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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 com.android.internal.widget;
18 
19 import java.lang.Math;
20 
21 import com.android.internal.R;
22 
23 import android.animation.Animator;
24 import android.animation.Animator.AnimatorListener;
25 import android.animation.AnimatorSet;
26 import android.animation.ObjectAnimator;
27 import android.content.Context;
28 import android.content.res.TypedArray;
29 import android.graphics.Color;
30 import android.graphics.drawable.ColorDrawable;
31 import android.graphics.drawable.Drawable;
32 import android.graphics.drawable.StateListDrawable;
33 import android.util.AttributeSet;
34 import android.util.Log;
35 import android.util.StateSet;
36 import android.view.View;
37 import android.view.ViewDebug;
38 import android.view.ViewGroup;
39 import android.widget.RemoteViews.RemoteView;
40 
41 /**
42  * A layout that switches between its children based on the requested layout height.
43  * Each child specifies its minimum and maximum valid height.  Results are undefined
44  * if children specify overlapping ranges.  A child may specify the maximum height
45  * as 'unbounded' to indicate that it is willing to be displayed arbitrarily tall.
46  *
47  * <p>
48  * See {@link SizeAdaptiveLayout.LayoutParams} for a full description of the
49  * layout parameters used by SizeAdaptiveLayout.
50  */
51 @RemoteView
52 public class SizeAdaptiveLayout extends ViewGroup {
53 
54     private static final String TAG = "SizeAdaptiveLayout";
55     private static final boolean DEBUG = false;
56     private static final boolean REPORT_BAD_BOUNDS = true;
57     private static final long CROSSFADE_TIME = 250;
58 
59     // TypedArray indices
60     private static final int MIN_VALID_HEIGHT =
61             R.styleable.SizeAdaptiveLayout_Layout_layout_minHeight;
62     private static final int MAX_VALID_HEIGHT =
63             R.styleable.SizeAdaptiveLayout_Layout_layout_maxHeight;
64 
65     // view state
66     private View mActiveChild;
67     private View mLastActive;
68 
69     // animation state
70     private AnimatorSet mTransitionAnimation;
71     private AnimatorListener mAnimatorListener;
72     private ObjectAnimator mFadePanel;
73     private ObjectAnimator mFadeView;
74     private int mCanceledAnimationCount;
75     private View mEnteringView;
76     private View mLeavingView;
77     // View used to hide larger views under smaller ones to create a uniform crossfade
78     private View mModestyPanel;
79     private int mModestyPanelTop;
80 
SizeAdaptiveLayout(Context context)81     public SizeAdaptiveLayout(Context context) {
82         super(context);
83         initialize();
84     }
85 
SizeAdaptiveLayout(Context context, AttributeSet attrs)86     public SizeAdaptiveLayout(Context context, AttributeSet attrs) {
87         super(context, attrs);
88         initialize();
89     }
90 
SizeAdaptiveLayout(Context context, AttributeSet attrs, int defStyle)91     public SizeAdaptiveLayout(Context context, AttributeSet attrs, int defStyle) {
92         super(context, attrs, defStyle);
93         initialize();
94     }
95 
initialize()96     private void initialize() {
97         mModestyPanel = new View(getContext());
98         // If the SizeAdaptiveLayout has a solid background, use it as a transition hint.
99         Drawable background = getBackground();
100         if (background instanceof StateListDrawable) {
101             StateListDrawable sld = (StateListDrawable) background;
102             sld.setState(StateSet.WILD_CARD);
103             background = sld.getCurrent();
104         }
105         if (background instanceof ColorDrawable) {
106             mModestyPanel.setBackgroundDrawable(background);
107         } else {
108             mModestyPanel.setBackgroundColor(Color.BLACK);
109         }
110         SizeAdaptiveLayout.LayoutParams layout =
111                 new SizeAdaptiveLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
112                                                     ViewGroup.LayoutParams.MATCH_PARENT);
113         mModestyPanel.setLayoutParams(layout);
114         addView(mModestyPanel);
115         mFadePanel = ObjectAnimator.ofFloat(mModestyPanel, "alpha", 0f);
116         mFadeView = ObjectAnimator.ofFloat(null, "alpha", 0f);
117         mAnimatorListener = new BringToFrontOnEnd();
118         mTransitionAnimation = new AnimatorSet();
119         mTransitionAnimation.play(mFadeView).with(mFadePanel);
120         mTransitionAnimation.setDuration(CROSSFADE_TIME);
121         mTransitionAnimation.addListener(mAnimatorListener);
122     }
123 
124     /**
125      * Visible for testing
126      * @hide
127      */
getTransitionAnimation()128     public Animator getTransitionAnimation() {
129         return mTransitionAnimation;
130     }
131 
132     /**
133      * Visible for testing
134      * @hide
135      */
getModestyPanel()136     public View getModestyPanel() {
137         return mModestyPanel;
138     }
139 
140     @Override
onAttachedToWindow()141     public void onAttachedToWindow() {
142         mLastActive = null;
143         // make sure all views start off invisible.
