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Android Development with Kotlin

You're reading from   Android Development with Kotlin Enhance your skills for Android development using Kotlin

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Product type Paperback
Published in Aug 2017
Publisher Packt
ISBN-13 9781787123687
Length 440 pages
Edition 1st Edition
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Authors (2):
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Marcin Moskala Marcin Moskala
Author Profile Icon Marcin Moskala
Marcin Moskala
Igor Wojda Igor Wojda
Author Profile Icon Igor Wojda
Igor Wojda
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Table of Contents (10) Chapters Close

Preface 1. Beginning Your Kotlin Adventure FREE CHAPTER 2. Laying a Foundation 3. Playing with Functions 4. Classes and Objects 5. Functions as First-Class Citizens 6. Generics Are Your Friends 7. Extension Functions and Properties 8. Delegates 9. Making Your Marvel Gallery Application

Top-level functions


Another thing we can observe in a simple Hello, World! program is that the main function is not located inside any class. In Chapter 2, Laying a Foundation, we already mentioned that Kotlin can define various entities at the top level. A function that is defined at the top level is called a top-level function. Here is an example of one of them:

    // Test.kt 
    package com.example 
 
    fun printTwo() { 
        print(2) 
    } 

Top-level functions can be used all around the code (assuming that they are public, which is the default visibility modifier). We can call them in the same way as functions from the local context. To access a top-level function, we need to explicitly import it into a file by using the import statement. Functions are available in the code hint list in Android Studio, so imports are automatically added when a function is selected (used). As an example, let's see a top-level function defined in Test.kt and use it inside the Main.kt file:

    //...
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