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Swift Coroutines with
KMP-NativeCoroutines
Aleksander Jaworski @ FootballCo - 07.07.2023 Droidcon Berlin
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Aleksander Jaworski
- Android Developer @
FootballCo
- Blog akjaw.com
(Kotlin Multiplatform
and Testing)
- Twitter @akjaworski1
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What is Kotlin
Multiplatform?
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What is Kotlin
Multiplatform?
You probably know
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What is Kotlin
Multiplatform?
- One codebase,
different
platforms (iOS,
Desktop, Web)
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What is Kotlin
Multiplatform?
- One codebase,
different
platforms (iOS,
Desktop, Web)
- Kotlin has the
logic,platform
has the UI*
* Compose Multiplatform is a thing
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How to call Kotlin from
Swift?
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How to call Kotlin from Swift?
- Just call the generated Kotlin Multiplatform framework
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How to call Kotlin from Swift?
// Kotlin
fun execute() {
print("Exe")
}
- Just call the generated Kotlin Multiplatform framework
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How to call Kotlin from Swift?
// Kotlin
fun execute() {
print("Exe")
}
// Generated
open func execute()
- Just call the generated Kotlin Multiplatform framework
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How to call Kotlin from Swift?
// Kotlin
fun execute() {
print("Exe")
}
// Generated
open func execute()
// Swift
execute()
- Just call the generated Kotlin Multiplatform framework
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How to call coroutines
from Swift?
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How to call coroutines from Swift?
- It’s not so simple...
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// Kotlin
suspend fun execute() {
print("Exe")
}
How to call coroutines from Swift?
- It’s not so simple...
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// Generated
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are
fatal.
open func execute(completionHandler:
@escaping (Error?) -> Void)
// Kotlin
suspend fun execute() {
print("Exe")
}
How to call coroutines from Swift?
- It’s not so simple...
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// Kotlin
suspend fun execute() {
print("Exe")
}
// Swift
execute { error in
print(error)
}
// Generated
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are
fatal.
open func execute(completionHandler:
@escaping (Error?) -> Void)
How to call coroutines from Swift?
- It’s not so simple...
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// Generated
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are
fatal.
open func execute(completionHandler:
@escaping (Error?) -> Void)
// Kotlin
suspend fun execute() {
print("Exe")
}
How to call coroutines from Swift?
- It’s not so simple...
- How to cancel?
// Swift
execute { error in
print(error)
}
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// Generated
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are
fatal.
open func execute(completionHandler:
@escaping (Error?) -> Void)
How to call coroutines from Swift?
- It’s not so simple...
- How to cancel?
- Changing threads?
// Kotlin
suspend fun execute() {
print("Exe")
}
// Swift
execute { error in
print(error)
}
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- How to cancel?
- Changing threads?
- Exception handling?
// Generated
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are
fatal.
open func execute(completionHandler:
@escaping (Error?) -> Void)
How to call coroutines from Swift?
- It’s not so simple...
// Kotlin
suspend fun execute() {
print("Exe")
}
// Swift
execute { error in
print(error)
}
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Agenda
- Calling default Suspend and Flows directly from Swift
- Creating Coroutine Adapters
- Using KMP-NativeCoroutines
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Agenda
- Calling default Suspend and Flows directly from Swift
- Creating Coroutine Adapters
- Using KMP-NativeCoroutines
- Exception Handling
- Cancellation
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Agenda
- Calling default Suspend and Flows directly from Swift
- Creating Coroutine Adapters
- Using KMP-NativeCoroutines
- Exception Handling
- Cancellation
- SwiftUI integrations*
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Why am I talking about
this?
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Why am I talking about this?
- It’s important
- When trying out Kotlin Multiplatform, we have to
convince the iOS team
- The biggest hurdles come when connecting Swift and
Kotlin
- This talk tries to address both these issues
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Why am I talking about this?
- It’s important
- When trying out Kotlin Multiplatform, we have to
convince the iOS team
- The biggest hurdles come when connecting Swift and
Kotlin
- This talk tries to address both these issues
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Why am I talking about this?
