TCP/Modbus for android, (Android,Jamod)

Question

I'm making a program for smartphones which attempts to connect to a PLC via TCP / Modbus and I am using the library Jamod, this same program I put in java and if connected, but no change in android .... , Someone can help me?.

I have also given permission for the application to use the internet and do not know why not connect, please I'm desperate!

        package com.JR.scada;

import java.net.InetAddress;

import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.io.ModbusTCPTransaction;
import net.wimpi.modbus.msg.ReadInputDiscretesRequest;
import net.wimpi.modbus.msg.ReadInputDiscretesResponse;
import net.wimpi.modbus.net.TCPMasterConnection;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;




public class Main extends Activity implements OnClickListener{
    TextView text, depurar;
    EditText IP;
    Button boton;
    //Thread comm = new Thread(this);
    int i=0;
    /*private final int PUERTO=502;
    private Socket socket = null;
    private OutputStream output = null;
    private BufferedInputStream input = null;
    private byte buffer[] = new byte[261];*/

    TCPMasterConnection con = null;     //the TCP connection
    ModbusTCPTransaction trans = null;  //the Modbus transaction

    InetAddress addr = null;        //direccion del esclavo
    int port = Modbus.DEFAULT_PORT;//puerto por defecto 502 


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

        text = (TextView) findViewById(R.id.lblRegistro);
        IP = (EditText) findViewById(R.id.txtIp);
        depurar = (TextView) findViewById(R.id.txtdepurar);
        boton = (Button)findViewById(R.id.btnVerRegistro);
        boton.setOnClickListener(this);



    }

            @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }   
    @Override
    protected void onStop() {
        super.onStop();
        //Close the TCP connection
        con.close();
    }
    @Override
    /*public void run() {*/
    protected void onResume() {
        super.onResume();

        try {
            text.setText("Entro en el try");
             //IP address;
            addr = InetAddress.getByName("212.170.50.238");
            // Open the connection
            con = new TCPMasterConnection(addr);
            con.setPort(port);
            con.connect ();
            if(con.isConnected()){
                depurar.setText("conecta");
            }


        } catch (Exception e) {
            Log.d("MODBUS","connection error");
           depurar.setText("no conecta");
        }

    }

it gives me error:

         08-20 10:25:39.299: D/MODBUS(1238): connection error
08-20 10:25:39.299: D/MODBUS(1238): android.os.NetworkOnMainThreadException
08-20 10:25:39.299: D/MODBUS(1238):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
08-20 10:25:39.299: D/MODBUS(1238):     at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
08-20 10:25:39.299: D/MODBUS(1238):     at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
08-20 10:25:39.299: D/MODBUS(1238):     at libcore.io.IoBridge.connect(IoBridge.java:112)
08-20 10:25:39.299: D/MODBUS(1238):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
08-20 10:25:39.299: D/MODBUS(1238):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
08-20 10:25:39.299: D/MODBUS(1238):     at java.net.Socket.startupSocket(Socket.java:566)
08-20 10:25:39.299: D/MODBUS(1238):     at java.net.Socket.<init>(Socket.java:225)
08-20 10:25:39.299: D/MODBUS(1238):     at net.wimpi.modbus.net.TCPMasterConnection.connect(TCPMasterConnection.java:65)
08-20 10:25:39.299: D/MODBUS(1238):     at com.JR.scada.Main.onResume(Main.java:96)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1185)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.Activity.performResume(Activity.java:5182)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2732)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2771)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2235)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
08-20 10:25:39.299: D/MODBUS(1238):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-20 10:25:39.299: D/MODBUS(1238):     at android.os.Looper.loop(Looper.java:137)
08-20 10:25:39.299: D/MODBUS(1238):     at android.app.ActivityThread.main(ActivityThread.java:5041)
08-20 10:25:39.299: D/MODBUS(1238):     at java.lang.reflect.Method.invokeNative(Native Method)
08-20 10:25:39.299: D/MODBUS(1238):     at java.lang.reflect.Method.invoke(Method.java:511)
08-20 10:25:39.299: D/MODBUS(1238):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-20 10:25:39.299: D/MODBUS(1238):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-20 10:25:39.299: D/MODBUS(1238):     at dalvik.system.NativeStart.main(Native Method)
08-20 10:25:40.140: D/dalvikvm(1238): GC_CONCURRENT freed 117K, 9% free 2653K/2892K, paused 15ms+23ms, total 236ms
08-20 10:25:40.449: D/gralloc_goldfish(1238): Emulator without GPU emulation detected

.

Answer 1

If you are executing this on API level 11 or above, it might be related to doing blocking network operations on the main thread (onResume is executed on the main thread, thus blocking UI updates). This answer should be of help: https://stackoverflow.com/a/6343299/1045199

Source: http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html

P.S. you really should post the exception stacktrace to let others know what is the actual error.

Answer 2

This doesn't look like a Modbus specific bug, as you fail to establish basic TCP connection.

Perhaps get NetworkInfo out of ConnectivityManager first, and check if the device is connected?