UIView: How to find out if a view is already exists?

Question

I was wondering how to find out if a subview (in my case pageShadowView) has already been added to my view.

I've come up with this, but it doesn't really work:

if ([pageShadowView isKindOfClass:[self.view class]]) {         [self.view addSubview:pageShadowView];     } 

Also, I'm still confused about the self.-thing. I know that this has to do with making clear that we are talking about the view of the current ViewController ... but do I really need it if there (1) are no other ViewControllers or (2) if it doesn't really matter because if I ever wanted to refer to another viewController, I'd make sure to call it?

I'm sorry if this is all very basic, but I'd be very grateful for your comments.

Answer 1

Here:

BOOL doesContain = [self.view.subviews containsObject:pageShadowView]; 

And yes, you need this self. There is no explicit ivar "view" on UIViewController. The self.view statement is actually a call on method [self view] which is a getter for UIViewController's view.

Answer 2

Give it a unique tag: view.tag = UNIQUE_TAG, then check the container view for existence:

BOOL alreadyAdded = [containerView viewWithTag:UNIQUE_TAG] != nil;