Book Image

Android Studio 4.0 Development Essentials - Java Edition

By : Neil Smyth
Book Image

Android Studio 4.0 Development Essentials - Java Edition

By: Neil Smyth

Overview of this book

Android rolls out frequent updates to meet the demands of the dynamic mobile market and to enable its developer community to lead advancements in application development. This book focuses on the updated features of Android Studio (the fully integrated development environment launched by Google) to build reliable Android applications using Java. The book starts by outlining the steps necessary to set up an Android development and testing environment. You’ll then learn how to create user interfaces with the help of Android Studio Layout Editor, XML files, and by writing the code in Java. The book introduces you to Android architecture components and advanced topics such as intents, touchscreen handling, gesture recognition, multi-window support integration, and biometric authentication, and lets you explore key features of Android Studio 4.0, including the layout editor, direct reply notifications, and dynamic delivery. You’ll also cover Android Jetpack in detail and create a sample app project using the ViewModel component. Finally, you’ll upload your app to the Google Play Console and handle the build process with Gradle. By the end of this book, you’ll have gained the skills necessary to develop applications using Android Studio 4.0 and Java.
Table of Contents (88 chapters)
88
Index

15.5 Restoring the State

The saved dynamic state can be restored in those lifecycle methods that are passed the Bundle object as an argument. This leaves the developer with the choice of using either onCreate() or onRestoreInstanceState(). The method to use will depend on the nature of the activity. In instances where state is best restored after the activity’s initialization tasks have been performed, the onRestoreInstanceState() method is generally more suitable. For the purposes of this example we will add code to the onRestoreInstanceState() method to extract the saved state from the Bundle using the “savedText” key. We can then display the text on the editText component using the object’s setText() method:

@Override

protected void onRestoreInstanceState(Bundle savedInstanceState) {

   super.onRestoreInstanceState(savedInstanceState);

   Log.i(TAG, "onRestoreInstanceState");

 

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