Dear Quincey,
thank you very much for your infos and hints.
What you write makes sense to me.
I've read the documentation that you pointed me to before. And on
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Documents/Tasks/ImplementingDocApp.html
in the section "Implementing a Document-Based Application" I found I
noce table that said, that only the implementation of the subclass of
NSDocument is required.
That's why I have put everything into the same class. But this seems not
to work for Archiving the model data as I learn now.
Thank you very much
Best regards
Arno
Am 18.08.2011 09:40, schrieb Quincey Morris:
On Aug 17, 2011, at 04:34 , Arno Oesterheld wrote:
I am a beginner with Xcode and Objective-C and stuck with a quite
simple thing for over two days now. I hope you can help me.
My Project is deployed for OS X 10.6, it uses Garbage Collection and
I am using Xcode 4.0.1.
I made a multi document application starting with the template
provided by Xcode. I just have one class as subclass of NSDocument.
For opening documents I use initWithCoder. The decoding mithin this
method works fine - I get the values that were saved.
But these values are "lost" when I would like to use them in an other
method (of the same class).
I assume that I make some mistakes with using the right comibation of
init: / initWithCoder: / initWithContentsOfURL: etc.
The self-object does always have a different adress in the
initWithCoder method then in the other methods.
I tried plenty of combinations of the above methods and even tried to
call differend methods in the super class (NSDocument) within
initWithCoder.
Well, it's hard to answer your questions very clearly, because you
have some basic confusions here. You're going to have to go back and
study the documentation some more, and possibly get hold of a Cocoa
tutorial boom that leads you through some of the basics.
I think the central (but not only) point of confusion is that you seem
to be trying to archive a NSDocument object. This isn't how it works.
The NSDocument object (well, your subclass object) is a transient
object, created when you open the document and destroyed when you
close it.
The *contents* of your document, also known as your data model, is
what is archived, usually to a file. It's an object or a hierarchy of
objects of some *other* class than NSDocument.
So, it makes no sense to declare your NSDocument subclass as
conforming to NSCoding.
I think what's happening now (very roughly, since you didn't show
enough code to be sure of this) is that you're archiving a NSDocument
object as your data model. When you re-open the document file, you
unarchive the object, which contains the archived data (so there is
the *appearance* that it did something right). Now you have 2
NSDocument objects -- the one that was created for you as a result of
opening the document file, and the one that was unarchived. The second
one isn't expecting to be created this way, and it kind of messes
things up.
Try reading here:
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CocoaFundamentals/CocoaDesignPatterns/CocoaDesignPatterns.html#//apple_ref/doc/uid/TP40002974-CH6-SW1
especially about the MVC pattern. The NSDocument object is a
*controller*. Your archived data is a *model*.
You're also going to need to understand the information here:
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Documents/Concepts/OverviewDocArchitecture.html#//apple_ref/doc/uid/20000023-BAJBBBAH
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