android.os.NetworkOnMainThreadException 异常处理

android.os.NetworkOnMainThreadException 异常处理

博客分类：  android

 

在android 4.0上运行时报android.os.NetworkOnMainThreadException异常，在4.0中，访问网络不能在主程序中进行，有三个方法可以解决，一个是在主程序中增加： 

 //安卓2.3以后访问网络增加内容
         StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
                     .detectDiskReads()
                     .detectDiskWrites()
                     .detectNetwork()
                     .penaltyLog()
                     .build());
         StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
                     .detectLeakedSqlLiteObjects()
                     .detectLeakedClosableObjects()
                     .penaltyLog()
                     .penaltyDeath()
                     .build());

第二种采用异步方式： 

 private class GeocodeingOnclickListener implements OnClickListener{
         @Override
         public void onClick(View v) {
             new GeocodeingTask().execute();
         }
     }
     private class GeocodeingTask extends AsyncTask{
         @Override
         protected Integer doInBackground(Integer... params) {
             String url="http://maps.googleapis.com/maps/api/geocode/json?" +
                     "latlng=35.95405270,117.30649970&sensor=false";
             //创建一个Httpclient对象
             HttpClient httpClient=new DefaultHttpClient();
             String responseData="";
             try {
                 //向指定的Http地址发送请求
                 HttpResponse httpResponse=httpClient.execute(new HttpPost(url));
                 //取得服务器返回的响应
                 HttpEntity httpEntity=httpResponse.getEntity();
                 BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(httpEntity.getContent()));
                 String line="";
                 while((line=bufferedReader.readLine())!=null){
                     responseData=responseData+line;
                 }
             } catch (ClientProtocolException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }
             Gson gson=new Gson();
             TestResult result=gson.fromJson(responseData, TestResult.class);
             System.out.println(result.toString());
             return null;
         }
     }

第三种采用线程的方式（与第二种类似 都是异步的方式） 

       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       // 启动线程执行下载任务
       new Thread(downloadRun).start();
   }

   /**
    * 下载线程
    */
   Runnable downloadRun = new Runnable(){

 @Override
 public void run() {
     // TODO Auto-generated method stub
     updateListView();
 }
   };