用处：开关空间，用于处理两种状态

-(void)viewDidLoad

{

  [super viewDidLoad];

  CGRect frame = CGRectMake(20,20,0,0);

  self.switch = [[UISwitch alloc]initWithFrame:frame];

  //设置初始状态

 [self.switch setOn:YES];

//底色颜色

self.switch.tintColor = [UIColor redColor];

//开启底色颜色

self.switch.ontintColor = [UIColor brownColor];

//滑块颜色

self.switch.thumbtintColor = [UIColor greenColor];

//添加值改变事件方法

[self.switch addTarget:self action:@selector(change:) forControlEvents:UIControlEventValueChanged];

[self.view addSubView:self.switch];

}

-(IBAction) change:(id)sender

{

  UISwitch* switch = (UISwitch*)sender;

  if(switch.on)

      {NSLog(@"set on");}

  else

      {NSLog(@"set off");}

}