iOS开发技巧系列---使用链式编程和Block来实现UIAlertView

1 //使用普通的赋值模式
2 txtUserName.placeHolder = "请输入用户名"
3 txtUserName.font = UIFont.systemFont(15)
4 txtUserName.textColor = UIColor.GrayColor()
5 //使用链式编程的语句
6 txtUserName.setPlaceHolder("请输入用户名").setFont(15).setTextColor(UIColor.GrayColor())

 1 class BlockAlert:UIAlertView,UIAlertViewDelegate{
 2     var completion:((buttonIndex:Int,alert:UIAlertView)->Void)? //定义各个Block用来回调,其参数名和Delegate回调的函数参数名一至
 3     var willDismissBlock:((buttonIndex:Int,alert:UIAlertView)->Void)?
 4     var didDismissBlock:((buttonIndex:Int,alert:UIAlertView)->Void)?
 5     var didPresentBlock:((alert:UIAlertView)->Void)?
 6     var willPresentBlock:((alert:UIAlertView)->Void)?
 7     var alertWithCancelBlock:((alert:UIAlertView)->Void)?
 8     override init(frame: CGRect) {
 9         super.init(frame: frame)
10         self.delegate = self //将delegate设为自己
11     }
12     func alertView(alertView: UIAlertView, clickedButtonAtIndex buttonIndex: Int) {
13         if let block = completion{ //最主要的Block,当用户点了按钮时回调,先要判断这个Block存在不?
14             block(buttonIndex: buttonIndex, alert: alertView)
15         }
16     }
17     func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int) {
18         if let block = didDismissBlock{//其他根据相应的Delegate回调函数依次调用各个Block
19             block(buttonIndex: buttonIndex, alert: alertView)
20         }
21     }
22     func alertView(alertView: UIAlertView, willDismissWithButtonIndex buttonIndex: Int) {
23         if let block = willDismissBlock{
24             block(buttonIndex: buttonIndex, alert: alertView)
25         }   
26     }
27     // 其他几个委托方法也省略了,原理都是一样的
28     required init?(coder aDecoder: NSCoder) {
29         fatalError("init(coder:) has not been implemented")
30     }
31 }

 1 extension UIAlertView {
 2     static func setMessage(msg:String)->UIAlertView{//在这里设定这个为静态函数,在里面实例化一个BlockAlert对象,再返回该对象
 3         let alert = BlockAlert()
 4         alert.message = msg
 5         return alert
 6     }
 7 
 8     func addAlertStyle(style:UIAlertViewStyle)->UIAlertView{ //直接在各个函数中封装一些操作.再返回自身
 9         self.alertViewStyle = style
10         return self
11     }
12 
13     func addTitle(title:String)->UIAlertView{
14         self.title = title
15         return self
16     }
17 
18     func addFirstButton(btnTitle:String)->UIAlertView{
19         self.addButtonWithTitle(btnTitle)
20         return self
21     }
22 
23     func addSecondButton(btnTitle:String)->UIAlertView{
24         self.addButtonWithTitle(btnTitle)
25         return self
26     }
27 
28     func addButtons(btnTitles:[String])->UIAlertView{
29         for title in btnTitles{
30             self.addButtonWithTitle(title)
31         }
32         return self
33     }
34 
35     func addButtonClickEvent(clickButton:((buttonIndex:Int,alert:UIAlertView)->Void)?)->UIAlertView{
36         if let alert = self as? BlockAlert{//对于block,先要判断它是不是BlockAlert,如果是的话才添加该block,后面都是这种操作
37             alert.completion = clickButton
38         }
39         return self
40     }
41 
42     //这里也是省略了部分函数,因为原理都是一样的
43     func addAlertCancelEvent(event:((alert:UIAlertView)->Void)?)->UIAlertView{
44         if let alert = self as? BlockAlert{
45             alert.alertWithCancelBlock = event
46         }
47         return self
48     }
49 
50 
51     func alertWithButtonClick(clickButton:((buttonIndex:Int,alert:UIAlertView)->Void)?){
52         if let alert = self as? BlockAlert{ //这个为终结函数,没有返回值,在里面直接调用了show()方法.
53             alert.completion = clickButton
54             alert.show()
55         }
56     }
57 }

UIAlertView.setMessage("这里要设置信息").addTitle("我是标题").addFirstButton("取消").addSecondButton("确认").alertWithButtonClick { (buttonIndex, alert) -> Void in
            print("你按下了第\(buttonIndex)个按键")
            //你按下了第1个按键
            //你按下了第0个按键
        }

1    UIAlertView.setMessage("这里要设置信息").addTitle("我是标题").addFirstButton("取消").addSecondButton("确认").addWillPresentEvent { (alert) in
2              print("the alertView will present")
3         }.addDidPresentEvent { (alert) in
4             print("the alertView did present")
5         }.alertWithButtonClick { (buttonIndex, alert) in
6               print("你按下了第\(buttonIndex)个按键")
7         }

1  UIAlertView.setMessage("这里要设置信息").addTitle("我是标题").addFirstButton("取消").addSecondButton("确认").addAlertStyle(.LoginAndPasswordInput).addDidPresentEvent { (alert) in
2             print("the alertView did present")
3         }.alertWithButtonClick { (buttonIndex, alert) in
4             let txt1 = alert.textFieldAtIndex(0)?.text
5             let txt2 = alert.textFieldAtIndex(1)?.text
6             print("userName:\(txt1) password:\(txt2)")
7             //打印出the alertView did present
8             //userName:Optional("111") password:Optional("222")
9         }