AyncTask for Bluetooth on Android

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".MainActivity">

    <android.support.constraint.ConstraintLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <Button
            android:id="@+id/btnRelay1On"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:text="@string/relay_1_on"
            android:textAllCaps="false"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/btnRelay2On"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:text="@string/relay_2_on"
            android:textAlignment="center"
            android:textAllCaps="false"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/btnRelay1Off" />

        <Button
            android:id="@+id/btnRelay1Off"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:text="@string/relay_1_off"
            android:textAllCaps="false"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/btnRelay1On" />

        <Button
            android:id="@+id/btnRelay2Off"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:text="@string/relay_2_off"
            android:textAlignment="center"
            android:textAllCaps="false"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/btnRelay2On" />
    </android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>

AlernateFallbackSocketCreation.java

class SomeClass {
  public void SomeMethod() {
    Class<?> clazz = bluetoothSocket.getRemoteDevice().getClass();
    Class<?>[] paramTypes = new Class<?>[]{Integer.TYPE};
    @SuppressWarnings("JavaReflectionMemberAccess")
    Method m = clazz.getMethod("createRfcommSocket", paramTypes);
    Object[] params = new Object[]{1};
    bluetoothSocket = (BluetoothSocket) m.invoke(bluetoothSocket.getRemoteDevice(), params);
  }
}

AsyncBluetoothComm.java

package gmedina.wedev.tk.purebluetoothtestforhc05;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.AsyncTask;
import android.util.Log;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

public class AsyncBluetoothComm extends AsyncTask<String, Void, Void> {
    private final static String TAG = AsyncBluetoothComm.class.getSimpleName();

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        Log.i(TAG, "Somehow this thing finished...");
    }

    @Override
    protected void onProgressUpdate(Void... voids) {
        super.onProgressUpdate(voids);
    }

    @Override
    protected Void doInBackground(String... commands) {
        BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        List<BluetoothDevice> bluetoothDeviceList = new ArrayList<>();
        BluetoothDevice bluetoothDevice;

        for (BluetoothDevice currentDevice : bluetoothAdapter.getBondedDevices()) {
            if (currentDevice.getName().startsWith("Rha7Bt")) {
                bluetoothDeviceList.add(currentDevice);
            }
        }

        if (bluetoothDeviceList.size() == 0)
            throw new RuntimeException("No Rha7Bt devices available!");

        bluetoothDevice = bluetoothDeviceList.get(0);

        Log.i(TAG, bluetoothDevice.getName());

        BluetoothSocket bluetoothSocket;
        try {
            bluetoothSocket = bluetoothDevice.createInsecureRfcommSocketToServiceRecord(UUID.fromString("62285383-deab-4616-c932-e09c7f3d7793"));
            bluetoothSocket.connect();
        } catch (IOException e) {
            try {
                //noinspection JavaReflectionMemberAccess
                Method createRfcommSocket =
                        bluetoothDevice
                                .getClass()
                                .getMethod(
                                        "createRfcommSocket",
                                        int.class
                                );
                bluetoothSocket = (BluetoothSocket) createRfcommSocket.invoke(bluetoothDevice, 1);
                bluetoothSocket.connect();
            } catch (
                    IllegalAccessException |
                            NoSuchMethodException |
                            InvocationTargetException |
                            IOException e1
                    ) {
                e1.printStackTrace();
                return null;
            }
        }

        OutputStream outputStream;
        InputStream inputStream;

        try {
            inputStream = bluetoothSocket.getInputStream();
            outputStream = bluetoothSocket.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

        try {
            outputStream.write((commands[0] + "\r\r").getBytes());
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
            return null;
        }

        try {
            StringBuilder str = new StringBuilder();
            while (inputStream.available() > 0) {
                str.append(((char) inputStream.read()));
            }
            Log.i(TAG, str.toString());
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

        try {
            bluetoothSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

        return null;
    }
}

MainActivity.java

package gmedina.wedev.tk.purebluetoothtestforhc05;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {
    Button btnRelay1On;
    Button btnRelay1Off;
    Button btnRelay2On;
    Button btnRelay2Off;

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

        this.btnRelay1On = findViewById(R.id.btnRelay1On);
        this.btnRelay1Off = findViewById(R.id.btnRelay1Off);
        this.btnRelay2On = findViewById(R.id.btnRelay2On);
        this.btnRelay2Off = findViewById(R.id.btnRelay2Off);

        View.OnClickListener btnOnClickListener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                MainActivity.this.buttonsOnClickHandler(v);
            }
        };

        this.btnRelay1On.setOnClickListener(btnOnClickListener);
        this.btnRelay1Off.setOnClickListener(btnOnClickListener);
        this.btnRelay2On.setOnClickListener(btnOnClickListener);
        this.btnRelay2Off.setOnClickListener(btnOnClickListener);
    }

    private void buttonsOnClickHandler(View v) {
        switch (v.getId()) {
            case R.id.btnRelay1On:
                Toast.makeText(this, "Sending command...", Toast.LENGTH_SHORT).show();
                new AsyncBluetoothComm().execute("relay 1 on");
                break;
            case R.id.btnRelay1Off:
                Toast.makeText(this, "Sending command...", Toast.LENGTH_SHORT).show();
                new AsyncBluetoothComm().execute("relay 1 off");
                break;
            case R.id.btnRelay2On:
                Toast.makeText(this, "Sending command...", Toast.LENGTH_SHORT).show();
                new AsyncBluetoothComm().execute("relay 2 on");
                break;
            case R.id.btnRelay2Off:
                Toast.makeText(this, "Sending command...", Toast.LENGTH_SHORT).show();
                new AsyncBluetoothComm().execute("relay 2 off");
                break;
        }
    }
}