ios UIButton

1、什么是控件：
凡是UIController类以及子类的对象才叫控件
控件会触发事件

**2、UIButton **

UIButton 是 UIControl的子类
UIControl 是 UIView的子类

2.1 作用：与用户交互，用户可以点击，并提供响应
2.2 核心属性：

title： 按键上的文字
image： 按键上的图片
backgroundImage： 背景图片
state：状态
tag 值用来辨别button
frame: 大小

2.3 高级事件：
touchUpInside 事件 在button区域内抬起

核心属性：

UIButtonTypeCustom 自定义样式
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
     UIButtonTypeSystem 系统样式
     UIButtonTypeDetailDisclosure, 圆圈i
     UIButtonTypeInfoLight, 圆圈i
     UIButtonTypeInfoDark, 圆圈i
     UIButtonTypeContactAdd, 圆圈+

UIButton大小：
button.frame = CGRectMake(100, 100, 100, 60);

UIButton 状态：
    UIControlStateNormal   
    UIControlStateHighlighted  
    UIControlStateDisabled     
    UIControlStateSelected             
    UIControlStateFocused NS_ENUM_AVAILABLE_IOS(9_0)  // Applicable only when the screen supports focus
    UIControlStateApplication              // additional flags available for application use
    UIControlStateReserved                 // flags reserved for internal framework use


UIButton 上文字以及文字颜色：
[button setTitle:@"正常" forState:UIControlStateNormal];
[button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];

UIButton 背景图片：
button.backgroundColor = [UIColor purpleColor];

UIButton 按键上的图片：
[button setImage:[UIImage imageNamed:@"abc"] forState:UIControlStateNormal]; //正常时的背景图片
注意：/*选中状态 和 失效状态必须通过代码修改*/
[button setBackgroundImage:[UIImage imageNamed:@"BTN2"] forState:UIControlStateSelected]; //选中时的背景图片
 [button setBackgroundImage:[UIImage imageNamed:@"disable"] forState:UIControlStateDisabled]; //失效状态时的背景图片
[button setImage:[UIImage imageNamed:@"stop"] forState:UIControlStateHighlighted];//鼠标移动到按钮上

tag 在父视图中的一个标示
button.tag = 100;

让button失效
button.enabled = NO;

高级事件:UIControlEvents

UIControlEventTouchDown     = 1 <<  0,      // on all touch downs
    UIControlEventTouchDownRepeat        = 1 <<  1,      // on multiple touchdowns (tap count > 1)
    UIControlEventTouchDragInside      = 1 <<  2,
    UIControlEventTouchDragOutside       = 1 <<  3,
    UIControlEventTouchDragEnter       = 1 <<  4,
    UIControlEventTouchDragExit        = 1 <<  5,//在距button顶端70像素时才会
    UIControlEventTouchUpInside       = 1 <<  6,
    UIControlEventTouchUpOutside         = 1 <<  7,
    UIControlEventTouchCancel        = 1 <<  8,

    UIControlEventValueChanged           = 1 << 12,     // sliders, etc.
    UIControlEventPrimaryActionTriggered NS_ENUM_AVAILABLE_IOS(9_0) = 1 << 13,     // semantic action: for buttons, etc.

    UIControlEventEditingDidBegin             = 1 << 16,     // UITextField
    UIControlEventEditingChanged            = 1 << 17,
    UIControlEventEditingDidEnd          = 1 << 18,
    UIControlEventEditingDidEndOnExit         = 1 << 19,     // 'return key' ending editing

    UIControlEventAllTouchEvents      = 0x00000FFF,  // for touch events
    UIControlEventAllEditingEvents          = 0x000F0000,  // for UITextField
    UIControlEventApplicationReserved       = 0x0F000000,  // range available for application use
    UIControlEventSystemReserved      = 0xF0000000,  // range reserved for internal framework use
    UIControlEventAllEvents          = 0xFFFFFFFF

[button addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
-(void)click:(id)sender{
    NSLog(@"kwgf");
}