UIButton

UIButton 按钮控件 点击按钮，会触发某个事件
1）、初始化UIButton

 UIButton *button=[UIButton buttonWithType:UIButtonTypeCustom];

//这里的样式是系统自带的一个枚举（一般我们选择的样式是UIButtonTypeCustom）

typedef NS_ENUM(NSInteger, UIButtonType) {
    UIButtonTypeCustom = 0,                         // no button type
    UIButtonTypeSystem NS_ENUM_AVAILABLE_IOS(7_0),  // standard system button

    UIButtonTypeDetailDisclosure,
    UIButtonTypeInfoLight,
    UIButtonTypeInfoDark,
    UIButtonTypeContactAdd,

    UIButtonTypeRoundedRect = UIButtonTypeSystem,   // Deprecated, use UIButtonTypeSystem instead
};

2）、设置范围

button.frame=CGRectMake(140, 400, 100, 100);

3）、为button添加一个触发方法，使点击按钮触发一个方法

[button addTarget:self action:@selector(changeTitle:) forControlEvents:UIControlEventTouchUpInside];

4）、给button起个名字

[button setTitle:@"变变变" forState:UIControlStateNormal]

//这里forState也是系统自带的枚举

typedef NS_OPTIONS(NSUInteger, UIControlState) {
    UIControlStateNormal       = 0,//常规状态
    UIControlStateHighlighted  = 1 << 0,    //高亮状态              // used when UIControl isHighlighted is set
    UIControlStateDisabled     = 1 << 1,
    UIControlStateSelected     = 1 << 2,     //选中状态             // flag usable by app (see below)
    UIControlStateApplication  = 0x00FF0000,              // additional flags available for application use
    UIControlStateReserved     = 0xFF000000               // flags reserved for internal framework use
};

5)、设置字体颜色

[button setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];

6）、设置按钮点击成高亮状态

[button setTitle:@"变变变." forState:UIControlStateHighlighted];
//显示高亮

button.showsTouchWhenHighlighted=YES;

7)、为button按钮添加一个背景图片

[button setBackgroundImage:[UIImage imageNamed:@"头像1.PNG"] forState:UIControlStateNormal];

8）点击按钮变换图片（这里是高亮状态）（设置高亮状态下得图片）

[button setBackgroundImage:[UIImage imageNamed:@"头像2.png"] forState:UIControlStateHighlighted];

9）、判断button是否被点击了（按钮式否被选中）
//这里selected是一个BOOl值

button.selected=NO;

10）、设置button的背景颜色

  button.backgroundColor=[UIColor whiteColor];

11）、添加button到视图上

[self.view addSubview:button];

12）、触发方法

-(void)changeTitle:(UIButton *)sender
{
//判断是否是选中状态
if(sender.selected!=YES){
}else{
}


}