- It’s important
- When trying out Kotlin Multiplatform, we have to
convince the iOS team
- One of the biggest hurdles come when connecting Swift
and Kotlin
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The App
- KaMPKit Starter
from Touchlab
- Downloads from
API i and saves
to a Database
- 3 Coroutines call
implementations
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github.com/AKJAW/Swift-Coroutines-With-KMP-NativeCoroutines
- KaMPKit Starter
from Touchlab
- Downloads from
API i and saves
to a Database
- 3 Coroutines call
implementations
The App
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What are we
calling
- Ordinary function
class BreedViewModel() : ViewModel() {
val breedState: StateFlow
suspend fun refreshBreeds(): Boolean
fun updateBreedFavorite(breed: Breed): Job
}
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What are we
calling
- Ordinary function
- Suspend function
class BreedViewModel() : ViewModel() {
val breedState: StateFlow
suspend fun refreshBreeds(): Boolean
fun updateBreedFavorite(breed: Breed): Job
}
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What are we
calling
- Ordinary function
- Suspend function
- Data stream
class BreedViewModel() : ViewModel() {
val breedState: StateFlow
suspend fun refreshBreeds(): Boolean
fun updateBreedFavorite(breed: Breed): Job
}
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actual abstract class ViewModel {
actual val viewModelScope = MainScope()
fun clear() {
viewModelScope.coroutineContext
.cancelChildren()
}
}
class BreedViewModel() : ViewModel() {
val breedState: StateFlow
suspend fun refreshBreeds(): Boolean
fun updateBreedFavorite(breed: Breed): Job
}
What are we
calling
- Ordinary function
- Suspend function
- Data stream
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The easiest one is the Ordinary
function
fun updateBreedFavorite(breed: Breed): Job {
return viewModelScope.launch {
breedRepository.updateBreedFavorite(breed)
}
}
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func onBreedFavorite(_ breed: Breed) {
viewModel?.updateBreedFavorite(breed: breed)
}
The easiest one is the Ordinary
function
fun updateBreedFavorite(breed: Breed): Job {
return viewModelScope.launch {
breedRepository.updateBreedFavorite(breed)
}
}
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Ordinary
functions
- Fire and forget
- Modify internal
state
- CoroutineScope is
available
fun updateBreedFavorite(breed: Breed): Job {
return viewModelScope.launch {
breedRepository.updateBreedFavorite(breed)
}
}
func onBreedFavorite(_ breed: Breed) {
viewModel?.updateBreedFavorite(breed: breed)
}
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Suspend functions
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- Default generated framework
- Manual Adaptera / Wrapper
- KMP-NativeCoroutines Plugin
Suspending functions in Swift
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Suspending functions
- We want to know when
it completes
- The return value
- The ability to cancel
it
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suspend fun refreshBreeds(): Boolean {
return try {
breedRepository.refreshBreeds()
true
} catch (exception: Exception) {
handleBreedError(exception)
false
}
}
Suspending functions
- We want to know when
it completes
- The return value
- The ability to cancel
it
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Generated
function
viewModel?.refreshBreeds { wasRefreshed, error in
print("refresh: \(wasRefreshed), \(error)")
}
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Generated
function
- Forces an
Optional value
- Cannot be
cancelled
viewModel?.refreshBreeds { wasRefreshed, error in
print("refresh: \(wasRefreshed), \(error)")
}
refresh: Optional(1), error: nil
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/**
* @note This method converts instances of
CancellationException to errors.
* Other uncaught Kotlin exceptions are fatal.
