Question

我试图在PopupViewController中单击一个按钮，在DagbogsindlaegViewController中的文本字段中填充字符串“ svimmelhed”。

运行代码时没有出现任何错误，但是当我运行应用程序仿真并在类PopupViewController中按“ ButtonPressSvimmelhed”时，文本不存在。有没有一个陌生人可以帮助我，告诉我我做错了什么？

下面的代码：

import UIKit
import EventKit
class DagbogsindlaegViewController: UIViewController{

    @IBAction func BackToSVC(_ sender: Any){
        self.performSegue(withIdentifier: "BackToSVCSegue", sender: self)
    }

    @IBAction func ToCalenderButtonPress(_ sender: Any) {
        self.performSegue(withIdentifier: "ToCalenderSegue", sender: self)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        TitleTextField.delegate = self
        DescriptionTextField.delegate = self


        // Do any additional setup after loading the view.
    }

    @IBOutlet weak var TitleTextField: UITextField!
    @IBOutlet weak var DescriptionTextField: UITextField!

    func addEventToCalendar(title: String, description: String?, startDate: Date, endDate: Date, completion: ((_ success: Bool, _ error: NSError?) -> Void)? = nil) {
        let eventStore = EKEventStore()

        eventStore.requestAccess(to: .event, completion: { (granted, error) in
            if (granted) && (error == nil) {
                let event = EKEvent(eventStore: eventStore)
                event.title = title
                event.startDate = startDate
                event.endDate = endDate
                event.notes = description
                event.calendar = eventStore.defaultCalendarForNewEvents
                do {
                    try eventStore.save(event, span: .thisEvent)
                } catch let e as NSError {
                    completion?(false, e)
                    return
                }
                completion?(true, nil)
            } else {
                completion?(false, error as NSError?)
            }
        })
    }

    @IBAction func ButtonPressGemDagbog(_ sender: Any) {
        addEventToCalendar(title: "\(String(describing: TitleTextField.text!))", description: "\(String(describing: DescriptionTextField.text!))", startDate: NSDate() as Date, endDate: NSDate() as Date)
    }

    @IBAction func ButtonPressPopupMenu(_ sender: Any) {
        let popOverVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "PopupViewControllerID") as! PopupViewController
        self.addChild(popOverVC)
        popOverVC.view.frame = self.view.frame
        self.view.addSubview(popOverVC.view)
        popOverVC.didMove(toParent: self)
    }

}

extension DagbogsindlaegViewController : UITextFieldDelegate {
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }
}

extension DagbogsindlaegViewController : TextFraPopupDelegate {
    func Symptomer(Svimmelhed: String) {
        TitleTextField.text = Svimmelhed
    }
}

另一个视图控制器：

import UIKit

protocol TextFraPopupDelegate{
    func Symptomer(Svimmelhed: String)
}

class PopupViewController: UIViewController {

    var symptomDelegate: TextFraPopupDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        self.showAnimate()
        self.view.backgroundColor = UIColor.black.withAlphaComponent(0.8)
        // Do any additional setup after loading the view.
    }

    @IBAction func ButtonPressBackToDagbogsindlaeg(_ sender: Any) {
        self.removeAnimate()

        //self.view.removeFromSuperview()
    }
    func showAnimate()
    {
        self.view.transform = CGAffineTransform(scaleX: 1.3, y: 1.3)
        self.view.alpha = 0.0;
        UIView.animate(withDuration: 0.25, animations: {
            self.view.alpha = 1.0
            self.view.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
        });
    }

    func removeAnimate()
    {
        UIView.animate(withDuration: 0.25, animations: {
            self.view.transform = CGAffineTransform(scaleX: 1.3, y: 1.3)
            self.view.alpha = 0.0;
            }, completion:{(finished : Bool)  in
                if (finished)
                {
                    self.view.removeFromSuperview()
                }
        });
    }

    @IBAction func ButtonPressSvimmelhed(_ sender: UIButton) {
         if sender.isSelected {
            sender.isSelected = false
        } else {
            sender.isSelected = true
        }
        symptomDelegate?.Symptomer(Svimmelhed: "Svimmelhed, ")


    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    }


}

Answer 1

如评论中所述，未设置代理人。

但是，在Swift中，有一种更方便的方法将字符串传递回呈现的视图控制器，即回调闭包。您摆脱了协议和设置委托的责任

删除

~~protocol TextFraPopupDelegate{ func Symptomer(Svimmelhed: String) }~~

在PopupViewController中替换

var symptomDelegate: TextFraPopupDelegate?

使用

var callback : ((String) -> Void)?

和

@IBAction func ButtonPressSvimmelhed(_ sender: UIButton) {
     if sender.isSelected {
        sender.isSelected = false
    } else {
        sender.isSelected = true
    }
    symptomDelegate?.Symptomer(Svimmelhed: "Svimmelhed, ")
}

使用

@IBAction func ButtonPressSvimmelhed(_ sender: UIButton) {
    sender.isSelected.toggle()  
    callback?("Svimmelhed, ")
}

在DagbogsindlaegViewController的{{1}}中添加闭包
```
ButtonPressPopupMenu
```
最后删除

@IBAction func ButtonPressPopupMenu(_ sender: Any) { let popOverVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "PopupViewControllerID") as! PopupViewController self.addChild(popOverVC) popOverVC.view.frame = self.view.frame popOverVC.callback = { string in self.TitleTextField.text = string } self.view.addSubview(popOverVC.view) popOverVC.didMove(toParent: self) }

注意：

语法extension DagbogsindlaegViewController : TextFraPopupDelegate { func Symptomer(Svimmelhed: String) { TitleTextField.text = Svimmelhed } }已过时。由于Swift 3的参数标签不见了，这就足够了：(_ success: Bool, _ error: NSError?) -> Void)?
如果有本机副本，例如(Bool, NSError?) -> Void)?

NS...

请遵循命名约定，以小写字母开头的变量和函数/方法。
语法Date是双重冗余的。您从一个字符串中的一个字符串创建一个字符串。将其替换为"\(String(describing: TitleTextField.text!))"

快速使用委托从一个视图控制器向另一个视图控制器发送字符串

下面的代码：

1 个答案: