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

59.8 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...