android - 如何将这个(AdsWizz)Kotlin回调函数包装在协程中？

Question

我是协程新手，很难弄清楚如何在协程中正确包装现有的回调。

我的目标是能够执行以下操作:

lifecycleScope.launch {
    withContext(Dispatchers.Main) {
        val theResult = getPreRollAd()      //1. call this suspending func and wait for result

        doSomethingWithResult(theResult)    //2. now that the result is returned from AdsWizz API (below), do something with it 
    }
}

这是我要“包装”的AdsWizz API调用:

val adReqInterface: AdRequestHandlerInterface =  object :
    AdRequestHandlerInterface {

    override fun onResponseError(error: AdswizzSDKError) {
        Timber.e("onResponseError $error")
    }

    override fun onResponseReady(adResponse: AdResponse) {
        Timber.d( "onResponseReadySingleAd")

        //this contains the url to the ad, title, etc..
        !!!*** I WANT TO RETURN THE adResponse.mediaFile?.source string back to "theResult" variable above (in lifecycleScope.launch {.... )


    }
}

try {
    AdswizzSDK.getAdsLoader().requestAd(adReqParams, adReqInterface)

} catch (e: IllegalArgumentException) {
    Timber.d( "IllegalArgumentException")
} catch (e: SecurityException) {
    Timber.d( "SecurityException")
} catch (e: Exception) {
    Timber.d( "other exception")
    e.printStackTrace()
}

我尝试使用 suspendCoroutine {...进行包装，但是没有任何效果。非常感谢有人帮助您以正确的方式实现这一目标。

Answer 1

正确的方法是使用suspendCancellableCoroutine。它可以返回结果或可以取消，但有异常(exception)。

suspend fun getPreRollAd(): AdResponse {
return suspendCancellableCoroutine {

    ...

    val adReqInterface: AdRequestHandlerInterface =  object : AdRequestHandlerInterface {

        override fun onResponseError(error: AdswizzSDKError) {
            Timber.e("onResponseError $error")
            it.cancel(error)
        }

        override fun onResponseReady(adResponse: AdResponse) {
            Timber.d( "onResponseReadySingleAd")
            it.resume(adResponse)
        }

    }

    AdswizzSDK.getAdsLoader().requestAd(adReqParams, adReqInterface)
}

}


viewModelScope.launch {
  val result = try {
    getPreRollAd()
  } catch(e: Throwable) {
    null
  }

  ...
}