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

40.4 Accessing the Navigation Controller

Navigating from one destination to another will usually take place in response to an event of some kind within an app such as a button click or menu selection. Before a navigation action can be triggered, the code must first obtain a reference to the navigation controller instance. This requires a call to the findNavController() method of the Navigation or NavHostFragment classes. The following code, for example, can be used to access the navigation controller of an activity. Note that for the code to work, the activity must contain a navigation host fragment:

NavController controller =

         Navigation.findNavController(activity, R.id.demo_nav_host_fragment);

In this case, the method call is passed a reference to the activity and the id of the NavHostFragment embedded in the activity’s layout.

Alternatively, the navigation controller associated with any view may be identified...