Can we animate "shadowOpacity" using UIView animation block?

We are pretty much used to the UIView animation block for properties like frame and transforms.

+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations

Lets say there is a UIView *userView and you would like to show animation of shadow turned on or off.

    [UIView animateWithDuration:01 animations:^{

        if(showShadow){

            self.userView.layer.shadowOpacity=0.5;

        }else{

            self.userView.layer.shadowOpacity=0.0;

        }

    }];

The above code is not going to work. UIView animates  frame, bounds, center, tranform, alpha, background Color and contentStretch.i.e simple animation.

The View Programming guide - Animations url gives more details on it. 

It does not animate layer properties. So , we will have to use CABasicAnimation. The following code will work perfectly fine.

   float start=0.5,end=0.0;//example

    CABasicAnimation *animation  = [CABasicAnimation animation];

    animation.fromValue= @(start);

    animation.toValue= @(end);

    animation.duration = 1.0;

    [self.userView.layer addAnimation:animation forKey:@"shadowOpacity"];

    self.userView.layer.shadowOpacity=end;