Why Choose Kotlin for Android Development?

1. Introduction

This tutorial aims to introduce Kotlin, a statically typed programming language that is fully interoperable with Java, and explain why it is a preferred choice for Android development. After completing this tutorial, you will understand the advantages of using Kotlin over Java, including its concise syntax, null safety, and functional programming features.

Prerequisites:
Basic knowledge of Android development and Java is recommended but not mandatory.

2. Step-by-Step Guide

Kotlin provides several key features that make it a more efficient and productive choice for developers:

Concise: Kotlin reduces the amount of boilerplate code, making your code more readable and concise.

Interoperability: Kotlin is fully interoperable with Java. You can use existing Java libraries and frameworks in your Kotlin projects without any issues.

Null Safety: Kotlin's type system is aimed to eliminate the NullPointerExceptions from your code. It distinguishes nullable types and non-nullable types.

Coroutines: Kotlin simplifies asynchronous programming by providing native support for coroutines, which also helps to write cleaner and more manageable code.

Let's take a look at some code examples to understand these concepts better.

3. Code Examples

Example 1: Null Safety

var name: String = "John Doe"           // Non-nullable type
name = null                             // Compilation error

var nullableName: String? = "John Doe"  // Nullable type
nullableName = null                     // No error

In the above example, name cannot be assigned null because it's a non-nullable type. On the other hand, nullableName can be assigned null, as indicated by the question mark (?).

Example 2: Coroutines

import kotlinx.coroutines.*

fun main() {
    GlobalScope.launch { // launch new coroutine in background and continue
        delay(1000L) // non-blocking delay for 1 second (default time unit is ms)
        println("World!") // print after delay
    }
    println("Hello,") // main continues while coroutine is delayed
    Thread.sleep(2000L) // block main thread for 2 seconds to keep JVM alive
}

In this example, the launch coroutine builder launches a new coroutine in the background. delay is a special suspending function that does not block the main thread but suspends the coroutine and it gets resumed when the delay is over.

4. Summary

In this tutorial, we've learned why Kotlin is a preferred choice for Android development. Kotlin provides several advantages over Java, including a concise syntax, null safety, and native support for coroutines.

To further enhance your Kotlin skills, you can follow the official Kotlin documentation and Kotlin for Android developers course on Udacity.

5. Practice Exercises

Exercise 1:

Create a function in Kotlin that accepts two integers and returns their sum.

Solution:

fun addNumbers(num1: Int, num2: Int): Int {
    return num1 + num2
}

In this code, addNumbers is a function that takes two integers as parameters and returns their sum.

Exercise 2:

Create a simple Kotlin program that uses coroutines to print "Hello, World!" with a delay of 1 second between the two words.

Solution:

import kotlinx.coroutines.*

fun main() {
    GlobalScope.launch {
        delay(1000L)
        println("World!")
    }
    println("Hello,")
    Thread.sleep(2000L)
}

This code uses launch to start a new coroutine. Inside the coroutine, it first delays for 1 second, then prints "World!". Meanwhile, the main thread continues to run, printing "Hello," before the coroutine completes.

Keep practicing more Kotlin exercises to strengthen your understanding and skills.