Question

I want to create an application in android that will send bits continuously to another bluetooth device. I have done everything, I just don’t know how to send bit or a single character a text message will also work upon receiving the bluetooth device will perform some task like turn LEDs on or off.

The remote bluetooth device is linvor bluetooth.

My current code is:

 import java.io.IOException;
import java.util.UUID;

import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;


public class ConnectThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final BluetoothDevice mmDevice;

    public ConnectThread(BluetoothDevice device) {
        // Use a temporary object that is later assigned to mmSocket,
        // because mmSocket is final
        BluetoothSocket tmp = null;
        mmDevice = device;

        // Get a BluetoothSocket to connect with the given BluetoothDevice
        try {
            // MY_UUID is the app's UUID string, also used by the server code
            tmp = device.createRfcommSocketToServiceRecord(UUID.fromString("device uuid"));
        } catch (IOException e) { }
        mmSocket = tmp;
    }

    public void run() {
        // Cancel discovery because it will slow down the connection
        MyService.mBluetoothAdapter.cancelDiscovery();

        try {
            // Connect the device through the socket. This will block
            // until it succeeds or throws an exception
            mmSocket.connect();
        } catch (IOException connectException) {
            // Unable to connect; close the socket and get out
            try {
                mmSocket.close();
            } catch (IOException closeException) { }
            return;
        }

        // Do work to manage the connection (in a separate thread)
        //manageConnectedSocket(mmSocket);
    }

    /** Will cancel an in-progress connection, and close the socket */
    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) { }
    }
}

Right now it just crashes when I try to initialize an object of this class.

Answer 1

As Gabe Sechan said, you will create an output stream and then call write method for the output stream.

private final OutputStream mmOutStream;
\\ other lines of code ...
mmOutStream = mmSocket.getOutputStream();

/**
     * Write to the connected OutStream.
     * @param buffer  The bytes to write
     */
    public void write(byte[] buffer) {
        try {
            mmOutStream.write(buffer);
            }
        catch(IOException e)
        {
            Log.e(TAG, "Exception during write", e);
        }
   }

You can also view the example of Bluetooth Chat from where you have installed Android. It is located on android-sdk\samples\android-7\BluetoothChat. Here is the version for api 7.

Hope it helps.