Question

I have a core data iPhone application.

I have two views on a navigation controller (view A = root, view B = child).

I would like to tell view A to update it’s tableView when view B is popped off the navigation controller (i.e. when the user presses the ‘back’ button). What method is called when this occurs? Do I need to setup some sort of protocol or notification?

Thanks,

Answer 1

You could implement the viewWillDisappear method of your view controller B.

The best way would be to declare a “viewBDelegate”-protocol in view controller B which will be implemented by view A.

@protocol viewBDelegate <NSObject>
@required
-(void) viewBWillBeClosed;
@end

Then you need an instance variable in view controller B holding a reference to view controller A (set that when pushing view B).

@property (nonatomic, retain) id<viewBDelegate> delegate;

In viewWillDisappear method of you view controller B you can than inform the delegate (view controller A) by calling a method of the delegate protocol.

- (void)viewWillDisappear:(BOOL)animated{
    [delegate viewBWillBeClosed];
    [super viewWillDisappear:animated];
}