在委托方法上添加完成处理程序

Question

我很难理解完成处理程序。我正在尝试让一个函数 (purchaseRequest) 等待另一个函数 (didReceiveResponse) 完成，该函数不是由我调用的，而是作为委托调用的。有人可以指导我如何完成此操作吗？

func productsRequest(request: SKProductsRequest, didReceiveResponse response: SKProductsResponse) {
    print("response received")
    if response.products.count != 0 {
        productsArray = response.products[0]
        print(productsArray)
    } else { print("No Products Found") }
}

func purchaseRequest() {
    requestProductInfo()

    //NEED TO HOLD UNTIL didReceiveResponse (which, as a delegate method, is not called by me) IS DONE.
        print("Product1: \(self.productsArray)")
    let aSC = UIAlertController(title: "Premium App Required", message: "Premium App is Required for this feature. Would you like to purchase it for [=10=].99?", preferredStyle: UIAlertControllerStyle.ActionSheet)
    let buyAction = UIAlertAction(title: "Purchase", style: UIAlertActionStyle.Default) { (action) -> Void in
        let payment = SKPayment(product: self.productsArray)
        SKPaymentQueue.defaultQueue().addPayment(payment)

    }
    let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel) { (action) -> Void in
    }
    aSC.addAction(buyAction)
    aSC.addAction(cancelAction)
    self.presentViewController(aSC, animated: true, completion:  nil)
}

Answer 1

• 推送进度微调器视图控制器

• 在 requestProductInfo()

之后立即制作 purchaseRequest return

• 在新方法

中捕获 requestProductInfo() 之后的代码

• 在委托方法中，dispatch_async()到主队列并调用新方法

• 在新方法中，弹出微调器视图控制器，然后进行高级购买舞蹈

在委托方法上添加完成处理程序

Adding a completion handler on a delegate method

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