Android3.0版本以上出现android.os.NetworkOnMainThreadException异常与处理方式

 

以前用2.2 访问WebService没有问题，到3.0上访问出现android.os.NetworkOnMainThreadException

找了资料经过实践，解决方法如下：

 

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StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()

                .detectDiskReads().detectDiskWrites().detectNetwork() // or

                                                                        // .detectAll()

                                                                        // for

                                                                        // all

                                                                        // detectable

                                                                        // problems

                .penaltyLog().build());

        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()

                .detectLeakedSqlLiteObjects().detectLeakedClosableObjects()

                .penaltyLog().penaltyDeath().build());

 

PS：1.在2.3版本以后加入了StrictMode类，而在3.0在网络上能感觉到有更加严格的限制，更多的查询API上的StrictMode ;       2.使用的时候只需要在你项目运行的入口Activity的OnCreate中放入这段代码，那么整个项目程序都有用。不需要每个Activity里面加入。

      3.StrictMode类一般是用来调试的，在程序运行中会打印很多消息，那是告诉你你的项目程序需要改进的地方。在Android项目中，最好的是让界面与后台装载程序分开来。总之，如果你的程序代码非常符合Android规范要求，那么你完全可以不使用上面的代码...

 

别一种方法handler中更新UI。

    TextView text1, text2;

    Button button;

    Thread th;

 

     

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        text1 = (TextView)findViewById(R.id.text1);

        text2 = (TextView)findViewById(R.id.text2);

        button = (Button)findViewById(R.id.button1);

        button.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                // TODO Auto-generated method stub

                 

                th = new Thread(runnable);

                th.start();

            }

        });

    }

 Handler myHandler = new Handler(){

        @Override

        public void handleMessage(Message msg) {

            // TODO Auto-generated method stub

            switch (msg.what) {

            case 1:

                System.out.println(msg.getData().getString("s1"));

                System.out.println(msg.getData().getString("s2"));

                try{

                 text1.setText(msg.getData().getString("s1"));

                 text2.setText(msg.getData().getString("s1"));

                }catch(Exception e){

                    e.printStackTrace();

                }

                break;

 

            default:

                break;

            }

            super.handleMessage(msg);

        }

    };

 

    Runnable runnable = new Runnable() {

        @Override

        public void run() {

              String s1 = "fsdfsgfdsgdfgfdgdhshshs";

              String s2 = "fsfsdgdshdhdshrehreherh";

 

              Message msg = new Message();

              msg.what = 1;

              Bundle bundle = new Bundle();

              bundle.putString("s1", s1);

              bundle.putString("s2", s2);

              msg.setData(bundle);

              MainActivity.this.myHandler.sendMessage(msg);

        }

    };