Android Studio Beginner: Questions and problems regarding reading data from bluetooth

Hello! I am currently working on acheiving certain tasks depending on the data received from a Bluetooth module using the input buffer. Currently I am trying to play a sound depending on the input using MediaPlayer.Create, but only seems to work when I have the device plugged in and hit "Apply Changes and Restart Activity." It does not seem to work if I were to just open the app and test, only after going through the process stated before. Is there a better way of reading the inputstream and handling that data? Is there also a better way to go about how I am playing a sound in the run() function of the ConnectedThread thread? This is my current code. I am also thinking of switching from MediaPlayer to SoundPool because I would like to play multiple sounds simultaneously, would that also be a good option?

Code (Text):

1.  
2. class ControlActivity: AppCompatActivity() {
3.  
4.    companion object {
5.        var m_myUUID: UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")
6.        var m_bluetoothSocket: BluetoothSocket? = null
7.        lateinit var m_progress: ProgressDialog
8.        lateinit var m_bluetoothAdapater: BluetoothAdapter
9.        var m_isConnected: Boolean = false
10.        lateinit var  m_address: String
11.        private const val TAG = "MY_APP_DEBUG_TAG"
12.        const val MESSAGE_READ: Int = 0
13.        const val MESSAGE_WRITE: Int = 1
14.        const val MESSAGE_TOAST: Int = 2
15.        private lateinit var handler: Handler
16.    }
17.    var mMediaPlayer: MediaPlayer? = null
18.    override fun onCreate(savedInstanceState: Bundle?) {
19.  
20.        super.onCreate(savedInstanceState)
21.        setContentView(R.layout.control_layout)
22.        m_address = intent.getStringExtra(SettingsActivity.EXTRA_ADDRESS)!!
23.        ConnectToDevice(this).execute()
24.  
25.        control_led_on.setOnClickListener { sendCommand("1") }
26.        control_led_off.setOnClickListener { sendCommand("0") }
27.        control_led_disconnect.setOnClickListener { disconnect() }
28.    }
29.  
30.    private fun sendCommand(input: String){
31.        if (m_bluetoothSocket != null){
32.            try {
33.                m_bluetoothSocket!!.outputStream.write(input.toByteArray())
34.                Log.i("data", "sending..")
35.            } catch (e: IOException) {
36.                e.printStackTrace()
37.                Log.i("data", "couldn't send")
38.                }
39.                return
40.  
41.            }
42.  
43.    }
44.    private fun disconnect(){
45.        if (m_bluetoothSocket != null){
46.            try {
47.                m_bluetoothSocket!!.close()
48.                m_bluetoothSocket = null
49.                m_isConnected = false
50.            } catch (e: IOException) {
51.                e.printStackTrace()
52.            }
53.        }
54.        finish()
55.    }
56.  
57.    private class ConnectedThread(private val mmSocket: BluetoothSocket?, c : Context) : Thread() {
58.        private val mmBuffer: ByteArray = ByteArray(10) // mmBuffer store for the stream
59.        var mMediaPlayer: MediaPlayer? = null
60.        var context: Context
61.        init{
62.            this.context = c
63.        }
64.        override fun run() {
65.            var numBytes: Int = 0// bytes returned from read()
66.            //var begin: Int = 0
67.            // Keep listening to the InputStream until an exception occurs.
68.            while (true) {
69.                // Read from the InputStream.
70.                try {
71.                    numBytes =
72.                        mmSocket!!.inputStream.read(mmBuffer, numBytes, mmBuffer.size - numBytes)
73.  
74.  
75.                } catch (e: IOException) {
76.                    Log.d(TAG, "Input stream was disconnected", e)
77.                    break
78.                }
79.  
80.                playNote(context)
81.  
82.                println(numBytes)
83.                println(String(mmBuffer))
84.  
85.  
86.  
87.  
88.  
89.            }
90.        }
91.        fun playNote(c: Context) {
92.            if (mMediaPlayer == null) {
93.                mMediaPlayer = MediaPlayer.create(c, R.raw.c3)
94.                mMediaPlayer!!.start()
95.            } else if (mMediaPlayer != null) {
96.                mMediaPlayer!!.stop()
97.                mMediaPlayer!!.release()
98.                mMediaPlayer = null
99.            } else mMediaPlayer!!.start()
100.        }
101.  
102.    }
103.  
104.  
105.  
106.  
107.    private class ConnectToDevice(c: Context) : AsyncTask<Void, Void, String>(){
108.        private var connectSuccess: Boolean = true
109.        private val context: Context
110.  
111.        init {
112.            this.context = c
113.        }
114.        override fun onPreExecute() {
115.            super.onPreExecute()
116.            m_progress = ProgressDialog.show(context, "Connecting...", "please wait")
117.        }
118.        override fun doInBackground(vararg p0: Void?) : String? {
119.            try {
120.                if (m_bluetoothSocket == null || !m_isConnected){
121.                    m_bluetoothAdapater = BluetoothAdapter.getDefaultAdapter()
122.                    val device: BluetoothDevice = m_bluetoothAdapater.getRemoteDevice(m_address)
123.                    m_bluetoothSocket = device.createInsecureRfcommSocketToServiceRecord(m_myUUID)
124.                    BluetoothAdapter.getDefaultAdapter().cancelDiscovery()
125.                    m_bluetoothSocket!!.connect()
126.  
127.                }
128.            } catch (e: IOException){
129.                connectSuccess = false
130.                e.printStackTrace()
131.            }
132.            return null
133.        }
134.        override fun onPostExecute(result: String?) {
135.            super.onPostExecute(result)
136.            if(!connectSuccess){
137.                Log.i("data", "couldn't connect")
138.            } else {
139.                m_isConnected = true
140.                var connectedthread= ConnectedThread(m_bluetoothSocket, context)
141.                connectedthread.start()
142.                Log.i("data", "connected")
143.            }
144.            m_progress.dismiss()
145.  
146.  
147.        }
148.  
149.    }
150. }
151.  

I feel like the problem I have might be the way I am passing the context to the MediaPlayer in the ConnectedThread thread, but I'm honestly not too sure because i just started learning kotlin. What other options do I have for evaluating the bytearray being sent from the Bluetooth?