Share ViewModel between fragments that are in different Activity

Question

I have a ViewModel named SharedViewModel:

public class SharedViewModel extends ViewModel {

    private final MutableLiveData selected = ne         


        

Answer 1

you can use factory to make viewmodel and this factor will return single object of view model.. As:

class ViewModelFactory() : ViewModelProvider.Factory {

override fun create(modelClass: Class): T {
    if (modelClass.isAssignableFrom(UserProfileViewModel::class.java)) {
    val key = "UserProfileViewModel"
    if(hashMapViewModel.containsKey(key)){
        return getViewModel(key) as T
    } else {
        addViewModel(key, UserProfileViewModel())
        return getViewModel(key) as T
    }
    }
    throw IllegalArgumentException("Unknown ViewModel class")
}

companion object {
    val hashMapViewModel = HashMap()
    fun addViewModel(key: String, viewModel: ViewModel){
        hashMapViewModel.put(key, viewModel)
    }
    fun getViewModel(key: String): ViewModel? {
        return hashMapViewModel[key]
    }
}
}

In Activity:

viewModelFactory = Injection.provideViewModelFactory(this)

// Initialize Product View Model
userViewModel = ViewModelProviders.of(this, viewModelFactory).get(
UserProfileViewModel::class.java)`

This will provide only single object of UserProfileViewModel which you can share between Activities.