*/
- (void)refreshBreedsWithCompletionHandler:(void (^)(SharedBoolean *
_Nullable, NSError * _Nullable))completionHandler
__attribute__((swift_name("refreshBreeds(completionHandler:)")));
Generated
function
- Forces an
Optional value
- Cannot be
cancelled
- No error handling
viewModel?.refreshBreeds { wasRefreshed, error in
print("refresh: \(wasRefreshed), \(error)")
}
refresh: Optional(1), error: nil
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Generated function developer experience
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Adapter / Wrapper - Kotlin
class SuspendAdapter(
private val scope: CoroutineScope,
private val suspender: suspend () -> T
) {
fun subscribe(
onSuccess: (item: T) -> Unit,
onThrow: (error: Throwable) -> Unit
) = scope.launch {
try {
onSuccess(suspender())
} catch (error: Throwable) {
onThrow(error)
}
}
}
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Adapter / Wrapper - Kotlin
fun refreshBreeds() =
SuspendAdapter(viewModel.scope) {
viewModel.refreshBreeds()
}
class SuspendAdapter(
private val scope: CoroutineScope,
private val suspender: suspend () -> T
) {
fun subscribe(
onSuccess: (item: T) -> Unit,
onThrow: (error: Throwable) -> Unit
) = scope.launch {
try {
onSuccess(suspender())
} catch (error: Throwable) {
onThrow(error)
}
}
}
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Adapter / Wrapper - Kotlin
class SuspendAdapter(
private val scope: CoroutineScope,
private val suspender: suspend () -> T
) {
fun subscribe(
onSuccess: (item: T) -> Unit,
onThrow: (error: Throwable) -> Unit
) = scope.launch {
try {
onSuccess(suspender())
} catch (error: Throwable) {
onThrow(error)
}
}
}
fun refreshBreeds() =
SuspendAdapter(viewModel.scope) {
viewModel.refreshBreeds()
}
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Adapter/Wrapper -
Swift
viewModel.refreshBreeds().subscribe(
onSuccess: { value in
print("completion \(value)")
},
onThrow: { error in
print("error \(error)")
}
)
- Better error
handling
- No Optional value
- Additional
boilerplate
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Adapter/Wrapper -
Swift
- Better error
handling
- No Optional value
- Additional
boilerplate
- Ability to
integrate with
Combine or other
viewModel.refreshBreeds().subscribe(
onSuccess: { value in
print("completion \(value)")
},
onThrow: { error in
print("error \(error)")
}
)
createFuture(suspendAdapter: adapter)
.sink { completion in
print("completion \(completion)")
} receiveValue: { value in
print("recieveValue \(value)")
}.store(in: &cancellables)
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Adapter/Wrapper developer experience
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KMP-NativeCoroutines
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Suspend KMP-NativeCoroutines
@NativeCoroutines
suspend fun nativeRefreshBreeds(): Boolean =
refreshBreeds()
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NativeCoroutines
@NativeCoroutines
suspend fun nativeRefreshBreeds(): Boolean =
refreshBreeds()
- No boilerplate
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NativeCoroutines
- No boilerplate
- No Optional
- Dedicated Swift
packages Combine,
Async, RxSwift
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
do {
let value =
try await asyncFunction(for: suspend)
print("Async Success: \(value)")
} catch {
print("Async Failed with error: \(error)")
}
}
@NativeCoroutines
suspend fun nativeRefreshBreeds(): Boolean =
refreshBreeds()
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NativeCoroutines
- No boilerplate
- No Optional
- Dedicated Swift
packages Combine,
Async, RxSwift
- Error handling
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
do {
let value =
try await asyncFunction(for: suspend)
print("Async Success: \(value)")
} catch {
print("Async Failed with error: \(error)")
}
}
@NativeCoroutines
suspend fun nativeRefreshBreeds(): Boolean =
refreshBreeds()
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NativeCoroutines
- No boilerplate
- No Optional
- Dedicated Swift
packages Combine,
Async, RxSwift
- Error handling
- Automatic
cancelling
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
do {
let value =
try await asyncFunction(for: suspend)
print("Async Success: \(value)")
} catch {
print("Async Failed with error: \(error)")
}
}
@NativeCoroutines
suspend fun nativeRefreshBreeds(): Boolean =
refreshBreeds()
