Java IO exception while using the library in kotlin

[shashankRanaNW]

Hello. I used the library in my application which is written in Kotlin. I translated the code into kotlin and did some fixes but I am getting
java.io.IOException: read failed, socket might closed or timeout, read ret: -1

again and again. This post from stackEx() deals with this but I guess that deals with a different problem.

I am afixing my mainActivity which is just the java code translated into kotlin. To be precise onError is giving the error which is called onConnect
Thanks

---

package com.bottlerunner.bluetoothlibrabrytesting

import android.Manifest
import android.bluetooth.BluetoothDevice
import android.bluetooth.BluetoothSocket
import android.content.pm.PackageManager
import android.os.Bundle
import android.util.Log
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import com.harrysoft.androidbluetoothserial.BluetoothManager
import com.harrysoft.androidbluetoothserial.BluetoothSerialDevice
import com.harrysoft.androidbluetoothserial.SimpleBluetoothDeviceInterface
import io.reactivex.android.schedulers.AndroidSchedulers
import io.reactivex.functions.Consumer
import io.reactivex.schedulers.Schedulers
import javax.xml.transform.ErrorListener


class MainActivity : AppCompatActivity() {

    val bluetoothManager: BluetoothManager = BluetoothManager.getInstance() //Harry's bluetooth manager

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        connectDevice("FC:AA:B6:AA:AC:22")

        val pairedDevices: Collection<BluetoothDevice> = bluetoothManager.pairedDevicesList
        for (device in pairedDevices) {
            if (ActivityCompat.checkSelfPermission(
                    this,
                    Manifest.permission.BLUETOOTH_CONNECT
                ) != PackageManager.PERMISSION_GRANTED
            ) {
                Toast.makeText(this,"permission denied",Toast.LENGTH_SHORT).show()

            }

            Log.d("My Bluetooth App", "Device name: " + device.name)
            Log.d("My Bluetooth App", "Device MAC Address: " + device.address)
            Log.d("Debugg",device.bondState.toString())
        }


        val btn = findViewById<Button>(R.id.button)
        btn.setOnClickListener {
            connectDevice("FC:AA:B6:AA:AC:22")          //Tab
            ActivityCompat.requestPermissions(this, arrayOf( Manifest.permission.BLUETOOTH),0  )
            Log.d("Permission","Reached end of btn")
        }

    }


    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        if (requestCode == 1) {
            // Request for camera permission.
            if (grantResults.size == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // Permission has been granted. Start camera preview Activity.
                Log.d("Permission","Reached onRequestPermissionResult")
                ActivityCompat.requestPermissions(this, arrayOf( Manifest.permission.BLUETOOTH),0  )
                Toast.makeText(this,"Permission granted",Toast.LENGTH_SHORT).show()
            } else {
                Toast.makeText(this,grantResults.toString(),Toast.LENGTH_SHORT).show()}
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
    }


    var onMessageSentListener = SimpleBluetoothDeviceInterface.OnMessageSentListener{
        Toast.makeText(this, "Sent a message! Message was: " + it, Toast.LENGTH_LONG).show() // Replace context with your context instance.
    }

    var onMessageReveivedListener = SimpleBluetoothDeviceInterface.OnMessageReceivedListener{
        // We received a message! Handle it here.
        Toast.makeText(this, "Received a message! Message was: " + it, Toast.LENGTH_LONG).show(); // Replace context with your context instance.
    }

    var errorListener = SimpleBluetoothDeviceInterface.OnErrorListener{
        Toast.makeText(this,"Durr phite muh, error" + it.message, Toast.LENGTH_SHORT).show()
    }

    lateinit var deviceInterface: SimpleBluetoothDeviceInterface

    var onConnected = Consumer<BluetoothSerialDevice>{
        // You are now connected to this device!
        // Here you may want to retain an instance to your device:
        deviceInterface = it.toSimpleDeviceInterface()

        // Listen to bluetooth events
        deviceInterface.setListeners(onMessageReveivedListener, onMessageSentListener, errorListener)

        // Let's send a message:
        deviceInterface.sendMessage("Hello world!")
    }

    var onError = Consumer<Throwable> {
        Toast.makeText(this, "How lovely error" +it.message,Toast.LENGTH_SHORT).show()
        Log.d("onError" ,it.message + "\n"+ it.cause)

    }

    fun connectDevice(mac:String) {
        bluetoothManager.openSerialDevice(mac)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(onConnected, onError)
        Log.d("Debugg","reached 114")
    }

}

[mignacio]

Hi @shashankRanaNoidaWala where you able to solve this issue? I'm running into the same and I'm trying to know if the stack exchange that you posted helped you solving it or not. Thanks!

[shashankRanaNW]

No it didn't help, in the end I used Android Bluetooth Standard Library, which is more fragmented and cumbersome but did the job.

[mignacio]

Thank you. Was the device you were trying to connect a Bluetooth Low-Energy or Bluetooth Classic? I read in another issue that this library does not support BLE devices.

[shashankRanaNW]

Bluetooth classic HC-05.

[mcanyucel]

The issue still persists. sad.