ImageLoader的用法：

1.實作ImageCache，緩存大小5M。

public class Cache implements ImageCache {  

    private LruCache<String, Bitmap> mCache;  

    public BitmapCache() {  
        int maxSize = 5 * 1024 * 1024;  
        mCache = new LruCache<String, Bitmap>(maxSize) {  
            @Override  
            protected int sizeOf(String key, Bitmap bitmap) {  
                return bitmap.getRowBytes() * bitmap.getHeight();  
            }  
        };  
    }  

    @Override  
    public Bitmap getBitmap(String url) {  
        return mCache.get(url);  
    }  

    @Override  
    public void putBitmap(String url, Bitmap bitmap) {  
        mCache.put(url, bitmap);  
    }  

}

2.修改ImageLoader第二個參數

ImageLoader mImageLoader = new ImageLoader(mQueue, new Cache ());