Hi all, I have this issue with StateFlow: MainAct...

# compose

[Mike Speed]

Hi all, I have this issue with StateFlow:

MainActivity:

...
    val loading = binding.loading
    loading.setContent {
        LoadingSpinner()
    }
...

@Preview
@Composable
fun LoadingSpinner() {
    if (viewModel.loadingState.value) {
        CircularProgressIndicator()
    }
}

in my viewmodel:

_loadingState.value = true
viewModelScope.launch {
    doSomeLongTask()
    _loadingState.value = false //or calling this at some later point
}

LoadingSpinner() is updated correctly when value == true, but then when I set it to false, LoadingSpinner does not get updated and so stays on screen.
Any help appreciated!

[flosch]

Use the StateFlow.collectAsState extension in your composable

@Preview
@Composable
fun LoadingSpinner() {
    val loading = viewModel.loadingState.collectAsState()
    if (loading) {
        CircularProgressIndicator()
    }
}

[Zach Klippenstein (he/him) [MOD]]

Would be nice to have a warning about this, filed: https://issuetracker.google.com/issues/195445764

[Mike Speed]

Yes it worked! Thank you @flosch.
Only difference was I needed to do

if (loading.value) {

instead 🙂

[flosch]

Ah sorry, yea I forgot it is a delegate, you can also instead write
val loading by viewModel.loadingState.collectAsState()
Then you do not need the .value

[Mike Speed]

awesome thanks!