从一个视图控制器向多个视图控制器发送“StringValue”的可能方法?

发送通知可能是一种解决方案,但我认为从架构的角度来看,这要好得多(更易于维护和扩展等)。 例如,使用观察者(多个代理)模式。创建这样的协议。实施后,考虑 this 用于解析阵列的保留周期。

protocol DatePickerProtocol {
    func dateStringChanged(to newString: String)
}

class CustomDatePickerViewController: UIViewController {
    ...
    var delegates: [DatePickerProtocol]?

    @IBAction func saveDateAction(_ sender: Any) {
        .....
        if let delegates {
            for delegate in delegates {
                delegate.dateStringChanged(to: "selectedDate string")
            }
        }
        ...
    }
}

class SelectDateViewController: UIViewController, DatePickerProtocol {
    ...
    // get a reference to CustomDatePickerViewController and register this class like:
    dataPickerViewController.delegates.append(self)

    func dateStringChanged(to newString: String) {
        // Do whatever with the new date string
    }
}

你可以开一个 通知 具有 通知中心 您可以在viewController中添加观察者并更新标签。

当您想要发送日期时,可以发布如下通知:

NotificationCenter.default.post(name: "SelectedDate", object: nil, userInfo: ["selectedDate": Date that you selected])

之后,您可以在另一个viewController中添加观察者,以便接收该通知。

NotificationCenter.default.addObserver(self, selector: #selector(datePicked(notification:)), name: "SelectedDate", object: nil)


@objc func datePicked(notification: Notification) {
      //get the date here
      print(notification.userInfo?["selectedDate"])
}

最后,我采纳了@Bence Pattogato的建议,解决了我的问题。请参阅以下更新的代码。

我创建了一个协议类。文件名为CustomDatePickerDelegate。敏捷的

protocol CustomDatePickerDelegate {
        func CustomDateSeletced(value: String)
}

现在,这是我在CustomDatePickerViewController类中更新的代码。

import UIKit

class CustomDatePickerViewController: UIViewController {


    @IBOutlet var myDatePicker: UIDatePicker!
    var delegate: CustomDatePickerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        view.frame.size.height =  UIScreen.main.bounds.height
        self.view.backgroundColor = UIColor.black.withAlphaComponent(0.6)
    }


    @IBAction func saveDateAction(_ sender: Any) {

        myDatePicker.datePickerMode = UIDatePickerMode.date
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd MMM yyyy"
        let saveDate = dateFormatter.string(from: myDatePicker.date)
        print("selectedDate",saveDate)
        delegate?.CustomDateSeletced(value: saveDate) **//This is the way i am saving date value  from date picker**
        self.removeAnimate()
        self.navigationController?.navigationBar.isHidden = false

    }
    func showAnimate()
    {
        self.view.transform = CGAffineTransform(scaleX: 1.3, y: 1.3)
        self.view.alpha = 0.0;
        UIView.animate(withDuration: 0.10, animations: {
            self.view.alpha = 1.0
            self.view.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
        });
    }

    func removeAnimate()
    {
        UIView.animate(withDuration: 0.05, 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()
            }
        });
    }

}

现在,我在SelectDateViewController中使用此委托。请参阅以下更新的代码。

  import UIKit

class SelectDateViewController: UIViewController {

    @IBOutlet var selectedDateLabel: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()

    }
    @IBAction func selectDateAction(_ sender: Any) {

        let popOverVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "CustomDatePickerViewController") as! CustomDatePickerViewController
        self.addChildViewController(popOverVC)
        self.view.addSubview(popOverVC.view)
        popOverVC.view.frame = view.bounds
        popOverVC.delegate = self
        popOverVC.didMove(toParentViewController: self)

        self.navigationController?.navigationBar.isHidden = true
    }
}
extension SelectDateViewController:CustomDatePickerDelegate
{
    func CustomDateSeletced(value: String) {
        selectedDateLabel.text = value
    }    
}

代码清理目的我正在使用那边的扩展。

创建 DataSource 并在您需要的视图中阅读它们:

class DateDataSource {
    var date : Date?
    static let sharedInstance = DateDataSource()
    private init() {}
}

当您从选取器中获取日期时,您会将其设置为:

DateDataSouce.sharedInstance.date = theDate

然后在需要显示它的视图中,您将调用

let theDate = DateDataSouce.sharedInstance.date