Im currently working on an app which needs simple communication between a bluetooth button (basically a selfie button) and the connected phone through the app. Now, i can connect normally with my phone and it does work as intended, but as soon as i want to achieve this communication via code im running into problems. I got the discovery of devices and can connect via their mac adress. The device is a no name brand so there is no documentation on the UUIDS, but i have used ble apps to find out the UUIDS i need, or at least the ones i think i need. This is my current code when the device gets “clicked” in the device list. Im pretty new to this so i might be wrong but im basically trying to activate the notification by writing to the human interface UUID (on the physical button press)so i can later get notifications on button press to use for my app.Im trying this because simply trying to get communicate with the correspondant notification UUID hasnt worked so far. The whole setup notifcation part has yet to work. It would be a blessing if anyone was able to help me out here. Thanks in advance lads.

    package com.example.androidcounterapp

import android.annotation.SuppressLint
import android.bluetooth.BluetoothAdapter
import android.bluetooth.BluetoothGattDescriptor
import android.content.ContentValues.TAG
import android.content.Context
import android.util.Log
import com.polidea.rxandroidble3.RxBleClient
import com.polidea.rxandroidble3.RxBleDevice
import io.reactivex.rxjava3.disposables.Disposable
import java.util.UUID

class BluetoothConnection {

    val serviceUuidUUID = UUID.fromString("00001812-0000-1000-8000-00805f9b34fb")
    val characteristicUUID = UUID.fromString("00002a4d-0000-1000-8000-00805f9b34fb")
    val cccdUUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")

    inner class ConnectThread(
        private val context: Context,
        private val macAddress: String,
        private val bluetoothAdapter: BluetoothAdapter
    ) : Thread() {

        private val rxBleClient: RxBleClient by lazy(LazyThreadSafetyMode.NONE) {
            RxBleClient.create(context)
        }

        private var connectionDisposable: Disposable? = null

        @SuppressLint("MissingPermission")
        private fun connectAndSetupNotification(
            device: RxBleDevice,
            characteristicUUID: UUID,
            cccdUUID: UUID,
        ) {

            Log.i(TAG, "Entered connectAndSetupNotification")

            connectionDisposable = device.establishConnection(false)
                .flatMap { rxBleConnection ->

                    Log.i(TAG, "GATT connection established")


                    rxBleConnection.setupNotification(characteristicUUID)
                        .flatMap { notificationObservable ->
                            val enableNotificationValue = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
                            val descriptor = BluetoothGattDescriptor(
                                cccdUUID,
                                BluetoothGattDescriptor.PERMISSION_WRITE
                            ).apply {
                                value = enableNotificationValue
                            }

                            rxBleConnection.writeDescriptor(descriptor, enableNotificationValue)
                                .andThen(notificationObservable)
                        }
                }
                .subscribe(
                    { notificationData ->
                        Log.i(TAG, "Notification data: ${notificationData.joinToString(", ")}")
                        val readableValue = CharacteristicConverter.convert(notificationData)
                        Log.i(TAG, "Readable value: $readableValue")
                    },
                    { throwable ->
                        Log.e(TAG, "Error occurred while setting up notification", throwable)
                    }
                )
        }

        @SuppressLint("MissingPermission")
        override fun run() {

            bluetoothAdapter.cancelDiscovery()
            Log.i(TAG, "Trying to connect")
            val device = rxBleClient.getBleDevice(macAddress)
            connectAndSetupNotification(device, characteristicUUID, cccdUUID)
        }

        fun cancel() {
            connectionDisposable?.dispose()
        }
    }
}

I have tried communcating with basically every UUID that the Bluetooth ble app tied to my button device to no avail. So my last hope is that the notification needs to be enabled to work and that im not overseeing something big along the way.