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

37.1 Understanding ViewModel State Saving

As outlined in the previous chapters, the ViewModel brings many benefits to app development, including UI state restoration in the event of configuration changes such as a device rotation. To see this in action, run the ViewModelDemo app (or if you have not yet created the project, load into Android Studio the ViewModelDemo_LiveData project from the sample code download that accompanies the book).

Once running, enter a dollar value and convert it to euros. With both the dollar and euro values displayed, rotate the device or emulator and note that, once the app has responded to the orientation change, both values are still visible.

Unfortunately, this behavior does not extend to the termination of a background app process. With the app still running, tap the device home button to place the ViewModelDemo app into the background, then terminate it by opening the Logcat tool window in Android Studio and clicking on the terminate button as...