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

66.6 Adding the Repository

Add a new class named ProductRepository to the project, with the Kind menu set to Class and None enabled in the Modifiers section of the Create New Class dialog.

The repository class will be responsible for interacting with the Room database on behalf of the ViewModel and will need to provide methods that use the DAO to insert, delete and query product records. With the exception of the getAllProducts() DAO method (which returns a LiveData object) these database operations will need to be performed on separate threads from the main thread using the AsyncTask class.

Remaining within the ProductRepository.java file, add the code for the search AsyncTask. Also add a method named asyncFinished() which will be called by the query AsyncTask to return the search results to the repository thread:

package com.ebookfrenzy.roomdemo;

 

import android.os.AsyncTask;

import androidx.lifecycle.MutableLiveData;

import java.util.List;

 

...