KOTLIN

Certainly! Here’s a brief overview of basic Kotlin concepts:

Variables and Constants: In Kotlin, you declare variables using var and constants (immutable variables) using val. For example:kotlinCopy codevar x = 10 val y = 20
Data Types: Kotlin provides various data types such as Int, Long, Float, Double, Boolean, Char, etc. The type can be inferred by the compiler, but you can also explicitly specify it.kotlinCopy codeval name: String = "John" val age: Int = 30
Functions: Functions are declared using the fun keyword. Functions can have parameters and return types.kotlinCopy codefun add(x: Int, y: Int): Int { return x + y }
Classes and Objects: You define classes using the class keyword. Instances of classes are created using the new keyword.kotlinCopy codeclass Person(val name: String, val age: Int) val person = Person("Alice", 25)
Null Safety: Kotlin has a strong emphasis on null safety. Variables cannot hold null values by default, but you can declare nullable types by appending ? to the type.kotlinCopy codevar nullableString: String? = null
Control Flow: Kotlin supports traditional control flow structures like if, when, for, and while. when is similar to the switch statement in other languages.kotlinCopy codeval score = 85 when { score >= 90 -> println("A") score >= 80 -> println("B") else -> println("C") }
Collections: Kotlin provides a rich set of collections such as List, Set, and Map. They can be created using constructors or using convenience methods.kotlinCopy codeval numbersList = listOf(1, 2, 3, 4, 5) val numbersSet = setOf(1, 2, 3, 4, 5) val map = mapOf("key1" to 1, "key2" to 2)
Extension Functions: Kotlin allows you to add new functionality to existing classes without modifying their code by using extension functions.kotlinCopy codefun Int.isEven(): Boolean { return this % 2 == 0 } println(4.isEven()) // true
Lambda Expressions: Kotlin supports lambda expressions which are often used for functional programming constructs like map, filter, reduce, etc.kotlinCopy codeval numbers = listOf(1, 2, 3, 4, 5) val squaredNumbers = numbers.map { it * it }

This is just a brief overview of Kotlin’s basic concepts. There’s much more to explore, including coroutines, properties, delegation, and more.

1. Before you begin

Install Android Studio on your computer if you haven’t done so already. Check that your computer meets the system requirements required for running Android Studio (located at the bottom of the download page). If you need more detailed instructions on the setup process, refer to the Download and install Android Studio codelab.

In this codelab, you create your first Android app with a project template provided by Android Studio. You use Kotlin and Jetpack Compose to customize your app. Note that Android Studio gets updated and sometimes the UI changes so it is okay if your Android Studio looks a little different than the screenshots in this codelab.

Prerequisites

Basic Kotlin knowledge

What you’ll need

The latest version of Android Studio

What you’ll learn

How to create an Android App with Android Studio
How to run apps with the Preview tool in Android Studio
How to update text with Kotlin
How to update a User Interface (UI) with Jetpack Compose
How to see a preview of your app with Preview in Jetpack Compose

What you’ll build

An app that lets you customize your introduction!

Here’s what the app looks like when you complete this codelab (except it will be customized with your name!):

What you’ll need

A computer with Android Studio installed.

2. Create a project using the template

In this codelab, you create an Android app with the Empty Activity project template provided by Android Studio.

To create a project in Android Studio:

Double click the Android Studio icon to launch Android Studio.

In the Welcome to Android Studio dialog, click New Project.

new project open project and other options

The New Project window opens with a list of templates provided by Android Studio.

In Android Studio, a project template is an Android project that provides the blueprint for a certain type of app. Templates create the structure of the project and the files needed for Android Studio to build your project. The template that you choose provides starter code to get you going faster.

Make sure the Phone and Tablet tab is selected.
Click the Empty Activity template to select it as the template for your project. The Empty Activity template is the template to create a simple project that you can use to build a Compose app. It has a single screen and displays the text "Hello Android!".
Click Next. The New Project dialog opens. This has some fields to configure your project.
Configure your project as follows:

The Name field is used to enter the name of your project, for this codelab type “Greeting Card”.

Leave the Package name field as is. This is how your files will be organized in the file structure. In this case, the package name will be com.example.greetingcard.

Leave the Save location field as is. It contains the location where all the files related to your project are saved. Take a note of where that is on your computer so that you can find your files.

Select API 24: Android 7.0 (Nougat) from the menu in the Minimum SDK field. Minimum SDK indicates the minimum version of Android that your app can run on.

Click Finish. This may take a while – this is a great time to get a cup of tea! While Android Studio is setting up, a progress bar and message indicates whether Android Studio is still setting up your project. It may look like this:

This image shows a progress bar spinning and the text reads,

A message that looks similar to this informs you when the project set up is created.

This image shows a Gradle sync message that reads,

You may see a What’s New pane which contains updates on new features in Android Studio. Close it for now.

Click Split on the top right of Android Studio, this allows you to view both code and design. You can also click Code to view code only or click Design to view design only.

