How to Implement Press Back Again to Exit in Android using Jetpack Compose? Last Updated : 26 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The back button is used in many android applications. It is generally used to navigate to the previous page or simply exit the application. Many applications nowadays ask users to press the back button twice to exit the application. In this article, we will be building a simple application in which we will implement press back again to exit the android application using Jetpack Compose. Step by Step ImplementationStep 1: Create a New Project in Android StudioTo create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Select Empty Activity as the template. Select Kotlin as the programming language.Step 2: Working with MainActivity.kt file. Navigate to app > java+kotlin > {package-name} > MainActivity.kt file and add the below code to it. Comments are added in the code to get to know in detail.MainActivity.kt: Kotlin package com.geeksforgeeks.demo import android.os.Bundle import android.widget.Toast import androidx.activity.ComponentActivity import androidx.activity.compose.setContent import androidx.compose.foundation.layout.* import androidx.compose.material3.* import androidx.compose.runtime.* import androidx.compose.ui.* import androidx.compose.ui.text.font.FontWeight import androidx.compose.ui.unit.* class MainActivity : ComponentActivity() { private var pressedTime: Long = 0 override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContent { PressBackAgainToExit() } } // calling on back press method. override fun onBackPressed() { // checking if the press time is greater than 2 sec if (pressedTime + 2000 > System.currentTimeMillis()) { // if time is greater than 2 sec, closing the application super.onBackPressed() finish() } else { // in else condition displaying a toast message Toast.makeText(baseContext, "Press back again to exit", Toast.LENGTH_SHORT).show(); } // initializing press time variable pressedTime = System.currentTimeMillis(); } } @Composable fun PressBackAgainToExit() { Column( modifier = Modifier .fillMaxSize() .padding(all = 30.dp), horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.Center, ) { Text( text = "Press Back Again to Exit in Android", fontSize = 20.sp, fontWeight = FontWeight.Bold ) } } Output Comment More infoAdvertise with us C chaitanyamunje Follow Improve Article Tags : Kotlin Android-Jetpack Similar Reads Kotlin Tutorial This Kotlin tutorial is designed for beginners as well as professional, which covers basic and advanced concepts of Kotlin programming language. In this Kotlin tutorial, you'll learn various important Kotlin topics, including data types, control flow, functions, object-oriented programming, collecti 4 min read OverviewIntroduction to KotlinKotlin is a statically typed, general-purpose programming language developed by JetBrains, which has built world-class IDEs like IntelliJ IDEA, PhpStorm, Appcode, etc. It was first introduced by JetBrains in 2011 as a new language for the JVM. Kotlin is an object-oriented language, and a better lang 4 min read Kotlin Environment setup for Command LineTo set up a Kotlin environment for the command line, you need to do the following steps:Install the Java Development Kit (JDK): Kotlin runs on the Java virtual machine, so you need to have the JDK installed. You can download the latest version from the official Oracle website.Download the Kotlin com 2 min read Kotlin Environment setup with Intellij IDEAKotlin is a statically typed, general-purpose programming language developed by JetBrains that has built world-class IDEs like IntelliJ IDEA, PhpStorm, Appcode, etc. It was first introduced by JetBrains in 2011. Kotlin is object-oriented language and a better language than Java, but still be fully i 2 min read Hello World program in KotlinHello, World! It is the first basic program in any programming language. Let's write the first program in the Kotlin programming language. The "Hello, World!" program in Kotlin: Open your favorite editor, Notepad or Notepad++, and create a file named firstapp.kt with the following code. // Kotlin He 2 min read BasicsKotlin Data TypesThe most fundamental data type in Kotlin is the Primitive data type and all others are reference types like array and string. Java needs to use wrappers (java.lang.Integer) for primitive data types to behave like objects but Kotlin already has all data types as objects.There are different data types 3 min read Kotlin VariablesIn Kotlin, every variable should be declared before it's used. Without declaring a variable, an attempt to use the variable gives a syntax error. The declaration of the variable type also decides the kind of data you are allowed to store in the memory location. In case of local variables, the type o 2 min read Kotlin OperatorsOperators are the symbols that operate on values to perform specific mathematical or logical computations on given values. They are the foundation of any programming language. Example:Kotlinfun main(args: Array<String>) { var a= 10 + 20 println(a) }Output:30Explanation: Here, ‘+‘ is an additio 4 min read Kotlin Standard Input/OutputIn this