How to Quit Android Application Programmatically?

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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);
            }
        });
    }
}