Aplikacja mobilna do sterowania RASPBERRY PI ZERO W przez bluetooth

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    tools:context="com.example.user.joysyickbb8.MainActivity">

    <io.github.controlwear.virtual.joystick.android.JoystickView
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/joystickView"
        app:JV_borderWidth="4dp"
        app:JV_fixedCenter="false"
        app:JV_buttonColor="#FF8C00"
        app:JV_borderColor="#FF8C00"
        app:JV_backgroundColor="#FFFFFF"
        app:JV_buttonSizeRatio="20%"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="kąt"
        android:id="@+id/tv_angle"
        />
        
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="siła"
        android:id="@+id/tv_strength"
        android:layout_alignParentEnd="true"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="kierunek"
        android:id="@+id/id_arrow"
        android:layout_centerHorizontal="true"/>

    <Button
        android:id="@+id/id_bt_connect"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/id_arrow"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="46dp"
        android:text="Button" />


</RelativeLayout>

package com.example.user.joysyickbb8;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

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

import io.github.controlwear.virtual.joystick.android.JoystickView;

public class MainActivity extends AppCompatActivity {

    private final String DEVICE_ADDRESS = "B8:27:BB:26:7D:77";
    private final UUID  PORT_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");

    private BluetoothDevice device;
    private BluetoothSocket socket;
    private OutputStream outputStream;

    Button bluetooth_connect_btn;


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

        final JoystickView joystickView= (JoystickView)  findViewById(R.id.joystickView);
        final TextView tv_angle= (TextView) findViewById(R.id.tv_angle);
        final TextView tv_strength= (TextView) findViewById(R.id.tv_strength);

        final TextView id_arrow = (TextView) findViewById(R.id.id_arrow);
         bluetooth_connect_btn=(Button) findViewById(R.id.id_bt_connect);

        joystickView.setOnMoveListener(new JoystickView.OnMoveListener() {
            @Override
            public void onMove(int angle, int strength){

                Object arrow;

                tv_angle.setText("kąt: " + angle);
                tv_strength.setText("siła: " + strength + "%");

                if (strength == 0)
                {
                    arrow = "x";
                    id_arrow.setText("kierunek: " + arrow);
                    try
                    {
                        outputStream.write(arrow.toString().getBytes());
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }

                }
                else if ((angle>315 || angle<=45) & strength !=0) {

                    arrow = "d";
                    id_arrow.setText("kierunek: " + arrow);
                   try
                    {
                        outputStream.write(arrow.toString().getBytes());
                    }
                    catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                else if (angle > 45 & angle <=135 & strength !=0){
                    arrow = "w";
                    id_arrow.setText("kierunek: " + arrow);
                    try
                    {
                        outputStream.write(arrow.toString().getBytes());
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }
                }
                else if  (angle > 135 & angle <= 225 & strength !=0){
                    arrow = "a";
                    id_arrow.setText("kierunek: " + arrow);
                   try
                    {
                        outputStream.write(arrow.toString().getBytes());
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }
                }
                else if (angle > 225 & angle<=315 & strength !=0){
                    arrow = "s";
                    id_arrow.setText("kierunek: " + arrow);
                    try
                    {
                        outputStream.write(arrow.toString().getBytes());
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        });

        bluetooth_connect_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(BTinit()){
                    BTconnect();
                }
            }
        });
    }

    public boolean BTinit()
    {
        boolean found =false;
        BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (bluetoothAdapter == null)
        {
            Toast.makeText(getApplicationContext(),"Urządzenie nie wspiera bluetooth",Toast.LENGTH_SHORT).show();
        }
        if (!bluetoothAdapter.isEnabled())
        {
            Intent enableAdapter = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableAdapter,0);
            try
            {
                Thread.sleep(1000);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
        Set<BluetoothDevice> bondedDevices = bluetoothAdapter.getBondedDevices();
        if(bondedDevices.isEmpty())
        {
            Toast.makeText(getApplicationContext(),"Sparuj urządzenia",Toast.LENGTH_SHORT).show();
        }
        else
        {
            for (BluetoothDevice interator:bondedDevices)
            {
                if (interator.getAddress().equals(DEVICE_ADDRESS))
                {
                    device = interator;
                    found = true;
                    break;
                }
            }
        }
        return found;
    }

    public  boolean BTconnect()
    {
        boolean connected = true;

        try
        {
            socket = device.createRfcommSocketToServiceRecord(PORT_UUID);
            socket.connect();
            Toast.makeText(getApplicationContext(),"Połączono z bluetooth",Toast.LENGTH_SHORT).show();
        }
        catch(IOException e)
        {
            e.printStackTrace();
            connected=false;
        }

        if (connected)
        {
            try
            {
                outputStream = socket.getOutputStream();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }
        return connected;
    }
@Override
    protected void onStart()
    {
           super.onStart();
    }
}

if (socket.isConnected()){
setMoveListener();
} else {
waitForConnection();
}