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NativeCoroutines - asyncFunction
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
do {
let value =
try await asyncFunction(for: suspend)
print("Async Success: \(value)")
} catch {
print("Async Failed with error: \(error)")
}
}
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NativeCoroutines - asyncResult
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
let value = await asyncResult(for: suspend)
switch value {
case .success(let result):
print("Async Success: \(result)")
case .failure(let error):
print("Async Failed with error: \(error)")
}
}
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NativeCoroutines - asyncResult
func refresh() async {
let suspend = viewModel.nativeRefreshBreeds()
let value = await asyncResult(for: suspend)
if case .success(let result) = value {
print("Async Success: \(result)")
}
}
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NativeCoroutines developer experience
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Flow Data Streams
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Data streams
- Generated framework - Many limitations + Boilerplate
- Adapter / Wrapper - Additional boilerplate
- KMP-NativeCoroutines
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Flow Generated framework
class Collector:
Kotlinx_coroutines_coreFlowCollector {
private let callback: (T) -> Void
init(callback: @escaping (T) -> Void) {
self.callback = callback
}
func emit(value: Any?, completionHandler:
@escaping (Error?) -> Void) {
callback(value as! T)
completionHandler(nil)
}
}
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Flow Generated framework
class Collector:
Kotlinx_coroutines_coreFlowCollector {
private let callback: (T) -> Void
init(callback: @escaping (T) -> Void) {
self.callback = callback
}
func emit(value: Any?, completionHandler:
@escaping (Error?) -> Void) {
callback(value as! T)
completionHandler(nil)
}
}
viewModel.breedState.collect(
collector: Collector {
[weak self] dogsState in
self?.loading = dogsState.isLoading
self?.breeds = dogsState.breeds
self?.error = dogsState.error
},
completionHandler: { error in
print("breed collection completion
error: \(error)")
}
)
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Flow Adapter / Wrapper
class FlowAdapter(
private val scope: CoroutineScope,
private val flow: Flow
) {
fun subscribe(
onEach: (item: T) -> Unit,
onComplete: () -> Unit,
onThrow: (error: Throwable) -> Unit
): Canceller = JobCanceller(
flow.onEach { onEach(it) }
.catch { onThrow(it) }
.onCompletion { onComplete() }
.launchIn(scope)
)
}
interface Canceller {
fun cancel()
}
private class JobCanceller(private val job:
Job) : Canceller {
override fun cancel() {
job.cancel()
}
}
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Flow Adapter / Wrapper
class FlowAdapter(
private val scope: CoroutineScope,
private val flow: Flow
) {
fun subscribe(
onEach: (item: T) -> Unit,
onComplete: () -> Unit,
onThrow: (error: Throwable) -> Unit
): Canceller = JobCanceller(
flow.onEach { onEach(it) }
.catch { onThrow(it) }
.onCompletion { onComplete() }
.launchIn(scope)
)
}
interface Canceller {
fun cancel()
}
private class JobCanceller(private val job:
Job) : Canceller {
override fun cancel() {
job.cancel()
}
}
viewModel.breeds.subscribe(
onEach: { [weak self] dogsState in
self?.loading = dogsState.isLoading
self?.breeds = dogsState.breeds
self?.error = dogsState.error
},
onComplete: { print("Subscription end") },
onThrow: { error in print("Subscription
error: \(error)") }
)
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Flow KMP-NativeCoroutines
private val mutableBreedState =
MutableStateFlow(
BreedViewState(isLoading = true)
)
@NativeCoroutinesState
val nativeBreedState: StateFlow =
breedState
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Flow KMP-NativeCoroutines
private val mutableBreedState =
MutableStateFlow(
BreedViewState(isLoading = true)
)
@NativeCoroutinesState
val nativeBreedState: StateFlow =
breedState
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Native Flow
- Integration with
Native solutions
func activate() async {
let nativeFlow = viewModel.nativeBreedStateFlow
do {
let sequence = asyncSequence(for: nativeFlow)
for try await dogsState in sequence {
self.loading = dogsState.isLoading
self.breeds = dogsState.breeds
self.error = dogsState.error
}
} catch {
print("Async Failed with error: \(error)")
}
}
