Book Image

Android Studio 3.5 Development Essentials - Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 3.5 Development Essentials - Kotlin Edition

By: Neil Smyth

Overview of this book

Popularity of Kotlin as an Android-compatible language keeps growing every day. This book will help you to build your own Android applications using Kotlin. Android Studio 3.5 Development Essentials Kotlin Edition first teaches you to install Android development and test environment on different operating systems. Next, you will create an Android app and a virtual device in Android studio, and install an Android application on emulators. You will test apps on physical android devices, then study Android Studio code editor, Android architecture, and the anatomy of an Android app. The focus then shifts to Kotlin language. You’ll get an overview of Kotlin language and practice converting code from Java to Kotlin. You’ll also explore Kotlin data types, operators, expressions, loops, functions, and the basics of OOP concept in Kotlin. This book will then cover Android Jetpack and how to create an example app project using ViewModel component, as well as advanced topics such as views and widgets implementation, multi-window support integration, and biometric authentication. Finally, you will learn to upload your app to the Google Play Console and handle the build process with Gradle. By the end of this book, you will have gained enough knowledge to develop powerful Android applications using Kotlin.
Table of Contents (93 chapters)
93
Index

32.1 Understanding Android Events

Events in Android can take a variety of different forms, but are usually generated in response to an external action. The most common form of events, particularly for devices such as tablets and smartphones, involve some form of interaction with the touch screen. Such events fall into the category of input events.

The Android framework maintains an event queue into which events are placed as they occur. Events are then removed from the queue on a first-in, first-out (FIFO) basis. In the case of an input event such as a touch on the screen, the event is passed to the view positioned at the location on the screen where the touch took place. In addition to the event notification, the view is also passed a range of information (depending on the event type) about the nature of the event such as the coordinates of the point of contact between the user’s fingertip and the screen.

In order to be able to handle the event that it has been passed...