144         for (int i = 0; i < getChildCount(); i++) {
145             getChildAt(i).setVisibility(View.GONE);
146         }
147     }
148 
149     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)150     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
151         if (DEBUG) Log.d(TAG, this + " measure spec: " +
152                          MeasureSpec.toString(heightMeasureSpec));
153         View model = selectActiveChild(heightMeasureSpec);
154         SizeAdaptiveLayout.LayoutParams lp =
155           (SizeAdaptiveLayout.LayoutParams) model.getLayoutParams();
156         if (DEBUG) Log.d(TAG, "active min: " + lp.minHeight + " max: " + lp.maxHeight);
157         measureChild(model, widthMeasureSpec, heightMeasureSpec);
158         int childHeight = model.getMeasuredHeight();
159         int childWidth = model.getMeasuredHeight();
160         int childState = combineMeasuredStates(0, model.getMeasuredState());
161         if (DEBUG) Log.d(TAG, "measured child at: " + childHeight);
162         int resolvedWidth = resolveSizeAndState(childWidth, widthMeasureSpec, childState);
163         int resolvedHeight = resolveSizeAndState(childHeight, heightMeasureSpec, childState);
164         if (DEBUG) Log.d(TAG, "resolved to: " + resolvedHeight);
165         int boundedHeight = clampSizeToBounds(resolvedHeight, model);
166         if (DEBUG) Log.d(TAG, "bounded to: " + boundedHeight);
167         setMeasuredDimension(resolvedWidth, boundedHeight);
168     }
169 
clampSizeToBounds(int measuredHeight, View child)170     private int clampSizeToBounds(int measuredHeight, View child) {
171         SizeAdaptiveLayout.LayoutParams lp =
172                 (SizeAdaptiveLayout.LayoutParams) child.getLayoutParams();
173         int heightIn = View.MEASURED_SIZE_MASK & measuredHeight;
174         int height = Math.max(heightIn, lp.minHeight);
175         if (lp.maxHeight != SizeAdaptiveLayout.LayoutParams.UNBOUNDED) {
176             height = Math.min(height, lp.maxHeight);
177         }
178 
179         if (REPORT_BAD_BOUNDS && heightIn != height) {
180             Log.d(TAG, this + "child view " + child + " " +
181                   "measured out of bounds at " + heightIn +"px " +
182                   "clamped to " + height + "px");
183         }
184 
185         return height;
186     }
187 
188     //TODO extend to width and height
selectActiveChild(int heightMeasureSpec)189     private View selectActiveChild(int heightMeasureSpec) {
190         final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
191         final int heightSize = MeasureSpec.getSize(heightMeasureSpec);
192 
193         View unboundedView = null;
194         View tallestView = null;
195         int tallestViewSize = 0;
196         View smallestView = null;
197         int smallestViewSize = Integer.MAX_VALUE;
198         for (int i = 0; i < getChildCount(); i++) {
199             View child = getChildAt(i);
200             if (child != mModestyPanel) {
201                 SizeAdaptiveLayout.LayoutParams lp =
202                     (SizeAdaptiveLayout.LayoutParams) child.getLayoutParams();
203                 if (DEBUG) Log.d(TAG, "looking at " + i +
204                                  " with min: " + lp.minHeight +
205                                  " max: " +  lp.maxHeight);
206                 if (lp.maxHeight == SizeAdaptiveLayout.LayoutParams.UNBOUNDED &&
207                     unboundedView == null) {
208                     unboundedView = child;
209                 }
210                 if (lp.maxHeight > tallestViewSize) {
211                     tallestViewSize = lp.maxHeight;
212                     tallestView = child;
213                 }
214                 if (lp.minHeight < smallestViewSize) {
215                     smallestViewSize = lp.minHeight;
216                     smallestView = child;
217                 }
218                 if (heightMode != MeasureSpec.UNSPECIFIED &&
219                     heightSize >= lp.minHeight && heightSize <= lp.maxHeight) {
220                     if (DEBUG) Log.d(TAG, "  found exact match, finishing early");
221                     return child;
222                 }
