CODEWITHSUNDEEP
androidkotlinandroid-livedatakotlin-coroutines
Ma2340
Ma2340

Reputation: 737

Using emit with Kotlin StateFlow

Until now I was using Flow and mapping it to LiveData like below -

The MyService looks like this -

override fun provideData(action: MyAction) = flow {
   emit(MyResult.Loading)
   emit(dataRepository.getNewData())
}

The ViewModel looks like this -

fun getData() = myService.provideData(MyAction.GetData).map {
                
}.asLiveData(Dispatchers.Default + viewModelScope.coroutineContext)

I want to move to StateFlow. How can I use emit function with StateFlow like I used it with Flow.

Upvotes: 1

Views: 2190

Answers (1)

Roman Elizarov
Roman Elizarov

Reputation: 28658

You can write your flow as before, but replace .asLiveData(scope) with .stateIn(scope, SharingStarted.Eagerly, null) to get an instance of StateFlow running in the corresponding scope with a similar behavior that you were getting with LiveData before — sharing is started immediately and the initial value is null (just like with LiveData).

You can read here for more details and explanation of all stateIn operator parameters here https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/state-in.html

Upvotes: 6

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