iOS CAKeyframeAnimation 示例

view抖动示例：

//角度#define Angle2Radian(angle) ((angle) / 180.0 * M_PI)- (void)start{    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];    anim.keyPath = @"transform.rotation";        anim.values = @[@(Angle2Radian(-15)),  @(Angle2Radian(15)), @(Angle2Radian(-15))];    anim.duration = 0.25;    // 动画的重复执行次数    anim.repeatCount = MAXFLOAT;        // 保持动画执行完毕后的状态    anim.removedOnCompletion = NO;    anim.fillMode = kCAFillModeForwards;        [self.iconView.layer addAnimation:anim forKey:@"shake"];}- (void)stop{    [self.iconView.layer removeAnimationForKey:@"shake"];}