Android Bluetooth Client Server Connection

Question

I want to created simple Android bluetooth Client-Server program

Server Code:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tv1=(TextView)findViewById(R.id.textView1);
    tv2=(TextView)findViewById(R.id.textView2);
    mBluetoothAdapter=BluetoothAdapter.getDefaultAdapter();
    try {
        mBluetoothServerSocket=mBluetoothAdapter.listenUsingRfcommWithServiceRecord(name,uUID);
        mBluetoothAdapter.cancelDiscovery();
        mBluetoothSocket=mBluetoothServerSocket.accept();
        mInputStream=mBluetoothSocket.getInputStream();
        //if(mInputStream.available()>0){
            mBufferedReader=new BufferedReader(new InputStreamReader(mInputStream));
            data = mBufferedReader.readLine();
            tv1.setText(data);
        //} 
            if(mInputStream.available()>0){
            data=mBufferedReader.readLine();
            tv2.setText(data);
            x++;
        }

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


}

Client Code:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lb=(Button)findViewById(R.id.button1);
    btAdapter = BluetoothAdapter.getDefaultAdapter();

      BluetoothDevice device = btAdapter.getRemoteDevice(addressHTC);
      try {
        btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
        btAdapter.cancelDiscovery();
        btSocket.connect();
        String message = "Hello.............. from....... Android......\n";
        outStream = btSocket.getOutputStream();
        byte[] msgBuffer = message.getBytes();
        outStream.write(msgBuffer);
      }
    catch(IOException e){
        e.printStackTrace();    
    }
      lb.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            String m1="msg 2";
            byte[] msgBuffer = m1.getBytes();
            try {
                outStream.write(msgBuffer);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });
}

This application work in one side mode, just Send message to server and show received buffer, But i need to Send back some messages from server to client continuously.

How to do it?

if you have any idea. please share it.

Answer 1

This is works for me for contineously reading. Try it.

       try {
            BufferedReader Reader = new BufferedReader(
                    new InputStreamReader(mmSocket.getInputStream()));

            while(true)
            {                   
                String receivedMsg;
                while((receivedMsg = Reader.readLine()) != null)
                {
                     // what you do with your message 
                }

            }
        } catch (Exception ex) {
            System.out.println(ex);
        }

Answer 2

you should have a different thread for listening which will send the message to the activity, this thread can be also the thread sending messages. that way your the UI wont get stuck and you could receive messages continuously. an example of such thread:

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.app.Activity;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.util.Log;

public class MessageManager extends Thread {

private static final String TAG = "MessageListener thread";
private BluetoothSocket btConnectedSocket;
private InputStream inStream;
private OutputStream outStream;
private Activity parent;
private boolean run = true;

public MessageManager(BluetoothSocket btConnectedSocket, Activity parent) throws IOException {
    this.btConnectedSocket = btConnectedSocket;
    this.parent = parent;
    inStream =  btConnectedSocket.getInputStream();
    outStream = btConnectedSocket.getOutputStream();        
}

/* this method will listen continuously to messages received through the BT socket until you call cancel
public void run() {
    byte[] buffer = new byte[1024];
    int bytes; 

    while (run) {
        try {
            bytes = inStream.read(buffer);
        }
        catch(IOException ex) {
            Log.e(TAG, "error while reading from bt socket");

        }
        parent.doStuffWithTheMessage(buffer); // pay attention: its in bytes. u need to convert it to a string
    }
}

/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) throws IOException{
        outStream.write(bytes);
}

/* Call this from the main activity to shutdown the connection */
public void cancel() {
    run = false;
    try {
        btConnectedSocket.close();
    } catch (IOException e) { }

}

}