怎么在iOS中实现一个图片抖动效果

#import "ViewController.h"

#define angle2Rad(angle) ((angle) / 180.0 *M_PI)

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIImageView *imageV;
@end

@implementation ViewController

- (void)viewDidLoad {
 [super viewDidLoad];

 self.imageV.userInteractionEnabled = YES;
 //添加长按手势
 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];

 [self.imageV addGestureRecognizer:longPress];
}

- (void)longPress:(UILongPressGestureRecognizer *)longPress{

 //创建动画对象
 CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];

 anim.keyPath = @"transform.rotation";
 anim.values = @[@(angle2Rad(-5)),@(angle2Rad(5))];
 anim.repeatCount = MAXFLOAT;
// anim.duration = 1;
 anim.autoreverses = YES;


 [self.imageV.layer addAnimation:anim forKey:nil];

}

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


@end

/**
 * 抖动效果
 *
 * @param view 要抖动的view
 */
- (void)shakeAnimationForView:(UIView *) view {
 CALayer *viewLayer = view.layer;
 CGPoint position = viewLayer.position;
 CGPoint x = CGPointMake(position.x + 1, position.y);
 CGPoint y = CGPointMake(position.x - 1, position.y);
 CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];
 [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault]];
 [animation setFromValue:[NSValue valueWithCGPoint:x]];
 [animation setToValue:[NSValue valueWithCGPoint:y]];
 [animation setAutoreverses:YES];
 [animation setDuration:.06];
 [animation setRepeatCount:3];
 [viewLayer addAnimation:animation forKey:nil];
}