KViewModel

KViewModel it's a lightweight library for MVVM or MVI pattern. Works with Jetpack Compose, XML, UIKit.

Works with Kotlin Multiplatform and Compose Multiplatform!

Implementation

Kotlin DSL

implementation("io.github.alexgladkov:kviewmodel:0.17") // Core functions
implementation("io.github.alexgladkov:kviewmodel-compose:0.17") // Compose extensions
implementation("io.github.alexgladkov:kviewmodel-odyssey:0.17") // Odyssey extensions

implementation "io.github.alexgladkov:kviewmodel:0.17" // Core functions
implementation "io.github.alexgladkov:kviewmodel-compose:0.17" // Compose extensions
implementation "io.github.alexgladkov:kviewmodel-odyssey:0.17" // Odyssey extensions

How to use

Common Code

class TestViewModel : BaseSharedViewModel<TestViewState, TestAction, TestEvent>(initialState = TestViewState())

Events - for user interaction

sealed class TestEvent {
    object IncrementClick : TestEvent()
    object DecrementClick : TestEvent()
    object DetailClick : TestEvent()
}

Actions - single action from view model like show snackbar or navigation

sealed class TestAction {
    data class OpenDetail(val param: Int) : TestAction()
}

ViewState - your current screen state (fields, loaders, etc)

data class TestViewState(
    val titleText: String = "",
    val counter: Int = 0
)

Compose Multiplatform

ViewModel(factory = { TestViewModel() }) { viewModel ->
    val viewState = viewModel.viewStates().observeAsState()
    val viewAction = viewModel.viewActions().observeAsState()

    Text(text = viewState.titleText)
    
    viewAction.value?.let { action -> 
        when (action) {
            is TestAction.FirstCase -> TODO()
            is TestAction.SecondCase -> TODO()
        }
    }
}

Custom ViewModel's exception handlers

Note: When using a custom exception handler you need to take care about crash reporting

Shared exception handlers (for all ViewModels)

class App: Application() {

    override fun onCreate() {
        super.onCreate()
        KViewModel.setupSharedExceptionHandler(CoroutineExceptionHandler { _, throwable ->
            // There is you can log common exceptions for all ViewModels
        })
    }
}

Single exception handlers (for only current ViewModel)

class TestViewModel: BaseSharedViewModel<TestViewState, TestAction, TestEvent>(initialState = TestViewState()) {
    
    override fun getCoroutineExceptionHandler(): CoroutineExceptionHandler {
        return CoroutineExceptionHandler { _, throwable ->
            // There is you can log exceptions only for TestViewModel
        }
    }
}

Odyssey integration

Allows you to save the ViewModel

setupNavigation(
    startScreen = "YourStartScreen",
    providers = yourCustomProviders
) {
    LocalRootController.current.setupWithViewModels()
    generateGraph()
}

StoredViewModel(factory = { TestViewModel() }) { viewModel ->
    // usual code like above
}

iOS

// ViewState
testViewModel.viewStates().watch { [weak self] viewState in
    guard let self = self else { return }
    
    self.titleView.text = viewState.someText 
}

// Action
testViewModel.viewActions().watch { [weak self] viewAction in
    guard let self = self, let viewAction = viewAction else { return }
    
    switch viewAction {
        case let args as TestAction.OpenDetail:
            self.presentDetail(param: args.param)
                    
        default: break 
    }
}

Problems

Feel free to make issues, we will try to fix it as fast as we can! For proposals, you can also use issue section