 0.5f);
263 
264         final ViewConfiguration viewConfig = ViewConfiguration.get(context);
265 
266         setWillNotDraw(false);
267 
268         ViewCompat.setAccessibilityDelegate(this, new AccessibilityDelegate());
269         ViewCompat.setImportantForAccessibility(this, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
270 
271         mDragHelper = ViewDragHelper.create(this, 0.5f, new DragHelperCallback());
272         mDragHelper.setMinVelocity(MIN_FLING_VELOCITY * density);
273     }
274 
275     /**
276      * Set a distance to parallax the lower pane by when the upper pane is in its
277      * fully closed state. The lower pane will scroll between this position and
278      * its fully open state.
279      *
280      * @param parallaxBy Distance to parallax by in pixels
281      */
setParallaxDistance(int parallaxBy)282     public void setParallaxDistance(int parallaxBy) {
283         mParallaxBy = parallaxBy;
284         requestLayout();
285     }
286 
287     /**
288      * @return The distance the lower pane will parallax by when the upper pane is fully closed.
289      *
290      * @see #setParallaxDistance(int)
291      */
getParallaxDistance()292     public int getParallaxDistance() {
293         return mParallaxBy;
294     }
295 
296     /**
297      * Set the color used to fade the sliding pane out when it is slid most of the way offscreen.
298      *
299      * @param color An ARGB-packed color value
300      */
setSliderFadeColor(@olorInt int color)301     public void setSliderFadeColor(@ColorInt int color) {
302         mSliderFadeColor = color;
303     }
304 
305     /**
306      * @return The ARGB-packed color value used to fade the sliding pane
307      */
308     @ColorInt
getSliderFadeColor()309     public int getSliderFadeColor() {
310         return mSliderFadeColor;
311     }
312 
313     /**
314      * Set the color used to fade the pane covered by the sliding pane out when the pane
315      * will become fully covered in the closed state.
316      *
317      * @param color An ARGB-packed color value
318      */
setCoveredFadeColor(@olorInt int color)319     public void setCoveredFadeColor(@ColorInt int color) {
320         mCoveredFadeColor = color;
321     }
322 
323     /**
324      * @return The ARGB-packed color value used to fade the fixed pane
325      */
326     @ColorInt
getCoveredFadeColor()327     public int getCoveredFadeColor() {
328         return mCoveredFadeColor;
329     }
330 
setPanelSlideListener(PanelSlideListener listener)331     public void setPanelSlideListener(PanelSlideListener listener) {
332         mPanelSlideListener = listener;
333     }
334 
dispatchOnPanelSlide(View panel)335     void dispatchOnPanelSlide(View panel) {
336         if (mPanelSlideListener != null) {
337             mPanelSlideListener.onPanelSlide(panel, mSlideOffset);
338         }
339     }
340 
dispatchOnPanelOpened(View panel)341     void dispatchOnPanelOpened(View panel) {
342         if (mPanelSlideListener != null) {
343             mPanelSlideListener.onPanelOpened(panel);
344         }
345         sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
346     }
347 
dispatchOnPanelClosed(View panel)348     void dispatchOnPanelClosed(View panel) {
349         if (mPanelSlideListener != null) {
350             mPanelSlideListener.onPanelClosed(panel);
351         }
352         sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
353     }
354 
updateObscuredViewsVisibility(View panel)355     void updateObscuredViewsVisibility(View panel) {
356         final boolean isLayoutRtl = isLayoutRtlSupport();
357         final int startBound = isLayoutRtl ? (getWidth() - getPaddingRight()) :
358             getPaddingLeft();
359         final int endBound = isLayoutRtl ? getPaddingLeft() :
360             (getWidth() - getPaddingRight());
361         final int topBound = getPaddingTop();
362         final int bottomBound = getHeight() - getPaddingBottom();
363         final int left;
364         final int right;
365         final int top;
366         final int bottom;
367         if (panel != null && viewIsOpaque(panel)) {
368             left = panel.getLeft();
369             right = panel.getRight();
370             top = panel.getTop();
371             bottom = panel.getBottom();
372         } else {
373             left = right = top = bottom = 0;
374         }
375 
376         for (int i = 0, childCount = getChildCount(); i < childCount; i++) {
377             final View child = getChildAt(i);
378 
379             if (child == panel) {
380                 // There are still more children above the panel but they won't be affected.
381                 break;
382             }
383 
384             final int clampedChildLeft = Math.max((isLayoutRtl ? endBound :
385                 startBound), child.getLeft());
386             final int clampedChildTop = Math.max(topBound, child.getTop());
387             final int clampedChildRight = Math.min((isLayoutRtl ? startBound :
388                 endBound), child.getRight());
389             final int clampedChildBottom = Math.min(bottomBound, child.getBottom());
390             final int vis;
391             if (clampedChildLeft >= left && clampedChildTop >= top &&
392                     clampedChildRight <= right && clampedChildBottom <= bottom) {
393                 vis = INVISIBLE;
394             } else {
395                 vis = VISIBLE;
396             }
397             child.setVisibility(vis);
398         }
399     }
400 
setAllChildrenVisible()401     void setAllChildrenVisible() {
402         for (int i = 0, childCount = getChildCount(); i < childCount; i++) {
403             final View child = getChildAt(i);
404             if (child.getVisibility() == INVISIBLE) {
405                 child.setVisibility(VISIBLE);
406             }
407         }
408     }
409 
viewIsOpaque(View v)410     private static boolean viewIsOpaque(View v) {
411         if (ViewCompat.isOpaque(v)) return true;
412 
413         // View#isOpaque didn't take all valid opaque scrollbar modes into account
414         // before API 18 (JB-MR2). On newer devices rely solely on isOpaque above and return false
415         // here. On older devices, check the view's background drawable directly as a fallback.
416         if (Build.VERSION.SDK_INT >= 18) return false;
417 
418         final Drawable bg = v.getBackground();
419         if (bg != null) {
420             return bg.getOpacity() == PixelFormat.OPAQUE;
421         }
422         return false;
423     }
424 
425     @Override
onAttachedToWindow()426     protected void onAttachedToWindow() {
427         super.onAttachedToWindow();
428         mFirstLayout = true;
429     }
430 
431     @Override
onDetachedFromWindow()432     protected void onDetachedFromWindow() {
433         super.onDetachedFromWindow();
434         mFirstLayout = true;
435 
436         for (int i = 0, count = mPostedRunnables.size(); i < count; i++) {
437             final DisableLayerRunnable dlr = mPostedRunnables.get(i);
438             dlr.run();
439         }
440         mPostedRunnables.clear();
441     }
442 
443     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)444     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
445         int widthMode = MeasureSpec.getMode(widthMeasureSpec);
446         int widthSize = MeasureSpec.getSize(widthMeasureSpec);
447         int heightMode = MeasureSpec.getMode(heightMeasureSpec);
448         int heightSize = MeasureSpec.getSize(heightMeasureSpec);
449 
450         if (widthMode != MeasureSpec.EXACTLY) {
451             if (isInEditMode()) {
452                 // Don't crash the layout editor. Consume all of the space if specified
453                 // or pick a magic number from thin air otherwise.
