swift之代理传值(delegate的用法)

目录(?)[+]

具体的代码，详见Demo：链接: http://download.csdn.net/download/riven_wn/9401970

rootViewController

[objc]
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class ViewController: UIViewController,GetMessageDelegate
{
var _button:UIButton?
var _label:UILabel?

override func viewDidLoad()
{
super.viewDidLoad()

self.title = "RootViewController"
//创建label 用来接收传过来的值
_label = UILabel(frame: CGRect(x: 50, y: 100, width: 220, height: 44))
_label?.text = "get message from next page"

_label?.textAlignment = NSTextAlignment.Center
_label?.backgroundColor = UIColor.cyanColor()
self.view.addSubview(_label!)

//创建button 点击跳转到下一个界面
_button = UIButton(frame:CGRect(x:60,y:200,width:200,height:44))
_button?.setTitle("go to next page", forState: UIControlState.Normal)
_button?.setTitleColor(UIColor.yellowColor(), forState: UIControlState.Normal)
_button?.backgroundColor = UIColor.blueColor()
_button?.addTarget(self, action: "nextPage", forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(_button!)
}

//push
func nextPage()
{
let nextVC = NextViewController()
//指定代理
nextVC.delegate = self
self.navigationController!.pushViewController(nextVC,animated:true)
}
//接收传过来的值
func getMessage(controller:NextViewController,string:String)
{
_label?.text = string
if(string == "")
{
_label?.text = "null"
}

}

}

secondViewController

[objc]
view plain
copy

print?





//创建协议
protocol GetMessageDelegate:NSObjectProtocol
{
//回调方法 传一个String类型的值
func getMessage(controller:NextViewController,string:String)
}
class NextViewController: UIViewController
{
var delegate:GetMessageDelegate?
var _textField:UITextField?
override func viewDidLoad()
{
super.viewDidLoad()
self.title = "SecondViewController"
self.view.backgroundColor = UIColor.whiteColor()

//创建textField 用来输入要传的值
_textField = UITextField(frame: CGRect(x: 60, y: 100, width: 200, height: 44))
_textField?.borderStyle = UITextBorderStyle.RoundedRect
_textField?.placeholder = "input sth to send back"
self.view.addSubview(_textField!)

//创建返回的button
var myButton = UIButton(frame:CGRect(x:60,y:200,width:200,height:44))
myButton.center = CGPointMake(160,200)
myButton.setTitle("send message back",forState:.Normal)
myButton.addTarget(self,action:"goBack",forControlEvents:.TouchUpInside)
myButton.backgroundColor = UIColor.blueColor()
self.view.addSubview(myButton)
}

func goBack()
{
//调用代理方法
if((delegate) != nil)
{
delegate?.getMessage(self,string:_textField!.text)
self.navigationController?.popToRootViewControllerAnimated(true)
}

}
}