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      1 /*
      2  * Copyright (C) 2015 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.documentsui.dirlist;
     18 
     19 import android.animation.Animator;
     20 import android.animation.ArgbEvaluator;
     21 import android.animation.ValueAnimator;
     22 import android.content.Context;
     23 import android.support.v4.util.ArrayMap;
     24 import android.support.v7.widget.DefaultItemAnimator;
     25 import android.support.v7.widget.RecyclerView;
     26 import android.util.TypedValue;
     27 
     28 import com.android.documentsui.R;
     29 
     30 import java.util.ArrayList;
     31 import java.util.List;
     32 import java.util.Map;
     33 
     34 /**
     35  * Performs change animations on Items in DirectoryFragment's RecyclerView.  This class overrides
     36  * the way selection animations are normally performed - instead of cross fading the old Item with a
     37  * new Item, this class manually animates a background color change.  This enables selected Items to
     38  * correctly maintain focus.
     39  */
     40 class DirectoryItemAnimator extends DefaultItemAnimator {
     41     private final List<ColorAnimation> mPendingAnimations = new ArrayList<>();
     42     private final Map<RecyclerView.ViewHolder, ColorAnimation> mRunningAnimations =
     43             new ArrayMap<>();
     44     private final Integer mDefaultColor;
     45     private final Integer mSelectedColor;
     46 
     47     public DirectoryItemAnimator(Context context) {
     48         mDefaultColor = context.getResources().getColor(R.color.item_doc_background);
     49         mSelectedColor = context.getResources().getColor(R.color.item_doc_background_selected);
     50     }
     51 
     52     @Override
     53     public void runPendingAnimations() {
     54         super.runPendingAnimations();
     55         for (ColorAnimation anim: mPendingAnimations) {
     56             anim.start();
     57             mRunningAnimations.put(anim.viewHolder, anim);
     58         }
     59         mPendingAnimations.clear();
     60     }
     61 
     62     @Override
     63     public void endAnimation(RecyclerView.ViewHolder vh) {
     64         super.endAnimation(vh);
     65 
     66         for (int i = mPendingAnimations.size() - 1; i >= 0; --i) {
     67             ColorAnimation anim = mPendingAnimations.get(i);
     68             if (anim.viewHolder == vh) {
     69                 mPendingAnimations.remove(i);
     70                 anim.end();
     71             }
     72         }
     73 
     74         ColorAnimation anim = mRunningAnimations.get(vh);
     75         if (anim != null) {
     76             anim.cancel();
     77         }
     78     }
     79 
     80     @Override
     81     public ItemHolderInfo recordPreLayoutInformation(
     82         RecyclerView.State state,
     83         RecyclerView.ViewHolder viewHolder,
     84         @AdapterChanges int changeFlags,
     85         List<Object> payloads) {
     86         ItemInfo info = (ItemInfo) super.recordPreLayoutInformation(state,
     87                 viewHolder, changeFlags, payloads);
     88         info.isActivated = viewHolder.itemView.isActivated();
     89         return info;
     90     }
     91 
     92 
     93     @Override
     94     public ItemHolderInfo recordPostLayoutInformation(
     95         RecyclerView.State state, RecyclerView.ViewHolder viewHolder) {
     96         ItemInfo info = (ItemInfo) super.recordPostLayoutInformation(state,
     97                 viewHolder);
     98         info.isActivated = viewHolder.itemView.isActivated();
     99         return info;
    100     }
    101 
    102     @Override
    103     public ItemHolderInfo obtainHolderInfo() {
    104         return new ItemInfo();
    105     }
    106 
    107     @Override
    108     public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder vh) {
    109         return true;
    110     }
    111 
    112     class ItemInfo extends DefaultItemAnimator.ItemHolderInfo {
    113         boolean isActivated;
    114     };
    115 
    116     /**
    117      * Animates changes in background color.
    118      */
    119     class ColorAnimation
    120             implements ValueAnimator.AnimatorUpdateListener, Animator.AnimatorListener {
    121         ValueAnimator mValueAnimator;
    122         final RecyclerView.ViewHolder viewHolder;
    123         int mEndColor;
    124 
    125         public ColorAnimation(RecyclerView.ViewHolder vh, int startColor, int endColor)
    126         {
    127             viewHolder = vh;
    128             mValueAnimator = ValueAnimator.ofObject(new ArgbEvaluator(), startColor, endColor);
    129             mValueAnimator.addUpdateListener(this);
    130             mValueAnimator.addListener(this);
    131 
    132             mEndColor = endColor;
    133         }
    134 
    135         public void start() {
    136             mValueAnimator.start();
    137         }
    138 
    139         public void cancel() {
    140             mValueAnimator.cancel();
    141         }
    142 
    143         public void end() {
    144             mValueAnimator.end();
    145         }
    146 
    147         @Override
    148         public void onAnimationUpdate(ValueAnimator animator) {
    149             viewHolder.itemView.setBackgroundColor((Integer)animator.getAnimatedValue());
    150         }
    151 
    152         @Override
    153         public void onAnimationEnd(Animator animator) {
    154             viewHolder.itemView.setBackgroundColor(mEndColor);
    155             mRunningAnimations.remove(viewHolder);
    156             dispatchAnimationFinished(viewHolder);
    157         }
    158 
    159         @Override
    160         public void onAnimationStart(Animator animation) {
    161             dispatchAnimationStarted(viewHolder);
    162         }
    163 
    164         @Override
    165         public void onAnimationCancel(Animator animation) {}
    166 
    167         @Override
    168         public void onAnimationRepeat(Animator animation) {}
    169     };
    170 };
    171