กดปุ่มแล้วจะแสดง dialog ถ้าตอบ Proceed จะปิด app

ไฟล์ที่เกี่ยวข้อง

• activity_main.xml
• MainActivity.kt

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <Button
            android:id="@+id/btnShowAlert"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Show Alert"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt

package com.phaisarn.myapplication

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.app.AlertDialog
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

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

        // when button is clicked, show the alert
        btnShowAlert.setOnClickListener {
            // build alert dialog
            val dialogBuilder = AlertDialog.Builder(this)

            // set message of alert dialog
            dialogBuilder.setMessage("Do you want to close this application ?")
                // if the dialog is cancelable
                .setCancelable(false)
                // positive button text and action
                .setPositiveButton("Proceed") { _, _ ->
                    finish()
                }
                // negative button text and action
                .setNegativeButton("Cancel") { dialog, _ ->
                    dialog.cancel()
                }

            // create dialog box
            val alert = dialogBuilder.create()
            // set title for alert dialog box
            alert.setTitle("AlertDialogExample")
            // show alert dialog
            alert.show()
        }
    }
}

Link

• Kotlin Android – AlertDialog – Example