article, we will discuss how to take input and how to display the output on the screen in Kotlin. Kotlin standard I/O operations are performed to flow a sequence of bytes or byte streams from an input device, such as a Keyboard, to the main memory of the system and from main memory to an out 4 min read Kotlin Type ConversionType conversion (also called as Type casting) refers to changing the entity of one data type variable into another data type. As we know Java supports implicit type conversion from smaller to larger data types. An integer value can be assigned to the long data type. Example: Javapublic class Typecas 2 min read Kotlin Expression, Statement and BlockEvery Kotlin program is made up of parts that either calculate values, called expressions, or carry out actions, known as statements. These parts can be organized into sections called blocks. Table of ContentKotlin ExpressionKotlin StatementKotlin BlockKotlin ExpressionAn expression in Kotlin is mad 4 min read Control FlowKotlin if-else expressionDecision Making in programming is similar to decision-making in real life. In programming too, a certain block of code needs to be executed when some condition is fulfilled. A programming language uses control statements to control the flow of execution of a program based on certain conditions. If t 4 min read Kotlin while loopIn programming, loop is used to execute a specific block of code repeatedly until certain condition is met. If you have to print counting from 1 to 100 then you have to write the print statement 100 times. But with help of loop you can save time and you need to write only two lines.While loopIt cons 2 min read Kotlin do-while loopLike Java, the do-while loop is a control flow statement that executes a block of code at least once without checking the condition, and then repeatedly executes the block, or not, depending on a Boolean condition at the end of the do-while block. It contrasts with the while loop because the while l 2 min read Kotlin for loopIn Kotlin, the for loop is equivalent to the foreach loop of other languages like C#. Here for loop is used to traverse through any data structure that provides an iterator. It is used very differently then the for loop of other programming languages like Java or C. The syntax of the for loop in Kot 4 min read Kotlin when expressionIn Kotlin, when replaces the switch operator of other languages like Java. A certain block of code needs to be executed when some condition is fulfilled. The argument of when expression compares with all the branches one by one until some match is found. After the first match is found, it reaches to 6 min read Kotlin Unlabelled breakWhen we are working with loops and want to stop the execution of loop immediately if a certain condition is satisfied, in this case, we can use either break or return expression to exit from the loop. In this article, we will discuss learn how to use break expression to exit a loop. When break expre 4 min read Kotlin labelled continueIn this article, we will learn how to use continue in Kotlin. While working with a loop in programming, sometimes, it is desirable to skip the current iteration of the loop. In that case, we can use the continue statement in the program. continue is used to repeat the loop for a specific condition. 4 min read Array & StringKotlin ArrayAn Array is one of the most fundamental data structures in practically all programming languages. The idea behind an array is to store multiple items of the same data type, such as an integer or string, under a single variable name. Arrays are used to organize data in programming so that a related s 6 min read Kotlin StringAn array of characters is called a string. Kotlin strings are similar to Java strings but have some newly added functionalities. They are also immutable, which means we can not change the elements and length of the String. The String class in Kotlin is defined as: class String : Comparable<String 4 min read FunctionsKotlin functionsIn Kotlin, functions are used to encapsulate a piece of behavior that can be executed multiple times. Functions can accept input parameters, return values, and provide a way to encapsulate complex logic into reusable blocks of code. Table of ContentWhat are Functions?Example of a FunctionTypes of Fu 7 min read Kotlin Default and Named argumentIn most programming languages, we need to specify all the arguments that a function accepts while calling that function, but in Kotlin, we need not specify all the arguments that a function accepts while calling that function, so it is one of the most important features. We can get rid of this const 7 min read Kotlin RecursionIn this tutorial, we will learn about Kotlin Recursive functions. Like other programming languages, we can use recursion in Kotlin. A function that calls itself is called a recursive function, and this process of repetition is called recursion. Whenever a function is called then there are two possib 3 min read Kotlin Tail RecursionIn a traditional recursion call, we perform our recursive call first, and then we take the return value of the recursive call and calculate the result. But