仿iOS图标抖动

#import "LHViewController.h"#define angelToRandian(x) ((x)/180.0*M_PI)@interface LHViewController ()@property (strong, nonatomic) IBOutlet UIImageView *imageView;@end@implementation LHViewController- (void)viewDidLoad{  [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib.  UILongPressGestureRecognizer* longPress=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];  [self.imageView addGestureRecognizer:longPress];}-(void)longPress:(UILongPressGestureRecognizer*)longPress{  if (longPress.state==UIGestureRecognizerStateBegan) {    CAKeyframeAnimation* anim=[CAKeyframeAnimation animation];    anim.keyPath=@"transform.rotation";    anim.values=@[@(angelToRandian(-7)),@(angelToRandian(7)),@(angelToRandian(-7))];    anim.repeatCount=MAXFLOAT;    anim.duration=0.2;    [self.imageView.layer addAnimation:anim forKey:nil];    self.btn.hidden=NO;  }}- (IBAction)delete:(id)sender {  [self.imageView removeFromSuperview];  [self.btn removeFromSuperview];}@end