如何在我所有的视图模型中共享同一个数据实例 class？

Question

I'm very new to android development and struggling to find this answer. Is it possible to share the same instance of a data class across all my view models?

Currently when my app first starts, I'm fetching my user's app preferences from a Firestore DB and instantiating a data class instance I have defined to hold all user preferences. I want to have all my view models to have access to the user preferences without every view model having to make the Firestore DB call and creating its own data class instance. Is it possible to share the same instance of a data class between all of my view models?

I could use dagger hilt to to fetch the preferences from Firestore, create my data class instance, and provide that as a dependency of injection....but if a user updates their preferences after loading the app then those updates won't reflect in the data class instance that is injected via dagger hilt, correct?

Admittedly I might be going about this the wrong way. I'm ultimately trying to understand what the best way to share my app preferences that are stored in an external DB to all of my view models.

Answer 1

After getting the data in your viewModel, initialize the related viewmodel in your fragment as activityViewModel as below;

val shareViewModel by activityViewModels<ShareViewModel>()

If you use it in your activity just set this for owner parameter as below;

val shareViewModel = ViewModelProvider(this)[ShareViewModel::class.java]

It provides you sharing data across your app

Moreover, check this codelab https://developer.android.com/codelabs/basic-android-kotlin-training-shared-viewmodel