Support androidx viewmodel for kotlin multiplatform

[Vivecstel]

https://developer.android.com/jetpack/androidx/releases/lifecycle#2.8.0-alpha03 added view model support for kotlin multiplatform. Ideally koin should support this also. Thanks

[fluttertutorialin]

Can you explain how to add viewmodel library in kmm

[frankois1234]

Hello, some reference here

• https://touchlab.co/kmp-viewmodel

A full demo how to use viewmodel here :

• https://github.com/joreilly/FantasyPremierLeague

It should be OK that koin move the viewmodel support to KMP.

[ghost]

The is the official repo used in google codelabe https://github.com/MatkovIvan/nav_cupcake

[AbdelrahmanEsam]

@frankois1234 it doesn't work with koin .... iam getting this error

Uncaught Kotlin exception: org.koin.core.error.InstanceCreationException: Could not create instance for '[Factory:'viewModel class Name']' at 0 shared

also I am creating this viewModel by factory or single ..... I think koin should support the viewModel{} at the common main

[Leedwon]

@AbdelrahmanEsam

Inspired by https://github.com/MatkovIvan/nav_cupcake/blob/master/composeApp/src/commonMain/kotlin/com/matkovivan/nav_cupcake/ViewModels.kt which uses androidx viewmodel. I'm using the following code to make it work with Koin:

ViewModels.kt in commonMain:

internal expect fun <VM : ViewModel> viewModel(
    modelClass: KClass<VM>,
    factory: ViewModelProvider.Factory = rememberViewModelFactory()
): VM

// Can't be private as it causes Exception during IR lowering
@Composable
internal fun rememberViewModelFactory(): ViewModelProvider.Factory {
    val koin = getKoin()
    return remember {
        viewModelFactory {
            initializer { MyViewModel(myDependency = koin.get()) }
            ... // more VM initializers
        }
    }
}

ViewModels.android.kt in androidMain:

@Composable
internal actual fun <VM : ViewModel> viewModel(
    modelClass: KClass<VM>,
    factory: ViewModelProvider.Factory
): VM = androidx.lifecycle.viewmodel.compose.viewModel(modelClass.java, factory = factory)

ViewModels.ios.kt in iosMain:

@Composable
internal actual fun <VM : ViewModel> viewModel(
    modelClass: KClass<VM>,
    factory: ViewModelProvider.Factory
): VM = androidx.lifecycle.viewmodel.compose.viewModel(modelClass, factory = factory)

And wiring it in the Composables:

@Composable
fun MyScreen(
    myViewModel: MyViewModel = viewModel(MyViewModel::class)
) {

}

I doesn't guarantee that it's the most correct approach, but it works and can be a workaround until Koin officially suports it.

[AbdelrahmanEsam]

@Leedwon the problem is on the ios side not the android one .... android is working perfectly

class DIHelper : KoinComponent { private val notesViewModel: NotesViewModel by inject() private val noteDetailsViewModel: NoteDetailsViewModel by inject()

fun getNotesViewModel(): NotesViewModel = notesViewModel
fun getNoteDetailsViewModel(): NoteDetailsViewModel = noteDetailsViewModel

}

this is my DIHelper in the iosMain to access the viewModels in the ios app

[Leedwon]

@AbdelrahmanEsam I see, I'm using Compose Multiplatform, so for me the setup above does the job on both platforms. But if you are having the setup with separate UIs for iOS and Android, then I think you can take a look at joreilly FantasyPremierLeague, he's using VMs with Koin. I haven't checked the whole thing, but this PR might be helpful.

[AbdelrahmanEsam]

@Leedwon unfortunately his viewModels doesn't have any other injected dependencies (usecases /repositories) so he just take object from it at the view in ios side

[frankois1234]

The ViewModel in the common Main is more for the Compose Multiplatform than SwiftUI.

Nothing will change for iOS UIKit/SwiftUI.

The best example is https://github.com/joreilly/FantasyPremierLeague.

Also, the usage of Koin viewmodel in the commonMain must be also for Koin annotation.

[AbdelrahmanEsam]

@frankois1234 that really doesn't work .... I am using the helper in the ios main module and for the android side everything working perfectly .... but when I am trying to run the ios app koin can't inject the viewModel with the following error

org.koin.core.error.InstanceCreationException: Could not create instance for '[Factory:

[frankois1234]

This issue is for demanding the implementation of koin ViewModel support in kmp commonMain project, not how to use it.

As the import org.koin.androidx.viewmodel.dsl.viewModel is not available in commonMain project but the import of androidx.lifecycle.ViewModel is now possible with the latest androidx.lifecycle:lifecycle-viewmodel dependancies

[Vivecstel]

This issue is for demanding the implementation of koin ViewModel support in kmp commonMain project, not how to use it.

