MainActivity.txt

package com.example.mkntu;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.Switch;
import java.io.OutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Set;
import java.util.UUID;



public class MainActivity extends AppCompatActivity {

    public static OutputStream op = null;


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

        //region view objects

        Switch  power       = findViewById(R.id.power);
        SeekBar bright_bar  = findViewById(R.id.bright_bar);
        Button  go_left     = findViewById(R.id.go_left);
        Button  go_right    = findViewById(R.id.go_right);
        Button  turn_up     = findViewById(R.id.turn_up);
        Button  turn_down   = findViewById(R.id.turn_down);
        //endregion
////////////////////////////////////////////////////////////////////////////////////////////////////

        //region Bluetooth connection

        BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();
        Set<BluetoothDevice> srcDevices = btAdapter.getBondedDevices();
        BluetoothSocket btSocket = null;

        //create Socket
        for(BluetoothDevice it : srcDevices){
            Log.e("found",it.getName());

            boolean found = false;

            if(it.getName().equals("LTC4736")){
                Log.e("Success","found LTC4736");

                UUID uuid = it.getUuids()[0].getUuid();
                try{
                    btSocket = it.createRfcommSocketToServiceRecord(uuid);
                }catch (IOException e) { }

                Log.e("Success",uuid.toString());
                found = true;
            }

            if(found) {
                btAdapter.cancelDiscovery();
                break;
            }
        }

        //connect Socket
        
        try {
            btSocket.connect();
        } catch (IOException connectException) {
            Log.e("Fail connect", connectException.getMessage());
        }
           

        if(btSocket.isConnected()) Log.e("Success","socket connect");


        //endregion

        //region SET OUTPUT STREAM


        try{
            op = btSocket.getOutputStream();
        }catch (IOException e){
            Log.e("FAIL","op");
        }

        //endregion
////////////////////////////////////////////////////////////////////////////////////////////////////

        //region POWER

        power.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(power.isChecked()){
                    String cmd = "a";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                else{
                    String cmd = "b";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
            }

        });
        //endregion

        //region BRIGHT_BAR

        bright_bar.setMax(99);

        bright_bar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {

            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                String cmd = "c";
                try{op.write(cmd.getBytes());}catch (IOException e){ }
                int value = bright_bar.getProgress();
                int t = value/10;
                try{op.write(Integer.toString(t).getBytes());}catch (IOException e){ }
                t = value%10;
                try{op.write(Integer.toString(t).getBytes());}catch (IOException e){ }
            }
        });

        //endregion

        go_left.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(event.getAction()==MotionEvent.ACTION_DOWN){
                    String cmd = "d";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                if(event.getAction()== MotionEvent.ACTION_UP){
                    String cmd = "s";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                return false;
            }
        });

        //region GO_RIGHT
        go_right.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(event.getAction()==MotionEvent.ACTION_DOWN){
                    String cmd = "e";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                if(event.getAction()== MotionEvent.ACTION_UP){
                    String cmd = "s";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                return false;
            }
        });

        //endregion

        //region TURN_UP

        turn_up.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(event.getAction()==MotionEvent.ACTION_DOWN){
                    String cmd = "f";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                if(event.getAction()== MotionEvent.ACTION_UP){
                    String cmd = "s";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                return false;
            }
        });

        //endregion

        //region TURN_DOWN

        turn_down.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(event.getAction()==MotionEvent.ACTION_DOWN){
                    String cmd = "g";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                if(event.getAction()== MotionEvent.ACTION_UP){
                    String cmd = "s";
                    try{op.write(cmd.getBytes());}catch (IOException e){ }
                }
                return false;
            }
        });

        //endregion

    }
}