454                 // TODO Better communication with tools of this bogus state.
455                 // It will crash on a real device.
456                 if (widthMode == MeasureSpec.AT_MOST) {
457                     widthMode = MeasureSpec.EXACTLY;
458                 } else if (widthMode == MeasureSpec.UNSPECIFIED) {
459                     widthMode = MeasureSpec.EXACTLY;
460                     widthSize = 300;
461                 }
462             } else {
463                 throw new IllegalStateException("Width must have an exact value or MATCH_PARENT");
464             }
465         } else if (heightMode == MeasureSpec.UNSPECIFIED) {
466             if (isInEditMode()) {
467                 // Don't crash the layout editor. Pick a magic number from thin air instead.
468                 // TODO Better communication with tools of this bogus state.
469                 // It will crash on a real device.
470                 if (heightMode == MeasureSpec.UNSPECIFIED) {
471                     heightMode = MeasureSpec.AT_MOST;
472                     heightSize = 300;
473                 }
474             } else {
475                 throw new IllegalStateException("Height must not be UNSPECIFIED");
476             }
477         }
478 
479         int layoutHeight = 0;
480         int maxLayoutHeight = -1;
481         switch (heightMode) {
482             case MeasureSpec.EXACTLY:
483                 layoutHeight = maxLayoutHeight = heightSize - getPaddingTop() - getPaddingBottom();
484                 break;
485             case MeasureSpec.AT_MOST:
486                 maxLayoutHeight = heightSize - getPaddingTop() - getPaddingBottom();
487                 break;
488         }
489 
490         float weightSum = 0;
491         boolean canSlide = false;
492         final int widthAvailable = widthSize - getPaddingLeft() - getPaddingRight();
493         int widthRemaining = widthAvailable;
494         final int childCount = getChildCount();
495 
496         if (childCount > 2) {
497             Log.e(TAG, "onMeasure: More than two child views are not supported.");
498         }
499 
500         // We'll find the current one below.
501         mSlideableView = null;
502 
503         // First pass. Measure based on child LayoutParams width/height.
504         // Weight will incur a second pass.
505         for (int i = 0; i < childCount; i++) {
506             final View child = getChildAt(i);
507             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
508 
509             if (child.getVisibility() == GONE) {
510                 lp.dimWhenOffset = false;
511                 continue;
512             }
513 
514             if (lp.weight > 0) {
515                 weightSum += lp.weight;
516 
517                 // If we have no width, weight is the only contributor to the final size.
518                 // Measure this view on the weight pass only.
519                 if (lp.width == 0) continue;
520             }
521 
522             int childWidthSpec;
523             final int horizontalMargin = lp.leftMargin + lp.rightMargin;
524             if (lp.width == LayoutParams.WRAP_CONTENT) {
525                 childWidthSpec = MeasureSpec.makeMeasureSpec(widthAvailable - horizontalMargin,
526                         MeasureSpec.AT_MOST);
527             } else if (lp.width == LayoutParams.FILL_PARENT) {
528                 childWidthSpec = MeasureSpec.makeMeasureSpec(widthAvailable - horizontalMargin,
529                         MeasureSpec.EXACTLY);
530             } else {
531                 childWidthSpec = MeasureSpec.makeMeasureSpec(lp.width, MeasureSpec.EXACTLY);
532             }
533 
534             int childHeightSpec;
535             if (lp.height == LayoutParams.WRAP_CONTENT) {
536                 childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight, MeasureSpec.AT_MOST);
537             } else if (lp.height == LayoutParams.FILL_PARENT) {
538                 childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight, MeasureSpec.EXACTLY);
539             } else {
540                 childHeightSpec = MeasureSpec.makeMeasureSpec(lp.height, MeasureSpec.EXACTLY);
541             }
542 
543             child.measure(childWidthSpec, childHeightSpec);
544             final int childWidth = child.getMeasuredWidth();
545             final int childHeight = child.getMeasuredHeight();
546 
547             if (heightMode == MeasureSpec.AT_MOST && childHeight > layoutHeight) {
548                 layoutHeight = Math.min(childHeight, maxLayoutHeight);
549             }
550 
551             widthRemaining -= childWidth;
552             canSlide |= lp.slideable = widthRemaining < 0;
553             if (lp.slideable) {
554                 mSlideableView = child;
555             }
556         }
557 
558         // Resolve weight and make sure non-sliding panels are smaller than the full screen.
559         if (canSlide || weightSum > 0) {
560             final int fixedPanelWidthLimit = widthAvailable - mOverhangSize;
561 
562             for (int i = 0; i < childCount; i++) {
563                 final View child = getChildAt(i);
564 
565                 if (child.getVisibility() == GONE) {
566                     continue;
567                 }
568 
569                 final LayoutParams lp = (LayoutParams) child.getLayoutParams();
570 
571                 if (child.getVisibility() == GONE) {
572                     continue;
573                 }
574 
575                 final boolean skippedFirstPass = lp.width == 0 && lp.weight > 0;
576                 final int measuredWidth = skippedFirstPass ? 0 : child.getMeasuredWidth();
577                 if (canSlide && child != mSlideableView) {
578                     if (lp.width < 0 && (measuredWidth > fixedPanelWidthLimit || lp.weight > 0)) {
579                         // Fixed panels in a sliding configuration should
580                         // be clamped to the fixed panel limit.
581                         final int childHeightSpec;
582                         if (skippedFirstPass) {
583                             // Do initial height measurement if we skipped measuring this view
584                             // the first time around.
585                             if (lp.height == LayoutParams.WRAP_CONTENT) {
586                                 childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight,
587                                         MeasureSpec.AT_MOST);
588                             } else if (lp.height == LayoutParams.FILL_PARENT) {
589                                 childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight,
590                                         MeasureSpec.EXACTLY);
591                             } else {
592                                 childHeightSpec = MeasureSpec.makeMeasureSpec(lp.height,
593                                         MeasureSpec.EXACTLY);
594                             }
595                         } else {
596                             childHeightSpec = MeasureSpec.makeMeasureSpec(
597                                     child.getMeasuredHeight(), MeasureSpec.EXACTLY);
598                         }
599                         final int childWidthSpec = MeasureSpec.makeMeasureSpec(
600                                 fixedPanelWidthLimit, MeasureSpec.EXACTLY);
601                         child.measure(childWidthSpec, childHeightSpec);
602                     }
603                 } else if (lp.weight > 0) {
604                     int childHeightSpec;
605                     if (lp.width == 0) {
606                         // This was skipped the first time; figure out a real height spec.