As the import org.koin.androidx.viewmodel.dsl.viewModel is not available in commonMain project but the import of androidx.lifecycle.ViewModel is now possible with the latest androidx.lifecycle:lifecycle-viewmodel dependancies

exactly

[AbdelrahmanEsam]

@frankois1234 I didn't said that I am using it with koin viewModel ..... actually I am creating it with factory or single in koin .... but koin failed to give me my instance

[AbdelrahmanEsam]

@frankois1234 this happen in the ios side only for some reason I really don't know .... in the android side everything working perfectly

[frankois1234]

@AbdelrahmanEsam Please make another issue, it's not the target of the current one

[hoc081098]

https://github.com/hoc081098/kmp-viewmodel/blob/master/viewmodel-koin-compose/src/commonMain/kotlin/com/hoc081098/kmp/viewmodel/koin/compose/koinKmpViewModel.kt

I did it before AndroidX. Hope it is useful

[marcellogalhardo]

@arnaudgiuliani, now that JetBrains has published their artifact (which includes JS and WASM support), we should be able to add official ViewModel KMP support to Koin.

Note that the new artifact is still experimental, so we might want to wait for it to reach a more stable stage, but we can start exploring it and reporting any challenge we may find to JB.

Please see: https://github.com/JetBrains/compose-multiplatform/releases/tag/v1.6.10-beta01

[PMARZV]

Experimental support for koin viewmodel multiplatform would be helpful!

[arnaudgiuliani]

Great, let's add it for one of next milestone quickly 💪 thanks @marcellogalhardo

[frankois1234]

@arnaudgiuliani koin annotations will have the support?

[arnaudgiuliani]

it should be possible yes 👍

[ronjunevaldoz]

Following this!

[arnaudgiuliani]

Work in progress: https://github.com/InsertKoinIO/koin/pull/1875

[arnaudgiuliani]

Release in 3.6.0-Beta4 🎉

[ColtonIdle]

❤️

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Release in 3.6.0-Beta4 🎉

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[agabeyalioglu]

Hello @arnaudgiuliani i tried 3.6.0-Beta4

factory {
    ListViewModel(get(), get(named(IODispatcher)))
}

I was creating my viewmodel like this previously. Now if i use viewModelOf(::ListViewModel) how can i specify the dispatcher parameter to use named(IODispatcher)?

[DavidGrygar]

Hi, can I get and use viewModelOf in commonMain if we use SwiftUI on iOS side? What import/imports is needed for this? I have 3.6.0-Beta4 version.

[arnaudgiuliani]

Hello @arnaudgiuliani i tried 3.6.0-Beta4

factory {
    ListViewModel(get(), get(named(IODispatcher)))
}

I was creating my viewmodel like this previously. Now if i use viewModelOf(::ListViewModel) how can i specify the dispatcher parameter to use named(IODispatcher)?

you need manual dsl then to describe your qualifier and use named.

[arnaudgiuliani]

Hi, can I get and use viewModelOf in commonMain if we use SwiftUI on iOS side? What import/imports is needed for this? I have 3.6.0-Beta4 version.

For compose MP for now. Still need a bit of work for Swift integration

[frankois944]

Hi, can I get and use viewModelOf in commonMain if we use SwiftUI on iOS side? What import/imports is needed for this? I have 3.6.0-Beta4 version.

@DavidGrygar It's not that simple, take a look at https://github.com/joreilly/FantasyPremierLeague and https://github.com/joreilly/FantasyPremierLeague/issues/231.

You can use a Android ViewModel almost like a SwiftUI ViewModel but you need to manage the lifecycle yourself.

[frankois944]

@DavidGrygar @ColtonIdle For the iOS developer hear, I made a playground with a lot of interesting things with Koin and MVVM

https://github.com/frankois944/kmp-mvvm-exploration

[romanatexn]

Not sure if this is the best place to ask, but related: I'm trying 3.6.0-Beta4 and everything looks great, but is it ok to instantiate a kotlin multiplatform viewmodel on iOS using a factory{} inside an Observable object and manually cancel it's scope on deinit of the Observable object?

It seems to be working fine, but I'm afraid of the viewModel comments: "You should never manually create a [ViewModel] outside of a [ViewModelProvider.Factory]"

Maybe I'm missing something important?

Context: I want to use the same ViewModel inside Compose using koinViewModel, and iOS SwiftUI using factory

[frankois944]

@romanatexn The official Kotlin ViewModel is made to be working on an Android/Compose not a SwiftUI/iOS environment. I think the usage on swift language is kind of experimental as we need to fill the holes. So, I guess, this rule doesn't apply for Swift.

The most important thing is the respect of the lifecycle of the viewmodel (init()/onCleared()). The kotlin ViewModel on SwiftUI/iOS target must be used like a SwiftUI ViewModel not like an Android/Compose ViewModel, they can't be used the same way.