一、简介
<<UISwitch 的作用是给用户提供开关，在系统的设置界面很常见
<<继承关系：UISwitch-->UIControl-->UIView-->UIResponder-->NSObject
格式为
1-->设置开状态下的颜色（作用）
switch.onTintColor = [UIColor yellowColor]; （这是具体的例子）
@property(nullable, nonatomic, strong) UIColor *onTintColor NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;（这是说明）
二、UISwitch的属性(属性的顺序与苹果API一致)
1--> 设置开状态下的颜色
switch.onTintColor = [UIColor yellowColor];
@property(nullable, nonatomic, strong) UIColor *onTintColor NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;
2-->设置关状态下的背景颜色
switch.tintColor = [UIColor redColor];
@property(null_resettable, nonatomic, strong) UIColor *tintColor NS_AVAILABLE_IOS(6_0);
3-->设置滑块的背景颜色
switch.thumbTintColor = [UIColor blueColor];
@property(nullable, nonatomic, strong) UIColor *thumbTintColor NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
4-->设置开关处于开启状态时的图片(iOS7及之后设置无效)
switch.onImage = [UIImage imageNamed:@"on.png"];
@property(nullable, nonatomic, strong) UIImage *onImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
5-->设置开关处于关闭状态时的图片(iOS7及之后设置无效)
switch.offImage = [UIImage imageNamed:@"off.png"];
@property(nullable, nonatomic, strong) UIImage *offImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
6--> 设置switch的开关
swith.on = YES;
@property(nonatomic,getter=isOn) BOOL on;
7-->初始化方法
UISwitch *switchButton = [[UISwitch alloc] initWithFrame:CGRectMake(50, 100, 20, 10)];
-(instancetype)initWithFrame:(CGRect)frame NS_DESIGNATED_INITIALIZER;
8-->初始化方法
-(nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;
9-->设置开关状态
[switch2 setOn:YES animated:YES]
-(void)setOn:(BOOL)on animated:(BOOL)animated;
