SWIFT语言实现代理传值/闭包传值

 1 class ViewController: UIViewController, ChangeTestLabelDelegate {
 2     var testLabel: UILabel?
 3     override func viewDidLoad() {
 4         super.viewDidLoad()
 5         // Do any additional setup after loading the view, typically from a nib.
 6         self.title = "swift代理传值";
 7         let rightButtonItem: UIBarButtonItem = UIBarButtonItem(title: "下一页", style: .Plain, target: self, action: "nextPage");
 8         self.navigationItem.rightBarButtonItem = rightButtonItem;
 9         
10         testLabel = UILabel(frame: CGRectMake(0, 200, 320, 50));
11         testLabel?.layer.borderColor = UIColor.redColor().CGColor;
12         testLabel?.layer.borderWidth = 1;
13         testLabel?.layer.cornerRadius = 5;
14         testLabel?.text = "学雨燕";
15         testLabel?.textAlignment = NSTextAlignment.Center;
16         self.view.addSubview(testLabel!);
17     }
18 
19     func nextPage() {
20         let secondVC: SecondViewController = SecondViewController();
21         secondVC.delegate = self;
22         self.navigationController?.pushViewController(secondVC, animated: true);
23     }
24     
25     func changeLabelText(controller: SecondViewController, string: String) {
26         testLabel?.text = string;
27         println("testLabel.text == \(string)");
28     }
29     override func didReceiveMemoryWarning() {
30         super.didReceiveMemoryWarning()
31         // Dispose of any resources that can be recreated.
32     }
33 
34 
35 }

 1 import Foundation
 2 import UIKit
 3 
 4 //定义协议改变Label内容
 5 protocol ChangeTestLabelDelegate: NSObjectProtocol {
 6     //回调方法
 7     func changeLabelText(controller: SecondViewController, string: String);
 8 }
 9 
10 class SecondViewController: UIViewController {
11     var temp = 0;
12     var delegate: ChangeTestLabelDelegate?
13     override func viewDidLoad(){
14         super.viewDidLoad()
15         self.title = "SecondViewController";
16         self.view.backgroundColor = UIColor.yellowColor();
17         let rect = CGRect(x:50,y:200,width:150,height:50);
18         var myButton = UIButton(frame:rect);
19         myButton.center = CGPointMake(160,200);
20         myButton.setTitle("改变Label内容",forState:.Normal);
21         myButton.setTitleColor(UIColor.redColor(), forState: UIControlState.Normal);
22         myButton.addTarget(self,action:"btnClicked",forControlEvents:.TouchUpInside);
23         self.view.addSubview(myButton);
24         
25     }
26     func btnClicked(){
27         temp++;
28         println("我被点击了\(temp)次.")
29         if(delegate != nil) {
30             delegate?.changeLabelText(self, string: "学雨燕" + "\(temp)");
31         }    
32     }
33 }

 1 import UIKit
 2 
 3 class ViewController: UIViewController {
 4     var testLabel: UILabel?
 5     override func viewDidLoad() {
 6         super.viewDidLoad()
 7         // Do any additional setup after loading the view, typically from a nib.
 8         self.title = "swift闭包传值";
 9         let rightButtonItem: UIBarButtonItem = UIBarButtonItem(title: "下一页", style: .Plain, target: self, action: "nextPage");
10         self.navigationItem.rightBarButtonItem = rightButtonItem;
11         
12         testLabel = UILabel(frame: CGRectMake(0, 200, 320, 50));
13         testLabel?.layer.borderColor = UIColor.redColor().CGColor;
14         testLabel?.layer.borderWidth = 1;
15         testLabel?.layer.cornerRadius = 5;
16         testLabel?.text = "swift闭包";
17         testLabel?.textAlignment = NSTextAlignment.Center;
18         self.view.addSubview(testLabel!);
19     }
20 
21     func nextPage() {
22         let secondVC: SecondViewController = SecondViewController();
23         secondVC.initWithClosure(someFunctionThatTakesAClosure);
24         self.navigationController?.pushViewController(secondVC, animated: true);
25     }
26     func someFunctionThatTakesAClosure(string:String) -> Void {
27         testLabel!.text = string
28     }
29     override func didReceiveMemoryWarning() {
30         super.didReceiveMemoryWarning()
31         // Dispose of any resources that can be recreated.
32     }
33 
34 
35 }

 1 import Foundation
 2 import UIKit
 3 //类似于OC中的typedef
 4 typealias changeLabelTextClosure = (string:String) -> Void;
 5 
 6 class SecondViewController: UIViewController {
 7     var myClosure: changeLabelTextClosure?   //声明一个闭包
 8     var temp = 0;
 9     func initWithClosure(closure: changeLabelTextClosure?) {
10         myClosure = closure; //将函数指针赋值给myClosure闭包，该闭包中涵盖了someFunctionThatTakesAClosure函数中的局部变量等的引用
11     }
12     override func viewDidLoad(){
13         super.viewDidLoad()
14         self.title = "SecondViewController";
15         self.view.backgroundColor = UIColor.yellowColor();
16         let rect = CGRect(x:50,y:200,width:150,height:50);
17         var myButton = UIButton(frame:rect);
18         myButton.center = CGPointMake(160,200);
19         myButton.setTitle("改变Label内容",forState:.Normal);
20         myButton.setTitleColor(UIColor.redColor(), forState: UIControlState.Normal);
21         myButton.addTarget(self,action:"btnClicked",forControlEvents:.TouchUpInside);
22         self.view.addSubview(myButton);
23         
24     }
25     func btnClicked(){
26         temp++;
27         println("我被点击了\(temp)次.")
28             if (myClosure != nil){
29                 //闭包隐式调用someFunctionThatTakesAClosure函数：回调。
30                 myClosure!(string: "闭包传值\(temp)");
31             }
32     }
33 }