在A设置了B中的一个imageView的动画，A presentViewController B

Studio
#1

有AViewController和BViewController，在A中alloc一个imageView，

CABasicAnimation *translation2 = CABasicAnimation animationWithKeyPath:@"position"];

translation2.timingFunction = CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

translation2.fromValue = NSValue valueWithCGPoint:CGPointMake(160, 95)];

translation2.toValue = NSValue valueWithCGPoint:CGPointMake(160, 345)];

translation2.autoreverses = YES;

translation2.duration = 3;

translation2.repeatCount = 100;

imageView.layer addAnimation:translation2 forKey:@"translation2"

［B.view addSubview:imageView］

然后A presentViewController:B animated:YES completion:Nil

在B中显示出来的imageView没有动画效果怎么回事？？？

iOS6.1系统中有动画，iOS7中没有