android异步回调加载网络图片
在做应用的时候很多时候都会去从网络加载图片，而且还要做各种各样的加载效果。比如，加载图片的时候在图片上显示loading的图片，图片加载完成时loading消失，加载失败又有相应的处理。如果处理不好就会很麻烦，下面总结了一个轻量级的从网络加载图片方法。
package com.jacp.util;
import java.io.File;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
public class Utils
{
/**
* 加载图片
* @param url 图片的url
* @param listener 回调易做图
*/
public void loadImage(final String url, final OnLoadImageListener listener)
{
if (null == url || null == listener)
{
return;
}
final Handler handler = new Handler()
{
public void handleMessage(Message msg)
{
listener.onLoadImage((Bitmap) msg.obj, url);
}
};
// 之前根据url写入本地缓存的路径
String path = "";
File file = new File(path);
if (file.exists())
{
Bitmap bm = BitmapFactory.decodeFile(path);
sendMessage(handler, bm);
return;
}
new Thread(new Runnable()
{
public void run()
{
try
{
// 网络加载图片，还可以加入延迟(time out)条件
URL u = new URL(url);
HttpURLConnection httpConnection = (HttpURLConnection) u.openConnection();
if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK)
{
Bitmap bm = BitmapFactory.decodeStream(httpConnection.getInputStream());
sendMessage(handler, bm);
// 同时对图片进行缓存...
return;
}
// 没有请求到图片
sendMessage(handler, null);
} catch (MalformedURLException e)
{
sendMessage(handler, null);
} catch (IOException e)
{
sendMessage(handler, null);
}
}
}).start();
}
/**
* 向handler发送处理的消息
* @param handler
* @param bm
*/
private void sendMessage(Handler handler, Bitmap bm)
{
Message msg = handler.obtainMessage();
msg.obj = bm;
handler.sendMessage(msg);
}
/**
* 加载图片时的回调
*
*/
public inte易做图ce OnLoadImageListener&n
补充：移动开发 , Android ,
