ios - 在 Swift 中使用 shouldPerformSegue() 检查字段后如何继续使用 segue

Question

使用 shouldPerforSegue() 函数，我可以在转场之前检查一些字段，但是，我需要它继续转场，即使在触发转场时字段很糟糕。

现在，当用户点击触发 segue 的按钮时，我正在检查图像是否已经上传到服务器。我会显示一个进度条和一个警报以指示剩余百分比。然而，此时图片上传到服务器后，进度条显示为100%。我仍然必须手动单击“确定”并重新单击 seguing 按钮。我想看看是否有办法通过继续 segue 来绕过这个障碍。

我已经尝试在上传图像后以编程方式触发 segue 按钮，但它没有按预期工作。

UIApplication.shared.sendAction(self.saveButton.action!, to: self.saveButton.target, from: nil, for: nil)

我拥有的检查验证的功能:

override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
        if ((sender as? UIBarButtonItem) != nil) && uploadingImagesToFirebase  {
            // Create the alert controller
            let alertController = UIAlertController(title: "Uploading Images...", message: "", preferredStyle: .alert)
            // Create an ok button
            let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.default) { (result : UIAlertAction) -> Void in
                print("OK")
            }
            alertController.addAction(okAction)

            self.present(alertController, animated: true, completion: {
                //  Add your progressbar after alert is shown (and measured)
                let rect = CGRect(x: alertController.view.frame.width * 0.10, y: alertController.view.frame.height / 2, width: alertController.view.frame.width * 0.80, height: 100)
                self.progressView = UIProgressView(frame: rect)
                alertController.view.addSubview(self.progressView!)
            })

            return false
        }
        return true
    }
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // If user clicks on a job cell
        if segue.identifier == "showJobDetails" {
            ...
        }
        else if addJobButton == sender as? UIButton {
            print("Adding a new job from customer view")
            ...
        }
        // If save button was choice selected by user
        else if segue.identifier == "identifier {
            customer.firstName = firstNameTextField.text
            customer.middleName = middleNameTextField.text
            customer.lastName = lastNameTextField.text
            customer.address = addressTextField.text
            customer.email = emailTextField.text
            customer.phone = phoneTextField.text

            customer.jobs = customerJobs

            updateCustomerValuesInFirebase()
            updateJobValuesInFirebase()
        }
    }

Answer 1

在检查之前(通过使用 shouldPerformSegue(withIdentifier:sender:) )，你应该先执行它，你可以通过使用 performSegueWithIdentifier:sender: 来实现。 :

Initiates the segue with the specified identifier from the current view controller's storyboard file.

实际上，shouldPerformSegue(withIdentifier:sender:) 方法执行以下操作:

Determines whether the segue with the specified identifier should be performed.

所以你应该这样做:

performSegue(withIdentifier: "identifier", sender: self)

在使用 shouldPerformSegue(withIdentifier:sender:) 检查之前。

如果您不知道如何为 segue 设置标识符，请查看 this answer .