LruCache.java

private LruCache<String, BitmapDrawable> mMemoryCache;

final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

// 使用最大可使用内存的1/8作为缓存
final int cacheSize = maxMemory / 8;

mMemoryCache = new LruCache<String, BitmapDrawable>(cacheSize) {

    /**
     * 衡量某个bitmap大小的方法
     */
    @Override
    protected int sizeOf(String key, BitmapDrawable value) {
        final int bitmapSize = getBitmapSize(value) / 1024;
        return bitmapSize == 0 ? 1 : bitmapSize;
    }
};