Introduction to Kotlin

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If you're an Android app developer or looking to become one, you've probably heard of Kotlin. It's a relatively new kid on the block, but it's one that's quickly making a name for itself. Kotlin is a modern, statically typed programming language that is fully interoperable with Java.

Why Kotlin?

Android developers have long been using Java to create apps. So why the sudden shift towards Kotlin? Well, it's not that sudden. Kotlin was designed to address some of the issues that developers face with Java, such as null pointer exceptions, boilerplate code, and more. It's no wonder that Google officially announced Kotlin as a preferred language for Android app development at Google I/O 2019.

Now let's dive into some fundamental Kotlin concepts.

Hello Kotlin

The first step in learning a new language is typically creating a "Hello, World!" program. In Kotlin, it's as straightforward as this:

fun main() {
    println("Hello, World!")
}

This code declares a function named main that takes no arguments and returns no value. The function prints out the string "Hello, World!" when executed.

Variables

In Kotlin, you can create variables using the var (mutable) and val (immutable) keywords. Here's how you can declare variables in Kotlin:

var mutable: String = "I can be changed"
val immutable: String = "I cannot be changed"

For more details on variables in Kotlin, you can visit our comprehensive guide.

Functions

In Kotlin, functions are declared with the fun keyword. Here is an example:

fun greet(name: String): String {
    return "Hello, $name"
}

This function takes a string as input and returns a string. The function greeting is explained in more detail in our functions guide.

Null Safety

One of Kotlin's standout features is its built-in null safety. If you've programmed in Java, you're likely all too familiar with the dreaded NullPointerException. In Kotlin, you have to be explicit about whether a variable can hold a null value.

var canBeNull: String? = "I can be null"
var cannotBeNull: String = "I cannot be null"

For a deep dive into null safety in Kotlin, check out our complete guide.

Kotlin for Android

Kotlin's modern language features, seamless interoperability with Java, and Google's strong backing make it a solid choice for Android app development. Understanding Kotlin fundamentals is a stepping stone in your journey to becoming an Android app developer.

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