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

66.6 The Repository

The repository is responsible for getting a Room Database instance, using that instance to access associated DAOs and then making calls to DAO methods to perform database operations. A typical constructor for a repository designed to work with a Room Database might read as follows:

public class CustomerRepository {

 

    private CustomerDao customerDao;

    private CustomerRoomDatabase db;

 

    public CustomerRepository(Application application) {

        db = CustomerRoomDatabase.getDatabase(application);

        customerDao = db.customerDao();

    }

.

.

}

Once the repository has access to the DAO, it can make calls to the data access methods. The following code, for example, calls the getAllCustomers() DAO method:

private LiveData<List<Customer&gt...