图片绕中心点旋转

• (UIImageView *)rotate360DegreeWithImageView:(UIImageView *)imageView{
  CABasicAnimation *animation = [ CABasicAnimation
  animationWithKeyPath: @"transform" ];
  animation.fromValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];

  //围绕Z轴旋转，垂直与屏幕
  animation.toValue = [ NSValue valueWithCATransform3D:

                     CATransform3DMakeRotation(M_PI, 0.0, 0.0, 1.0) ];
  

  animation.duration = 0.5;
  //旋转效果累计，先转180度，接着再旋转180度，从而实现360旋转
  animation.cumulative = YES;
  animation.repeatCount = 1000;

  //在图片边缘添加一个像素的透明区域，去图片锯齿
  CGRect imageRrect = CGRectMake(0, 0,imageView.frame.size.width, imageView.frame.size.height);
  UIGraphicsBeginImageContext(imageRrect.size);
  [imageView.image drawInRect:CGRectMake(1,1,imageView.frame.size.width-2,imageView.frame.size.height-2)];
  imageView.image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  [imageView.layer addAnimation:animation forKey:nil];
  return imageView;
  }

animation.repeatCount = 1000;
这个你要想一直旋转，设置一个无穷大就得了

停止的话直接这样就停止了
[self.view.layer removeAllAnimates];

from http://blog.sina.com.cn/s/blog_9075354e0101t72s.html