607                         if (lp.height == LayoutParams.WRAP_CONTENT) {
608                             childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight,
609                                     MeasureSpec.AT_MOST);
610                         } else if (lp.height == LayoutParams.FILL_PARENT) {
611                             childHeightSpec = MeasureSpec.makeMeasureSpec(maxLayoutHeight,
612                                     MeasureSpec.EXACTLY);
613                         } else {
614                             childHeightSpec = MeasureSpec.makeMeasureSpec(lp.height,
615                                     MeasureSpec.EXACTLY);
616                         }
617                     } else {
618                         childHeightSpec = MeasureSpec.makeMeasureSpec(
619                                 child.getMeasuredHeight(), MeasureSpec.EXACTLY);
620                     }
621 
622                     if (canSlide) {
623                         // Consume available space
624                         final int horizontalMargin = lp.leftMargin + lp.rightMargin;
625                         final int newWidth = widthAvailable - horizontalMargin;
626                         final int childWidthSpec = MeasureSpec.makeMeasureSpec(
627                                 newWidth, MeasureSpec.EXACTLY);
628                         if (measuredWidth != newWidth) {
629                             child.measure(childWidthSpec, childHeightSpec);
630                         }
631                     } else {
632                         // Distribute the extra width proportionally similar to LinearLayout
633                         final int widthToDistribute = Math.max(0, widthRemaining);
634                         final int addedWidth = (int) (lp.weight * widthToDistribute / weightSum);
635                         final int childWidthSpec = MeasureSpec.makeMeasureSpec(
636                                 measuredWidth + addedWidth, MeasureSpec.EXACTLY);
637                         child.measure(childWidthSpec, childHeightSpec);
638                     }
639                 }
640             }
641         }
642 
643         final int measuredWidth = widthSize;
644         final int measuredHeight = layoutHeight + getPaddingTop() + getPaddingBottom();
645 
646         setMeasuredDimension(measuredWidth, measuredHeight);
647         mCanSlide = canSlide;
648 
649         if (mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE && !canSlide) {
650             // Cancel scrolling in progress, it's no longer relevant.
651             mDragHelper.abort();
652         }
653     }
654 
655     @Override
onLayout(boolean changed, int l, int t, int r, int b)656     protected void onLayout(boolean changed, int l, int t, int r, int b) {
657         final boolean isLayoutRtl = isLayoutRtlSupport();
658         if (isLayoutRtl) {
659             mDragHelper.setEdgeTrackingEnabled(ViewDragHelper.EDGE_RIGHT);
660         } else {
661             mDragHelper.setEdgeTrackingEnabled(ViewDragHelper.EDGE_LEFT);
662         }
663         final int width = r - l;
664         final int paddingStart = isLayoutRtl ? getPaddingRight() : getPaddingLeft();
665         final int paddingEnd = isLayoutRtl ? getPaddingLeft() : getPaddingRight();
666         final int paddingTop = getPaddingTop();
667 
668         final int childCount = getChildCount();
669         int xStart = paddingStart;
670         int nextXStart = xStart;
671 
672         if (mFirstLayout) {
673             mSlideOffset = mCanSlide && mPreservedOpenState ? 1.f : 0.f;
674         }
675 
676         for (int i = 0; i < childCount; i++) {
677             final View child = getChildAt(i);
678 
679             if (child.getVisibility() == GONE) {
680                 continue;
681             }
682 
683             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
684 
685             final int childWidth = child.getMeasuredWidth();
686             int offset = 0;
687 
688             if (lp.slideable) {
689                 final int margin = lp.leftMargin + lp.rightMargin;
690                 final int range = Math.min(nextXStart,
691                         width - paddingEnd - mOverhangSize) - xStart - margin;
692                 mSlideRange = range;
693                 final int lpMargin = isLayoutRtl ? lp.rightMargin : lp.leftMargin;
694                 lp.dimWhenOffset = xStart + lpMargin + range + childWidth / 2 >
695                         width - paddingEnd;
696                 final int pos = (int) (range * mSlideOffset);
697                 xStart += pos + lpMargin;
698                 mSlideOffset = (float) pos / mSlideRange;
699             } else if (mCanSlide && mParallaxBy != 0) {
700                 offset = (int) ((1 - mSlideOffset) * mParallaxBy);
701                 xStart = nextXStart;
702             } else {
703                 xStart = nextXStart;
704             }
705 
706             final int childRight;
707             final int childLeft;
708             if (isLayoutRtl) {
709                 childRight = width - xStart + offset;
710                 childLeft = childRight - childWidth;
711             } else {
712                 childLeft = xStart - offset;
713                 childRight = childLeft + childWidth;
714             }
715 
716             final int childTop = paddingTop;
717             final int childBottom = childTop + child.getMeasuredHeight();
718             child.layout(childLeft, paddingTop, childRight, childBottom);
719 
720             nextXStart += child.getWidth();
721         }
722 
723         if (mFirstLayout) {
724             if (mCanSlide) {
725                 if (mParallaxBy != 0) {
726                     parallaxOtherViews(mSlideOffset);
727                 }
728                 if (((LayoutParams) mSlideableView.getLayoutParams()).dimWhenOffset) {
729                     dimChildView(mSlideableView, mSlideOffset, mSliderFadeColor);
730                 }
731             } else {
732                 // Reset the dim level of all children; it's irrelevant when nothing moves.
733                 for (int i = 0; i < childCount; i++) {
734                     dimChildView(getChildAt(i), 0, mSliderFadeColor);
735                 }
736             }
737             updateObscuredViewsVisibility(mSlideableView);
738         }
739 
740         mFirstLayout = false;
741     }
742 
743     @Override
onSizeChanged(int w, int h, int oldw, int oldh)744     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
745         super.onSizeChanged(w, h, oldw, oldh);
746         // Recalculate sliding panes and their details
747         if (w != oldw) {
748             mFirstLayout = true;
749         }
750     }
751 
752     @Override
requestChildFocus(View child, View focused)753     public void requestChildFocus(View child, View focused) {
754         super.requestChildFocus(child, focused);
755         if (!isInTouchMode() && !mCanSlide) {
756             mPreservedOpenState = child == mSlideableView;
757         }
758     }
759 
760     @Override
onInterceptTouchEvent(MotionEvent ev)761     public boolean onInterceptTouchEvent(MotionEvent ev) {
762         final int action = MotionEventCompat.getActionMasked(ev);
763 
764         // Preserve the open state based on the last view that was touched.
765         if (!mCanSlide && action == MotionEvent.ACTION_DOWN && getChildCount() > 1) {
766             // After the first things will be slideable.
