“#selector”的参数未引用初始化程序或方法

Question

我在委托中有一个名为 selectionDidFinish(controller:) 的方法来关闭委托提出的 viewController。呈现的控制器采用我的 Dismissable 协议，有一个 UIBarButtonItem 附加了一个应该调用 selectionDidFinish(controller:) 方法的操作，但它给了我 "Argument of '#selector' does not 'refer' to an initializer or method" 错误。

错误在此呈现UIViewController:

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.
    }
}

我已经确认 dismissalDelegate 已正确设置为 FormulasTableViewController，所以我不明白为什么它看不到 dismissalDelegate?.selectionDidFinish(self))。

我的呈现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)
    }
}

我对如何使用 #selector 进行了各种研究，我认为 this post 有所有答案，但事实并非如此。

我已经尝试过这个 Dismissable 协议，无论是否将其暴露给 @objc:

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

我也用我的 DismissalDelegate 协议试过了：

@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公开给 @objc - 这就是为什么它不起作用的原因吗？我的 #selector 真的是这里的问题吗？它与我的协议有关吗？

编辑：最终修复

基于接受的答案，我添加了一个函数来执行解雇：

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。它需要调用一个特定的选择器——一个 class 并在 class 中运行。

您需要在 class 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)
    }
}

“#selector”的参数未引用初始化程序或方法

Argument of '#selector' does not refer to an initializer or method

protocols

selector

ios

swift