MainActivity.java

package example.botton.testapplication;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.ParcelUuid;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.SeekBar;
import android.widget.TextView;
import android.bluetooth.BluetoothDevice;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Set;

public class MainActivity extends AppCompatActivity
{
    //declare variables
    SeekBar seekbar1, seekbar2; //Your SeekBar
    SeekBarChangeListener listener1, listener2;
    TextView result;  //The TextView which will display the result
    BluetoothAdapter BA = BluetoothAdapter.getDefaultAdapter();
    BluetoothSocket robotSock;
    OutputStream outputStream;

    /**
     * A listener for the seek bars
     * Designed to be somewhat agnostic, so that the seekbar it corresponds to can represent either a motor or servo
     * Thus to change between tank steering and servo steering, you should only need to modify the Arduino code
     */
    private class SeekBarChangeListener implements SeekBar.OnSeekBarChangeListener
    {
        private int idNum, value;
        private static final int RANGE = 7; //range of the control axis in one direction (e.g. if RANGE = 7, the range of possible values to send is -7 to 7)

        public SeekBarChangeListener(int num)
        {
            this.idNum = num;
            this.value = 0;

        }

        public int getValue()
        {
            return value;
        }

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
        {
            //result.setText ("Value:"+ progress);
            this.value = progress - RANGE;
            seekBarChanged();
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar){}

        @Override
        public void onStopTrackingTouch(SeekBar seekBar)
        {
            seekBar.setProgress(RANGE);
        }
    }

    public void exitMethod(){
        System.exit(0);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        seekbar1 = (SeekBar)findViewById(R.id.motorBar1);
        seekbar2 = (SeekBar)findViewById(R.id.motorBar2);
        seekbar1.setProgress(SeekBarChangeListener.RANGE);
        seekbar2.setProgress(SeekBarChangeListener.RANGE);
        //result = (TextView)findViewById(R.id.tvResult);


        //set change listener
        listener1 = new SeekBarChangeListener(1);
        listener2 = new SeekBarChangeListener(2);
        seekbar1.setOnSeekBarChangeListener(listener1);
        seekbar2.setOnSeekBarChangeListener(listener2);

        if(!BA.isEnabled()){
            Intent turnOn = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(turnOn, 0);
        }
         Set<BluetoothDevice> pairedDevices;
         pairedDevices = BA.getBondedDevices();
        Log.d("some tag", "DOES IT WORK?");
        BluetoothDevice btModule = null;
        for (BluetoothDevice bt : pairedDevices)
        {
            Log.d("some tag", bt.getName());
            if ("HC-06".equals(bt.getName()))
                btModule = bt;
        }
        try {
            ParcelUuid[] uuids = btModule.getUuids();
            robotSock = btModule.createRfcommSocketToServiceRecord(uuids[0].getUuid());
           // UUID myUUID = UUID.fromString("00000000-0000-1000-8000-00805F9B34FB");
           // BluetoothSocket robotSock = btModule.createRfcommSocketToServiceRecord(myUUID);
            Log.d("bt", "Created a connection with the JY-MCU");
            robotSock.connect();
            outputStream = robotSock.getOutputStream();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void seekBarChanged()
    {
        byte toSend = (byte)(listener1.getValue()<<4 | (listener2.getValue() & 0xf));
        Log.d("seekbars", String.format("Motor value: %d\nServo value: %d", listener1.getValue(), listener2.getValue()));
        //Log.d("bt", String.format("Sending value: %x", toSend));
        sendToRobot(toSend);
    }

    public void sendToRobot(byte msg) {
        if (outputStream != null)
        {
            try {
                byte[] bytes = {msg};
                outputStream.write(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        else
        {
            Log.d("bt", "output stream hasn't been created yet. Please make sure that a device is connected");
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}