用于ping的Android应用无法正常工作

Question

I try to write simple ping app on Android but it doesn't work. it's stop working when I try to ping IP address. here is code

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

Button pingbtn = (Button) findViewById(R.id.Ping_btn);
   final  TextView Ipinfo = (TextView) findViewById(R.id.Ping_info);
    final EditText Ipfield = (EditText) findViewById(R.id.Ip_field);
    Ipfield.setText("127.0.0.1");
    pingbtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Editable host = Ipfield.getText();

            InetAddress Address = null;
            try
            {
                Address = InetAddress.getByName(host.toString());
            }
            catch (UnknownHostException e)
            {
            e.printStackTrace();
            }
               try {
                   if (Address.isReachable(5000)) {
                       Ipinfo.append("\n" + host + "- Response ok");
                   } else {
                       Ipinfo.append("\n" + host);
                   }
               }
        catch(IOException e)
            {
              Ipinfo.append("\n "+ e.toString());
            }
        }
    });

}

}

And here is Error

FATAL EXCEPTION: main Process: com.example.reaper.simpleping, PID: 15226 android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147) at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:110) at libcore.io.IoBridge.connectErrno(IoBridge.java:154) at libcore.io.IoBridge.connect(IoBridge.java:122) at java.net.InetAddress.isReachable(InetAddress.java:761) at java.net.InetAddress.isReachable(InetAddress.java:715) at java.net.InetAddress.isReachable(InetAddress.java:685) at com.example.reaper.simpleping.MainActivity$1.onClick(MainActivity.java:43) at android.view.View.performClick(View.java:4756) at android.view.View$PerformClick.run(View.java:19749) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.M ethod.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

I can't understand what is a problem and please help me find how fix this error. thanks for Attention.

Answer 1

The exception that is thrown when an application attempts to perform a networking operation on its main thread.

This is only thrown for applications targeting the Honeycomb SDK or higher. Applications targeting earlier SDK versions are allowed to do networking on their main event loop threads, but it's heavily discouraged. See the document Designing for Responsiveness .

Answer 2

As @dhiku said it is heavily discouraged but you can run this piece of code to allow all kinds of threads. Run in your onCreate() after setting the content:

    //allow all threading policies
    if(Build.VERSION.SDK_INT >9){
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }