Launch inside callback of of AlertDialog not executing code

When i place a launch statement inside the callback of an AlertDialog the code does not get executed. Calling the launch on GlobalScope fixes it.

import android.os.Bundle
import android.util.Log
import android.view.ViewGroup.LayoutParams.MATCH_PARENT
import android.widget.Button
import android.widget.FrameLayout
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {

    companion object {

        private val TAG = MainActivity::class.java.simpleName
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(FrameLayout(this).also { it.addView(Button(this).apply {
            text = "ask me"
            setOnClickListener { onButtonClicked() }
        })}, FrameLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT))
    }

    private fun onButtonClicked() = GlobalScope.launch(Dispatchers.Main) {
        AlertDialog.Builder(this@MainActivity).setMessage("Do it?").setPositiveButton("Yes") { _, _ ->
            Log.w(TAG, "answered yes")
            launch {
                Log.w(TAG, "inside launch without GlobalScope") // this does not get executed
            }
            GlobalScope.launch {
                Log.w(TAG, "inside launch with GlobalScope")
            }
        }.setNegativeButton("No") { _, _ ->}.show()
    }
}

[AllanWang]

This is because your inner launch is executed within the job of your parent launch. As the parent finishes once the dialog is created, all children are cancelled.

Using global scope again avoids that hierarchy, so they are independent

[mtangoo]

for completion just use lifecycleScope as launcher and it will work fine!

        AlertDialog.Builder(this@MainActivity).setMessage("Do it?").setPositiveButton("Yes") { _, _ ->
            Log.w(TAG, "answered yes")
            lifecycleScope.launch {
                Log.w(TAG, "inside launch with lifecycleScope") 
            }
        }.show()