Book Image

Kickstart Modern Android Development with Jetpack and Kotlin

By : Catalin Ghita
5 (1)
Book Image

Kickstart Modern Android Development with Jetpack and Kotlin

5 (1)
By: Catalin Ghita

Overview of this book

With Jetpack libraries, you can build and design high-quality, robust Android apps that have an improved architecture and work consistently across different versions and devices. This book will help you understand how Jetpack allows developers to follow best practices and architectural patterns when building Android apps while also eliminating boilerplate code. Developers working with Android and Kotlin will be able to put their knowledge to work with this condensed practical guide to building apps with the most popular Jetpack libraries, including Jetpack Compose, ViewModel, Hilt, Room, Paging, Lifecycle, and Navigation. You'll get to grips with relevant libraries and architectural patterns, including popular libraries in the Android ecosystem such as Retrofit, Coroutines, and Flow while building modern applications with real-world data. By the end of this Android app development book, you'll have learned how to leverage Jetpack libraries and your knowledge of architectural concepts for building, designing, and testing robust Android applications for various use cases.
Table of Contents (17 chapters)
1
Part 1: Exploring the Core Jetpack Suite and Other Libraries
7
Part 2: A Guide to Clean Application Architecture with Jetpack Libraries
13
Part 3: Diving into Other Jetpack Libraries

Creating your own lifecycle-aware component

We need to make our CustomCountdown aware of the lifecycle of MainActivity. In other words, our countdown logic should observe and react to the lifecycle events of our LifecycleOwner – that is, MainActivity.

To make our CustomCountdown lifecycle-aware, we must force it to implement the DefaultLifecycleObserver interface. By doing so, the CustomCountdown will be observing the lifecycle events or states defined by the Lifecycle object that LifecycleOwner provides.

Our main goal is to pause the countdown when the app is put in the background and to resume it when the app is brought back into the foreground. More precisely, our CustomCountdown must react to the following lifecycle events of MainActivity:

  • onPause(): When the onPause() callback comes in MainActivity, CustomCountdown must pause its countdown.
  • onResume(): When the onResume() callback comes in MainActivity, CustomCountdown must resume its countdown.
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