「android学習」LruCache で Bitmap をメモリキャッシュするサンプルコード

2015年3月4日

Javaコード
private LruCache mMemoryCache;
@Override
protected void onCreate(Bundle savedInstanceState) {
…
// Get memory class of this device, exceeding this amount will throw an
// OutOfMemory exception.
final int memClass = ((ActivityManager) context.getSystemService(
Context.ACTIVITY_SERVICE)).getMemoryClass();

// Use 1/8th of the available memory for this memory cache.
final int cacheSize = 1024 * 1024 * memClass / 8;

mMemoryCache = new LruCache(cacheSize) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
// The cache size will be measured in bytes rather than number of items.
return bitmap.getByteCount();
}
};
…
}

public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mMemoryCache.put(key, bitmap);
}
}

public Bitmap getBitmapFromMemCache(String key) {
return mMemoryCache.get(key);
}