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Native Flow
- Integration with
Native solutions
- No casting needed
func activate() async {
let nativeFlow = viewModel.nativeBreedStateFlow
do {
let sequence = asyncSequence(for: nativeFlow)
for try await dogsState in sequence {
self.loading = dogsState.isLoading
self.breeds = dogsState.breeds
self.error = dogsState.error
}
} catch {
print("Async Failed with error: \(error)")
}
}
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Native Flow
- Integration with
Native solutions
- No casting needed
func activate() async {
let nativeFlow = viewModel.nativeBreedStateFlow
do {
let sequence = asyncSequence(for: nativeFlow)
for try await dogsState in sequence {
self.loading = dogsState.isLoading
self.breeds = dogsState.breeds
self.error = dogsState.error
}
} catch {
print("Async Failed with error: \(error)")
}
}
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Native Flow
- Integration with
Native solutions
- No casting needed
- Automatic
cancellation
func activate() async {
let nativeFlow = viewModel.nativeBreedStateFlow
do {
let sequence = asyncSequence(for: nativeFlow)
for try await dogsState in sequence {
self.loading = dogsState.isLoading
self.breeds = dogsState.breeds
self.error = dogsState.error
}
} catch {
print("Async Failed with error: \(error)")
}
}
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Native Flow
- Integration with
Native solutions
- No casting needed
- Automatic
cancellation
- Collection on
Default
dispatcher
@MainActor
func activate() async {
let nativeFlow = viewModel.nativeBreedStateFlow
do {
let sequence = asyncSequence(for: nativeFlow)
for try await dogsState in sequence {
self.loading = dogsState.isLoading
self.breeds = dogsState.breeds
self.error = dogsState.error
}
} catch {
print("Async Failed with error: \(error)")
}
}
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Controlling the Scope
- Ability to cancel directly
from Kotlin
- Specify which thread
should the suspension
happen
@NativeCoroutineScope
actual val viewModelScope =
MainScope()
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Controlling the Scope
- Ability to cancel directly
from Kotlin
- Specify which thread
should the suspension
happen
- MainActor still required
@NativeCoroutineScope
actual val viewModelScope =
MainScope()
@MainActor
func activate() async {
}
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Playground Screen
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Playground
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Playground
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Playground
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Suspend Exception Handling
@NativeCoroutines
suspend fun throwException() {
delay(1000)
throw IllegalStateException()
}
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Suspend Exception Handling
print("async exception start")
do {
let result = try await asyncFunction(for: suspend)
print("async exception success \(result)")
} catch {
print("async exception failure \(error)")
}
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Suspend Exception Handling
18:07:03 async exception start
18:07:04 async exception failure
(ErrorDomain=KotlinExcepton Code=0 "(null)"
UserInfo={KotlinException=kotlin.IllegalStateException})
print("async exception start")
do {
let result = try await asyncFunction(for: suspend)
print("async exception success \(result)")
} catch {
print("async exception failure \(error)")
}
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Suspend Exception Handling - Variant
18:07:53 async exception start
18:07:54 async exception completion
failure(ErrorDomain=KotlinExcepton Code=0 "(null)"
UserInfo={KotlinException=kotlin.IllegalStateException})
print("async exception start")
let result = await asyncResult(for: suspend)
switch result {
case .success(let value):
print("async exception success \(value)")
case .failure(let error):
print("async exception failure \(error)")
}
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Flow Exception Handling
@NativeCoroutines
val errorFlow: Flow = flow {
repeat(3) { number ->
emit(number)
delay(1000)
}
throw IllegalStateException()
}
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Flow Exception Handling
do {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
} catch {
print("sequence exception error: \(error)")
}
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Flow Exception Handling
