Question

我在委托中有一个名为selectionDidFinish(controller:)的方法来解除委托给出的viewController。所提出的控制器采用我的Dismissable协议，其UIBarButtonItem附加了一个操作，应该调用selectionDidFinish(controller:)方法，但它会给我＆＃34; ＆＃39;＃selector＆＃39;的争论没有＆＃39;引用＆＃39;初始化器或方法＆＃34;错误。

错误出现在UIViewController：

中

class FormulaInfoViewController: UIViewController, Dismissable {

    weak var dismissalDelegate: DismissalDelegate?
    override func viewDidLoad() {
        super.viewDidLoad()

    // Xcode doesn't like this selector
    navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .Plain, target: self, action: #selector(dismissalDelegate?.selectionDidFinish(self)))
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

我已确认dismissalDelegate已正确设置为FormulasTableViewController，因此我无法理解为什么它无法看到dismissalDelegate?.selectionDidFinish(self))。

我提交的UIViewController的相关代码是：

class FormulasTableViewController: UITableViewController, DismissalDelegate {

  let formulas: [CalculationFormula] = [
    CalculationFormula.epley,
    CalculationFormula.baechle,
    CalculationFormula.brzychi,
    CalculationFormula.lander,
    CalculationFormula.lombardi,
    CalculationFormula.mayhewEtAl,
    CalculationFormula.oConnerEtAl]

  override func viewDidLoad() {
    super.viewDidLoad()

    let liftInfoImage = UIImage(named: "info_icon")
    let liftInfoButton = UIBarButtonItem(image: liftInfoImage, style: .Plain, target: self, action: #selector(self.segueToFormulaInfo(_:)))
    self.navigationItem.rightBarButtonItem = liftInfoButton 
  }

  func selectionDidFinish(controller: UIViewController) {
    self.dismissViewControllerAnimated(true, completion: nil)
    }

  override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    let nav = segue.destinationViewController as! UINavigationController
    let vc = nav.topViewController as! Dismissable
    vc.dismissalDelegate = self
    }

  func segueToFormulaInfo(sender: UIButton) {
      performSegueWithIdentifier("segueToFormulaInfo", sender: self)
    }
}

我已经完成了有关如何使用#selector的各种研究，我认为this post有所有答案，但它没有。

我已经试过这个可以拒绝的协议，有没有将它暴露给@objc：

@objc protocol Dismissable: class {
    weak var dismissalDelegate: DismissalDelegate? {
        get set }
    }

我也尝试过我的DismissalDelegate协议：

@objc protocol DismissalDelegate : class {
    func selectionDidFinish(controller: UIViewController)
}

extension DismissalDelegate where Self: UIViewController {
    func selectionDidFinish(viewController: UIViewController) {
    self.dismissViewControllerAnimated(true, completion: nil)
    }
}

我无法将我的协议扩展程序公开给@objc - 这就是为什么这不起作用的原因？我的#selector真的是问题吗？它与我的协议有关吗？

编辑：最后修复

根据接受的答案，我添加了一个解雇的功能：

func dismiss() {
    dismissalDelegate?.selectionDidFinish(self)
}

然后像这样调用选择器：

    navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .Plain, target: self, action: #selector(dismiss))

Answer 1

您不能让action参数指定任意表达式。它需要调用特定的选择器 - 该类中的类和函数。

您需要在类中创建一个调用委托方法的函数：

class FormulaInfoViewController: UIViewController, Dismissable {

    weak var dismissalDelegate: DismissalDelegate?
    override func viewDidLoad() {
        super.viewDidLoad()

      navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .Plain, target: self, action: #selector(FormulaInfoViewController.selectionDidFinish)
    }  

    @objc func selectionDidFinish() {
        self.dismissalDelegate?.selectionDidFinish(self)
    }
}

＆＃39;＃selector＆＃39;的争论不是指初始化器或方法

1 个答案: