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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.benchmark.ui;
     18 
     19 import android.graphics.Bitmap;
     20 import android.os.AsyncTask;
     21 import android.view.LayoutInflater;
     22 import android.view.View;
     23 import android.view.ViewGroup;
     24 import android.widget.BaseAdapter;
     25 import android.widget.ImageView;
     26 import android.widget.ListAdapter;
     27 import android.widget.TextView;
     28 
     29 import com.android.benchmark.R;
     30 
     31 import java.lang.ref.WeakReference;
     32 import java.util.HashMap;
     33 
     34 public class ImageListViewScrollActivity extends ListViewScrollActivity {
     35 
     36     private static final int LIST_SIZE = 100;
     37 
     38     private static final int[] IMG_RES_ID = new int[]{
     39             R.drawable.img1,
     40             R.drawable.img2,
     41             R.drawable.img3,
     42             R.drawable.img4,
     43             R.drawable.img1,
     44             R.drawable.img2,
     45             R.drawable.img3,
     46             R.drawable.img4,
     47             R.drawable.img1,
     48             R.drawable.img2,
     49             R.drawable.img3,
     50             R.drawable.img4,
     51             R.drawable.img1,
     52             R.drawable.img2,
     53             R.drawable.img3,
     54             R.drawable.img4,
     55     };
     56 
     57     private static Bitmap[] mBitmapCache = new Bitmap[IMG_RES_ID.length];
     58 
     59     private static final String[] WORDS = Utils.buildStringList(LIST_SIZE);
     60 
     61     private HashMap<View, BitmapWorkerTask> mInFlight = new HashMap<>();
     62 
     63     @Override
     64     protected ListAdapter createListAdapter() {
     65         return new ImageListAdapter();
     66     }
     67 
     68     @Override
     69     protected String getName() {
     70         return getString(R.string.image_list_view_scroll_name);
     71     }
     72 
     73     class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
     74         private final WeakReference<ImageView> imageViewReference;
     75         private int data = 0;
     76         private int cacheIdx = 0;
     77         volatile boolean cancelled = false;
     78 
     79         public BitmapWorkerTask(ImageView imageView, int cacheIdx) {
     80             // Use a WeakReference to ensure the ImageView can be garbage collected
     81             imageViewReference = new WeakReference<>(imageView);
     82             this.cacheIdx = cacheIdx;
     83         }
     84 
     85         // Decode image in background.
     86         @Override
     87         protected Bitmap doInBackground(Integer... params) {
     88             data = params[0];
     89             return Utils.decodeSampledBitmapFromResource(getResources(), data, 100, 100);
     90         }
     91 
     92         // Once complete, see if ImageView is still around and set bitmap.
     93         @Override
     94         protected void onPostExecute(Bitmap bitmap) {
     95             if (bitmap != null) {
     96                 final ImageView imageView = imageViewReference.get();
     97                 if (imageView != null) {
     98                     if (!cancelled) {
     99                         imageView.setImageBitmap(bitmap);
    100                     }
    101                     mBitmapCache[cacheIdx] = bitmap;
    102                 }
    103             }
    104         }
    105     }
    106 
    107     @Override
    108     protected void onPause() {
    109         super.onPause();
    110         for (int i = 0; i < mBitmapCache.length; i++) {
    111             mBitmapCache[i] = null;
    112         }
    113     }
    114 
    115     class ImageListAdapter extends BaseAdapter {
    116 
    117         @Override
    118         public int getCount() {
    119             return LIST_SIZE;
    120         }
    121 
    122         @Override
    123         public Object getItem(int postition) {
    124             return null;
    125         }
    126 
    127         @Override
    128         public long getItemId(int postition) {
    129             return postition;
    130         }
    131 
    132         @Override
    133         public View getView(int position, View convertView, ViewGroup parent) {
    134             if (convertView == null) {
    135                 convertView = LayoutInflater.from(getBaseContext())
    136                         .inflate(R.layout.image_scroll_list_item, parent, false);
    137             }
    138 
    139             ImageView imageView = (ImageView) convertView.findViewById(R.id.image_scroll_image);
    140             BitmapWorkerTask inFlight = mInFlight.get(convertView);
    141             if (inFlight != null) {
    142                 inFlight.cancelled = true;
    143                 mInFlight.remove(convertView);
    144             }
    145 
    146             int cacheIdx = position % IMG_RES_ID.length;
    147             Bitmap bitmap = mBitmapCache[(cacheIdx)];
    148             if (bitmap == null) {
    149                 BitmapWorkerTask bitmapWorkerTask = new BitmapWorkerTask(imageView, cacheIdx);
    150                 bitmapWorkerTask.execute(IMG_RES_ID[(cacheIdx)]);
    151                 mInFlight.put(convertView, bitmapWorkerTask);
    152             }
    153 
    154             imageView.setImageBitmap(bitmap);
    155 
    156             TextView textView = (TextView) convertView.findViewById(R.id.image_scroll_text);
    157             textView.setText(WORDS[position]);
    158 
    159             return convertView;
    160         }
    161     }
    162 }
    163