下面演示如何创建开关，以及监听它值的改变，代码如下：

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class ViewController : UIViewController {      var uiswitch: UISwitch !;      override func viewDidLoad() {              super .viewDidLoad()              uiswitch = UISwitch ()              //设置位置（开关大小无法设置）              uiswitch.center= CGPointMake (100,50);              //设置默认值              uiswitch.on= true ;              uiswitch.addTarget( self , action: Selector ( "switchDidChange" ),              forControlEvents: UIControlEvents . ValueChanged )              self .view.addSubview(uiswitch);      }        func switchDidChange(){              //打印当前值              println (uiswitch.on)      } }