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

57.8 Modifying the User Interface

As will become evident when the application runs, failing to create a new thread for the service to perform tasks creates a serious usability problem. In order to be able to appreciate fully the magnitude of this issue, it is going to be necessary to add a Button view to the user interface of the MainActivity and configure it to call a method when “clicked” by the user.

Locate and load the activity_main.xml file in the Project tool window (app -> res -> layout -> activity_main.xml). Delete the TextView and add a Button view to the layout. Select the new button, change the text to read “Start Service” and extract the string to a resource named start_service.

With the new Button still selected, locate the onClick property in the Attributes panel and assign to it a method named buttonClick.

Next, edit the MainActivity.java file to add the buttonClick() method and remove the code from the onCreate() method...