in tail recursion, we perform the calculation first, and then we execute the recursive call, passing the results of the current step to the next 2 min read Kotlin Lambdas Expressions and Anonymous FunctionsIn this article, we are going to learn lambdas expression and anonymous function in Kotlin. While syntactically similar, Kotlin and Java lambdas have very different features. Lambdas expression and Anonymous function both are function literals means these functions are not declared but passed immedi 6 min read Kotlin Inline FunctionsIn Kotlin, higher-order functions and lambda expressions are treated like objects. This means they can use up memory, which can slow down your program. To help with this, we can use the 'inline' keyword. This keyword tells the compiler not to create separate memory spaces for these functions. Instea 5 min read Kotlin infix function notationIn this article, we will learn about infix notation used in Kotlin functions. In Kotlin, a function marked with infix keyword can also be called using infix notation means calling without using parenthesis and dot. There are two types of infix function notation in KotlinTable of ContentStandard libr 5 min read Kotlin Higher-Order FunctionsKotlin language has superb support for functional programming. Kotlin functions can be stored in variables and data structures, passed as arguments to and returned from other higher-order functions. Higher-Order FunctionIn Kotlin, a function that can accept a function as a parameter or return a func 6 min read CollectionsKotlin CollectionsIn Kotlin, collections are used to store and manipulate groups of objects or data. There are several types of collections available in Kotlin, including:Collection NameDescriptionLists Ordered collections of elements that allow duplicates.Sets Unordered collections of unique elements.Maps Collection 6 min read Kotlin list : ArraylistThe ArrayList class is used to create a dynamic array in Kotlin. Dynamic array states that we can increase or decrease the size of an array as a prerequisite. It also provides read and write functionalities. ArrayList may contain duplicates and is non-synchronized in nature. We use ArrayList to acce 6 min read Kotlin list : listOf()In Kotlin, a List is a generic, ordered collection of elements. Lists are very common in everyday programming as they allow us to store multiple values in a single variable. Kotlin provides two types of lists - Immutable Lists (which cannot be changed and created using listOf()) and Mutable Lists (w 7 min read Kotlin Set : setOf()In Kotlin, a Set is a generic unordered collection of elements that does not allow duplicate elements. Kotlin provides two main types of sets:Immutable Set: Created using setOf() – supports only read-only operations.Mutable Set: Created using mutableSetOf() – supports both read and write operations. 4 min read Kotlin hashSetOf()In Kotlin, a HashSet is a generic, unordered collection that holds unique elements only. It does not allow duplicates and provides constant-time performance for basic operations like add, remove, and contains, thanks to its internal hashing mechanism. The hashSetOf() function in Kotlin creates a mut 4 min read Kotlin Map : mapOf()In Kotlin, a Map is a collection that stores data in key-value pairs. Each key in a map is unique, and the map holds only one value for each key. If a key is repeated, only the last value is retained.Kotlin distinguishes between:Immutable maps (mapOf()) - read-onlyMutable maps (mutableMapOf()) - rea 5 min read Kotlin HashmapIn Kotlin, a HashMap is a collection that stores key-value pairs, where each key must be unique, but values can be duplicated. It is a hash table based implementation of the MutableMap interface. Map keys are unique and the map holds only one value for each key. It is represented as HashMap<key, 7 min read OOPs ConceptKotlin Class and ObjectsIn Kotlin, classes and objects are used to represent objects in the real world. A class is a blueprint for creating objects (a particular data structure), providing initial values for state (member variables or fields), and implementations of behavior (member functions or methods). An object is an i 4 min read Kotlin Nested class and Inner classIn Kotlin, you can define a class inside another class. Such classes are categorized as either nested classes or inner classes, each with different behavior and access rules.Nested ClassA nested class is a class declared inside another class without the inner keyword. By default, a nested class does 3 min read Kotlin Setters and GettersIn Kotlin, properties are a core feature of the language, providing a clean and concise way to encapsulate fields while maintaining control over how values are accessed or modified. Each property can have getters and setters, which are automatically generated but can be customized as needed.Kotlin P 4 min read Kotlin Class Properties and Custom AccessorsIn object-oriented programming, encapsulation is one of the most fundamental principles. It refers to bundling data (fields) and the code that operates on that data (methods) into a single unit - the class. Kotlin takes this principle even