src/com/android/settings/PreviewPagerAdapter.java

   1 /*
   2  * Copyright (C) 2016 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;
  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.support.v4.view.PagerAdapter;
  23 import android.view.LayoutInflater;
  24 import android.view.View;
  25 import android.view.ViewGroup;
  26 import android.view.animation.AccelerateInterpolator;
  27 import android.view.animation.DecelerateInterpolator;
  28 import android.view.animation.Interpolator;
  29 import android.widget.FrameLayout;
  30 import android.widget.LinearLayout;
  31 import android.widget.ScrollView;
  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     public PreviewPagerAdapter(Context context, boolean isLayoutRtl,
  57             int[] previewSampleResIds, Configuration[] configurations) {
  58         mIsLayoutRtl = isLayoutRtl;
  59         mPreviewFrames = new FrameLayout[previewSampleResIds.length];
  60
  61         for (int i = 0; i < previewSampleResIds.length; ++i) {
  62             int p = mIsLayoutRtl ? previewSampleResIds.length - 1 - i : i;
  63             mPreviewFrames[p] = new FrameLayout(context);
  64             mPreviewFrames[p].setLayoutParams(new LinearLayout.LayoutParams(
  65                     LinearLayout.LayoutParams.MATCH_PARENT,
  66                     LinearLayout.LayoutParams.MATCH_PARENT));
  67
  68             for (Configuration configuration : configurations) {
  69                 // Create a new configuration for the specified value. It won't
  70                 // have any theme set, so manually apply the current theme.
  71                 final Context configContext = context.createConfigurationContext(configuration);
  72                 configContext.setTheme(context.getThemeResId());
  73
  74                 final LayoutInflater configInflater = LayoutInflater.from(configContext);
  75                 final View sampleView = configInflater.inflate(previewSampleResIds[i],
  76                         mPreviewFrames[p], false);
  77                 sampleView.setAlpha(0);
  78                 sampleView.setVisibility(View.INVISIBLE);
  79                 mPreviewFrames[p].addView(sampleView);
  80             }
  81         }
  82     }
  83
  84     @Override
  85     public void destroyItem (ViewGroup container, int position, Object object) {
  86         container.removeView((View) object);
  87     }
  88
  89     @Override
  90     public int getCount() {
  91         return mPreviewFrames.length;
  92     }
  93
  94     @Override
  95     public Object instantiateItem(ViewGroup container, int position) {
  96         container.addView(mPreviewFrames[position]);
  97         return mPreviewFrames[position];
  98     }
  99
 100     @Override
 101     public boolean isViewFromObject(View view, Object object) {
 102         return (view == object);
 103     }
 104
 105     boolean isAnimating() {
 106         return mAnimationCounter > 0;
 107     }
 108
 109     void setAnimationEndAction(Runnable action) {
 110         mAnimationEndAction = action;
 111     }
 112
 113     void setPreviewLayer(int newIndex, int currentIndex, int currentItem, boolean animate) {
 114         for (FrameLayout previewFrame : mPreviewFrames) {
 115             if (currentIndex >= 0) {
 116                 final View lastLayer = previewFrame.getChildAt(currentIndex);
 117                 if (animate && previewFrame == mPreviewFrames[currentItem]) {
 118                     lastLayer.animate()
 119                             .alpha(0)
 120                             .setInterpolator(FADE_OUT_INTERPOLATOR)
 121                             .setDuration(CROSS_FADE_DURATION_MS)
 122                             .setListener(new PreviewFrameAnimatorListener())
 123                             .withEndAction(new Runnable() {
 124                                 @Override
 125                                 public void run() {
 126                                     lastLayer.setVisibility(View.INVISIBLE);
 127                                 }
 128                             });
 129                 } else {
 130                     lastLayer.setAlpha(0);
 131                     lastLayer.setVisibility(View.INVISIBLE);
 132                 }
 133             }
 134
 135             final View nextLayer = previewFrame.getChildAt(newIndex);
 136             if (animate && previewFrame == mPreviewFrames[currentItem]) {
 137                 nextLayer.animate()
 138                         .alpha(1)
 139                         .setInterpolator(FADE_IN_INTERPOLATOR)
 140                         .setDuration(CROSS_FADE_DURATION_MS)
 141                         .setListener(new PreviewFrameAnimatorListener())
 142                         .withStartAction(new Runnable() {
 143                             @Override
 144                             public void run() {
 145                                 nextLayer.setVisibility(View.VISIBLE);
 146                             }
 147                         });
 148             } else {
 149                 nextLayer.setVisibility(View.VISIBLE);
 150                 nextLayer.setAlpha(1);
 151             }
 152         }
 153     }
 154
 155     private void runAnimationEndAction() {
 156         if (mAnimationEndAction != null && !isAnimating()) {
 157             mAnimationEndAction.run();
 158             mAnimationEndAction = null;
 159         }
 160     }
 161
 162     private class PreviewFrameAnimatorListener implements AnimatorListener {
 163         @Override
 164         public void onAnimationStart(Animator animation) {
 165             mAnimationCounter++;
 166         }
 167
 168         @Override
 169         public void onAnimationEnd(Animator animation) {
 170             mAnimationCounter--;
 171             runAnimationEndAction();
 172         }
 173
 174         @Override
 175         public void onAnimationCancel(Animator animation) {
 176             // Empty method.
 177         }
 178
 179         @Override
 180         public void onAnimationRepeat(Animator animation) {
 181             // Empty method.
 182         }
 183     }
 184 }