使用 Swift 在 OSX 中的委托

Question

我正在尝试让代表使用 Swift 为 OSX 应用程序工作。

import Cocoa

class loginViewController: NSViewController {
    weak var delegate: recordViewControllerDelegate?

    override func viewDidLoad() {
      super.viewDidLoad()
      // Do view setup here.
      delegate?.trySomething()
      self.delegate?.trySomething()
      self.delegate?.testPrint("hello, is it me your looking for")
    }
}

protocol recordViewControllerDelegate: class {
  func testPrint(val: String)
  func trySomething()
}

class recordViewController: NSViewController, recordViewControllerDelegate {

  func testPrint(val: String) {
    print(val)
  }

  func trySomething() {
    print("aaa")
  }
}

一切看起来都正确，但 testPrint 和 trySomething 从未被调用，添加了断点但没有任何反应。

任何想法我错过了什么？

开车带我绕弯...

Answer 1

因为你self.delegate是nil对的？所以你应该先分配一个对象。像这样尝试，这是我的AppDelegate.swiftCocoa 演示项目中的代码：

import Cocoa

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    @IBOutlet weak var window: NSWindow!

    func applicationDidFinishLaunching(aNotification: NSNotification) {
        //This is not a good practice to call viewDidLoad directly
        //Its just a demonstration of quick way to call `recordViewControllerDelegate` protocol functions
        let vc = loginViewController()
        vc.viewDidLoad()
    }
}

//MARK:- login VC
class loginViewController: NSViewController {
    weak var delegate: recordViewControllerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        let recVC = recordViewController()
        self.delegate = recVC

        delegate?.trySomething()
        self.delegate?.trySomething()
        self.delegate?.testPrint("hello, is it me your looking for")
    }
}

protocol recordViewControllerDelegate: class {
    func testPrint(val: String)
    func trySomething()
}

class recordViewController: NSViewController, recordViewControllerDelegate {

    func testPrint(val: String) {
        print(val)
    }

    func trySomething() {
        print("aaa")
    }
}

一切正常，我可以看到打印的日志。请注意，就我而言，我viewDidLoad直接调用函数 - 只是为了向您展示委托模式的工作原理。Apple 不建议直接调用它。正确的方法是呈现视图控制器，并且viewDidLoad函数将由 OS X SDK API 调用。