How to close all Android activities at once using Kotlin?

Android Mobile Development Apps/Applications Kotlin

This example demonstrates how to close all Android activities at once using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="4dp">
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="70dp"
      android:background="#008080"
      android:padding="5dp"
      android:text="TutorialsPoint"
      android:textColor="#fff"
      android:textSize="24sp"
      android:textStyle="bold" />
   <TextView
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_above="@id/button"
      android:layout_marginBottom="20dp"
      android:gravity="center"
      android:text="Activity One"
      android:textColor="@android:color/background_dark"
      android:textStyle="bold" />
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="Start Activity two" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

package com.example.q28
import android.content.Intent
import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var button: Button
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      button = findViewById(R.id.button)
      button.setOnClickListener {
         val intent = Intent(this@MainActivity, SecondActivity::class.java)
         startActivity(intent)
      }
   }
}

Step 4 − Create a new activity and add the following code −

activity_second.xml −

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="4dp">
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="70dp"
      android:background="#008080"
      android:padding="5dp"
      android:text="TutorialsPoint"
      android:textColor="#fff"
      android:textSize="24sp"
      android:textStyle="bold" />
   <TextView
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_above="@id/terminateButton"
      android:layout_marginBottom="20dp"
      android:gravity="center"
      android:text="Activity Two"
      android:textColor="@android:color/background_dark"
      android:textStyle="bold" />
   <Button
      android:id="@+id/terminateButton"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="Terminate all the activities" />
</RelativeLayout>

SecondActivity.kt

import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import kotlin.system.exitProcess
class SecondActivity : AppCompatActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_second)
      title = "KotlinApp"
      val button: Button = findViewById(R.id.terminateButton)
      button.setOnClickListener {
         finish()
      }
   }
   override fun onDestroy() {
      super.onDestroy()
      exitProcess(0)
   }
}

Step 5 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.