After pressing Split you should see three areas:

The Project view (1) shows the files and folders of your project
The Code view (2) is where you edit code
The Design view (3) is where you preview what your app looks like

In the Design view, you will see a blank pane with this text:

Click Build & Refresh. It may take a while to build but when it is done the preview shows a text box that says “Hello Android!“. Empty Compose activity contains all the code necessary to create this app.

ANDROID STUDIO

Download Android Studio editor Android Gradle Plugin SDK tools Preview

Android Studio

Get the official Integrated Development Environment (IDE) for Android app development.

Download Android Studio Iguana

Read release notes

New features

FEATURE

Themed app icon preview

Preview how your themed app icons respond to dynamic background wallpaper changes.

Try app icon preview

FEATURE

Try Android Studio Bot

Studio Bot is an AI assistant that helps you generate code, fix code, and answer questions about Android app development. Available in Android Studio Jellyfish canary.

Try Studio Bot

Core features

DESIGN

Compose design tools

Create dynamic layouts with Jetpack Compose. Then preview your layouts on any screen size and inspect Compose animations using the built-in inspection tools.

Design with Compose

DEVELOP

Intelligent code editor

Write better code, work faster, and be more productive with an intelligent code editor that provides code completion for Kotlin, Java, and C/C++ programing languages. Moreover, when editing Jetpack Compose you can see your code changes reflected immediately with Live Edit.

More about the editor

BUILD

Flexible build system

Powered by Gradle, Android Studio’s build system lets you to customize your build to generate multiple build variants for different Android devices from a single project. Then analyze the performance of your builds and understand where potential build issues exist in your project with the Build Analyzer.

More about Android Build

TEST

Easily emulate any device

The Android Emulator lets you to test your application on a variety of Android devices. Unlock the full potential of your apps by using responsive layouts that adapt to fit phones, tablets, foldables, Wear OS, TV and ChromeOS devices.

Use Android Emulator

PUBLISH

Android App Bundle

Find opportunities to optimize your Android app size before publishing by inspecting the contents of your app APK file or Android App Bundle. Inspect the manifest file, resources, and DEX files. Compare two APKs or Android App Bundles to see how your app size changed between app versions.

More about the APK Analyzer

Get started with Android Studio

Getting started

Learn how to set up your app development environment, configure Android Studio, and start writing an Android app.

Start using Android Studio

GETTING STARTED

Install Android Studio

Android Studio can be installed on Microsoft® Windows®, MacOS®, Linux, and ChromeOS. Learn how to install it in a few simple clicks.

GETTING STARTED

Build your first app

Learn how to build a simple Android app in Android Studio by creating a “Hello, World!” project.

GETTING STARTED

Configure Android Studio

Learn to configure Android Studio according to system requirements, create preferred default settings, customize virtual machine options, and more.

GETTING STARTED

Training for beginners and pros

Whether you’re new to Android app development or just updating your skills, we offer training courses for a variety of levels and topics.

Android Studio downloads

Download the latest version of Android Studio. For more information, see the Android Studio release notes.

Platform	Android Studio package	Size	SHA-256 checksum
Windows (64-bit)	android-studio-2023.2.1.24-windows.exe Recommended	1.1 GB	e2f70d192b2ed97d13901b63ae777672961a8b6ff1d86cae65fd26a5688d0d41
Windows (64-bit)	android-studio-2023.2.1.24-windows.zip No .exe installer	1.2 GB	da1c548b6d57f1dd63737cb248cf6760eddbd79ab21e8b1e3c3b55123ab4ef57
Mac (64-bit)	android-studio-2023.2.1.24-mac.dmg	1.2 GB	1b7e1d5da8d88dadff7276d775372fa25e97a2bda2682fff7494f7ef46a93390
Mac (64-bit, ARM)	android-studio-2023.2.1.24-mac_arm.dmg	1.2 GB	985f39d146b6534f256694dec90a158a412a39b0da53f58bc135559703f7a830
Linux (64-bit)	android-studio-2023.2.1.24-linux.tar.gz	1.2 GB	0026427572849c9cbb0c94d6f9718ea08bc345dccfe3b372b54100a95fff99b5
ChromeOS	android-studio-2023.2.1.24-cros.deb	944.2 MB	4c0055429aa7ab10e7c2b870e8e3c03ca191c913d8f91474f61ea1b5d048e9f8

More downloads are available in the download archives. For Android Emulator downloads, see the Emulator download archives.

Command line tools only

Platform	SDK tools package	Size	SHA-256 checksum
Windows	commandlinetools-win-11076708_latest.zip	153.6 MB	4d6931209eebb1bfb7c7e8b240a6a3cb3ab24479ea294f3539429574b1eec862
Mac	commandlinetools-mac-11076708_latest.zip	153.6 MB	7bc5c72ba0275c80a8f19684fb92793b83a6b5c94d4d179fc5988930282d7e64
Linux	commandlinetools-linux-11076708_latest.zip	153.6 MB	2d2d50857e4eb553af5a6dc3ad507a17adf43d115264b1afc116f95c92e5e258

Command-line tools are included in Android Studio. If you do not need Android Studio, you can download the basic Android command-line tools above. You can use the included sdkmanager to download other SDK packages.