从iOS收听Kotlin协程流 [英] Listen to Kotlin coroutine flow from iOS

问题描述

我已经设置了一个Kotlin Multiplatform项目，并在其上附加了 SQLDelight 数据库.它的所有设置和运行正常，因为我已经使用以下命令在android端对其进行了测试:

I have setup a Kotlin Multiplatform project and attached a SQLDelight database to it. Its all setup and running correctly as i have tested it on the android side using the following:

commonMain:

commonMain:

    val backgroundColorFlow: Flow<Color> =
            dbQuery.getColorWithId(BGColor.id)
                    .asFlow()
                    .mapToOneNotNull()

使用以下命令在Android项目MainActivity.kt中触发正常:

which triggers fine in the Android projects MainActivity.kt using:

database.backgroundColorFlow.onEach { setBackgroundColor(it.hex) }.launchIn(lifecycleScope)

但是当尝试在iOS项目应用程序委托中访问相同的调用时，我得到以下选项，并且不确定如何使用它们或将它们转换为我的BGColor对象:

but when trying to access the same call in the iOS projects app delegate i get the following options and im unsure how to use them or convert them into my BGColor object:

database.backgroundColorFlow.collect(collector: T##Kotlinx_coroutines_coreFlowCollector, completionHandler: (KotlinUnit?, Error?) -> Void)

有人可以帮助我如何使用它吗?

can anyone help me with how to use this?

推荐答案

因此，通过创建流程助手来解决了这个问题:

So this was resolved by creating a flow helper:

import io.ktor.utils.io.core.Closeable
import kotlinx.coroutines.*
import kotlinx.coroutines.flow.*

fun <T> Flow<T>.asCommonFlow(): CommonFlow<T> = CommonFlow(this)
class CommonFlow<T>(private val origin: Flow<T>) : Flow<T> by origin {
    fun watch(block: (T) -> Unit): Closeable {
        val job = Job()

        onEach {
            block(it)
        }.launchIn(CoroutineScope(Dispatchers.Main + job))

        return object : Closeable {
            override fun close() {
                job.cancel()
            }
        }
    }
}

我的backgroundColorFlow var更新如下，以利用此帮助程序:

My backgroundColorFlow var is update as follows to utilise this helper:

    val backgroundColorFlow: CommonFlow<BGColor> =
            dbQuery.getColorWithId(BGColor.id)
                    .asFlow()
                    .mapToOneNotNull()
                    .map { BGColor(it.name) }
                    .asCommonFlow()

然后我的迅捷工作方式如下:

Then my swift works as follows:

database.backgroundColorFlow.watch { color in
            guard let colorHex = color?.hex else {
                return
            }
            self.colorBehaviourSubject.onNext(colorHex)
        }

和android一样:

and android like so:

database.backgroundColorFlow.watch { setBackgroundColor(it.hex) }

希望这可以帮助遇到此问题的任何人.我想将CommonFlow类转换为Flow的扩展，但是没有专有的atm，所以恕我直言，恕我直言将是一个更好的解决方案

Hope this helps anyone that comes across this. I would like to convert the CommonFlow class into an extension of Flow but don't have the know-how atm so if any could that IMHO would be a much nicer solution

这篇关于从iOS收听Kotlin协程流的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！