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#multiplatform
Title
# multiplatform
j
Josh
05/04/2021, 5:18 PMHey 👋 Im a student whos new to kotlin multiplatform. I am builing a KMM app and was wondering if anyone has used any projects that allow for shared view models in KMM
v
Vitor Prado
05/04/2021, 6:02 PMjust use flow instead of livedata and make your viewmodel just a simple class handling the flow logic.
example:
Copy code
class LoginViewModel(
private val login: Login = Login()
) {
private val _state = MutableStateFlow<ComponentState>(ComponentState.Idle)
val state = _state.asStateFlow()
private val _effects: Channel<LoginEffect> = Channel()
val effects = _effects.receiveAsFlow()
fun sendLogin(email: String, password: String) {
MainScope().launch {
_state.emit(login(LoginCredentials(email, password, "password"))))
}
}
}j
Josh
05/04/2021, 6:06 PM🤯
v
Vitor Prado
05/04/2021, 6:07 PMfor compose you just need the
state.asState()watch()j
Josh
05/04/2021, 6:08 PMand the watch method could use combine to update the view’s data automatically?
v
Vitor Prado
05/04/2021, 6:09 PMif you decide to use compose and swift ui .. you can split logic in state and effects.. state just hold the current component state and effects dispatch events to be handle (show toast / route to screen/ etc) .. effects is everything that cannot be a screen/component state.. everything that “happens”
you can write an extension inside your swift project to transform flow events in combine streams
j
Josh
05/04/2021, 6:12 PMoh wow thats awesome! I was hoping that there was a way to keep the combine/flow code in kmm
but this is still super helpful and likely the approach I will take! Thanks so much!
v
Vitor Prado
05/04/2021, 6:12 PMmy current problem is: state in my kotlin module is a sealed class (i need to describe state and hold a value for loaded state).. in android it’s perfect.. but in swift the better solution is to use a enum (enum can hold values) .. so in my ios project i create a extension to translate my state into swift enums.
if you find a solution to translate flows in combine streams or a way to transform flow output in swiftui binding using property wrapper.. send to me plx.
today i use the example of kotlin conf app and use a watch methods like it:
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fun <T> Flow<T>.watch(block: (T) -> Unit): Closeable {
val scope = MainScope()
onEach {
block(it)
}.launchIn(scope)
return object : Closeable {
override fun close() {
try {
scope.cancel()
} catch (e: Exception) {}
}
}
}j
Josh
05/04/2021, 6:15 PMI looooove enums in swift - theyre awesome but I can see how that issue would be a pain
I will definitely reply back here once ive got more context if im able to help you out 🙂
v
Vitor Prado
05/04/2021, 6:17 PMI think the kotlin compiler should evolve in future to transform sealed classes into enums.. makes more sense in my mind.
j
Josh
05/04/2021, 6:21 PMyeah that would be ideal. I feel like a more likely solution would be a kmm dependency that can convert the sealed class into enums in the ios lib so you dont need to know the sealed class existed in the ios app
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