In COCOA I uses fallwoing code for animation of an object on UIView.
[UIView beginAnimations:nil context:nil];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:0.8];
[ShieldImage setBounds:CGRectMake(obj.x, obj.y, width, height)];
// Here I will use scale property of sprite
ShieldImage.center=CGPointMake(obj.x, obj.y);
ShieldImage.alpha = alphavalue ;
[UIView commitAnimations];
Does any one know is there any property similar to above one to animate object on layer for specific time interval?