swift - 我的委托(delegate)出了什么问题？

Question

我是 swift 的新手，现在我正在学习 delegate。我认为我已经做了正确的事情，但仍然不起作用。

我正在做的是将数据从我的ViewController传递到TestViewController

View Controller :

protocol viewControllerDelegate: class {
  func viewcontrollerdelegate(setviewcontrollerdelegate: ViewController)
}

class ViewController: UIViewController ,UITextFieldDelegate {
  weak var delegate: viewControllerDelegate?

  @IBAction func nextViewandDelegate(sender: AnyObject) {
    self.delegate?.viewcontrollerdelegate(self)
  }

  override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "showTestSegue" {
      if let testViewController = segue.destinationViewController as? TestViewController {
        testViewController.address = address.text!
        testViewController.phone = phone.text!
      }
    }
  }
}

TestViewController:

class TestViewController: UIViewController {

  var name: String?
  var address: String?
  var phone: String?
  var trydelegate: String?

  override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let VC = storyboard.instantiateViewControllerWithIdentifier("viewcontroller") as! ViewController
    VC.delegate = self
  }

  override func viewWillAppear(animated: Bool) {
    addressLabel.text = address!
    phoneLabel.text = phone!
    trydelegateLabel.text = trydelegate //always nil here
  }
}

extension TestViewController:viewControllerDelegate {
  func viewcontrollerdelegate(setviewcontrollerdelegate: ViewController) {
    self.trydelegate = setviewcontrollerdelegate.address.text!
  }
}

我使用 segue 来传递地址和电话，效果很好。

但是我对委托(delegate)很不满意。谁能帮我一点忙吗？我知道这个问题对你来说有点简单。

非常感谢。

Answer 1

在viewDidLoad中的TestViewController中，您创建了新对象vc，该对象与调用prepareForSegue的对象不同> 所以这就是它不起作用的原因。

要解决此问题，请从 viewDidLoad 中删除代码:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("viewcontroller") as! ViewController
vc.delegate = self

并在prepareForSegue中添加一行:

testViewController.phone = phone.text!
// New line
self.delegate = testViewController

这应该有帮助。