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HandleEventsAndStateWithSharedFlowAndStateFlow
// ViewModel with SharedFlow and StateFlow
abstract class BaseViewModel<STATE, EVENT : UiEvent, EFFECT : UiEffect>(
initialState: UiState<STATE> = UiState.Loading
) : ViewModel() {
...
// Get Current State
val currentState: UiState<STATE>
get() = uiState.value
private val _uiState: MutableStateFlow<UiState<STATE>> = MutableStateFlow(initialState)
val uiState = _uiState.asStateFlow()
private val _event: MutableSharedFlow<EVENT> = MutableSharedFlow()
val event = _event.asSharedFlow()
protected fun setUiEvent(newEvent: EVENT) {
viewModelScope.launch { _event.emit(newEvent) }
}
protected fun updateUiState(update: (UiState<STATE>) -> UiState<STATE>) {
val newState = update(currentState)
if (newState != currentState) {
_uiState.value = newState
}
}
abstract fun handleEvent(event: EVENT)
...
}
// And how to pass info to ViewModel to handle events and update state
abstract class BaseFragment<STATE, EVENT : UiEvent, EFFECT : UiEffect,
VM : BaseViewModel<STATE, EVENT, EFFECT>, VDB : ViewDataBinding>(
@LayoutRes private val layoutId: Int,
vmKClass: KClass<VM>
) : Fragment() {
...
@InternalCoroutinesApi
final override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
with(viewModel) {
event
.onEach { handleEvent(it) }
.observeInLifecycle(viewLifecycleOwner)
uiState
.onEach { handleState(it) }
.observeInLifecycle(viewLifecycleOwner)
}
}
...
}
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