ViewModelModule and Factory is tied to an specific viewModel class

[jmcaldera]

Factory should not return an specific viewModel class, it should be a generic one. This is achieved by providing a Map of viewModels to Factory's constructor and look for the one that is being requested.

To do this, we create a Module and make use of @Binds @IntoMap and we provide a custom key of type Class. Dagger will create the map and add every new viewModel we add to our this Module.

Since dagger creates the map, we should not be passing this manually to our Factory class, so @Inject annotation should be added to its constructor.

Also, factory should not have a Data Source dependency

Refer to: https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/src/main/java/com/android/example/github/viewmodel/GithubViewModelFactory.kt

https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/src/main/java/com/android/example/github/di/ViewModelKey.kt

https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/src/main/java/com/android/example/github/di/ViewModelModule.kt

Once this is done, we can perform a field injection of Factory class into our activity by using: @Inject ViewModelFactory viewModelFactory

[KiranKala]

• Modified factory class to return generic viewmodel
• Created ViewModelModule with the use of @BINDS @Intomap and provided a custom key of type Class.
• Added @Inject for ViewModelFactory in Activity class.