listview异步加载图片

package com.example.testlistloadimage;

import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.widget.ImageView;

public class AsyncImageLoad {

private final int defaultimage;
private ExecutorService executorservice;
private MemoryCache mcache =new MemoryCache();
class MemoryCache {
private Map<String,SoftReference<Drawable>> cache =
Collections.synchronizedMap(new HashMap<String, SoftReference<Drawable>>());
//可再加入本地文件缓存

public Drawable get(String id){
if(cache.containsKey(id)){
return cache.get(id).get();
}
return null;
}
public void put(String id,Drawable drawable){
cache.put(id, new SoftReference<Drawable>(drawable));
}
public void clear(){
cache.clear();
}
}
class FileCache{

}
public AsyncImageLoad(int defaultimage){
this.defaultimage = defaultimage;
//创建一个纯种池
executorservice = Executors.newFixedThreadPool(5);

}
public void LoadImage(final ImageView imageview,final String imageurl,final ImageLoadCallBack callback){
imageview.setTag(imageurl);
//首先从内存中查找 ，如果没有再去开启新的线程加载图片
Drawable drawable = mcache.get(imageurl);
if(drawable != null){
imageview.setImageDrawable(drawable);
return;
}
//设置默认图片
imageview.setImageResource(defaultimage);

final Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
if(imageview.getTag().toString().equals(imageurl)){
imageview.setImageDrawable((Drawable)msg.obj);
callback.imageloaded((Drawable)msg.obj);
}

}
};
executorservice.submit(new Thread(){
@Override
public void run() {
// TODO Auto-generated method stub
super.run();


try {
URL url = new URL(imageurl);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setConnectTimeout(3000);
conn.setReadTimeout(3000);

InputStream inputStream = conn.getInputStream();
Drawable drawable = Drawable.createFromStream(inputStream, "src");
mcache.put(imageurl, drawable);
Message msg = handler.obtainMessage();
msg.obj = drawable;
handler.sendMessage(msg);

} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
});





}



public interface ImageLoadCallBack{
public void imageloaded(Drawable imagedrawable);
}
}