ImageLoader.java revision ef3b66039ff877b61bbc823921f6033d777cd3c8
1ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes/* 2ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * Copyright (C) 2014 The Android Open Source Project 3ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * 4ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * Licensed under the Apache License, Version 2.0 (the "License"); 5ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * you may not use this file except in compliance with the License. 6ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * You may obtain a copy of the License at 7ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * 8ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * http://www.apache.org/licenses/LICENSE-2.0 9ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * 10ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * Unless required by applicable law or agreed to in writing, software 11ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * distributed under the License is distributed on an "AS IS" BASIS, 12ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * See the License for the specific language governing permissions and 14ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * limitations under the License. 15ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes */ 16ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 17ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banespackage com.example.android.supportv7.graphics; 18ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 19ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.graphics.Bitmap; 20ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.os.AsyncTask; 21ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.provider.MediaStore; 22ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.support.v4.graphics.BitmapCompat; 23ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.support.v4.os.AsyncTaskCompat; 24ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.support.v4.util.LruCache; 25ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesimport android.widget.ImageView; 26ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 27ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes/** 28ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * A very naive lazily implemented image loader. Do not use this in production code. 29ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes */ 30ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banesclass ImageLoader { 31ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 32ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes /** 33ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * A LruCache used to store images which has a maximum size of 10% of the maximum heap size. 34ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes */ 35ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes private static final BitmapCache CACHE = new BitmapCache( 36ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes Math.round(Runtime.getRuntime().maxMemory() / 10)); 37ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 38ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes private ImageLoader() { 39ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 40ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 41ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes interface Listener { 42ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes void onImageLoaded(Bitmap bitmap); 43ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 44ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 45ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes static void loadMediaStoreThumbnail(final ImageView imageView, 46ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes final long id, 47ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes final Listener listener) { 48ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 49ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes final Bitmap cachedValue = CACHE.get(id); 50ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes if (cachedValue != null) { 51ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes // If the image is already in the cache, display the image, 52ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes // call the listener now and return 53ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes imageView.setImageBitmap(cachedValue); 54ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes if (listener != null) { 55ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes listener.onImageLoaded(cachedValue); 56ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 57ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes return; 58ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 59ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 60ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes AsyncTaskCompat.executeParallel(new AsyncTask<Void, Void, Bitmap>() { 61ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes @Override 62ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes protected Bitmap doInBackground(Void... params) { 63ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes return MediaStore.Images.Thumbnails.getThumbnail( 64ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes imageView.getContext().getContentResolver(), 65ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes id, 66ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes MediaStore.Images.Thumbnails.MINI_KIND, 67ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes null); 68ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 69ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 70ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes @Override 71ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes protected void onPostExecute(Bitmap bitmap) { 72ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes imageView.setImageBitmap(bitmap); 73ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 74ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes if (bitmap != null) { 75ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes // Add the image to the memory cache first 76ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes CACHE.put(id, bitmap); 77ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 78ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes if (listener != null) { 79ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes listener.onImageLoaded(bitmap); 80ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 81ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 82ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 83ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes }); 84ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 85ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 86ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes /** 87ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * A simple cache implementation for {@link android.graphics.Bitmap} instances which uses 88ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes * {@link android.support.v4.util.LruCache}. 89ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes */ 90ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes private static class BitmapCache extends LruCache<Long, Bitmap> { 91ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes BitmapCache(int maxSize) { 92ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes super(maxSize); 93ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 94ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 95ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes @Override 96ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes protected int sizeOf(Long key, Bitmap value) { 97ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes return BitmapCompat.getAllocationByteCount(value); 98ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 99ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes } 100ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes 101ef3b66039ff877b61bbc823921f6033d777cd3c8Chris Banes} 102