- (void)viewDidLoad
{
    
    //设置红色
    UIView *viewRed = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 120, 30)];
    viewRed.backgroundColor = [UIColor redColor];
    [self.view addSubview:viewRed];
    
    //设置橙色
    UIView *viewOrange = [[UIView alloc]initWithFrame:CGRectMake(100, 130, 120, 30)];
    viewOrange.backgroundColor = [UIColor orangeColor];
    [self.view addSubview:viewOrange];
    
    //设置黄色
   
    UIView *viewYellow = [[UIView alloc]initWithFrame:CGRectMake(100, 160, 120, 30)];
    viewYellow.backgroundColor = [UIColor yellowColor];
    [self.view addSubview:viewYellow];
    
    //设置绿色
    UIView *viewGreen = [[UIView alloc]initWithFrame:CGRectMake(100, 190, 120, 30)];
    viewGreen.backgroundColor = [UIColor greenColor];
    [self.view addSubview:viewGreen];
    
    //设置青色
    UIView *viewGray = [[UIView alloc]initWithFrame:CGRectMake(100, 220, 120, 30)];
    viewGray.backgroundColor = [UIColor grayColor];
    [self.view addSubview:viewGray];
    
    //设置蓝色
    UIView *viewBlue = [[UIView alloc]initWithFrame:CGRectMake(100, 250, 120, 30)];
    viewBlue.backgroundColor = [UIColor blueColor];
    [self.view addSubview:viewBlue];

    //设置紫色
    UIView *viewPurple = [[UIView alloc]initWithFrame:CGRectMake(100, 280, 120, 30)];
    viewPurple.backgroundColor = [UIColor purpleColor];
    [self.view addSubview:viewPurple];
    
    //设置按钮
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(100, 330, 120, 30);
    [button setTitle:@"开始" forState:UIControlStateNormal];
    button.backgroundColor = [UIColor blackColor];
    button.tag = 108;
    [button addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

-(void)btnAction:(id)sender
{
    UIButton *button = (UIButton*)sender;
    if (button.tag ==108) {
        timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(doChangeColor:) userInfo:nil repeats:YES];
        [timer fire];//计时器开始
    }
    
}

-(void)doChangeColor:(id)sender
{
    NSArray *arr = self.view.subviews;//得到所有的视图
    int count = [arr count]-1;//得到计数
    UIView *firstView = [arr objectAtIndex:0];
    UIColor *firstColor = firstView.backgroundColor;
    
    for (int i=0; i<count; i++) {
        UIView *view = [arr objectAtIndex:i];
        UIView *nextView = [arr objectAtIndex:(i+1)];
        view.backgroundColor = nextView.backgroundColor;
    }
    ((UIView*)[arr objectAtIndex:count]).backgroundColor = firstColor;
    self.view.backgroundColor = [UIColor colorWithRed:(arc4random()%255/255.0) green:(arc4random()%255/255.0) blue:(arc4random()%255/255.0) alpha:(arc4random()%255/255.0)];
    
}