What's the best way to get a bool value from a detailViewController?

Question

In my navigation based app, there is a button that if pressed, will change the view to a detailViewController. Here the user can set several options. One of those options is a bool value. When I return from the detailViewController how can I see what this bool value is?

Answer 1

Create a protocol (DetailViewDelegate?) and create a delegate property in your DetailViewController. When you instantiate your view controller, set the delegate property to self and use that property to send messages back to your master view controller. The only tricky part is that you need to declare the delegate property as "assign" so that you don't create a retain loop between your detail view and master view.

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DetailViewController.h:

@class DetailViewController; // Forward Declaration.
@protocol DetailViewDelegate
- (void)detailViewController:(DetailViewController *)controller didChangeBool:(BOOL)theBool;
@end

@interface DetailViewController : UIViewController {
    id <DetailViewDelegate> delegate;
}

@property (assign) id <DetailViewDelegate> delegate;

@end

That's just the interface, but it should get you most of the way there. Set the delegate property of the detail view and implement a detailViewController:didChangeBool: method in your master view and that's about it.

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To answer the questions in your comment:

1. Yes. Before you push the detail view controller set it's delegate property to self.
2. You need to declare that your master view controller implements the DetailViewDelegate protocol. Learn how to do that by reading Apple's Documentation.
3. After you declare that your master view controller will implement the protocol, you need to actually implement it. Add a detailViewController:didChangeBool: method to your master view controller.