passing data back to a previously allocated UIViewController

Question

I have a view controller that then has a button that passes to an option menu.

When options are set they need to be past back to the previously allocated viewcontroller.

Answer 1

You could use a shared singleton? http://cocoawithlove.com/2008/11/singletons-appdelegates-and-top-level.html

Or save the parameters to nsuserdefaults and read them back in in your first viewcontroller

or some other temporary store such as your appdelegate

I've used all three of the above approaches before.

Answer 2

When you init your option viewController, pass it a reference to its parent.

I.E.

[[OptionViewController alloc] initWith...: parent:];

Use a @property or a method or somesuch to call on the parent to pass the data back.

Answer 3

You can achieve this by using a delegate protocol. First view controller should become the delegate of the second view controller and then you can call this delegate method in your first view controller once the selection is done.

You can lookup google for implementation of delegates in objective-c. Its pretty simple. Add a

@protocol <delegatename>
<declare delegate method>
@end

Create a member variable in the second view controller for assigning the delegate. And define the method in the class implementing the delegate.