Question

有点难以解释，但如果达到一定条件，我需要停止我的程序。这是我使用的简化代码

func getNotificationData() {

    NetworkingService.fetchJSON(url: url, methodUsed: .post, parameters: parameters) { (result) in

        switch result {
        case .failure:
            // show alert error
        case .success(let jsonFromServer):

            let json = jsonFromServer as! JSON
            let validity = json["valid"].intValue

            if validity == 0 {
                // show alert
            } else if validity == 1 {
                guard let dataNotification = json["data"].arrayObject as? [[String:Any]] else {return}

                self.notificationData = dataNotification

                self.notificationData = nil <--- HARD CODED to test empty data

                print("xxx")
                guard let notificationData = self.notificationData else {
                    print("bbbbbb")
                    self.noNotificationLabel.isHidden = false
                    self.tableView.isHidden = true
                    SVProgressHUD.dismiss()
                    return
                }

                if notificationData.isEmpty {
                    self.noNotificationLabel.isHidden = false
                    self.tableView.isHidden = true
                    SVProgressHUD.dismiss()
                    return
                }

                print("yyyyy")
                self.thereIsAnError = false
                print("zzzz")
            }
        }
    }
}

我想重构我的代码以提高可读性。我想将上面代码的某些部分移动到类似下面代码的函数

func checkIfNotificationIsAvailable() {

        guard let notificationData = notificationData else {
            print("bbbbbb")
            noNotificationLabel.isHidden = false
            tableView.isHidden = true
            return
        }

        if notificationData.isEmpty {
            noNotificationLabel.isHidden = false
            tableView.isHidden = true
            return
        }
    }

所以我希望我的结束代码会像这样

func getNotificationData() {

    NetworkingService.fetchJSON(url: url, methodUsed: .post, parameters: parameters) { (result) in

        switch result {
        case .failure:

        // show alert error

        case .success(let jsonFromServer) :

            let json = jsonFromServer as! JSON
            let validity = json["valid"].intValue

            if validity == 0 {
                // show alert
            } else if validity == 1 {
                guard let dataNotification = json["data"].arrayObject as? [[String:Any]] else {return}

                self.notificationData = dataNotification

                self.notificationData = [] <--- HARD CODED to test empty data
                print("xxx")
                self.checkIfNotificationIsAvailable()
                print("yyyyy")
                print("zzzz")
            }
        }
    }
}

但如果在重构后运行应用程序，则在调试区域中将打印

XXXXX
YYYYY
ZZZZZZ

我希望yyyy和zzzz不会被打印，换句话说我的程序会在打印后排出{＆＃34; bbbbb＆＃34;），行if notificationData.isEmpty，所以如何停止程序为了阻止执行print("yyyy")和print("zzzz")？我认为可以使用return来完成，但它仍会执行checkIfNotificationIsAvailable()下面的代码

Answer 1

更改

case .back:
backButton.imageView?.image = #imageLiteral(resourceName: "arrow_left")
break

返回Bool

func checkIfNotificationIsAvailable() {
...
 }

并在函数func getNotificationData（）{..}

中

更改

func checkIfNotificationIsAvailable() -> Bool{
 guard let notificationData = notificationData else {
  print("bbbbbb")

    noNotificationLabel.isHidden = false
    tableView.isHidden = true
    return true
}

if notificationData.isEmpty {


    noNotificationLabel.isHidden = false
    tableView.isHidden = true
    return false
}
 return true
}

到

self.checkIfNotificationIsAvailable()

如何在达到某个条件后停止我的程序执行？

1 个答案: