1 /*
2  * Copyright (C) 2018 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 package com.android.settings.display;
17 
18 import android.animation.Animator;
19 import android.animation.Animator.AnimatorListener;
20 import android.content.Context;
21 import android.content.res.Configuration;
22 import android.view.View;
23 import android.view.ViewGroup;
24 import android.view.ViewStub;
25 import android.view.animation.AccelerateInterpolator;
26 import android.view.animation.DecelerateInterpolator;
27 import android.view.animation.Interpolator;
28 import android.widget.FrameLayout;
29 import android.widget.LinearLayout;
30 
31 import androidx.viewpager.widget.PagerAdapter;
32 
33 /**
34  * A PagerAdapter used by PreviewSeekBarPreferenceFragment that for showing multiple preview screen
35  * regarding a single setting and allowing the user to swipe across them.
36  */
37 public class PreviewPagerAdapter extends PagerAdapter {
38 
39     /** Duration to use when cross-fading between previews. */
40     private static final long CROSS_FADE_DURATION_MS = 400;
41 
42     /** Interpolator to use when cross-fading between previews. */
43     private static final Interpolator FADE_IN_INTERPOLATOR = new DecelerateInterpolator();
44 
45     /** Interpolator to use when cross-fading between previews. */
46     private static final Interpolator FADE_OUT_INTERPOLATOR = new AccelerateInterpolator();
47 
48     private FrameLayout[] mPreviewFrames;
49 
50     private boolean mIsLayoutRtl;
51 
52     private Runnable mAnimationEndAction;
53 
54     private int mAnimationCounter;
55 
56     private boolean[][] mViewStubInflated;
57 
PreviewPagerAdapter(Context context, boolean isLayoutRtl, int[] previewSampleResIds, Configuration[] configurations)58     public PreviewPagerAdapter(Context context, boolean isLayoutRtl,
59             int[] previewSampleResIds, Configuration[] configurations) {
60         mIsLayoutRtl = isLayoutRtl;
61         mPreviewFrames = new FrameLayout[previewSampleResIds.length];
62         mViewStubInflated = new boolean[previewSampleResIds.length][configurations.length];
63 
64         for (int i = 0; i < previewSampleResIds.length; ++i) {
65             int p = mIsLayoutRtl ? previewSampleResIds.length - 1 - i : i;
66             mPreviewFrames[p] = new FrameLayout(context);
67             mPreviewFrames[p].setLayoutParams(new LinearLayout.LayoutParams(
68                     LinearLayout.LayoutParams.MATCH_PARENT,
69                     LinearLayout.LayoutParams.MATCH_PARENT));
70             mPreviewFrames[p].setClipToPadding(true);
71             mPreviewFrames[p].setClipChildren(true);
72             for (int j = 0; j < configurations.length; ++j) {
73                 // Create a new configuration for the specified value. It won't
74                 // have any theme set, so manually apply the current theme.
75                 final Context configContext = context.createConfigurationContext(configurations[j]);
76                 configContext.getTheme().setTo(context.getTheme());
77 
78                 final ViewStub sampleViewStub = new ViewStub(configContext);
79                 sampleViewStub.setLayoutResource(previewSampleResIds[i]);
80                 final int fi = i, fj = j;
81                 sampleViewStub.setOnInflateListener((stub, inflated) -> {
82                     inflated.setVisibility(stub.getVisibility());
83                     mViewStubInflated[fi][fj] = true;
84                 });
85 
86                 mPreviewFrames[p].addView(sampleViewStub);
87             }
88         }
89     }
90 
91     @Override
destroyItem(ViewGroup container, int position, Object object)92     public void destroyItem(ViewGroup container, int position, Object object) {
93         container.removeView((View) object);
94     }
95 
96     @Override
getCount()97     public int getCount() {
98         return mPreviewFrames.length;
99     }
100 
101     @Override
instantiateItem(ViewGroup container, int position)102     public Object instantiateItem(ViewGroup container, int position) {
103         container.addView(mPreviewFrames[position]);
104         return mPreviewFrames[position];
105     }
106 
107     @Override
isViewFromObject(View view, Object object)108     public boolean isViewFromObject(View view, Object object) {
109         return (view == object);
110     }
111 
isAnimating()112     boolean isAnimating() {
113         return mAnimationCounter > 0;
114     }
115 
setAnimationEndAction(Runnable action)116     void setAnimationEndAction(Runnable action) {
117         mAnimationEndAction = action;
118     }
119 
setPreviewLayer(int newLayerIndex, int currentLayerIndex, int currentFrameIndex, final boolean animate)120     void setPreviewLayer(int newLayerIndex, int currentLayerIndex, int currentFrameIndex,
121             final boolean animate) {
122         for (FrameLayout previewFrame : mPreviewFrames) {
123             if (currentLayerIndex >= 0) {
124                 final View lastLayer = previewFrame.getChildAt(currentLayerIndex);
125                 if (mViewStubInflated[currentFrameIndex][currentLayerIndex]) {
126                     // Explicitly set to INVISIBLE only when the stub has
127                     // already been inflated.
128                     if (previewFrame == mPreviewFrames[currentFrameIndex]) {
129                         setVisibility(lastLayer, View.INVISIBLE, animate);
130                     } else {
131                         setVisibility(lastLayer, View.INVISIBLE, false);
132                     }
133                 }
134             }
135 
136             // Set next layer visible, as well as inflate necessary views.
137             View nextLayer = previewFrame.getChildAt(newLayerIndex);
138             if (previewFrame == mPreviewFrames[currentFrameIndex]) {
139                 // Inflate immediately if the stub has not yet been inflated.
140                 if (!mViewStubInflated[currentFrameIndex][newLayerIndex]) {
141                     nextLayer = ((ViewStub) nextLayer).inflate();
142                     nextLayer.setAlpha(0.0f);
143                 }
144                 setVisibility(nextLayer, View.VISIBLE, animate);
145             } else {
146                 setVisibility(nextLayer, View.VISIBLE, false);
147             }
148         }
149     }
150 
setVisibility(final View view, final int visibility, boolean animate)151     private void setVisibility(final View view, final int visibility, boolean animate) {
152         final float alpha = (visibility == View.VISIBLE ? 1.0f : 0.0f);
153         if (!animate) {
154             view.setAlpha(alpha);
155             view.setVisibility(visibility);
156         } else {
157             final Interpolator interpolator = (visibility == View.VISIBLE ? FADE_IN_INTERPOLATOR
158                     : FADE_OUT_INTERPOLATOR);
159             if (visibility == View.VISIBLE) {
160                 // Fade in animation.
161                 view.animate()
162                         .alpha(alpha)
163                         .setInterpolator(FADE_IN_INTERPOLATOR)
164                         .setDuration(CROSS_FADE_DURATION_MS)
165                         .setListener(new PreviewFrameAnimatorListener())
166                         .withStartAction(new Runnable() {
167                             @Override
168                             public void run() {
169                                 view.setVisibility(visibility);
170                             }
171                         });
172             } else {
173                 // Fade out animation.
174                 view.animate()
175                         .alpha(alpha)
176                         .setInterpolator(FADE_OUT_INTERPOLATOR)
177                         .setDuration(CROSS_FADE_DURATION_MS)
178                         .setListener(new PreviewFrameAnimatorListener())
179                         .withEndAction(new Runnable() {
180                             @Override
181                             public void run() {
182                                 view.setVisibility(visibility);
183                             }
184                         });
185             }
186         }
187     }
188 
runAnimationEndAction()189     private void runAnimationEndAction() {
190         if (mAnimationEndAction != null && !isAnimating()) {
191             mAnimationEndAction.run();
192             mAnimationEndAction = null;
193         }
194     }
195 
196     private class PreviewFrameAnimatorListener implements AnimatorListener {
197         @Override
onAnimationStart(Animator animation)198         public void onAnimationStart(Animator animation) {
199             mAnimationCounter++;
200         }
201 
202         @Override
onAnimationEnd(Animator animation)203         public void onAnimationEnd(Animator animation) {
204             mAnimationCounter--;
205             runAnimationEndAction();
206         }
207 
208         @Override
onAnimationCancel(Animator animation)209         public void onAnimationCancel(Animator animation) {
210             // Empty method.
211         }
212 
213         @Override
onAnimationRepeat(Animator animation)214         public void onAnimationRepeat(Animator animation) {
215             // Empty method.
216         }
217     }
218 }
219