Book Image

Android Studio 4.2 Development Essentials - Java Edition

By : Neil Smyth
Book Image

Android Studio 4.2 Development Essentials - Java Edition

By: Neil Smyth

Overview of this book

Android Studio is an Integrated Development Environment based on the JetBrains IntelliJ IDEA. It provides developers with a unique platform to design and develop Android apps using various developer tools. The new Android Studio 4.2 has an upgraded IntelliJ platform and a variety of new features designed to improve the productivity of Android app developers. Fully updated for Android Studio 4.2, the objective of this book is to help you master the skills necessary to develop Android applications using Java as the programming language. This book begins by outlining the steps necessary to set up an Android development and testing environment and introducing programming in Java, describing data types, flow control, functions, lambdas, and object-oriented programming. It includes an overview of Android Studio, covering areas such as tool windows, the code editor, and the Layout Editor tool. An introduction to Android architecture is followed by an in-depth explanation of the design of Android applications and user interfaces using the Android Studio environment. Early chapters detail Android Architecture components like view models, lifecycle management, Room database access, the Database Inspector, app navigation, live data, and data binding. Advanced topics such as intents are also covered, as are touch screen handling, gesture recognition, and the recording and playback of audio. You will also explore printing, transitions, cloud-based file storage, and foldable device support. Detailed descriptions of the concepts of material design are provided, including the use of floating action buttons, Snackbars, tabbed interfaces, card views, navigation drawers, and collapsing toolbars. Some key features of Android Studio 4.2 and Android discussed in-depth include the Layout Editor, the ConstraintLayout and ConstraintSet classes, MotionLayout Editor, view binding, constraint chains, barriers, and direct reply notifications. Later chapters cover advanced features of Android Studio such as App Links, Dynamic Delivery, the Android Studio Profiler, Gradle build configuration, and submitting apps to the Google Play Developer Console.
Table of Contents (87 chapters)
87
Index

56.8 Passing a Message to the Handler

While the previous example triggered a call to the handleMessage() handler callback, it did not take advantage of the message object to send data to the handler. In this phase of the tutorial, the example will be further modified to pass data between the thread and the handler. First, the updated thread in the buttonClick() method will obtain the date and time from the system in string format and store that information in a Bundle object. A call will then be made to the obtainMessage() method of the handler object to get a message object from the message pool. Finally, the bundle will be added to the message object before being sent via a call to the sendMessage() method of the handler object:

public void buttonClick(View view) {

  Runnable runnable = () -> {

       long endTime = System.currentTimeMillis() + 20 * 1000;

       while (System.currentTimeMillis...