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I have an AppController object that contains an instance variable int adventures. This is bound to a label through Interface Builder.

I also have a subclass of NSWindowController called PopUpWindow. When the enter button is clicked the value in the text field on the pop up window should change the variable adventures in the AppController object.

Even after using @public and @package for adventures it doesn't change. I'm also trying to use

[self willChangeValueForKey:@"adventures"];

from the PopUpWindow class. Will that work across classes? How can I do this?

Mat
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sud0
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1 Answers1

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This may be a good place for NSNotifications you AppController could register for a named notification, my be not even care what object sends it, you PopUpWindow can then post a notification that something changed which you AppController can receive the notification. Another possibility is if the PopUpWindow is owned by the AppController controller it can have the AppController as a delegate and send a message to its delegate. You line of code

[self willChangeValueForKey:@"adventures"];

seems to suggest that is happening in you AppController, but thus is no use because this will only tell observers of you AppController.adventures that it has changed and you want it to work the other way, I am asumming the enter button is clicked it sends a message to you PopUpWindow NSWindowController.

Nathan Day
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  • Actually it works the other way around. When the app loads a window panel pops up with a text field and button asking for a value. This value is supposed to set the variable adventures in the AppController. I'm not sure of how to use NSNotifications but I have reference book at hand to help. I have also tried creating a variable numOfAdventures in PopUpWindow and binding it to the label so why didn't it work when I created the object in IB and bound the label to PopUpWindow.numOfAdventures? – sud0 Jul 31 '11 at 18:27
  • As a quick correction I actually allocated AppController in my window controller and called `[controller willChangeValueForKey:@"adventures"];` not self. – sud0 Jul 31 '11 at 18:33
  • I fixed my problem by getting rid of the subclass of NSWindowController and using `IBOutlet NSWindow *popUpWindow;`, making it visible at launch, and making it close when the enter button is clicked. The only thing I don't know how to do yet is make it reopen when you need it to. I'm used to NSWindowController's `showWindow` method. This is my first time working with NSWindow. – sud0 Jul 31 '11 at 21:12
  • Nofications are very simple and are very useful mechanism to separate code and broadcast changes of state to many parts of you app. It is something you should get you head around. willChangeValueForKey: is usually used in key value bindings so that the accessor method for adventures will send this method to itself and then after send didChangeValueForKey:. That way any key value observers of this value set up in interface build can be notified of the change. – Nathan Day Jul 31 '11 at 21:17