MemoryCache

android 内存缓冲机制：

import java.lang.ref.SoftReference;
import java.util.LinkedHashMap;

import android.graphics.Bitmap;
import android.util.Log;
import android.util.LruCache;

/**
 * @ClassName: MemoryCache
 * @date 2014-6-11 下午05:30:25
 * @Description: idea:1,two memory cache 2,file cache 3,network get
 * @old modify:
 * @new modify:
 * @Version:
 */
public class MemoryCache {

	// 1,two memory cache 2,file cache 3,network get
	public static final String TAG = "memory";

	// hard cache memory size
	private final static int HARD_MEMORY_SIZE = 8 * 1024 * 1024;// 8m
	// sofe cache num
	private final static int SOFT_CACHE_CAPACITY = 6;
	// hard cache
	private final static LruCache mHardBitmapCache = new LruCache(
			HARD_MEMORY_SIZE) {

		@Override
		public int sizeOf(String key, Object value) {

			return ((Bitmap) value).getRowBytes() * ((Bitmap) value).getHeight();
			// return 0;//not recycle memory
		}

		@Override
		protected void entryRemoved(boolean evicted, String key,
				Object oldValue, Object newValue) {

			Log.v(TAG, "*********hard cache is full , push to soft cache*************");
			// 硬引用缓存区满，将一个最不经常使用的oldvalue推入到软引用缓存区
			mSoftBitmapCache.put(key, new SoftReference