223             }
224         }
225         if (unboundedView != null) {
226             tallestView = unboundedView;
227         }
228         if (heightMode == MeasureSpec.UNSPECIFIED || heightSize > tallestViewSize) {
229             return tallestView;
230         } else {
231             return smallestView;
232         }
233     }
234 
235     @Override
onLayout(boolean changed, int left, int top, int right, int bottom)236     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
237         if (DEBUG) Log.d(TAG, this + " onlayout height: " + (bottom - top));
238         mLastActive = mActiveChild;
239         int measureSpec = View.MeasureSpec.makeMeasureSpec(bottom - top,
240                                                            View.MeasureSpec.EXACTLY);
241         mActiveChild = selectActiveChild(measureSpec);
242         mActiveChild.setVisibility(View.VISIBLE);
243 
244         if (mLastActive != mActiveChild && mLastActive != null) {
245             if (DEBUG) Log.d(TAG, this + " changed children from: " + mLastActive +
246                     " to: " + mActiveChild);
247 
248             mEnteringView = mActiveChild;
249             mLeavingView = mLastActive;
250 
251             mEnteringView.setAlpha(1f);
252 
253             mModestyPanel.setAlpha(1f);
254             mModestyPanel.bringToFront();
255             mModestyPanelTop = mLeavingView.getHeight();
256             mModestyPanel.setVisibility(View.VISIBLE);
257             // TODO: mModestyPanel background should be compatible with mLeavingView
258 
259             mLeavingView.bringToFront();
260 
261             if (mTransitionAnimation.isRunning()) {
262                 mTransitionAnimation.cancel();
263             }
264             mFadeView.setTarget(mLeavingView);
265             mFadeView.setFloatValues(0f);
266             mFadePanel.setFloatValues(0f);
267             mTransitionAnimation.setupStartValues();
268             mTransitionAnimation.start();
269         }
270         final int childWidth = mActiveChild.getMeasuredWidth();
271         final int childHeight = mActiveChild.getMeasuredHeight();
272         // TODO investigate setting LAYER_TYPE_HARDWARE on mLastActive
273         mActiveChild.layout(0, 0, childWidth, childHeight);
274 
275         if (DEBUG) Log.d(TAG, "got modesty offset of " + mModestyPanelTop);
276         mModestyPanel.layout(0, mModestyPanelTop, childWidth, mModestyPanelTop + childHeight);
277     }
278 
279     @Override
generateLayoutParams(AttributeSet attrs)280     public LayoutParams generateLayoutParams(AttributeSet attrs) {
281         if (DEBUG) Log.d(TAG, "generate layout from attrs");
282         return new SizeAdaptiveLayout.LayoutParams(getContext(), attrs);
283     }
284 
285     @Override
generateLayoutParams(ViewGroup.LayoutParams p)286     protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
287         if (DEBUG) Log.d(TAG, "generate default layout from viewgroup");
288         return new SizeAdaptiveLayout.LayoutParams(p);
289     }
290 
291     @Override
generateDefaultLayoutParams()292     protected LayoutParams generateDefaultLayoutParams() {
293         if (DEBUG) Log.d(TAG, "generate default layout from null");
294         return new SizeAdaptiveLayout.LayoutParams();
295     }
296 
297     @Override
checkLayoutParams(ViewGroup.LayoutParams p)298     protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
299         return p instanceof SizeAdaptiveLayout.LayoutParams;
300     }
301 
302     /**
303      * Per-child layout information associated with ViewSizeAdaptiveLayout.
304      *
305      * TODO extend to width and height
306      *
307      * @attr ref android.R.styleable#SizeAdaptiveLayout_Layout_layout_minHeight
308      * @attr ref android.R.styleable#SizeAdaptiveLayout_Layout_layout_maxHeight
309      */
310     public static class LayoutParams extends ViewGroup.LayoutParams {
311 
312         /**
313          * Indicates the minimum valid height for the child.
314          */
315         @ViewDebug.ExportedProperty(category = "layout")
316         public int minHeight;
317 
318         /**
319          * Indicates the maximum valid height for the child.
320          */
321         @ViewDebug.ExportedProperty(category = "layout")
322         public int maxHeight;
323 
324         /**
325          * Constant value for maxHeight that indicates there is not maximum height.
326          */
327         public static final int UNBOUNDED = -1;
328 
329         /**
330          * {@inheritDoc}
331          */
LayoutParams(Context c, AttributeSet attrs)332         public LayoutParams(Context c, AttributeSet attrs) {
333             super(c, attrs);
334             if (DEBUG) {
335                 Log.d(TAG, "construct layout from attrs");
336                 for (int i = 0; i < attrs.getAttributeCount(); i++) {
337                     Log.d(TAG, " " + attrs.getAttributeName(i) + " = " +
338                           attrs.getAttributeValue(i));
339                 }
340             }
341             TypedArray a =
342                     c.obtainStyledAttributes(attrs,
343                             R.styleable.SizeAdaptiveLayout_Layout);
344 
345             minHeight = a.getDimensionPixelSize(MIN_VALID_HEIGHT, 0);
346             if (DEBUG) Log.d(TAG, "got minHeight of: " + minHeight);
347 
348             try {
349                 maxHeight = a.getLayoutDimension(MAX_VALID_HEIGHT, UNBOUNDED);
350                 if (DEBUG) Log.d(TAG, "got maxHeight of: " + maxHeight);
351             } catch (Exception e) {
352                 if (DEBUG) Log.d(TAG, "caught exception looking for maxValidHeight " + e);
353             }
354 
355             a.recycle();
356         }
357 
358         /**
359          * Creates a new set of layout parameters with the specified width, height
360          * and valid height bounds.
361          *
362          * @param width the width, either {@link #MATCH_PARENT},
363          *        {@link #WRAP_CONTENT} or a fixed size in pixels
364          * @param height the height, either {@link #MATCH_PARENT},
365          *        {@link #WRAP_CONTENT} or a fixed size in pixels
366          * @param minHeight the minimum height of this child
367          * @param maxHeight the maximum height of this child
368          *        or {@link #UNBOUNDED} if the child can grow forever
369          */
LayoutParams(int width, int height, int minHeight, int maxHeight)370         public LayoutParams(int width, int height, int minHeight, int maxHeight) {
371             super(width, height);
372             this.minHeight = minHeight;
373             this.maxHeight = maxHeight;
374         }
375 
376         /**
377          * {@inheritDoc}
378          */
LayoutParams(int width, int height)379         public LayoutParams(int width, int height) {
380             this(width, height, UNBOUNDED, UNBOUNDED);
381         }
382 
383         /**
384          * Constructs a new LayoutParams with default values as defined in {@link LayoutParams}.
385          */
LayoutParams()386         public LayoutParams() {
387             this(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
388         }
389 
390         /**
391          * {@inheritDoc}
392          */
LayoutParams(ViewGroup.LayoutParams p)393         public LayoutParams(ViewGroup.LayoutParams p) {
394             super(p);
395             minHeight = UNBOUNDED;
396             maxHeight = UNBOUNDED;
397         }
398 
debug(String output)399         public String debug(String output) {
400             return output + "SizeAdaptiveLayout.LayoutParams={" +
401                     ", max=" + maxHeight +
402                     ", max=" + minHeight + "}";
403         }
404     }
405 
406     class BringToFrontOnEnd implements AnimatorListener {
407         @Override
onAnimationEnd(Animator animation)408             public void onAnimationEnd(Animator animation) {
409             if (mCanceledAnimationCount == 0) {
410                 mLeavingView.setVisibility(View.GONE);
411                 mModestyPanel.setVisibility(View.GONE);
412                 mEnteringView.bringToFront();
413                 mEnteringView = null;
414                 mLeavingView = null;
415             } else {
416                 mCanceledAnimationCount--;
417             }
418         }
419 
420         @Override
onAnimationCancel(Animator animation)421             public void onAnimationCancel(Animator animation) {
422             mCanceledAnimationCount++;
423         }
424 
425         @Override
onAnimationRepeat(Animator animation)426             public void onAnimationRepeat(Animator animation) {
427             if (DEBUG) Log.d(TAG, "fade animation repeated: should never happen.");
428             assert(false);
429         }
430 
431         @Override
onAnimationStart(Animator animation)432             public void onAnimationStart(Animator animation) {
433         }
434     }
435 }
436