androidmultithreadingsocketsnetworkonmainthread

android.os.NetworkOnMainThreadException when the socket code seems to be executed on another thread


the error

 W/System.err: android.os.NetworkOnMainThreadException
    W/System.err:     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
            at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:110)
            at libcore.io.IoBridge.connectErrno(IoBridge.java:137)
            at libcore.io.IoBridge.connect(IoBridge.java:122)

the code

  final Thread receivingserveur = new Thread() {
                                public void run() {
                                    int i=0;
                                    while(i<3) {
                                        try {
                                            System.out.println( "start client" );
                                            sock = new Socket( "90.57.69.108", 1234);
                                        } catch (IOException e) {
                                            e.printStackTrace();
                                        }
                                        try {
                                            sock.setTcpNoDelay( true );
                                        } catch (SocketException e) {
                                            e.printStackTrace();
                                        }



                                        try {
                                            dis = new DataInputStream( sock.getInputStream() );
                                        } catch (IOException e) {
                                            e.printStackTrace();
                                        }
                                        final String message_entrant21;
                                        handler.post( new Runnable() {

                                            @Override


                                            public void run() {


                                                Toast.makeText( getApplicationContext(), "start receiving data", Toast.LENGTH_SHORT ).show();
                                            }
                                        } );
                                        try {
                                            message_entrant21 = bufferedReader.readLine();
                                        } catch (IOException e) {
                                            e.printStackTrace();
                                        }
                                        handler.post( new Runnable() {

                                            @Override


                                            public void run() {


                                                Toast.makeText( getApplicationContext(), " received data", Toast.LENGTH_SHORT ).show();
                                            }
                                        } );


                                        handler.post( new Runnable() {

                                            @Override


                                            public void run() {

                                                TextView tv = (TextView) findViewById( R.id.textView4 );
                                                tv.setMovementMethod( LinkMovementMethod.getInstance() );
                                                tv.setText( Html.fromHtml( Message232 ) );
                                                Toast.makeText( getApplicationContext(), Message232, Toast.LENGTH_LONG ).show();
                                            }
                                        } );
                                        i += 1;
                                        try {
                                            sock.close();
                                        } catch (IOException e) {
                                            System.out.println( "error to send" );
                                            e.printStackTrace();
                                        }

                                    }


                                }
                            };
                            int i=0;


                            receivingserveur.run();

my questioning

i wanted to know why when i send some data in a thread loop that for me seams that everything is not on the main thread, so why there his an error that says android.os.NetworkOnMainThreadException when for me t i am on a new thread, may it be that before i execute the serveur thread i execute another thread that use socket that connect but this time sends data? I don't think that it's the case because the other thread have not the same name than this one.

i think what is the most probable it's that i didn't created the thread loop correctly.

in all this questioning i wanted to know why the socket doesn't connects and puts this error?

If you are not happy with this question please tell me before making an impact.


Solution

  • Use start() and not run() to actually start a new thread.