CODEWITHSUNDEEP
javaandroidsocketsandroid-emulatoremulation
user3906490
user3906490

Reputation: 11

Android. Sockets. Fail Connection

I develop simple client-server app for Android by examples: http://android-er.blogspot.com/2014/02/android-sercerclient-example-server.html http://android-er.blogspot.com/2014/02/android-sercerclient-example-client.html Server code:

package com.example.androidserversocket;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;

import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;

public class MainActivity extends Activity {

    TextView info, infoip, msg;
    String message = "";
    ServerSocket serverSocket;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        info = (TextView) findViewById(R.id.info);
        infoip = (TextView) findViewById(R.id.infoip);
        msg = (TextView) findViewById(R.id.msg);

        infoip.setText(getIpAddress());

        Thread socketServerThread = new Thread(new SocketServerThread());
        socketServerThread.start();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    private class SocketServerThread extends Thread {

        static final int SocketServerPORT = 8080;
        int count = 0;

        @Override
        public void run() {
            try {
                serverSocket = new ServerSocket(SocketServerPORT);
                MainActivity.this.runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        info.setText("I'm waiting here: "
                                + serverSocket.getLocalPort());
                    }
                });

                while (true) {
                    Socket socket = serverSocket.accept();
                    count++;
                    message += "#" + count + " from " + socket.getInetAddress()
                            + ":" + socket.getPort() + "\n";

                    MainActivity.this.runOnUiThread(new Runnable() {

                        @Override
                        public void run() {
                            msg.setText(message);
                        }
                    });

                    SocketServerReplyThread socketServerReplyThread = new SocketServerReplyThread(
                            socket, count);
                    socketServerReplyThread.run();

                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    private class SocketServerReplyThread extends Thread {

        private Socket hostThreadSocket;
        int cnt;

        SocketServerReplyThread(Socket socket, int c) {
            hostThreadSocket = socket;
            cnt = c;
        }

        @Override
        public void run() {
            OutputStream outputStream;
            String msgReply = "Hello from Android, you are #" + cnt;

            try {
                outputStream = hostThreadSocket.getOutputStream();
                PrintStream printStream = new PrintStream(outputStream);
                printStream.print(msgReply);
                printStream.close();

                message += "replayed: " + msgReply + "\n";

                MainActivity.this.runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        msg.setText(message);
                    }
                });

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                message += "Something wrong! " + e.toString() + "\n";
            }

            MainActivity.this.runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    msg.setText(message);
                }
            });
        }

    }

    private String getIpAddress() {
        String ip = "";
        try {
            Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
                    .getNetworkInterfaces();
            while (enumNetworkInterfaces.hasMoreElements()) {
                NetworkInterface networkInterface = enumNetworkInterfaces
                        .nextElement();
                Enumeration<InetAddress> enumInetAddress = networkInterface
                        .getInetAddresses();
                while (enumInetAddress.hasMoreElements()) {
                    InetAddress inetAddress = enumInetAddress.nextElement();

                    if (inetAddress.isSiteLocalAddress()) {
                        ip += "SiteLocalAddress: " 
                                + inetAddress.getHostAddress() + "\n";
                    }

                }

            }

        } catch (SocketException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            ip += "Something Wrong! " + e.toString() + "\n";
        }

        return ip;
    }
}

Client code:

package com.example.androidclient;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import java.net.UnknownHostException;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {

    TextView textResponse;
    EditText editTextAddress, editTextPort; 
    Button buttonConnect, buttonClear;

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

        editTextAddress = (EditText)findViewById(R.id.address);
        editTextPort = (EditText)findViewById(R.id.port);
        buttonConnect = (Button)findViewById(R.id.connect);
        buttonClear = (Button)findViewById(R.id.clear);
        textResponse = (TextView)findViewById(R.id.response);

        buttonConnect.setOnClickListener(buttonConnectOnClickListener);

        buttonClear.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                textResponse.setText("");
            }});
    }

    OnClickListener buttonConnectOnClickListener = 
            new OnClickListener(){

                @Override
                public void onClick(View arg0) {
                    MyClientTask myClientTask = new MyClientTask(
                            editTextAddress.getText().toString(),
                            Integer.parseInt(editTextPort.getText().toString()));
                    myClientTask.execute();
                }};

    public class MyClientTask extends AsyncTask<Void, Void, Void> {

        String dstAddress;
        int dstPort;
        String response = "";

        MyClientTask(String addr, int port){
            dstAddress = addr;
            dstPort = port;
        }

        @Override
        protected Void doInBackground(Void... arg0) {

            Socket socket = null;

            try {
                socket = new Socket(dstAddress, dstPort);

                ByteArrayOutputStream byteArrayOutputStream = 
                        new ByteArrayOutputStream(1024);
                byte[] buffer = new byte[1024];

                int bytesRead;
                InputStream inputStream = socket.getInputStream();

                /*
                 * notice:
                 * inputStream.read() will block if no data return
                 */
                while ((bytesRead = inputStream.read(buffer)) != -1){
                    byteArrayOutputStream.write(buffer, 0, bytesRead);
                    response += byteArrayOutputStream.toString("UTF-8");
                }

            } catch (UnknownHostException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                response = "UnknownHostException: " + e.toString();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                response = "IOException: " + e.toString();
            }finally{
                if(socket != null){
                    try {
                        socket.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            textResponse.setText(response);
            super.onPostExecute(result);
        }

    }

}

I work with TWO emulators Android. When server starts it gets IP: 10.0.2.15

And in Client window I set IP: 10.0.2.15 and PORT:8080.

But I get exception: "Failed to connect to /10.0.2.15 (port 8080): connect failed: ECONNREFUSED (Connection refused)"

Why I can not connect?

Upvotes: 0

Views: 1660

Answers (1)

0101100101
0101100101

Reputation: 5911

Just to recap this as an answer: Testing on a real device should solve the issue. Apps generally have to be tested on at least one (better several) real device. Especially trying to connect an emulator to another emulator on the same PC is not even remotely close to a real situation. One device would be enough for you. That is, a real Android can connect to an emulator or the other way round as long as the PC allows the connection.

Upvotes: 1

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