Swift - 创建代理协议实现页面间参数传递和方法调用

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import UIKit

class ViewController: UIViewController,EditViewControllerDelegate{

    @IBOutlet weak var label: UILabel!

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    //页面跳转时

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if segue.identifier == "EditView"{

            //通过seque的标识获得跳转目标

            let controller = segue.destinationViewController as EditViewController

            //设置代理

            controller.delegate = self

            //将值传递给新页面

            controller.oldInfo = label.text

        }

    }

    func editInfo(controller:EditViewController, newInfo:String){

        label.text = newInfo;

        //关闭编辑页面

        controller.presentingViewController!.dismissViewControllerAnimated(true, completion: nil)

    }

    func editInfoDidCancer(controller:EditViewController){

        //关闭编辑页面

        controller.presentingViewController!.dismissViewControllerAnimated(true, completion: nil)

    }

}

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import UIKit

class EditViewController: UIViewController {

    @IBOutlet weak var textField: UITextField!

    var delegate:EditViewControllerDelegate?

    var oldInfo:String?

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view.

        if oldInfo  != nil{

            textField.text = oldInfo

        }

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    @IBAction func done(sender: AnyObject) {

        delegate?.editInfo(self, newInfo: textField.text)

    }

    @IBAction func cancel(sender: AnyObject) {

        delegate?.editInfoDidCancer(self)

    }

}

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protocol EditViewControllerDelegate{

    func editInfo(controller:EditViewController, newInfo:String)

    func editInfoDidCancer(controller:EditViewController)

}