iOS - Animate only the 'appendPath' of an UIBezierPath - ios

Question

there are a lot of examples how to animate along a UIBezierPath. But i can't figure it out, how to animate only the appendPath of an UIBezierPath.
In my case i have the following example:
// Create path from view controller
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:
CGRectMake(0, 0, tutorialController.bounds.size.width,
tutorialController.bounds.size.height) cornerRadius:0];
// Create circle path
UIBezierPath *circlePath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(x, y, 2.0*radius, 2.0*radius) cornerRadius:radius];
[path appendPath:circlePath];
[path setUsesEvenOddFillRule:YES];
// Create spot layer
spotLayer = [CAShapeLayer layer];
spotLayer.path = path.CGPath;
spotLayer.fillRule = kCAFillRuleEvenOdd;
spotLayer.fillColor = [UIColor blackColor].CGColor;
spotLayer.opacity = 0.90;
So basically its a circle inside a rect and i now want to animate only the circle. In all attempts the rect was also moved.
Here is my example, how i can animate "along" a path
CGPoint pathStart = CGPointMake(96.000000, 226.000000);
CGPoint pathEnd = CGPointMake(120.000000, 300.000000);
[circlePath moveToPoint:pathStart];
[circlePath addLineToPoint:pathEnd];
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim.path = circlePath.CGPath;
anim.duration = 5.0;
anim.calculationMode = kCAAnimationPaced;
[spotLayer addAnimation:anim forKey:#"bezierPathAnim"];
But that is not what i want...
What i want to do is, to move my circle path (which is an appended path of a rectangle path) via animation
Does anybody has some ideas?
Regards

Answer 1

I solved my Problem :-)
Here is the solution...
// If there is an old path animate to the new path
if(oldPath != nil){
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"path"];
[anim setFromValue:(__bridge id)oldPath];
[anim setToValue:(__bridge id)[path CGPath]];
[anim setDuration:0.3];
[anim setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[spotLayer addAnimation:anim forKey:#"path"];
}
First of all i kept the oldPath (starting point) and then animate to the new setted path.