从顶部/底部翻转UIViews

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    [UIView animateWithDuration:0.5 animations:^{
        self.transform = CGAffineTransformMakeScale(1.0, -1.0);
    }];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    [UIView animateWithDuration:0.5 animations:^{
        self.transform = CGAffineTransformMakeScale(1.0, 1.0);
    } completion:^(BOOL finished) {
        if (finished) {
            self.transform = CGAffineTransformMakeScale(1.0, 1.0);
        }
    }];
}