缓冲Bitmaps

最近在看Android Develop SDK，在讲Bitmap的缓冲时，我看到下面的这段话：

Note: In the past, a popular memory cache implementation was a SoftReference or WeakReference bitmap cache, however this is not recommended. Starting from Android 2.3 (API Level 9) the garbage collector is more aggressive with collecting soft/weak references which makes them fairly ineffective. In addition, prior to Android 3.0 (API Level 11), the backing data of a bitmap was stored in native memory which is not released in a predictable manner, potentially causing an application to briefly exceed its memory limits and crash.

SDK不再推荐SoftReference或者WeakReference来做Bitmap的缓冲，而是推荐LruCache来实现Memory Cache，另外SDK还提到，Memory Cache可以结合Disk Cache来实现更好的效果