2023-06-28 18:14:24 sequence exception number 0
2023-06-28 18:14:25 sequence exception number 1
2023-06-28 18:14:26 sequence exception number 2
2023-06-28 18:14:27 sequence exception error
(Error Domain=KotlinException Code=0 "(null)"
UserInfo={KotlinException=kotlin.IllegalStateException})
do {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
} catch {
print("sequence exception error: \(error)")
}
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Flow Exception Handling - Variant
func throwException() async throws {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
}
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Flow Exception Handling - Variant
func throwException() async throws {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
}
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Flow Exception Handling - Variant
func throwException() async throws {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
}
try? await observableModel.throwException()
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Flow Exception Handling - Variant
2023-06-28 18:15:24 sequence exception number 0
2023-06-28 18:15:25 sequence exception number 1
2023-06-28 18:15:26 sequence exception number 2
func throwException() async throws {
let sequence = asyncSequence(for: viewModel.errorFlow)
for try await number in sequence {
print("sequence exception n: \(number)")
}
}
try? await observableModel.throwException()
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Exception
Handling
- Exception
handling is
awkward in Swift
@NativeCoroutines
suspend fun throwException() {
delay(1000)
throw IllegalStateException()
}
@NativeCoroutines
val errorFlow: Flow = flow {
repeat(3) { number ->
emit(number)
delay(1000)
}
throw IllegalStateException()
}
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Exception
Handling
- Exception
handling is
awkward in Swift
- Better to return
an error value
@NativeCoroutines
suspend fun throwException() {
delay(1000)
throw IllegalStateException()
}
@NativeCoroutines
val errorFlow: Flow = flow {
repeat(3) { number ->
emit(number)
delay(1000)
}
throw IllegalStateException()
}
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Cancellation
@NativeCoroutines
val numberFlow: Flow = flow {
var i = 0
while (true) {
emit(i++)
delay(1000)
}
}.onEach { number ->
log.i("numberFlow onEach: $number")
}.onCompletion { throwable ->
log.i("numberFlow onCompletion: $throwable")
}
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Manual cancellation
func listenToNumbers() async {
numberTask = Task {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
}
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Manual cancellation
func cancel() {
numberTask?.cancel()
numberTask = nil
}
func listenToNumbers() async {
numberTask = Task {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
}
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Manual cancellation
func cancel() {
numberTask?.cancel()
numberTask = nil
}
func listenToNumbers() async {
numberTask = Task {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
}
2023-06-30 12:21:30 numberFlow onEach: 0
2023-06-30 12:21:31 numberFlow onEach: 1
2023-06-30 12:21:32 numberFlow onEach: 2
2023-06-30 12:21:33 numberFlow onCompletion:
kotlinx.coroutines.JobCancellationException: …
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Automatic cancellation
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Automatic cancellation
func listenToNumbers() async {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
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Automatic cancellation
var body: some View {
...
}.task {
await observableModel.listenToNumbers()
}
func listenToNumbers() async {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
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Automatic cancellation
var body: some View {
...
}.task {
await observableModel
.listenToNumbers()
}
func listenToNumbers() async {
let sequence =
asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
}
2023-03-24 12:28:13 init 0x00006000024be000
2023-03-24 12:28:13 numberFlow onEach: 0
2023-03-24 12:28:14 numberFlow onEach: 1
2023-03-24 12:28:15 numberFlow onEach: 2
2023-03-24 12:28:16 numberFlow onEach: 3
2023-03-24 12:28:16 deinit 0x00006000024be000
2023-03-24 12:28:16 numberFlow onCompletion:
kotlinx.coroutines.JobCancellationException: ...
