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

32.9 Testing the Project

With this phase of the project development completed, build and run the app on the simulator or a physical device, enter a dollar value and click on the Convert button. The converted amount should appear on the TextView indicating that the UI controller and ViewModel re-structuring appears to be working as expected.

When the original AndroidSample app was run, rotating the device caused the value displayed on the resultText TextView widget to be lost. Repeat this test now with the ViewModelDemo app and note that the current euro value is retained after the rotation. This is because the ViewModel remained in memory as the Fragment was destroyed and recreated and code was added to the onActivityCreated() method to update the TextView with the result data value from the ViewModel each time the Fragment re-started.

While this is an improvement on the original AndroidSample app, there is much more that can be achieved to simplify the project by making use...