android - 为什么在 CoroutineScope 内的 lambda 中调用挂起函数会产生错误？

Question

我有一个重试策略，它接受一个 lambda，启动一个 CoroutineScope ，增加重试计数器，检查是否达到最大重试次数，计算 waitTime根据重试次数，延迟这次的作用域，最后调用 lambda:

        fun connectionRetryPolicy(block: () -> Unit) {

            Timber.d("connectionRetryPolicy: called")

            // Launch the coroutine to wait for a specific delay
            val scope = CoroutineScope(Job() + Dispatchers.Main)
            scope.launch {

                // Get and increment the current retry counter
                val counter = retryCounter.getAndIncrement()

                // Check if the counter is smaller than the maximum retry count and if so, wait a bit and execute the given function
                if (counter < maxRetry) {

                    // Calculate the time to be waited
                    val waitTime: Long = (2f.pow(counter) * baseDelayMillis).toLong()

                    // Delay the scope for the calculated time
                    delay(waitTime)

                    // Execute the given function
                    block()

                }

                // Else, throw an exception
                else {

                    throw FirebaseNetworkException("Retry count reached")

                }

            }

        }

调用此方法以递归调用挂起函数作为 lambda，如下所示:

    private suspend fun connectToGooglePlayBillingService(): BillingResult? {

        Timber.d("connectToGooglePlayBillingService: called")

        return suspendCoroutine { continuation ->

            // If the billingClient is not already ready, start the connection
            if (!playStoreBillingClient.isReady) {

                // Start the connection and wait for its result in the listener
                playStoreBillingClient.startConnection(object: BillingClientStateListener {

                    override fun onBillingServiceDisconnected() {

                        Timber.d("onBillingServiceDisconnected: called")

                        // Retry to connect using the RetryPolicies
                        RetryPolicies.connectionRetryPolicy { connectToGooglePlayBillingService() }

                    }

                    override fun onBillingSetupFinished(billingResult: BillingResult?) {

                        // There is code that does not matter here

                    }

                })

            }

        }

    }

现在，Lint 告诉我， connectToGooglePlayBillingService不能在 lambda 内部调用，因为它是一个挂起函数，需要在 CoroutineScope 内部调用.如您所见，我确实将 lambda 称为 CoroutineScope在 connectionRetryPolicy .

这是 Lint 中的错误还是我在这里做错了什么？我知道，我可以新建一个 CoroutineScope在 lambda 中，然后调用 connectToGooglePlayBillingService关于性能，我不确定这是否明智。

Answer 1

代替

fun connectionRetryPolicy(block: () -> Unit)

和

fun connectionRetryPolicy(block: suspend () -> Unit)

因为您的 block()将在协程内运行，但其他方法不知道。