限制superview中的视图

I'm trying to move a UIView - "A" (Subview) inside another UIView - "B" (SuperView) using the touches moved method. I'm able to move the UIView outside the superview. I want to restrict the UIView inside the Superview bounds. Is there any way there can be a generic method to test if the subview is inside the visible rect of the superview ???I'm trying to move a UIView - "A" (Subview) ins