I want to add a Repeat button. Is it possible to r...

# compose

[Vitaliy Zarubin]

I want to add a Repeat button. Is it possible to restart flow like this? It seems to work, but Composable is not updated.

val user by viewModel.loadingUser.collectAsState(initial = null)
when {
    user.isSucceeded -> navController.navigate(NavScreen.Home.route)
    user.isError -> ErrorConnect { viewModel.repeat() }
    else -> Splash()
}

[knthmn]

Is the when block in a composable? Also what is ErrorConnect? Can you show more of your code.

[Vitaliy Zarubin]

@Composable

[Vitaliy Zarubin]

loadingUser

[Vitaliy Zarubin]

It works, but it seems to me that this is not the right way.

[Paul Woitaschek]

Why would you annotate a launching function as worker thread?

[knthmn]

There are multiple things

1. Your repeat() does not restart the .collectAsState(), instead it just starts collecting the flow independently. Is there a way you can get a flow of the latest user value from your ServiceUser?
2. Code with side effects (such as NavController.navigate() ) should not be in composable function (see [1]). In your case you can simply switch between what is being displayed by the value of user

val user by viewModel.loadingUser.collectAsState(null)
when {
    user.isSuceeded -> TabsHome(...)
    user.isError -> Error()
    null -> Splash()
}

Although I don't see the case here, if you really need to have the different screens as destinations , use LaunchedEffect()

val user by viewModel.loadingUser.collectAsState(null)
LaunchedEffect(user) {
  ... navigate depending on the value of user ...
}

[1] https://developer.android.com/jetpack/compose/side-effects

[Vitaliy Zarubin]

1. This looks like right. It works.

[Paul Woitaschek]

Hmm. Without a buffer capacity, wouldn't that tryEmit only work when there is a collector?

[Vitaliy Zarubin]

Is emit better? I'm probably missing something. I did by analogy with LiveData.

[knthmn]

Since RepositoryUser.loadingUser() finishes, I would probably do this

private val _loadingUser: MutableStateFlow<ResponseResult<ModelUser>> = MutableStateFlow(null)
val loadingUser = _loadingUser.asStateFlow()

init {
    reload()
}

fun reload() {
    repository.loadingUser()
        .onEach { loadingUser.value = it }
        .launchIn(viewModelScope)
}

[knthmn]

Ultimately, if ServiceUser.getUser() cannot be made reactive, I wouldn't bother to wrap it in a flow as you did in loadingUser(). If I see a Flow, I assume it to always provides me with the latest value

[Vitaliy Zarubin]

I don't think MutableStateFlow needs to be made public

[knthmn]

just fixed it

[Vitaliy Zarubin]

@knthmn it's working. THX

[Vitaliy Zarubin]

@Paul Woitaschek

Why would you annotate a launching function as worker thread?

https://developer.android.com/studio/write/annotations#thread-annotations

[Paul Woitaschek]

That makes no sense to me

[Paul Woitaschek]

You want to annotate functions that block as WorkerThread

[Paul Woitaschek]

Well actually in coroutines world I would just make blocking functions suspending and wrap it in a withContext(Io)