android 异步缓冲图片到内存 压缩图片 避免OOM 内存溢出

package com.yns.utils;import java.io.IOException;import java.net.MalformedURLException;import java.net.URL;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.AsyncTask;import android.support.v4.util.LruCache;import android.widget.ImageView;/** * 异步加载网络图片 并且缓存到内存中 *  * @author Administrator *  */public class AsyncImageLoader extends AsyncTask<String, String, Bitmap> {private ImageView img;private LruCache<String, Bitmap> lruCache;private int width;private int height;//url 本地ipprivate String url;public AsyncImageLoader(ImageView img, LruCache<String, Bitmap> lruCache,int width, int height, String url) {this.img = img;this.lruCache = lruCache;this.width = width;this.height = height;this.url = url;}@Overrideprotected Bitmap doInBackground(String... arg0) {// TODO Auto-generated method stub// 为位图设置100K的缓存BitmapFactory.Options opts = new BitmapFactory.Options();opts.inTempStorage = new byte[100 * 1024];// 设置位图颜色显示优化方式opts.inPreferredConfig = Bitmap.Config.RGB_565;// 4.设置图片可以被回收，创建Bitmap用于存储Pixel的内存空间在系统内存不足时可以被回收opts.inPurgeable = true;// 设置位图缩放比例opts.inSampleSize = 4;// 7.解码位图// decodeStream (InputStream is, Rect outPadding,// BitmapFactory.Options opts)Bitmap bitmap = null;try {                       // arg0 是图片名字  如aa.jpg  读者只有一张图片可以 直接写System.out.println("AsyncImageLoader.doInBackground()"+url + arg0[0]);bitmap = BitmapFactory.decodeStream(new URL(arg0[0]).openConnection().getInputStream(), null, opts);addBitmapToMemoryCache(url + arg0[0], bitmap);} catch (MalformedURLException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return bitmap;}@Overrideprotected void onPostExecute(Bitmap result) {// TODO Auto-generated method stubsuper.onPostExecute(result);img.setImageBitmap(result);}// 调用LruCache的put 方法将图片加入内存缓存中，要给这个图片一个key 方便下次从缓存中取出来private void addBitmapToMemoryCache(String key, Bitmap bitmap) {if (getBitmapFromMemoryCache(key) == null) {lruCache.put(key, bitmap);}}// 调用Lrucache的get 方法从内存缓存中取图片public Bitmap getBitmapFromMemoryCache(String key) {return lruCache.get(key);}}