How to close all Android activities at once using 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.

Click here to download the project code.