控件视图以及控件视图的事件处理

• UIControl
• 作用：具有处理事件处理的控件父类
• 事件响应的3种形式：基于触摸，基于值，基于编辑

UIView ------ UIControl------UIButton

UIDatePicker

UIPageControl

UISegmentedControl

UITextField

UISlider

UISwitch

• 常用方法

- (void)addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents//添加一个事件- (void)removeTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents//移除一个事件

• 事件处理

    //用户按下时触发    UIControlEventTouchDown    //点击次数大于1时触发    UIControlEventTouchDownRepeat    //当触摸在控件内拖动时触发    UIControlEventTouchDragInside    //当触摸在控件之外拖动时触发    UIControlEventTouchDragOutside    //当触摸从控件之外拖动到内部时触发    UIControlEventTouchDragEnter    //当触摸从控件内部拖动到外部时触发    UIControlEventTouchDragExit    //控件之内触摸抬起时    UIControlEventTouchUpInside    //控件之外触摸抬起时    UIControlEventTouchUpOutside    //触摸取消事件，设备被上锁或者电话呼叫打断    UIControlEventTouchCancel        //当控件的值发生改变时。用于滑块，分段控件等控件。    UIControlEventValueChanged             // sliders, etc.    //文本控件开始编辑时    UIControlEventEditingDidBegin          // UITextField    //文本控件的文本被改变    UIControlEventEditingChanged    //文本控件中编辑结束    UIControlEventEditingDidEnd    //文本控件内通过按下回车键结束编辑    UIControlEventEditingDidEndOnExit      // 'return key' ending editing    //所有触摸事件    UIControlEventAllTouchEvents           // for touch events    //文本编辑的所有事件    UIControlEventAllEditingEvents         // for UITextField    //    UIControlEventApplicationReserved      // range available for application use    //    UIControlEventSystemReserved           // range reserved for internal framework use    //所有事件    UIControlEventAllEvents