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Ios 在Swift中未调用协议委托方法

ios swift swift3

Ios 在Swift中未调用协议委托方法,ios,swift,swift3,Ios,Swift,Swift3,未调用协议委托方法 第一视图控制器代码 class ViewController: UIViewController,customDelegate { var seconviewcontroller : SecondViewController = SecondViewController() @IBOutlet weak var Label: UILabel! override func viewDidLoad() { super.viewDidLoad()

未调用协议委托方法

第一视图控制器代码

class ViewController: UIViewController,customDelegate {

  var seconviewcontroller : SecondViewController = SecondViewController()
  @IBOutlet weak var Label: UILabel!
    override func viewDidLoad() {
        super.viewDidLoad()

    seconviewcontroller.delegate = self
}
func didSelectData(_ result: String) {

    Label.text = result
  print("Didselect Data Call")

}

import UIKit
protocol customDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
     var delegate: customDelegate?

@IBOutlet weak var secondbutton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction func secondbuttonclick(_ sender: Any) {
     let selectedItem = "naga"

     delegate?.didSelectData(selectedItem)
}
第二视图控制器代码

class ViewController: UIViewController,customDelegate {

  var seconviewcontroller : SecondViewController = SecondViewController()
  @IBOutlet weak var Label: UILabel!
    override func viewDidLoad() {
        super.viewDidLoad()

    seconviewcontroller.delegate = self
}
func didSelectData(_ result: String) {

    Label.text = result
  print("Didselect Data Call")

}

import UIKit
protocol customDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
     var delegate: customDelegate?

@IBOutlet weak var secondbutton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction func secondbuttonclick(_ sender: Any) {
     let selectedItem = "naga"

     delegate?.didSelectData(selectedItem)
}
如何调用func didSelectData请帮助我

，因此基本上第行的
var seconviewcontroller:SecondViewController=SecondViewController（）
与推送视图控制器实例不同

您正在创建一个单独的
SecondViewController
实例，因此在使用类似于push的push对象进行push时，您已经完成了委托self

let secondVCInstance = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController
secondVCInstance.delegate = self
self.navigationController?.pushViewController(secondVCInstance, animated: true)
注意：-每个对象都有自己的属性

因此，基本上第行的
var seconviewcontroller:SecondViewController=SecondViewController（）
与您的视图控制器实例不同

您正在创建一个单独的
SecondViewController
实例，因此在使用类似于push的push对象进行push时，您已经完成了委托self

let secondVCInstance = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController
secondVCInstance.delegate = self
self.navigationController?.pushViewController(secondVCInstance, animated: true)
注意：-每个对象都有自己的属性

，因为您已经使用segue在视图之间导航了。您也可以在本例中使用它。我将以下内容作为代码示例，以便您可以跟踪自己以检测代码中的问题

第一视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第二视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
正如您已经使用segue在视图之间导航一样。您也可以在本例中使用它。我将以下内容作为代码示例，以便您可以跟踪自己以检测代码中的问题

第一视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第二视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第一视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第二视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第一视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
第二视图控制器

import UIKit

class ViewController: UIViewController, SecondVCDelegate {
    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let secondVC = segue.destination as? SecondViewController {
            secondVC.delegate = self
        }
    }        

    func didSelectData(_ result: String) {
        label.text = result
        print(result)
    }
}

import UIKit

protocol SecondVCDelegate: class {
    func didSelectData(_ result: String)
}

class SecondViewController: UIViewController {
    @IBOutlet weak var button: UIButton!

    weak var delegate: SecondVCDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonTapped(_ sender: UIButton) {
        delegate?.didSelectData("My result")
        dismiss(animated: true, completion: nil)
    }
}
别担心，很高兴这能帮上忙。我必须将第一视图控制器的数据传递给第二视图控制器我知道segue在那里，但我必须使用协议委托请帮助我如何计算第一视图控制器中的学生人数我必须将该数据传递给第二视图控制器如何在没有segue/用户默认值的情况下传递我想要打印它第二个视图控制器的计数如果我可以将该实例作为全局实例，我将访问另一个控制器中的学生计数有多种方法可以将数据从一个视图控制器传递到另一个视图控制器。如果您不再使用导航功能，从第一个VC开始，您只需执行
seconVC.dataList=self.dataList
和
navigationController？.pushViewController（secondVC，动画：true）
。无需担心，很高兴这能帮上忙。我必须将第一视图控制器的数据传递给第二视图控制器我知道segue在那里，但我必须使用协议委托请帮助我如何计算第一视图控制器中的学生人数我必须将该数据传递给第二视图控制器如何在没有segue/用户默认值的情况下传递我想要打印它第二个视图控制器的计数如果我可以将该实例作为全局实例，我将访问另一个控制器中的学生计数有多种方法可以将数据从一个视图控制器传递到另一个视图控制器。如果不再使用导航功能，从第一个VC开始，您只需执行
seconVC.dataList=self.dataList
和
navigationController？.pushViewController（secondVC，动画：true）
。