767             final View secondChild = getChildAt(1);
768             if (secondChild != null) {
769                 mPreservedOpenState = !mDragHelper.isViewUnder(secondChild,
770                         (int) ev.getX(), (int) ev.getY());
771             }
772         }
773 
774         if (!mCanSlide || (mIsUnableToDrag && action != MotionEvent.ACTION_DOWN)) {
775             mDragHelper.cancel();
776             return super.onInterceptTouchEvent(ev);
777         }
778 
779         if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
780             mDragHelper.cancel();
781             return false;
782         }
783 
784         boolean interceptTap = false;
785 
786         switch (action) {
787             case MotionEvent.ACTION_DOWN: {
788                 mIsUnableToDrag = false;
789                 final float x = ev.getX();
790                 final float y = ev.getY();
791                 mInitialMotionX = x;
792                 mInitialMotionY = y;
793 
794                 if (mDragHelper.isViewUnder(mSlideableView, (int) x, (int) y) &&
795                         isDimmed(mSlideableView)) {
796                     interceptTap = true;
797                 }
798                 break;
799             }
800 
801             case MotionEvent.ACTION_MOVE: {
802                 final float x = ev.getX();
803                 final float y = ev.getY();
804                 final float adx = Math.abs(x - mInitialMotionX);
805                 final float ady = Math.abs(y - mInitialMotionY);
806                 final int slop = mDragHelper.getTouchSlop();
807                 if (adx > slop && ady > adx) {
808                     mDragHelper.cancel();
809                     mIsUnableToDrag = true;
810                     return false;
811                 }
812             }
813         }
814 
815         final boolean interceptForDrag = mDragHelper.shouldInterceptTouchEvent(ev);
816 
817         return interceptForDrag || interceptTap;
818     }
819 
820     @Override
onTouchEvent(MotionEvent ev)821     public boolean onTouchEvent(MotionEvent ev) {
822         if (!mCanSlide) {
823             return super.onTouchEvent(ev);
824         }
825 
826         mDragHelper.processTouchEvent(ev);
827 
828         final int action = ev.getAction();
829         boolean wantTouchEvents = true;
830 
831         switch (action & MotionEventCompat.ACTION_MASK) {
832             case MotionEvent.ACTION_DOWN: {
833                 final float x = ev.getX();
834                 final float y = ev.getY();
835                 mInitialMotionX = x;
836                 mInitialMotionY = y;
837                 break;
838             }
839 
840             case MotionEvent.ACTION_UP: {
841                 if (isDimmed(mSlideableView)) {
842                     final float x = ev.getX();
843                     final float y = ev.getY();
844                     final float dx = x - mInitialMotionX;
845                     final float dy = y - mInitialMotionY;
846                     final int slop = mDragHelper.getTouchSlop();
847                     if (dx * dx + dy * dy < slop * slop &&
848                             mDragHelper.isViewUnder(mSlideableView, (int) x, (int) y)) {
849                         // Taps close a dimmed open pane.
850                         closePane(mSlideableView, 0);
851                         break;
852                     }
853                 }
854                 break;
855             }
856         }
857 
858         return wantTouchEvents;
859     }
860 
closePane(View pane, int initialVelocity)861     private boolean closePane(View pane, int initialVelocity) {
862         if (mFirstLayout || smoothSlideTo(0.f, initialVelocity)) {
863             mPreservedOpenState = false;
864             return true;
865         }
866         return false;
867     }
868 
openPane(View pane, int initialVelocity)869     private boolean openPane(View pane, int initialVelocity) {
870         if (mFirstLayout || smoothSlideTo(1.f, initialVelocity)) {
871             mPreservedOpenState = true;
872             return true;
873         }
874         return false;
875     }
876 
877     /**
878      * @deprecated Renamed to {@link #openPane()} - this method is going away soon!
879      */
880     @Deprecated
smoothSlideOpen()881     public void smoothSlideOpen() {
882         openPane();
883     }
884 
885     /**
886      * Open the sliding pane if it is currently slideable. If first layout
887      * has already completed this will animate.
888      *
889      * @return true if the pane was slideable and is now open/in the process of opening
890      */
openPane()891     public boolean openPane() {
892         return openPane(mSlideableView, 0);
893     }
894 
895     /**
896      * @deprecated Renamed to {@link #closePane()} - this method is going away soon!
897      */
898     @Deprecated
smoothSlideClosed()899     public void smoothSlideClosed() {
900         closePane();
901     }
902 
903     /**
904      * Close the sliding pane if it is currently slideable. If first layout
905      * has already completed this will animate.
906      *
907      * @return true if the pane was slideable and is now closed/in the process of closing
908      */
closePane()909     public boolean closePane() {
910         return closePane(mSlideableView, 0);
911     }
912 
913     /**
914      * Check if the layout is completely open. It can be open either because the slider
915      * itself is open revealing the left pane, or if all content fits without sliding.
916      *
917      * @return true if sliding panels are completely open
918      */
isOpen()919     public boolean isOpen() {
920         return !mCanSlide || mSlideOffset == 1;
921     }
922 
923     /**
924      * @return true if content in this layout can be slid open and closed
925      * @deprecated Renamed to {@link #isSlideable()} - this method is going away soon!
926      */
927     @Deprecated
canSlide()928     public boolean canSlide() {
929         return mCanSlide;
930     }
931 
932     /**
933      * Check if the content in this layout cannot fully fit side by side and therefore
934      * the content pane can be slid back and forth.
935      *
936      * @return true if content in this layout can be slid open and closed
937      */
isSlideable()938     public boolean isSlideable() {
939         return mCanSlide;
940     }
941 
onPanelDragged(int newLeft)942     private void onPanelDragged(int newLeft) {
943         if (mSlideableView == null) {
944             // This can happen if we're aborting motion during layout because everything now fits.
945             mSlideOffset = 0;
946             return;
947         }
948         final boolean isLayoutRtl = isLayoutRtlSupport();
949         final LayoutParams lp = (LayoutParams) mSlideableView.getLayoutParams();
950 
951         int childWidth = mSlideableView.getWidth();
952         final int newStart = isLayoutRtl ? getWidth() - newLeft - childWidth : newLeft;
953 
954         final int paddingStart = isLayoutRtl ? getPaddingRight() : getPaddingLeft();
955         final int lpMargin = isLayoutRtl ? lp.rightMargin : lp.leftMargin;
956         final int startBound = paddingStart + lpMargin;
957 
958         mSlideOffset = (float) (newStart - startBound) / mSlideRange;
959 
960         if (mParallaxBy != 0) {
961             parallaxOtherViews(mSlideOffset);
962         }
963 
964         if (lp.dimWhenOffset) {
965             dimChildView(mSlideableView, mSlideOffset, mSliderFadeColor);
966         }
967         dispatchOnPanelSlide(mSlideableView);
968     }
969 
dimChildView(View v, float mag, int fadeColor)970     private void dimChildView(View v, float mag, int fadeColor) {
971         final LayoutParams lp = (LayoutParams) v.getLayoutParams();
972 
973         if (mag > 0 && fadeColor != 0) {
974             final int baseAlpha = (fadeColor & 0xff000000) >>> 24;
975             int imag = (int) (baseAlpha * mag);
976             int color = imag << 24 | (fadeColor & 0xffffff);
977             if (lp.dimPaint == null) {
978                 lp.dimPaint = new Paint();
979             }
980             lp.dimPaint.setColorFilter(new PorterDuffColorFilter(color, PorterDuff.Mode.SRC_OVER));
981             if (ViewCompat.getLayerType(v) != ViewCompat.LAYER_TYPE_HARDWARE) {
982                 ViewCompat.setLayerType(v, ViewCompat.LAYER_TYPE_HARDWARE, lp.dimPaint);
983             }
984             invalidateChildRegion(v);
985         } else if (ViewCompat.getLayerType(v) != ViewCompat.LAYER_TYPE_NONE) {
986             if (lp.dimPaint != null) {
987                 lp.dimPaint.setColorFilter(null);
988             }
989             final DisableLayerRunnable dlr = new DisableLayerRunnable(v);
990             mPostedRunnables.add(dlr);
991             ViewCompat.postOnAnimation(this, dlr);
992         }
993     }
994 
995     @Override
drawChild(Canvas canvas, View child, long drawingTime)996     protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
997         final LayoutParams lp = (LayoutParams) child.getLayoutParams();
998         boolean result;
999         final int save = canvas.save(Canvas.CLIP_SAVE_FLAG);
1000 
1001         if (mCanSlide && !lp.slideable && mSlideableView != null) {
1002             // Clip against the slider; no sense drawing what will immediately be covered.
1003             canvas.getClipBounds(mTmpRect);
1004             if (isLayoutRtlSupport()) {
1005                 mTmpRect.left = Math.max(mTmpRect.left, mSlideableView.getRight());
1006             } else {
1007                 mTmpRect.right = Math.min(mTmpRect.right, mSlideableView.getLeft());
1008             }
1009             canvas.clipRect(mTmpRect);
1010         }
1011 
1012         if (Build.VERSION.SDK_INT >= 11) { // HC
1013             result = super.drawChild(canvas, child, drawingTime);
1014         } else {
1015             if (lp.dimWhenOffset && mSlideOffset > 0) {
1016                 if (!child.isDrawingCacheEnabled()) {
1017                     child.setDrawingCacheEnabled(true);
1018                 }
1019                 final Bitmap cache = child.getDrawingCache();
1020                 if (cache != null) {
1021                     canvas.drawBitmap(cache, child.getLeft(), child.getTop(), lp.dimPaint);
1022                     result = false;
1023                 } else {
1024                     Log.e(TAG, "drawChild: child view " + child + " returned null drawing cache");
1025                     result = super.drawChild(canvas, child, drawingTime);
1026                 }
1027             } else {
1028                 if (child.isDrawingCacheEnabled()) {
1029                     child.setDrawingCacheEnabled(false);
1030                 }
1031                 result = super.drawChild(canvas, child, drawingTime);
1032             }
1033         }
1034 
1035         canvas.restoreToCount(save);
1036 
1037         return result;
1038     }
1039 
invalidateChildRegion(View v)1040     private void invalidateChildRegion(View v) {
1041         IMPL.invalidateChildRegion(this, v);
1042     }
1043 
1044     /**
1045      * Smoothly animate mDraggingPane to the target X position within its range.
1046      *
1047      * @param slideOffset position to animate to
1048      * @param velocity initial velocity in case of fling, or 0.
1049      */
smoothSlideTo(float slideOffset, int velocity)1050     boolean smoothSlideTo(float slideOffset, int velocity) {
1051         if (!mCanSlide) {
1052             // Nothing to do.
1053             return false;
1054         }
1055 
1056         final boolean isLayoutRtl = isLayoutRtlSupport();
1057         final LayoutParams lp = (LayoutParams) mSlideableView.getLayoutParams();
1058 
1059         int x;
1060         if (isLayoutRtl) {
1061             int startBound = getPaddingRight() + lp.rightMargin;
1062             int childWidth = mSlideableView.getWidth();
1063             x = (int) (getWidth() - (startBound + slideOffset * mSlideRange + childWidth));
1064         } else {
1065             int startBound = getPaddingLeft() + lp.leftMargin;
1066             x = (int) (startBound + slideOffset * mSlideRange);
1067         }
1068 
1069         if (mDragHelper.smoothSlideViewTo(mSlideableView, x, mSlideableView.getTop())) {
1070             setAllChildrenVisible();
1071             ViewCompat.postInvalidateOnAnimation(this);
1072             return true;
1073         }
1074         return false;
1075     }
1076 
1077     @Override
computeScroll()1078     public void computeScroll() {
1079         if (mDragHelper.continueSettling(true)) {
1080             if (!mCanSlide) {
1081                 mDragHelper.abort();
1082                 return;
1083             }
1084 
1085             ViewCompat.postInvalidateOnAnimation(this);
1086         }
1087     }
1088 
1089     /**
1090      * @deprecated Renamed to {@link #setShadowDrawableLeft(Drawable d)} to support LTR (left to
1091      * right language) and {@link #setShadowDrawableRight(Drawable d)} to support RTL (right to left
1092      * language) during opening/closing.
1093      *
1094      * @param d drawable to use as a shadow
1095      */
1096     @Deprecated
setShadowDrawable(Drawable d)1097     public void setShadowDrawable(Drawable d) {
1098         setShadowDrawableLeft(d);
1099     }
1100 
1101     /**
1102      * Set a drawable to use as a shadow cast by the right pane onto the left pane
1103      * during opening/closing.
1104      *
1105      * @param d drawable to use as a shadow
1106      */
setShadowDrawableLeft(Drawable d)1107     public void setShadowDrawableLeft(Drawable d) {
1108         mShadowDrawableLeft = d;
1109     }
1110 
1111     /**
1112      * Set a drawable to use as a shadow cast by the left pane onto the right pane
1113      * during opening/closing to support right to left language.
1114      *
1115      * @param d drawable to use as a shadow
1116      */
setShadowDrawableRight(Drawable d)1117     public void setShadowDrawableRight(Drawable d) {
1118         mShadowDrawableRight = d;
1119     }
1120 
1121     /**
1122      * Set a drawable to use as a shadow cast by the right pane onto the left pane
1123      * during opening/closing.
1124      *
1125      * @param resId Resource ID of a drawable to use
1126      */
1127     @Deprecated
setShadowResource(@rawableRes int resId)1128     public void setShadowResource(@DrawableRes int resId) {
1129         setShadowDrawable(getResources().getDrawable(resId));
1130     }
1131 
1132     /**
1133      * Set a drawable to use as a shadow cast by the right pane onto the left pane
1134      * during opening/closing.
1135      *
1136      * @param resId Resource ID of a drawable to use
1137      */
setShadowResourceLeft(int resId)1138     public void setShadowResourceLeft(int resId) {
1139         setShadowDrawableLeft(getResources().getDrawable(resId));
1140     }
1141 
1142     /**
1143      * Set a drawable to use as a shadow cast by the left pane onto the right pane
1144      * during opening/closing to support right to left language.
1145      *
1146      * @param resId Resource ID of a drawable to use
1147      */
setShadowResourceRight(int resId)1148     public void setShadowResourceRight(int resId) {
1149         setShadowDrawableRight(getResources().getDrawable(resId));
1150     }
1151 
1152 
1153     @Override
draw(Canvas c)1154     public void draw(Canvas c) {
1155         super.draw(c);
1156         final boolean isLayoutRtl = isLayoutRtlSupport();
1157         Drawable shadowDrawable;
1158         if (isLayoutRtl) {
1159             shadowDrawable = mShadowDrawableRight;
1160         } else {
1161             shadowDrawable = mShadowDrawableLeft;
1162         }
1163 
1164         final View shadowView = getChildCount() > 1 ? getChildAt(1) : null;
1165         if (shadowView == null || shadowDrawable == null) {
1166             // No need to draw a shadow if we don't have one.
1167             return;
1168         }
1169 
1170         final int top = shadowView.getTop();
1171         final int bottom = shadowView.getBottom();
1172 
1173         final int shadowWidth = shadowDrawable.getIntrinsicWidth();
1174         final int left;
1175         final int right;
1176         if (isLayoutRtlSupport()) {
1177             left = shadowView.getRight();
1178             right = left + shadowWidth;
1179         } else {
1180             right = shadowView.getLeft();
1181             left = right - shadowWidth;
1182         }
1183 
1184         shadowDrawable.setBounds(left, top, right, bottom);
1185         shadowDrawable.draw(c);
1186     }
1187 
parallaxOtherViews(float slideOffset)1188     private void parallaxOtherViews(float slideOffset) {
1189         final boolean isLayoutRtl = isLayoutRtlSupport();
1190         final LayoutParams slideLp = (LayoutParams) mSlideableView.getLayoutParams();
1191         final boolean dimViews = slideLp.dimWhenOffset &&
1192                 (isLayoutRtl ? slideLp.rightMargin : slideLp.leftMargin) <= 0;
1193         final int childCount = getChildCount();
1194         for (int i = 0; i < childCount; i++) {
1195             final View v = getChildAt(i);
1196             if (v == mSlideableView) continue;
1197 
1198             final int oldOffset = (int) ((1 - mParallaxOffset) * mParallaxBy);
1199             mParallaxOffset = slideOffset;
1200             final int newOffset = (int) ((1 - slideOffset) * mParallaxBy);
1201             final int dx = oldOffset - newOffset;
1202 
1203             v.offsetLeftAndRight(isLayoutRtl ? -dx : dx);
1204 
1205             if (dimViews) {
1206                 dimChildView(v, isLayoutRtl ? mParallaxOffset - 1 :
1207                     1 - mParallaxOffset, mCoveredFadeColor);
1208             }
1209         }
1210     }
1211 
1212     /**
1213      * Tests scrollability within child views of v given a delta of dx.
1214      *
1215      * @param v View to test for horizontal scrollability
1216      * @param checkV Whether the view v passed should itself be checked for scrollability (true),
1217      *               or just its children (false).
1218      * @param dx Delta scrolled in pixels
1219      * @param x X coordinate of the active touch point
1220      * @param y Y coordinate of the active touch point
1221      * @return true if child views of v can be scrolled by delta of dx.
1222      */
canScroll(View v, boolean checkV, int dx, int x, int y)1223     protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
1224         if (v instanceof ViewGroup) {
1225             final ViewGroup group = (ViewGroup) v;
1226             final int scrollX = v.getScrollX();
1227             final int scrollY = v.getScrollY();
1228             final int count = group.getChildCount();
1229             // Count backwards - let topmost views consume scroll distance first.
1230             for (int i = count - 1; i >= 0; i--) {
1231                 // TODO: Add versioned support here for transformed views.
1232                 // This will not work for transformed views in Honeycomb+
1233                 final View child = group.getChildAt(i);
1234                 if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() &&
1235                         y + scrollY >= child.getTop() && y + scrollY < child.getBottom() &&
1236                         canScroll(child, true, dx, x + scrollX - child.getLeft(),
1237                                 y + scrollY - child.getTop())) {
1238                     return true;
1239                 }
1240             }
1241         }
1242 
1243         return checkV && ViewCompat.canScrollHorizontally(v, (isLayoutRtlSupport() ? dx : -dx));
1244     }
1245 
isDimmed(View child)1246     boolean isDimmed(View child) {
1247         if (child == null) {
1248             return false;
1249         }
1250         final LayoutParams lp = (LayoutParams) child.getLayoutParams();
1251         return mCanSlide && lp.dimWhenOffset && mSlideOffset > 0;
1252     }
1253 
1254     @Override
generateDefaultLayoutParams()1255     protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
1256         return new LayoutParams();
1257     }
1258 
1259     @Override
generateLayoutParams(ViewGroup.LayoutParams p)1260     protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
1261         return p instanceof MarginLayoutParams
1262                 ? new LayoutParams((MarginLayoutParams) p)
1263                 : new LayoutParams(p);
1264     }
1265 
1266     @Override
checkLayoutParams(ViewGroup.LayoutParams p)1267     protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
1268         return p instanceof LayoutParams && super.checkLayoutParams(p);
1269     }
1270 
1271     @Override
generateLayoutParams(AttributeSet attrs)1272     public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
1273         return new LayoutParams(getContext(), attrs);
1274     }
1275 
1276     @Override
onSaveInstanceState()1277     protected Parcelable onSaveInstanceState() {
1278         Parcelable superState = super.onSaveInstanceState();
1279 
1280         SavedState ss = new SavedState(superState);
1281         ss.isOpen = isSlideable() ? isOpen() : mPreservedOpenState;
1282 
1283         return ss;
1284     }
1285 
1286     @Override
onRestoreInstanceState(Parcelable state)1287     protected void onRestoreInstanceState(Parcelable state) {
1288         SavedState ss = (SavedState) state;
1289         super.onRestoreInstanceState(ss.getSuperState());
1290 
1291         if (ss.isOpen) {
1292             openPane();
1293         } else {
1294             closePane();
1295         }
1296         mPreservedOpenState = ss.isOpen;
1297     }
1298 
1299     private class DragHelperCallback extends ViewDragHelper.Callback {
1300 
1301         @Override
tryCaptureView(View child, int pointerId)1302         public boolean tryCaptureView(View child, int pointerId) {
1303             if (mIsUnableToDrag) {
1304                 return false;
1305             }
1306 
1307             return ((LayoutParams) child.getLayoutParams()).slideable;
1308         }
1309 
1310         @Override
onViewDragStateChanged(int state)1311         public void onViewDragStateChanged(int state) {
1312             if (mDragHelper.getViewDragState() == ViewDragHelper.STATE_IDLE) {
1313                 if (mSlideOffset == 0) {
1314                     updateObscuredViewsVisibility(mSlideableView);
1315                     dispatchOnPanelClosed(mSlideableView);
1316                     mPreservedOpenState = false;
1317                 } else {
1318                     dispatchOnPanelOpened(mSlideableView);
1319                     mPreservedOpenState = true;
1320                 }
1321             }
1322         }
1323 
1324         @Override
onViewCaptured(View capturedChild, int activePointerId)1325         public void onViewCaptured(View capturedChild, int activePointerId) {
1326             // Make all child views visible in preparation for sliding things around
1327             setAllChildrenVisible();
1328         }
1329 
1330         @Override
onViewPositionChanged(View changedView, int left, int top, int dx, int dy)1331         public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
1332             onPanelDragged(left);
1333             invalidate();
1334         }
1335 
1336         @Override
onViewReleased(View releasedChild, float xvel, float yvel)1337         public void onViewReleased(View releasedChild, float xvel, float yvel) {
1338             final LayoutParams lp = (LayoutParams) releasedChild.getLayoutParams();
1339 
1340             int left;
1341             if (isLayoutRtlSupport()) {
1342                 int startToRight =  getPaddingRight() + lp.rightMargin;
1343                 if (xvel < 0 || (xvel == 0 && mSlideOffset > 0.5f)) {
1344                     startToRight += mSlideRange;
1345                 }
1346                 int childWidth = mSlideableView.getWidth();
1347                 left = getWidth() - startToRight - childWidth;
1348             } else {
1349                 left = getPaddingLeft() + lp.leftMargin;
1350                 if (xvel > 0 || (xvel == 0 && mSlideOffset > 0.5f)) {
1351                     left += mSlideRange;
1352                 }
1353             }
1354             mDragHelper.settleCapturedViewAt(left, releasedChild.getTop());
1355             invalidate();
1356         }
1357 
1358         @Override
getViewHorizontalDragRange(View child)1359         public int getViewHorizontalDragRange(View child) {
1360             return mSlideRange;
1361         }
1362 
1363         @Override
clampViewPositionHorizontal(View child, int left, int dx)1364         public int clampViewPositionHorizontal(View child, int left, int dx) {
1365             final LayoutParams lp = (LayoutParams) mSlideableView.getLayoutParams();
1366 
1367             final int newLeft;
1368             if (isLayoutRtlSupport()) {
1369                 int startBound = getWidth() -
1370                         (getPaddingRight() + lp.rightMargin + mSlideableView.getWidth());
1371                 int endBound =  startBound - mSlideRange;
1372                 newLeft = Math.max(Math.min(left, startBound), endBound);
1373             } else {
1374                 int startBound = getPaddingLeft() + lp.leftMargin;
1375                 int endBound = startBound + mSlideRange;
1376                 newLeft = Math.min(Math.max(left, startBound), endBound);
1377             }
1378             return newLeft;
1379         }
1380 
1381         @Override
clampViewPositionVertical(View child, int top, int dy)1382         public int clampViewPositionVertical(View child, int top, int dy) {
1383             // Make sure we never move views vertically.
1384             // This could happen if the child has less height than its parent.
1385             return child.getTop();
1386         }
1387 
1388         @Override
onEdgeDragStarted(int edgeFlags, int pointerId)1389         public void onEdgeDragStarted(int edgeFlags, int pointerId) {
1390             mDragHelper.captureChildView(mSlideableView, pointerId);
1391         }
1392     }
1393 
1394     public static class LayoutParams extends ViewGroup.MarginLayoutParams {
1395         private static final int[] ATTRS = new int[] {
1396             android.R.attr.layout_weight
1397         };
1398 
1399         /**
1400          * The weighted proportion of how much of the leftover space
1401          * this child should consume after measurement.
1402          */
1403         public float weight = 0;
1404 
1405         /**
1406          * True if this pane is the slideable pane in the layout.
1407          */
1408         boolean slideable;
1409 
1410         /**
1411          * True if this view should be drawn dimmed
1412          * when it's been offset from its default position.
1413          */
1414         boolean dimWhenOffset;
1415 
1416         Paint dimPaint;
1417 
LayoutParams()1418         public LayoutParams() {
1419             super(FILL_PARENT, FILL_PARENT);
1420         }
1421 
LayoutParams(int width, int height)1422         public LayoutParams(int width, int height) {
1423             super(width, height);
1424         }
1425 
LayoutParams(android.view.ViewGroup.LayoutParams source)1426         public LayoutParams(android.view.ViewGroup.LayoutParams source) {
1427             super(source);
1428         }
1429 
LayoutParams(MarginLayoutParams source)1430         public LayoutParams(MarginLayoutParams source) {
1431             super(source);
1432         }
1433 
LayoutParams(LayoutParams source)1434         public LayoutParams(LayoutParams source) {
1435             super(source);
1436             this.weight = source.weight;
1437         }
1438 
LayoutParams(Context c, AttributeSet attrs)1439         public LayoutParams(Context c, AttributeSet attrs) {
1440             super(c, attrs);
1441 
1442             final TypedArray a = c.obtainStyledAttributes(attrs, ATTRS);
1443             this.weight = a.getFloat(0, 0);
1444             a.recycle();
1445         }
1446 
1447     }
1448 
1449     static class SavedState extends BaseSavedState {
1450         boolean isOpen;
1451 
SavedState(Parcelable superState)1452         SavedState(Parcelable superState) {
1453             super(superState);
1454         }
1455 
SavedState(Parcel in)1456         private SavedState(Parcel in) {
1457             super(in);
1458             isOpen = in.readInt() != 0;
1459         }
1460 
1461         @Override
writeToParcel(Parcel out, int flags)1462         public void writeToParcel(Parcel out, int flags) {
1463             super.writeToParcel(out, flags);
1464             out.writeInt(isOpen ? 1 : 0);
1465         }
1466 
1467         public static final Parcelable.Creator<SavedState> CREATOR =
1468                 new Parcelable.Creator<SavedState>() {
1469             public SavedState createFromParcel(Parcel in) {
1470                 return new SavedState(in);
1471             }
1472 
1473             public SavedState[] newArray(int size) {
1474                 return new SavedState[size];
1475             }
1476         };
1477     }
1478 
1479     interface SlidingPanelLayoutImpl {
1480         void invalidateChildRegion(SlidingPaneLayout parent, View child);
1481     }
1482 
1483     static class SlidingPanelLayoutImplBase implements SlidingPanelLayoutImpl {
invalidateChildRegion(SlidingPaneLayout parent, View child)1484         public void invalidateChildRegion(SlidingPaneLayout parent, View child) {
1485             ViewCompat.postInvalidateOnAnimation(parent, child.getLeft(), child.getTop(),
1486                     child.getRight(), child.getBottom());
1487         }
1488     }
1489 
1490     static class SlidingPanelLayoutImplJB extends SlidingPanelLayoutImplBase {
1491         /*
1492          * Private API hacks! Nasty! Bad!
1493          *
1494          * In Jellybean, some optimizations in the hardware UI renderer
1495          * prevent a changed Paint on a View using a hardware layer from having
1496          * the intended effect. This twiddles some internal bits on the view to force
1497          * it to recreate the display list.
1498          */
1499         private Method mGetDisplayList;
1500         private Field mRecreateDisplayList;
1501 
SlidingPanelLayoutImplJB()1502         SlidingPanelLayoutImplJB() {
1503             try {
1504                 mGetDisplayList = View.class.getDeclaredMethod("getDisplayList", (Class[]) null);
1505             } catch (NoSuchMethodException e) {
1506                 Log.e(TAG, "Couldn't fetch getDisplayList method; dimming won't work right.", e);
1507             }
1508             try {
1509                 mRecreateDisplayList = View.class.getDeclaredField("mRecreateDisplayList");
1510                 mRecreateDisplayList.setAccessible(true);
1511             } catch (NoSuchFieldException e) {
1512                 Log.e(TAG, "Couldn't fetch mRecreateDisplayList field; dimming will be slow.", e);
1513             }
1514         }
1515 
1516         @Override
invalidateChildRegion(SlidingPaneLayout parent, View child)1517         public void invalidateChildRegion(SlidingPaneLayout parent, View child) {
1518             if (mGetDisplayList != null && mRecreateDisplayList != null) {
1519                 try {
1520                     mRecreateDisplayList.setBoolean(child, true);
1521                     mGetDisplayList.invoke(child, (Object[]) null);
1522                 } catch (Exception e) {
1523                     Log.e(TAG, "Error refreshing display list state", e);
1524                 }
1525             } else {
1526                 // Slow path. REALLY slow path. Let's hope we don't get here.
1527                 child.invalidate();
1528                 return;
1529             }
1530             super.invalidateChildRegion(parent, child);
1531         }
1532     }
1533 
1534     static class SlidingPanelLayoutImplJBMR1 extends SlidingPanelLayoutImplBase {
1535         @Override
invalidateChildRegion(SlidingPaneLayout parent, View child)1536         public void invalidateChildRegion(SlidingPaneLayout parent, View child) {
1537             ViewCompat.setLayerPaint(child, ((LayoutParams) child.getLayoutParams()).dimPaint);
1538         }
1539     }
1540 
1541     class AccessibilityDelegate extends AccessibilityDelegateCompat {
1542         private final Rect mTmpRect = new Rect();
1543 
1544         @Override
onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info)1545         public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
1546             final AccessibilityNodeInfoCompat superNode = AccessibilityNodeInfoCompat.obtain(info);
1547             super.onInitializeAccessibilityNodeInfo(host, superNode);
1548             copyNodeInfoNoChildren(info, superNode);
1549             superNode.recycle();
1550 
1551             info.setClassName(SlidingPaneLayout.class.getName());
1552             info.setSource(host);
1553 
1554             final ViewParent parent = ViewCompat.getParentForAccessibility(host);
1555             if (parent instanceof View) {
1556                 info.setParent((View) parent);
1557             }
1558 
1559             // This is a best-approximation of addChildrenForAccessibility()
1560             // that accounts for filtering.
1561             final int childCount = getChildCount();
1562             for (int i = 0; i < childCount; i++) {
1563                 final View child = getChildAt(i);
1564                 if (!filter(child) && (child.getVisibility() == View.VISIBLE)) {
1565                     // Force importance to "yes" since we can't read the value.
1566                     ViewCompat.setImportantForAccessibility(
1567                             child, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
1568                     info.addChild(child);
1569                 }
1570             }
1571         }
1572 
1573         @Override
onInitializeAccessibilityEvent(View host, AccessibilityEvent event)1574         public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) {
1575             super.onInitializeAccessibilityEvent(host, event);
1576 
1577             event.setClassName(SlidingPaneLayout.class.getName());
1578         }
1579 
1580         @Override
onRequestSendAccessibilityEvent(ViewGroup host, View child, AccessibilityEvent event)1581         public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child,
1582                 AccessibilityEvent event) {
1583             if (!filter(child)) {
1584                 return super.onRequestSendAccessibilityEvent(host, child, event);
1585             }
1586             return false;
1587         }
1588 
filter(View child)1589         public boolean filter(View child) {
1590             return isDimmed(child);
1591         }
1592 
1593         /**
1594          * This should really be in AccessibilityNodeInfoCompat, but there unfortunately
1595          * seem to be a few elements that are not easily cloneable using the underlying API.
1596          * Leave it private here as it's not general-purpose useful.
1597          */
copyNodeInfoNoChildren(AccessibilityNodeInfoCompat dest, AccessibilityNodeInfoCompat src)1598         private void copyNodeInfoNoChildren(AccessibilityNodeInfoCompat dest,
1599                 AccessibilityNodeInfoCompat src) {
1600             final Rect rect = mTmpRect;
1601 
1602             src.getBoundsInParent(rect);
1603             dest.setBoundsInParent(rect);
1604 
1605             src.getBoundsInScreen(rect);
1606             dest.setBoundsInScreen(rect);
1607 
1608             dest.setVisibleToUser(src.isVisibleToUser());
1609             dest.setPackageName(src.getPackageName());
1610             dest.setClassName(src.getClassName());
1611             dest.setContentDescription(src.getContentDescription());
1612 
1613             dest.setEnabled(src.isEnabled());
1614             dest.setClickable(src.isClickable());
1615             dest.setFocusable(src.isFocusable());
1616             dest.setFocused(src.isFocused());
1617             dest.setAccessibilityFocused(src.isAccessibilityFocused());
1618             dest.setSelected(src.isSelected());
1619             dest.setLongClickable(src.isLongClickable());
1620 
1621             dest.addAction(src.getActions());
1622 
1623             dest.setMovementGranularities(src.getMovementGranularities());
1624         }
1625     }
1626 
1627     private class DisableLayerRunnable implements Runnable {
1628         final View mChildView;
1629 
DisableLayerRunnable(View childView)1630         DisableLayerRunnable(View childView) {
1631             mChildView = childView;
1632         }
1633 
1634         @Override
run()1635         public void run() {
1636             if (mChildView.getParent() == SlidingPaneLayout.this) {
1637                 ViewCompat.setLayerType(mChildView, ViewCompat.LAYER_TYPE_NONE, null);
1638                 invalidateChildRegion(mChildView);
1639             }
1640             mPostedRunnables.remove(this);
1641         }
1642     }
1643 
isLayoutRtlSupport()1644     private boolean isLayoutRtlSupport() {
1645         return ViewCompat.getLayoutDirection(this) == ViewCompat.LAYOUT_DIRECTION_RTL;
1646     }
1647 }
1648