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Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging
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Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging


  • Subject: Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging
  • From: Jason Wiggins <email@hidden>
  • Date: Sat, 21 Jun 2008 14:56:28 +1000

Thanks Henry for your response. I'll have to read that a couple times to let it sink into my thick skull. Not sure why the DL link is zero length. Here is a better link: http://members.optusnet.com.au/jwiggins/xcode/TestCase.zip
The reason I connected things in the way I did was to understand what was and wasn't happening. But then again, as stated, I'm doing something fundamentally wrong.


Regards,
Jason


On 21/06/2008, at 2:35 PM, Henry McGilton (Starbase) wrote:


On Jun 20, 2008, at 5:48 AM, Jason Wiggins wrote:

Hi everyone,

If possible, could someone please educate me on the fundamental mistake in my understanding of use of classes/instances/ encapsulation/messaging. I have reread the Object-Oriented Programming with Objective-C but didn't find my answer.
I have written a test program with three classes- Model, View and Controller and a Window with a button and a popup button. There are setters and getters to test getting data in/out of the Model Class, which works as expected.

Okay, so you have a model, and you have a Controller, and you have a View.
Where is this View ? Is it a sub-view of the window's content view ?


Both the Controller and View Classes are connected to the popup button in IB.

Connected in what way ? Do you have a connection *from* the Controller and
*from* the View to the popup button ? If so, why ? What do you expect to
happen ? And what is the other button expected to do ?


Sounds like the connections are going in the wrong direction.

Let's ask the fundamental question: when the popup button changes state, what do
you want to happen inside the program ?


If I were doing something like this, I would expect that the popup button
changing state would send an action message to the controller to tell the controller
there's been a change.


The controller would then tell the model to update its state, and finally, the
controller would send the new state to the view and possibly tell the view to
re-display itself.


What I want to do is have the View Class to return the value of the selected index of the popup button, but all I ever get is 0. I get the value OK from the Controller Class though. I am obviously doing something fundamentally wrong or misunderstanding "something".
Here is the program:


ftp://email@hidden:21/xcode/TestCase.zip

That .zip file is a zero-length file . . .

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  • Follow-Ups:
    • Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging
      • From: Graham Cox <email@hidden>
    • Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging
      • From: Graham Cox <email@hidden>
References: 
 >Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging (From: Jason Wiggins <email@hidden>)
 >Re: Fundamental mistake in my understanding of use of classes/instances/encapsulation/messaging (From: "Henry McGilton (Starbase)" <email@hidden>)

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