Swift interop

kmp-viewmodel and Swift interoperability

kmp-viewmodel can be exported and used in Swift as usual, however there are few limitations.

Exposing kmp-viewmodel sources to Swift

KotlinX Coroutines Flow are Kotlin interfaces with generic types. Since generics for interfaces are not exported to Swift, kmp-viewmodel provides Flow wrapper classes.

You can wrap Flows sources using corresponding wrap() extension functions:

• Flow<T: Any>.wrap(): NonNullFlowWrapper<T>
• Flow<T>.wrap(): NullableFlowWrapper<T>
• StateFlow<T: Any>.wrap(): NonNullStateFlowWrapper<T>
• StateFlow<T>.wrap(): NullableStateFlowWrapper<T>

Example:

// Kotlin code
class SharedViewModel : ViewModel() {
  private val _state = MutableStateFlow(State())
  val stateFlow: NonNullStateFlowWrapper<State> = _state.wrap()
}

Expose kmp-viewmodel and kotlinx-coroutines-core to Darwin native side

// Cocoapods
kotlin {
  cocoapods {
    [...]
    framework {
      baseName = "shared"
      export("io.github.hoc081098:kmp-viewmodel:0.8.0") // required to expose the classes to iOS.
      export("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.9.0")
    }
  }
}

// -- OR --

// Kotlin/Native as an Apple framework
kotlin {
  ios {
    binaries {
      framework {
        baseName = "shared"
        export("io.github.hoc081098:kmp-viewmodel:0.8.0") // required to expose the classes to iOS.
        export("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.9.0")
      }
    }
  }
}

Using wrappers in Swift

Flow wrappers can be used in Swift as usual:

// Swift code
func foo() {
  let viewModel = SharedViewModel()

  val closable = viewModel.stateFlow.subscribe(
    scope: viewModel.viewModelScope,
    onValue: { state in
      // do something with state
    }
  )

  // At some point later
  closable.close()
}

If Kotlin Code does not wrap Flows to FlowWrappers, we can also wrap them in Swift code.

// Swift code
let nonNull = NonNullFlowWrapperKt.wrap(self) as! NonNullFlowWrapper<T>
let nullable = NullableFlowWrapperKt.wrap(self) as! NullableFlowWrapper<T>
...

Combine interop

Please check kotlinxCoroutinesFlowExtensions.swift .

RxSwift interop

Please check kotlinxCoroutinesFlow+RxSwift.swift.