68.7 Modifying the ViewModel

The ViewModel is responsible for creating an instance of the repository and for providing methods and LiveData objects that can be utilized by the UI controller to keep the user interface synchronized with the underlying database. As implemented in ProductRepository.java, the repository constructor requires access to the application context in order to be able to get a Room Database instance. To make the application context accessible within the ViewModel so that it can be passed to the repository, the ViewModel needs to subclass AndroidViewModel instead of ViewModel. Begin, therefore, by editing the MainViewModel.java file (located in the Project tool window under app -> java -> com.ebookfrenzy.roomdemo -> ui.main) and changing the class to extend AndroidViewModel and to implement the default constructor:

package com.ebookfrenzy.roomdemo.ui.main;

 

import android.app.Application;

import androidx.lifecycle.AndroidViewModel;

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