android studio kotlin - bluetooth "ACTION REQUEST ENABLE" doesn't work-CodePudding

After start my program, click the button, app falls. When I tried tutorials from other developers, Google, ... it doesnt solve the problem. I am ignoring startActivityForResult() is deprecated, I wanna ask user for turn on bluetooth - thats all.

The problem is on device with android 12.

Here are my permission from manifest file:

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

Here is my code from MainActivity.kt

package com.example.piratsilnic

import android.bluetooth.BluetoothAdapter
import android.bluetooth.BluetoothManager
import android.content.Context
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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

        val BTadapter = getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
        BTadapter.getAdapter()
        var REQUEST_ENABLE_BT = 1

        val sparovatButton = findViewById<Button>(R.id.sparovatButton)
        sparovatButton.setOnClickListener{
            if (BTadapter != null) {
                if (BTadapter.adapter?.isEnabled == false) {
                    val enableBtIntent = Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)
                    startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT)
                }
                if (BTadapter.adapter.isEnabled) {
                    Toast.makeText(this, "bluetooth on", Toast.LENGTH_LONG).show()
                }
            } else {
                Toast.makeText(this, "Device doesnt support bluetooth", Toast.LENGTH_LONG).show()
            }
        }  
    }

}

I am lost little bit... thank you for help...

CodePudding user response：

You can use the newer registerForActivityResult() To read more about it, there's a good guide on developers.android.com: Getting a result from an activity

First you would need to register your callback:

    val registerForResult = registerForActivityResult(
        ActivityResultContracts.StartActivityForResult()
    ) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            val intent = result.data
            // Handle the Intent
        }
    }

Then, inside your onClickListener you would launch it.

if (BTadapter.adapter?.isEnabled == false) {
    val enableBtIntent = Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)
    regiterForResult.launch(enableBtIntent)
}