android HttpGet 另开线程获取网络数据问题

android跨线程通讯可以使用android.os.Handler-android.os.Message这两类对象完成。

public static void getResultForHttpGet(final String url,final Handler handler) throws ClientProtocolException, IOException{
    new Thread(){
         @Override
         public void run() {
            String result="";  
             HttpGet httpGet=new HttpGet(url);//
             HttpResponse response=new DefaultHttpClient().execute(httpGet);  
            int statusCode=response.getStatusLine().getStatusCode();
             if(statusCode==200){  
                     HttpEntity entity=response.getEntity();  
                     result=EntityUtils.toString(entity, HTTP.UTF_8);  
             }  
            Message msg=handler.obtainMessage(statusCode, result);  
            msg.sendToTarget();
         }
    }.start();

}
原获得返回值之后的代码写到 handler参数对象重写的handleMessage方法中,如果直接发起请求的类不是Activity，可以自定义接口来将信息传递给Activity。
private Handler handler1 = new MyHandler();
private class MyHandler extends Handler{
        public void handleMessage(Message msg) {
            int statusCode = msg.what;
            if(statusCode==200){  
                String result = msg.obj.toString();
                //do your business
            }else{
                // throw exception or show error message
            }
        }
    };
private Handler handler2 = new MyHandler2();
private class MyHandler2 extends Handler{
        public void handleMessage(Message msg) {
            int statusCode = msg.what;
            if(statusCode==200){  
                String result = msg.obj.toString();
                //do other business
            }else{
                // throw exception or show error message
            }
        }
    };
此外handler的post(Runnable r)方法也是跨线程操作的重要方法

//注意，若如此做，在Activity中构建的handler对象在Activity销毁后仍然有可能接收消息并执行handleMessage方法，应设法避免。关键字：handler内存泄漏