首先，UIControlEvents有这个几种：UIControlEventTouchDown           = 1 <<  0,      // on all touch downsUIControlEventTouchDownRepeat     = 1 <<  1,      // on multiple touchdowns (tap count > 1)UIControlEventTouchDragInside     = 1 <<  2,UIControlEventTouchDragOutside    = 1 <<  3,UIControlEventTouchDragEnter      = 1 <<  4,UIControlEventTouchDragExit       = 1 <<  5,UIControlEventTouchUpInside       = 1 <<  6,UIControlEventTouchUpOutside      = 1 <<  7,UIControlEventTouchCancel         = 1 <<  8,---------------------------------------------------------------------------------------------------UIControlEventValueChanged        = 1 << 12,     // sliders, etc.UIControlEventEditingDidBegin     = 1 << 16,     // UITextFieldUIControlEventEditingChanged      = 1 << 17,UIControlEventEditingDidEnd       = 1 << 18,UIControlEventEditingDidEndOnExit = 1 << 19,     // ‘return key‘ ending editingUIControlEventAllTouchEvents      = 0x00000FFF,  // for touch eventsUIControlEventAllEditingEvents    = 0x000F0000,  // for UITextFieldUIControlEventApplicationReserved = 0x0F000000,  // range available for application useUIControlEventSystemReserved      = 0xF0000000,  // range reserved for internal framework useUIControlEventAllEvents           = 0xFFFFFFFFhttp://blog.163.com/cz_jdton/blog/static/92732504201282543017312/在这个网友的日志里看到一些内容，大体如下：UIControlEventTouchDown单点触摸按下事件：用户点触屏幕，或者又有新手指落下的时候。UIControlEventTouchDownRepeat多点触摸按下事件，点触计数大于1：用户按下第二、三、或第四根手指的时候。UIControlEventTouchDragInside当一次触摸在控件窗口内拖动时。UIControlEventTouchDragOutside当一次触摸在控件窗口之外拖动时。UIControlEventTouchDragEnter当一次触摸从控件窗口之外拖动到内部时。UIControlEventTouchDragExit当一次触摸从控件窗口内部拖动到外部时。 UIControlEventTouchUpInside所有在控件之内触摸抬起事件。UIControlEventTouchUpOutside所有在控件之外触摸抬起事件(点触必须开始与控件内部才会发送通知)。UIControlEventTouchCancel所有触摸取消事件，即一次触摸因为放上了太多手指而被取消，或者被上锁或者电话呼叫打断。UIControlEventTouchChanged当控件的值发生改变时，发送通知。用于滑块、分段控件、以及其他取值的控件。你可以配置滑块控件何时发送通知，在滑块被放下时发送，或者在被拖动时发送。UIControlEventEditingDidBegin当文本控件中开始编辑时发送通知。UIControlEventEditingChanged当文本控件中的文本被改变时发送通知。UIControlEventEditingDidEnd当文本控件中编辑结束时发送通知。UIControlEventEditingDidOnExit当文本控件内通过按下回车键（或等价行为）结束编辑时，发送通知。UIControlEventAlltouchEvents通知所有触摸事件。UIControlEventAllEditingEvents通知所有关于文本编辑的事件。UIControlEventAllEvents通知所有事件。