android异步加载图片

package cn.com.mzba.service;

import java.io.InputStream;

import java.lang.ref.SoftReference;

import java.net.URL;

import java.util.HashMap;

import android.graphics.drawable.Drawable;

import android.os.Handler;

import android.os.Message;

import android.widget.ImageView;

/**

* 实现图片的异步载入显示

* @author kandanle

*

*/

public class AsyncImageLoader {

/**

* 软引用对象，在响应内存需要时，由垃圾回收器决定是否清除此对象。软引用对象最常用于实现内存敏感的缓存。

*/

private HashMap<String, SoftReference<Drawable>> imageCache;

public AsyncImageLoader(){

imageCache = new HashMap<String, SoftReference<Drawable>>();

}

public Drawable loadDrawable(final String imageUrl,final ImageView imageView,final ImageCallback imagecallback){

if(imageCache.containsKey(imageUrl)){

//从缓存中读取人人

SoftReference<Drawable> softReference = imageCache.get(imageUrl);

Drawable drawable = softReference.get();

if(drawable != null){

return drawable;

}

}

final Handler handler = new Handler(){

@Override

public void handleMessage(Message msg) {

super.handleMessage(msg);

imagecallback.imageLoaded((Drawable)msg.obj, imageView, imageUrl);

}

};

new Thread(){

public void run() {

Drawable drawable = loadImageFromUrl(imageUrl);

imageCache.put(imageUrl, new SoftReference<Drawable>(drawable));

Message message = handler.obtainMessage(0, drawable);

handler.sendMessage(message);

}

}.start();

return null;

}

public static Drawable loadImageFromUrl(String urlPath){

URL url;

InputStream is = null;

try{

url = new URL(urlPath);

is = (InputStream)url.getContent();

}catch(Exception e){

e.printStackTrace();

}

Drawable drawable = Drawable.createFromStream(is, "src");

return drawable;

}

}