swift 代理传值

swift中的代理传值跟oc中的用法基本一样，都是用于反向传值，这里假设a界面向b界面传值为正向传值，则：

在b界面

//设置代理方法

protocol BaseOneControllerDelegate {

          func sendMessage(message:NSString?)

}

class BaseOneController: UIViewController {

//定义代理属性

var delegate:BaseOneControllerDelegate?

override func viewDidLoad() {

super.viewDidLoad()

self.view.backgroundColor = UIColor.white

let segMentArray = ["代理返回"]

segment = UISegmentedControl(items: segMentArray)

segment.frame = CGRect.init(x: 0, y: 100, width: kWidth, height: 30)

//添加动作事件

segment.addTarget(self, action: #selector(BaseOneController.segmentAction(sender:)), for: UIControlEvents.valueChanged)

self.view.addSubview(segment)

}

func segmentAction(sender:UISegmentedControl) {

print("我点击了第 \(sender.selectedSegmentIndex) 选项")

  if sender.selectedSegmentIndex == 0 {

//完成代理事件

      if (delegate != nil) {

        self.delegate?.sendMessage(message: "代理传值成功，点击返回按钮")

      _ = self.navigationController?.popViewController(animated: true)

  }

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

// Dispose of any resources that can be recreated.

}

}

在a界面，首先添加b界面的代理BaseOneControllerDelegate

let baseOne = BaseOneController()

//跳转的时候记得设置好代理

baseOne.delegate = self

self.navigationController?.pushViewController(baseOne, animated: true)

//代理方法

func sendMessage(message: NSString?) {

print("\(message)")

}