I have an IPhone application in which i am adding a custom view inspite of a navigation bar view.i am hiding that custom view in the normal case and unhide it whenever needed.no
You have to enable user interaction of curtainsView.
Try this:
[curtainsView setUserInteractionEnabled:YES]
From Apple's UIImageView Class Reference
New image view objects are configured to disregard user events by default. If you want to handle events in a custom subclass of UIImageView, you must explicitly change the value of the userInteractionEnabled property to YES after initializing the object.