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

13.3 Dynamic State vs. Persistent State

A key objective of lifecycle management is ensuring that the state of the activity is saved and restored at appropriate times. When talking about state in this context we mean the data that is currently being held within the activity and the appearance of the user interface. The activity might, for example, maintain a data model in memory that needs to be saved to a database, content provider or file. Such state information, because it persists from one invocation of the application to another, is referred to as the persistent state.

The appearance of the user interface (such as text entered into a text field but not yet committed to the application’s internal data model) is referred to as the dynamic state, since it is typically only retained during a single invocation of the application (and also referred to as user interface state or instance state).

Understanding the differences between these two states is important because...