How to Return LiveData from Repository

Question

I just can\'t see how to chain LiveData from Repo to VM, so I have tried to boil this down to the most simple of example!:

Fragment

Answer 1

Actually If you are maintaining LiveData in repository, I don't think there's a need of separate LiveData in ViewModel as well. You just have to observe the LiveData once from the activity. Then make any changes to repository instance directly. So If I have to show it in your code, It might look something like this.

1. Activity class: Change makeToast method to observeCurrentName() like this:

   private fun observeCurrentName() {
       vm.getCurrentName().observe(this, Observer{ 
           //Toast here 
       })
   }
   

2. Your VM:

   class LoginViewModel : ViewModel() {
       ...
   
       fun getCurrentName(): MutableLiveData{
           return repository.getCurrentName()
       }
   
       fun setCurrentName(name: String?){
           repository.setCurrentName(name)
       }
   
       ...
   }
   

3. Your repository:

   class FirestoreRepository {
   
       private val mCurrentName = MutableLiveData()
   
       fun getCurrentName(): MutableLiveData{
           return mCurrentName
       }
   
       fun setCurrentName(name: String?){
           mCurrentName.value = name //This will trigger observer in Activity
       }
   }