further with properties, a feature that replaces traditional 3 min read Kotlin ConstructorA constructor is a special member function that is automatically called when an object of a class is created. Its main purpose is to initialize properties or perform setup operations. In Kotlin, constructors are concise, expressive, and provide significant flexibility with features like default para 6 min read Kotlin Visibility ModifiersIn Kotlin, visibility modifiers are used to control the visibility of a class, its members (properties, functions, and nested classes), and its constructors. The following are the visibility modifiers available in Kotlin:private: The private modifier restricts the visibility of a member to the conta 6 min read Kotlin InheritanceKotlin supports inheritance, which allows you to define a new class based on an existing class. The existing class is known as the superclass or base class, and the new class is known as the subclass or derived class. The subclass inherits all the properties and functions of the superclass, and can 10 min read Kotlin InterfacesIn Kotlin, an interface is a collection of abstract methods and properties that define a common contract for classes that implement the interface. An interface is similar to an abstract class, but it can be implemented by multiple classes, and it cannot have state.Interfaces are custom types provide 7 min read Kotlin Data ClassesIn Kotlin, we often create classes just to hold data. These are called data classes, and they are marked with the data keyword. Kotlin automatically creates some useful functions for these classes, so you don’t have to write them yourself.What Is a Data Class?A data class is a class that holds data. 3 min read Kotlin Sealed ClassesKotlin introduces a powerful concept that doesn't exist in Java: sealed classes. In Kotlin, sealed classes are used when you know in advance that a value can only have one of a limited set of types. They let you create a restricted class hierarchy, meaning all the possible subclasses are known at co 4 min read Kotlin Abstract classIn Kotlin, an abstract class is a class that cannot be instantiated and is meant to be subclassed. An abstract class may contain both abstract methods (methods without a body) and concrete methods (methods with a body).An abstract class is used to provide a common interface and implementation for it 5 min read Enum Classes in KotlinIn programming, sometimes we want a variable to have only a few specific values. For example, days of the week or card suits (like Heart, Spade, etc.). To make this possible, most programming languages support something called enumeration or enum.Enums are a list of named constants. Kotlin supports 4 min read Kotlin extension functionKotlin provides a powerful feature called Extension Functions that allows us to add new functions to existing classes without modifying them or using inheritance. This makes our code more readable, reusable, and clean.What is an Extension Function?An extension function is a function that is defined 4 min read Kotlin genericsGenerics are one of Kotlin's most powerful features. They allow us to write flexible, reusable, and type-safe code. With generics, we can define classes, methods, and properties that work with different types while still maintaining compile-time type safety.What Are Generics?A generic type is a clas 6 min read Exception HandlingKotlin Exception Handling - try, catch, throw and finallyException handling is an important part of programming that helps us manage errors in our code without crashing the entire application. In this article, we will learn about exception handling in Kotlin, how to use try, catch, throw, and finally blocks, and understand different types of exceptions.Ko 5 min read Kotlin Nested try block and multiple catch blockIn Kotlin, exception handling allows developers to manage errors gracefully and prevent application crashes. In this article, we will explore two advanced exception handling concepts in Kotlin:Nested try-catch blocksMultiple catch blocks, including how to simplify them using a when expression.Nested 3 min read Null SafetyKotlin Null SafetyKotlin has a powerful type system that helps developers avoid one of the most common problems in programming: Null Pointer Exceptions. In many languages like Java, trying to use a variable that holds null can cause a NullPointerException (NPE), which can crash your application if not handled properl 7 min read Kotlin Type Checking and Smart CastingKotlin allows you to determine the type of a variable at runtime using the is operator. This feature is commonly used to handle logic based on the dynamic type of an object, enabling type-safe operations within control flow blocks.Using if-else Blocks for Type CheckingKotlinfun main() { val name = " 3 min read Kotlin Explicit Type CastingKotlin provides both smart casting and explicit type casting mechanisms to handle type conversions safely and effectively. In Smart Casting, we generally use is or !is an operator to check the type of variable, and the compiler automatically casts the variable to the target type, but in explicit typ 3 min read Like