旋转动画

POPBasicAnimation *basicAnimation = [POPBasicAnimation animationWithPropertyNamed:kPOPLayerRotation]; // 绕z轴旋转
//    basicAnimation.fromValue = @(M_PI/180*360); // 逆时针旋转，每次旋转360度
    basicAnimation.toValue = @(M_PI/180*360); // 顺时针旋转，每次旋转360度
    basicAnimation.duration = 20; // 完成单次动画需要的时间，单位：秒
    basicAnimation.beginTime = CACurrentMediaTime(); // 马上开始
    basicAnimation.repeatCount = CGFLOAT_MAX; // 动画不断重复

    // 调速
    basicAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

    // 将动画添加到图层上
    [self.avatarImageView.layer pop_addAnimation:basicAnimation forKey:nil];