Book Image

Android Studio 4.1 Development Essentials – Java Edition

By : Neil Smyth
Book Image

Android Studio 4.1 Development Essentials – Java Edition

By: Neil Smyth

Overview of this book

For developers, Android 11 has a ton of new capabilities. The goal of this book is to teach the skills necessary to develop Android-based applications using the Java programming language. This book begins with the steps necessary to set up an Android development and testing environment. An overview of Android Studio along with the architecture of Android is covered next, 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, including the use of floating action buttons, Snackbars, tabbed interfaces, card views, navigation drawers, and collapsing toolbars are a highlight of this book. This edition of the book also covers printing, transitions, and cloud-based file storage; the 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, Java, and Android Jetpack. The code files for the book can be found here: https://www.ebookfrenzy.com/retail/androidstudio41/index.php
Table of Contents (88 chapters)
88
Index

38.3 Lifecycle Observers

In order for a lifecycle-aware component to observe the state of a lifecycle owner it must implement the LifecycleObserver interface and contain event listener handlers for any lifecycle change events it needs to observe.

public class SampleObserver implements LifecycleObserver {

    // Lifecycle event methods go here

}

An instance of this observer class is then created and added to the list of observers maintained by the Lifecycle object.

getLifecycle().addObserver(new SampleObserver());

An observer may also be removed from the Lifecycle object at any time if it no longer needs to track the lifecycle state.

Figure 38-1 illustrates the relationship between the key elements that provide lifecycle awareness:

Figure 38-1