Kotlin for Android Development — Boosting Productivity and Performance

Android is the most popular mobile operating system in the world, with over 3 billion active devices. Android development is a lucrative and rewarding career for many programmers, but it also comes with some challenges and frustrations. One of the main challenges is the choice of programming language. For a long time, Java was the official and dominant language for Android development, but it also had some drawbacks, such as verbosity, nullability issues, boilerplate code, and compatibility problems. In 2017, Google announced Kotlin as the second official language for Android development, and since then, Kotlin has gained a lot of popularity and adoption among Android developers. Kotlin is a modern, concise, expressive, and safe programming language that helps developers write better Android apps faster and easier.

In this article, we will explore how Kotlin can boost productivity and performance for Android development, and what are the benefits and challenges of using Kotlin.

What is Kotlin?

Kotlin is a cross-platform, statically typed, general-purpose programming language that runs on the Java Virtual Machine (JVM) and can interoperate with Java code. Kotlin was created by JetBrains, the company behind popular IDEs such as IntelliJ IDEA and Android Studio. Kotlin was designed to be a pragmatic, concise, readable, and safe alternative to Java, while also adding some features that Java lacks, such as null safety, data classes, extension functions, coroutines, lambdas, and more. Kotlin also supports multiple programming paradigms, such as object-oriented, functional, procedural, and declarative.

Why use Kotlin for Android development?

Over 50% of professional Android developers use Kotlin as their primary language, while only 30% use Java as their main language. 70% of developers whose primary language is Kotlin say that Kotlin makes them more productive. Using Kotlin for Android development, you can benefit from:

— Less code combined with greater readability: Kotlin allows you to write more expressive and concise code than Java, reducing the amount of boilerplate code and improving readability. For example, you can create a data class in Kotlin with just one line of code:

data class User(val name: String, val age: Int)

In Java, you would need to write at least 10 lines of code to achieve the same functionality:

public class User {
    private final String name;
    private final int age;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

— Safer code with null safety: One of the most common causes of crashes in Android apps is the NullPointerException (NPE), which occurs when you try to access or manipulate a null object reference. Kotlin helps you avoid NPEs by incorporating nullability into its type system. In Kotlin, you have to explicitly mark a variable or parameter as nullable (with a question mark) or non-nullable (without a question mark). For example:

var name: String = "Alice" // non-nullable
name = null // compile-time error

var age: Int? = null // nullable
age = 25 // OK

Kotlin also provides various operators and functions to deal with nullable values safely and elegantly, such as the safe call operator (?.), the Elvis operator (?:), the not-null assertion operator (!!), and the let function.

— Modern and powerful features: Kotlin adds some features that Java does not have or supports poorly, such as:

- Extension functions: These are functions that can be added to existing classes without modifying their source code or inheriting from them. For example, you can add an extension function to the String class to check if it is a valid email address:

fun String.isValidEmail(): Boolean {     
// some logic to validate email 
}  
val email = "[email protected]" 
println(email.isValidEmail()) // true

- Coroutines: These are lightweight threads that allow you to write asynchronous and concurrent code in a sequential and synchronous way. Coroutines can help you simplify tasks such as network calls, database operations, UI updates, etc. For example, you can use coroutines to fetch data from an API and update the UI without blocking the main thread:

// launch a coroutine on the main thread 
lifecycleScope.launch {    
 // switch to a background thread    
 val data = withContext(Dispatchers.IO) {        
 // make a network request         
api.getData()     
}     
// switch back to the main thread    
 // update the UI with the data    
 textView.text = data 
}

- Delegated properties: These are properties whose behavior is defined by another object or function. For example, you can use delegated properties to implement lazy initialization, observable properties, or dependency injection. For example, you can use the lazy delegate to initialize a property only when it is first accessed:

// a heavy object that takes time to create 
val heavyObject: HeavyObject by lazy {    
 // create and return the object    
 HeavyObject() 
}  
// the object is not created until it is used 
println(heavyObject) // HeavyObject@12345678

— Seamless interoperability with Java: Kotlin is fully compatible with Java, which means that you can use any existing Java libraries, frameworks, or tools in your Kotlin code, and vice versa. You can also mix Kotlin and Java code in the same project, and even in the same file. For example, you can call a Java method from Kotlin:

// a Java method
public static int add(int a, int b) {
    return a + b;
}

// call it from Kotlin
val result = JavaClass.add(2, 3) // 5

Or you can call a Kotlin function from Java:

// a Kotlin function
fun greet(name: String) {
    println("Hello, $name!")
}

// call it from Java
KotlinClass.INSTANCE.greet("Bob"); // Hello, Bob!

