Book Image

Android Studio 4.0 Development Essentials - Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 4.0 Development Essentials - Kotlin Edition

By: Neil Smyth

Overview of this book

Kotlin as an Android-compatible programming language is becoming increasingly popular. Fully updated for Android Studio 4.0, this book will teach you the skills necessary to develop Android-based applications using Kotlin. Starting with the basics, this book outlines the steps necessary to set up Android development and testing environments, and goes on to introduce you to programming in Kotlin. You’ll practice Java to Kotlin code conversion and explore data types, operators, expressions, loops, functions, as well as the basics of OOP in Kotlin. You’ll then learn about Android architecture components and advanced topics, such as intents, touchscreen handling, gesture recognition, multi-window support integration, and biometric authentication. As you make progress, you’ll explore Android Studio 4.0’s key features, including layout editor, direct reply notifications, and dynamic delivery. You’ll also delve into Android Jetpack and create a sample app project using ViewModel, the Android Jetpack component. Finally, you will upload your app to Google Play Console and model the build process using Gradle. By the end of this Android book, you’ll be fully prepared to develop applications using Android Studio 4.0 and Kotlin.
Table of Contents (97 chapters)
97
Index

45. Working with Android Lifecycle-Aware Components

The earlier chapter entitled “Understanding Android Application and Activity Lifecycles” described the use of lifecycle methods to track lifecycle state changes within a UI controller such as an activity or fragment. One of the main problems with these methods is that they place the burden of handling lifecycle changes onto the UI controller. On the surface this might seem like the logical approach since the UI controller is, after all, the object going through the state change. The fact is, however, that the code that is typically impacted by the state change invariably resides in other classes within the app. This led to complex code appearing in the UI controller that needed to manage and manipulate other objects in response to changes in lifecycle state. Clearly this is a scenario best avoided when following the Android architectural guidelines.

A much cleaner and logical approach would be for the objects within...