How to Quit Android Application Programmatically?

When we want to implement an exit AlertDialog in our android application we have to programmatically exit our android application. In this article, we will take a look at How to Quit the Android application programmatically. We will be adding a button and on clicking on that button we will be closing our application. A sample video is given below to get an idea about what we are going to do in this article.

Note: This Android article covered in both Java and Kotlin languages. 

Step by Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio.

Step 2: Working with the activity_main.xml file

Navigate to app > res > layout > activity_main.xml and add the below code to it. Comments are added in the code to get to know in detail. 

XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/idRLContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <!--on below line we are creating
        a text for our app-->
    <TextView
        android:id="@+id/idTVHeading"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@id/idBtnCloseApplication"
        android:layout_centerInParent="true"
        android:layout_margin="20dp"
        android:gravity="center"
        android:padding="10dp"
        android:text="Click the button to close the application"
        android:textAlignment="center"
        android:textColor="@color/black"
        android:textSize="20sp"
        android:textStyle="bold" />

    <!--on below line we are creating a button-->
    <Button
        android:id="@+id/idBtnCloseApplication"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_margin="20dp"
        android:text="Close the application"
        android:textAllCaps="false" />

</RelativeLayout>

Step 3: Working with the MainActivity file 

Navigate to app > java > your app’s package name > MainActivity file and add the code below. Comments are added in the code to get to know in detail. 

Kotlin

package com.gtappdevelopers.kotlingfgproject

import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

    // on below line we are creating a variable.
    lateinit var closeApplicationBtn: Button

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

        // on below line we are creating and
        // initializing variable for activity
        val activity: MainActivity = MainActivity()

        // on below line we are initializing our variables.
        closeApplicationBtn = findViewById(R.id.idBtnCloseApplication)

        // on below line we are adding click listener for our button
        closeApplicationBtn.setOnClickListener {
            // on below line we are finishing activity.
            activity.finish()

            // on below line we are exiting our activity
            System.exit(0)
        }
    }
}

Java

package com.gtappdevelopers.kotlingfgproject;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    // on the below line we are creating a variable.
    private Button closeApplicationBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // on below line we are initializing variables with ids.
        closeApplicationBtn = findViewById(R.id.idBtnCloseApplication);

        // on below line we are adding click listener for our button
        closeApplicationBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // on below line we are finishing activity.
                MainActivity.this.finish();

                // on below line we are exiting our activity
                System.exit(0);
            }
        });
    }
}

Now run your application to see the output of it. 

Output: