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

29.19 Summary

A gesture is essentially the motion of points of contact on a touch screen involving one or more strokes and can be used as a method of communication between user and application. Android allows gestures to be designed using the Gesture Builder application. Once created, gestures can be saved to a gestures file and loaded into an activity at application runtime using the GestureLibrary.

Gestures can be detected on areas of the display by overlaying existing views with instances of the transparent GestureOverlayView class and implementing an OnGesturePerformedListener event listener. Using the GestureLibrary, a ranked list of matches between a gesture performed by the user and the gestures stored in a gestures file may be generated, using a prediction score to decide whether a gesture is a close enough match.

Pinch gestures may be detected through the implementation of the ScaleGestureDetector class, an example of which was also provided in this chapter.

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