Shows how to use permissions with registerForActivityResult(). Code for https://devexperto.com/permisos-android-11

extensions.kt

private fun Context.openSettings() {
    Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
        addCategory(Intent.CATEGORY_DEFAULT)
        data = Uri.parse("package:$packageName")
    }.let(::startActivity)
}

MainActivity.kt

import android.Manifest.permission.ACCESS_COARSE_LOCATION
import android.content.Context
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.provider.Settings
import androidx.activity.ComponentActivity
import androidx.activity.result.contract.ActivityResultContracts.RequestPermission
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

    private val coarseLocation = PermissionRequester(this, ACCESS_COARSE_LOCATION,
        onDenied = { toast("Permission Denied") },
        onShowRationale = { toast("Should show Rationale") })

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

        button.setOnClickListener {
            coarseLocation.runWithPermission {
                toast("Success")
            }
        }
    }
}

PermissionRequeser.kt

class PermissionRequester(
    activity: ComponentActivity,
    private val permission: String,
    onDenied: () -> Unit = {},
    onShowRationale: () -> Unit = {}
) {
    private var onGranted: () -> Unit = {}

    private val launcher =
        activity.registerForActivityResult(RequestPermission()) { isGranted ->
            when {
                isGranted -> onGranted()
                activity.shouldShowRequestPermissionRationale(permission) -> onShowRationale()
                else -> onDenied()
            }
        }

    fun runWithPermission(onGranted: () -> Unit) {
        this.onGranted = onGranted
        launcher.launch(permission)
    }
}

In a fragment,
https://gist.github.com/antoniolg/edac2587da74668776c4838666102079#file-mainactivity-kt-L15
this is not ready yet and you get:

FragBlah not attached to an activity.

@Drjacky use fragment.registerForActivityResult(...) not fragment.requestActivity().registerForActivityResult(...)