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

58.7 Completing the Example

All that remains is to implement a mechanism for calling the getCurrentTime() method and displaying the result to the user. As is now customary, Android Studio will have created a template activity_main.xml file for the activity containing only a TextView. Load this file into the Layout Editor tool and, using Design mode, select the TextView component and change the ID to myTextView. Add a Button view beneath the TextView and change the text on the button to read “Show Time”, extracting the text to a string resource named show_time. On completion of these changes, the layout should resemble that illustrated in Figure 58-1. If any constraints are missing, click on the Infer Constraints button in the Layout Editor toolbar.

Figure 58-1

Complete the user interface design by selecting the Button and configuring the onClick property to call a method named showTime.

Finally, edit the code in the MainActivity.java file to implement the...