Book Image

Android Studio 4.1 Development Essentials – Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 4.1 Development Essentials – Kotlin Edition

By: Neil Smyth

Overview of this book

Android 11 has a ton of new capabilities. It comes up with three foci: a people-centric approach to communication, controls to let users quickly access and manage all of their smart devices, and privacy to give users more ways to control how data on devices is shared. This book starts off with the steps necessary to set up an Android development and testing environment, followed by an introduction to programming in Kotlin. An overview of Android Studio and its architecture is provided, followed by an in-depth look at the design of Android applications and user interfaces using the Android Studio environment. You will also learn about the Android architecture components along with some advanced topics such as touch screen handling, gesture recognition, the recording and playback of audio, app links, dynamic delivery, the AndroidStudio profiler, Gradle build configuration, and submitting apps to the Google Play Developer Console. The concepts of material design are also covered in detail. This edition of the book also covers printing, transitions, and cloud-based file storage; foldable device support is the cherry on the cake. By the end of this course, you will be able to develop Android 11 Apps using Android Studio 4.1, Kotlin, and Android Jetpack. The code files for the book can be found here: https://www.ebookfrenzy.com/retail/as41kotlin/index.php
Table of Contents (95 chapters)
95
Index

15.9 Lambda Expressions

Having covered the basics of functions in Kotlin it is now time to look at the concept of lambda expressions. Essentially, lambdas are self-contained blocks of code. The following code, for example, declares a lambda, assigns it to a variable named sayHello and then calls the function via the lambda reference:

val sayHello = { println("Hello") }

sayHello()

Lambda expressions may also be configured to accept parameters and return results. The syntax for this is as follows:

{<para name>: <para type>, <para name> <para type>, ... ->

         // Lambda expression here

}

The following lambda expression, for example, accepts two integer parameters and returns an integer result:

val multiply = { val1: Int, val2: Int -> val1 * val2 }

val result = multiply(10, 20)

Note that the above lambda examples have assigned the lambda code block to a variable. This...