动画需要iOS框架

Question

我有一个简单的动画来淡出图像，但它不起作用。正在调用该方法但没有动画。项目需要哪些框架？认为这可能是问题，因为图像恰好是alpha：0没有动画。

    #import "TutorialViewController.h"

@interface TutorialViewController ()

@end

@implementation TutorialViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    [self popupImage];

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)popupImage
{
    NSLog(@"It worked");
    _imageView.hidden = NO;
    _imageView.alpha = 1.0f;
    // Then fades it away after 2 seconds (the cross-fade animation will take 0.5s)
    [UIView animateWithDuration:1
     delay:2
     options:UIViewAnimationOptionCurveEaseIn
        animations:^{
            _imageView.alpha = .0f;
        }
        completion:^(BOOL finished) {
        // Once the animation is completed and the alpha has gone to 0.0, hide the view for good
        _imageView.hidden = NO;
    }];
}