Hello following the

Question

Hello following the <https developer android com jetpack compose architecture|recommended Compose architecture for Android> I usually provide a UI state in my ViewModels in the following way ```val uiState StateFlow lt UiState gt = combine firstFlow secondFlow thirdFlow first second third gt UiState first = first second = second third = third stateIn ```

svenjacobs · Answer

Now the problem is that <https kotlinlang org api kotlinx coroutines kotlinx coroutines core kotlinx coroutines flow combine html|combine> only provides overloads for up to five `Flow` arguments Starting with six or more arguments `combine` takes a `vararg Flow lt T gt ` or `Iterable lt Flow lt T gt gt ` This means all Flows must be of the same type or if not the type becomes `Any` Then we lose type safety and must cast to the right types which is subpar When I encounter this I combine logical units of Flows into their own data classes or `Pair` or `Triple` something like ```val combinedFlow = combine firstFlow secondFlow first second gt CombinedState first = first second = second val uiState StateFlow lt UiState gt = combine combinedFlow thirdFlow first second third gt UiState first = first second = second third = third stateIn ``` But even this solution has its limitations when there are no more logical units of Flows to build and there are still more than five distinct Flows How do you approach this problem What are your solutions

Zoltan Demant · Answer

Another approach is to instead use MutableStateFlow lt UiState gt updating its value whenever the state changes slightly smiling face

svenjacobs · Answer

< Zoltan Demant> I usually try to avoid using `MutableStateFlow` and setting attributes of `UiState` individually Because this usually also means launching multiple coroutines possibly in `init` of ViewModel I think having one public `StateFlow` is safer resource wise and less verbose

svenjacobs · Answer

< Grégory Lureau> Thanks I guess I have to add the required `combine` variants to my project myself like you suggested I m wondering if someone already wrote a library for that

Tgo1014 · Answer

< svenjacobs> Something like

svenjacobs · Answer

< Tgo1014> Yeah something like that Thanks

Csaba Szugyiczki · Answer

We always emit values individually from our ViewModels in our apps and collect them also individually in our Views and it works well I do not really see the advantage in combining all possible values in a State object So you end up with this ```MyViewModel repo Repo val name StateFlow lt String gt = repo name val description StateFlow lt String gt = repo description val cout StateFlow lt Int gt = repo count ``` Instead of this ```MyViewModel repo Repo val state StateFlow lt MyState gt = combine repo name repo description repo count name description count MyState name description count class MyState val name String val description String val count Int ```

svenjacobs · Answer

< Csaba Szugyiczki> But in your Compose code you then end up with ```val name = viewModel name collectAsState val description = viewModel description collectAsState ``` instead of one single ```val uiState = viewModel uiState collectAsState ``` In the end it s a matter of personal taste but Compose is able to efficiently only recompose those parts of a UI that are affected by changed UI state properties even if they are combined in a single data class assuming the data class itself is

svenjacobs · Answer

Using a single `UiState` is just what I saw in a lot of official Compose examples and blog posts lately

Csaba Szugyiczki · Answer

Yes that is correct And I agree it is a matter of personal taste indeed I just wanted to point out that it might not be necessary despite many sources doing it this way to combine all your values into one large object

svenjacobs · Answer

Another benefit of one exposed public Flow is <https medium com androiddevelopers consuming flows safely in jetpack compose cde014d0d5a3|consuming it safely from Android> Yes it can also be done with multiple Flows but it means more boilerplate code

AmrJyniat · Answer

<https tunjid github io Mutator > maybe this helps you