How to get started with Kotlin for Android development?

To get started with Kotlin for Android development, you need to have Android Studio, the official IDE for Android development. Android Studio provides first-class support for Kotlin, such as syntax highlighting, code completion, debugging, testing, refactoring, etc. You can also use Android Studio to convert your existing Java code to Kotlin with just a few clicks.

To create a new Android project with Kotlin, you need to follow these steps:

- Open Android Studio and select Start a new Android Studio project.

- Choose an app template and click Next.

- Enter a name, package name, and save location for your app and click Next.

- Select a minimum SDK level for your app and click Next.

- Check the Include Kotlin support checkbox and click Finish.

To add Kotlin to an existing Android project, you need to follow these steps:

- Open your project in Android Studio and select Tools > Kotlin > Configure Kotlin in Project.

- Select All modules containing Kotlin files and click OK.

- Add the following dependencies to your app’s build.gradle file:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

- Sync your project with Gradle files.

What are the best practices and resources for learning Kotlin for Android development?

To learn Kotlin for Android development effectively and efficiently, you should follow some best practices and use some resources that can help you along the way. Some of them are:

— Learn the basics of Kotlin: Before diving into Android-specific topics, you should learn the basics of Kotlin as a programming language, such as its syntax, data types, control structures, functions, classes, etc. You can use various online courses, books, tutorials, videos, podcasts, blogs, etc. to learn Kotlin at your own pace and level. Some of the recommended resources are:

- Kotlin Bootcamp for Programmers: A free online course by Google that teaches you the fundamentals of Kotlin.

- Kotlin Koans: A series of interactive exercises that help you learn Kotlin through practice.

- Kotlin in Action: A book by the creators of Kotlin that covers the language features and applications of Kotlin.

— Follow the official Android guides and documentation: The official Android guides and documentation provide comprehensive and up-to-date information on how to use Kotlin for Android development. You can find guides on topics such as Jetpack Compose, coroutines, data binding, testing, etc. You can also find API reference documentation in both Java and Kotlin. Some of the recommended resources are:

- Android Developers: The official website for Android development that contains guides, documentation, samples, tools, etc.

- Android Developers YouTube Channel: The official YouTube channel for Android development that contains videos on various topics and features related to Android and Kotlin.

- Android Developers Blog: The official blog for Android development that contains news, updates, tips, and best practices for Android and Kotlin.

These resources can help you learn the best practices and latest trends for Android development with Kotlin. You can also get feedback and support from the Android developer community through forums, events, podcasts, etc. Some of the recommended resources are:

- Kotlin Slack: A Slack workspace where you can chat with other Kotlin developers and get help from experts.

- Kotlin User Groups: A list of local user groups where you can meet and network with other Kotlin developers in your area.

- Android Dev Summit: An annual event where you can learn from Google experts and other Android developers about the latest technologies and best practices for Android development with Kotlin.

By following the official Android guides and documentation, you can stay updated and informed about the best ways to use Kotlin for Android development. You can also learn from the experiences and insights of other Android developers who use Kotlin.

Read more:

1. Documentation | Android Developers
2. Kotlin for Android | Kotlin Documentation (kotlinlang.org)
3. Saint Petersburg Russia March 12 2020 Stock Photo 1671806992 | Shutterstock
4. Improve performance | App quality | Android Developers
5. Kotlin and Android | Android Developers

Stackademic

Thank you for reading until the end. Before you go:

• Please consider clapping and following the writer! 👏
• Follow us on Twitter(X), LinkedIn, and YouTube.
• Visit Stackademic.com to find out more about how we are democratizing free programming education around the world.