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Cancellation
- Freeing up
resources func cancel() {
numberTask?.cancel()
numberTask = nil
}
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Cancellation
- Freeing up
resources
- Avoiding
unnecessary
networking
func cancel() {
numberTask?.cancel()
numberTask = nil
}
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Cancellation
- Freeing up
resources
- Avoiding
unnecessary
networking
- Avoiding Memory
leaks
func cancel() {
numberTask?.cancel()
numberTask = nil
}
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SwiftUI
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SwiftUI Integration
- Async await
- ObservableObject
- @Published
- @StateObject / @ObservedObject
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Playground
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Published Int
@NativeCoroutines
val numberFlow: Flow = flow {
var i = 0
while (true) {
emit(i++)
delay(1000)
}
}
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Published Int
private class CoroutinesExampleModel: ObservableObject {
@Published
var number: Int = -1
func listenToNumbers() async {
do {
let sequence = asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
} catch {
print("Async numberFlow Failed with error: \(error)")
}
}
}
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Published Int
private class CoroutinesExampleModel: ObservableObject {
@Published
var number: Int = -1
func listenToNumbers() async {
do {
let sequence = asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
} catch {
print("Async numberFlow Failed with error: \(error)")
}
}
}
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Published Int
private class CoroutinesExampleModel: ObservableObject {
@Published
var number: Int = -1
func listenToNumbers() async {
do {
let sequence = asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
} catch {
print("Async numberFlow Failed with error: \(error)")
}
}
}
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Published Int
private class CoroutinesExampleModel: ObservableObject {
@Published
var number: Int = -1
func listenToNumbers() async {
do {
let sequence = asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
} catch {
print("Async numberFlow Failed with error: \(error)")
}
}
}
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Published Int
private class CoroutinesExampleModel: ObservableObject {
@Published
var number: Int = -1
func listenToNumbers() async {
do {
let sequence = asyncSequence(for: viewModel.numberFlow)
for try await number in sequence {
self.number = number.intValue
}
} catch {
print("Async numberFlow Failed with error: \(error)")
}
}
}
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Published Int
struct CoroutinesExampleScreen: View {
@StateObject
private var observableModel = CoroutinesExampleModel()
var body: some View {
Text("Number: \(observableModel.number)")
}
}
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Published Int
struct CoroutinesExampleScreen: View {
@StateObject
private var observableModel = CoroutinesExampleModel()
var body: some View {
Text("Number: \(observableModel.number)")
}
}
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Published Int
struct CoroutinesExampleScreen: View {
@StateObject
private var observableModel = CoroutinesExampleModel()
var body: some View {
Text("Number: \(observableModel.number)")
}
}
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Published Int
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KmmViewModel - Bonus
- The same author
- Generates ObservableObject itd.
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KmmViewModel - Bonus
ObservableObject KMMViewModel
@StateObject @StateViewModel
@ObservedObject @ObservedViewModel
@EnvironmentObject @EnvironmentViewModel
environmentObject(_:) environmentViewModel(_:)
- The same author
- Generates ObservableObject itd.
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Summary
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What we’ve learned
- How to call Suspend and Flow from swift using different
approaches
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What we’ve learned
- How to call Suspend and Flow from swift using different
approaches
- How Kotlin Exceptions can affect the iOS App and how to
handle them
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What we’ve learned
- How to call Suspend and Flow from swift using different
approaches
- How Kotlin Exceptions can affect the iOS App and how to
handle then
- Why Cancelling coroutines is a good idea and how to do
it from Swift
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What we’ve learned
- How to call Suspend and Flow from swift using different
approaches
- How Kotlin Exceptions can affect the iOS App and how to
handle then
- Why Cancelling coroutines is a good idea and how to do
it from Swift
- Integrating KMP-NativeCoroutines with SwiftUi*
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Learning Kotlin Multiplatform
- https://johnoreilly.dev/
- https://touchlab.co/blog/
- https://www.marcogomiero.com/
- https://akjaw.com/
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My final message
KMP-NativeCoroutines makes the iOS developers life easier
and more fun.
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My final message
KMP-NativeCoroutines makes the iOS
developers life easier and more fun.
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Presentation Async
https://akjaw.com/assets/talks/NativeCoroutines-Async-Droidcon
-Berlin.pdf
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Presentation Combine
https://akjaw.com/assets/talks/NativeCoroutines-Combine-Droidc
on-Berlin.pdf
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Sources
- https://github.com/AKJAW/Swift-Coroutines-With-KMP-NativeCoroutines
- https://github.com/touchlab/KaMPKit
- https://github.com/rickclephas/KMP-NativeCoroutines
- https://github.com/rickclephas/KMM-ViewModel
- https://dev.to/touchlab/kotlin-coroutines-and-swift-revisited-j5h
- https://www.slideshare.net/ChristianMelchior/coroutines-for-kotlin-multiplatform-in
-practise
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Questions?