I have `sealed` class `AppState` with 4 states (3 object and 1 one data class having 1 immutable pr...

# android

[Danish Ansari]

I have sealed class AppState with 4 states (3 object and 1 one data class having 1 immutable property). It is used in ViewModel as private MutableLiveData and exposed to activity as LiveData I'm using it in compose using LiveData.observeAsState()

Now the issue I'm facing is that when I use the variable State<AppState> (variable name is appState) using when block I'm able to access that 1 data classess property but I'm getting compilation error (Smart cast to 'AppState.Success' is impossible, because 'appState' is a property that has open or custom getter)

Code snippet inside thread

[Danish Ansari]

// ViewModel

kotlin
private val _appState = MutableLiveData<AppState>(AppState.Loading)
val appState: LiveData<AppState> = _appState

// Sealed class

kotlin
sealed class AppState {
    object Loading : AppState()
    data class Success(val userList: List<User>) : AppState()
    object NoInternet : AppState()
    object UnExpectedError : AppState()
}

// UI Code

Surface {
	val appState by mainViewModel.appState.observeAsState()
	when (appState) {
		is AppState.Loading -> // ...
		is AppState.NoInternet -> // ...
		is AppState.UnExpectedError -> // ...
		is AppState.Success -> {
			LazyColumn {
				// Getting error in below line
				items(appState.userList) { 
					
				}
			}
		}
	}
}

[Danish Ansari]

image.png

[Zun]

when (val a = appState)

[Danish Ansari]

Thanks @Zun Although this works we get a lint warning as follows

[Danish Ansari]

What worked for me was to instead of using by delegate I used value property of State class

I changed

val appState by mainViewModel.appState.observeAsState()

to

val appState = mainViewModel.appState.observeAsState().value