single Rotation gesture event is not working?

I am using following code

recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotationFrom:)];
 [self.view addGestureRecognizer:recognizer];
 [recognizer release];

but when i do single finger rotation event. the function handleRotationFrom is not called? any help please开发者_C百科?I have added delegate method also in my UIView..any help please?

A rotation gesture always involves two touches. If you want to test it in iphone simulator hold down option key while clicking.