Book Image

Android Studio 3.5 Development Essentials - Java Edition

By : Neil Smyth
Book Image

Android Studio 3.5 Development Essentials - Java Edition

By: Neil Smyth

Overview of this book

Android applications have become an important part of our daily lives and lots of effort goes into developing an Android application. This book will help you to build you own Android applications using Java. Android Studio 3.5 Development Essentials – Java Edition first teaches you to install Android development and test environment on different operating systems. Next, you will create an Android app and a virtual device in Android Studio, and install an Android application on emulator. You will test apps on physical Android devices, then study Android Studio code editor and constraint layout, Android architecture, the anatomy of an Android app, and Android activity state changes. The book then covers advanced topics such as views and widgets implementation, multi-window support integration, and biometric authentication, and finally, you will learn to upload your app to Google Play console and handle the build process with Gradle. By the end of this book, you will have gained enough knowledge to develop powerful Android applications using Java.
Table of Contents (86 chapters)
86
Index

14.2 Default Saving of User Interface State

In the previous chapter, the diagnostic output from the StateChange example application showed that an activity goes through a number of state changes when the device on which it is running is rotated sufficiently to trigger an orientation change.

Launch the StateChange application once again, this time entering some text into the EditText field prior to performing the device rotation (on devices or emulators running Android 9 it may be necessary to tap the rotation button in the located in the status bar to complete the rotation). Having rotated the device, the following state change sequence should appear in the Logcat window:

onPause

onStop

onSaveInstanceState

onDestroy

onCreate

onStart

onRestoreInstanceState

onResume

Clearly this has resulted in the activity being destroyed and re-created. A review of the user interface of the running application, however, should show that the text entered into the EditText...