Question

SCENARIO

该应用逐个下载用户订阅。此呼叫将在多个地方进行（在另一个网络呼叫之后的完成模块中以及从UIAlertController按下按钮）。逻辑是下载所有订阅，一旦订阅下载停止，它将转到下一个，直到所有订阅都被下载，然后我们的SVProgressHUD解散。当我们从Xcode构建和运行时，代码工作得很好。但是当我们构建IPA并发送给我们的客户时，这种逻辑会产生某种失速，并且SVProgressHUD警报会继续旋转：

这是一个大问题，因为我们的应用程序专注于从订阅下载内容。

为什么这个逻辑在我归档并从中构建IPA后停止，但是当我从Xcode构建并运行时不？

以下代码：

// Making the call 

    DispatchQueue.main.async {
        DGWebService().syncUserSubscribedContent {
            DispatchQueue.main.async {
                self.finishLogin()
            }
        }
    }

// Sequentially going through each subscription and downloading them

    func syncUserSubscribedContent(completion: @escaping Constants.WebService.ContentCompletion) {
        let subscriptions = MPTUser.sharedUser.getSubscriptionsForDownload()
        DispatchQueue.global().async {
            if subscriptions.count > 0 {
                var index:Int = 0
                var t = subscriptions.count
                var downloading: Bool = false
                while t != 0 {
                    if downloading == false {
                        downloading = true
                        if index < 0 {
                            index = 0
                        }
                        if index > subscriptions.count - 1 {
                            index = subscriptions.count - 1
                        }
                        if index <= subscriptions.count {
                            let subscription = subscriptions[index]
                            if subscription.didDownloadContent == false {
                                if let subscriptionID = subscription.subscriptionID {
                                    DispatchQueue.main.async {
                                        SVProgressHUD.show(withStatus: "Downloading Documents\nfor\n\(subscription.functionalGroupName!)\n\(index+1) of \(subscriptions.count)")
                                    }
                                    self.getUserSubscribedContent(subscriptionID: subscriptionID, completion: { (success) in
                                        subscription.didDownloadContent = true
                                        index += 1
                                        t -= 1
                                        downloading = false
                                    })
                                }
                                else {
                                    index += 1
                                    t -= 1
                                    downloading = false
                                }
                            }
                        }
                        else {
                            index += 1
                            t -= 1
                            downloading = false
                        }
                    }
                }
            }
            completion()
        }
    }

self.getUserSubscribedContent是一个下载内容并在块中发回完成功能的函数。

如果有人可以帮助我，我将非常感激。

Answer 1

您可以尝试使用DispatchGroup。这是一个粗略（未经测试）的例子：

DispatchQueue.global().async {
    let subscriptions = MPTUser.sharedUser.getSubscriptionsForDownload()
    let group = DispatchGroup()
    var completed = 0
    let completion: (Bool) -> Void = {
        if $0 {
            completed += 1
        }
        group.leave()
        DispatchQueue.main.async {
            SVProgressHUD.show(withStatus: "Downloading Documents\nfor\n\(subscription.functionalGroupName!)\n\(completed) of \(subscriptions.count)")
        }
    }
    for subscription in subscriptions {
        self.getUserSubscribedContent(subscriptionID: subscription.subscriptionID, completion: completion)
        group.enter()
    }
    // However long you want to wait (in seconds) before timing out
    _ = group.wait(timeout: .now() + 30)
}

GCD：进行顺序下载呼叫;逐一

1 个答案: