Core Data Fetching Data Part 2 Semantic error

The warning the compiler's giving you: ** Incompatible pointer types sending 'UITableViewCell ' to parameter of type 'PunsTableViewCell *'*

Let's abstract that and talk about this warning more generically:

** Incompatible pointer types sending 'A ' to parameter of type 'B *'*

So, you have a pointer type A (you're passing an object of type A) to a method as a parameter that expects a type B.

Now, the way Amit has set the code up A is a parent class to B, that is B is a subclass of A. Because of the way that subclasses work, an object of type B is ALSO of type A.

All of the cells managed by the UITableView are B instances, so when you access a cell through the UITableView by calling

-(A*)cellForRowAtIndexPath:

You KNOW the object being returned is of type B, but the above method returns an object of type A. You then take the return value and hand it off immediately to the

- (void)configureCell:(B *)cell atIndexPath:(NSIndexPath *)indexPath

method. Since this method expects a B and you're passing it an A the compiler warns you. It happens to work out in this case because the A you're passing HAPPENS to be a B. This wouldn't be the case if, for example, your UITableView had additional cells that weren't of type B. In that case it would be possible that you'd be passing another object of type C.

To fix this issue, you can cast the A object to a B object. This would look like:

(B*)someObjectOfTypeA;

Doing this will shut the compiler up. But how would this work in the specific case you asked about?

Replace B with PunsTableViewCell and A with UITableViewCell.

(PunsTableViewCell*)cellOfTypeA;

[self configureCell:(PunsTableViewCell*)[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];

Hope this makes sense.

Thanks Aaron, yes it makes sense. I think A and B collided in my brain, but I will get the hang of it :o)