Re: [Pyobjc-dev] Re: Multiple Nibs

[Ronald O. <ron...@ma...>]

On 8-mei-04, at 7:58, Winston Wolff wrote:

> That's one thing I don't understand.  In Obj C, I would call [NSBundle 
> loadNibNamed: "myModelPanel owner: self] and this will connect 'self' 
> to the outlets and actions for the nib.  I.e. 'self' is the owner of 
> the NIB.  But with Python, you don't specify any owner.  How do you 
> choose which object gets to be the owner of the NIB file?
>
> For example, if I have:
> 	NibClassBuilder.extractClasses("MyModalPanel")
> 	myModal = MyModalPanel.alloc().init()

That won't work :-)

NibClassBuilder.extractClasses is a function that extracts class 
definitions from NIB files. That information is *only* used by 
NibClassBuilder.AutoBaseClass.

>
> Now MyModelPanel is a NIB file which specifies a 
> MyModelPanelController object.  So when the NIB file is unfrozen, it 
> will create an instance of MyModelPanelController.  First of all, 
> where exactly is the NIB file unfrozen?  Is it in extractClasses() or 
> in MyModelPanel.alloc().init()?  Second, how do I get a reference to 
> MyModelPanelController?

Neither, it is unfrozen by NSBundle.loadNibNamed_owner_

>   Normally I would say you attach it to an outlet of the NIB File's 
> Owner, but where do I get a reference to the Owner?
>
> Does this make any sense?

A slightly longer explanation...

You can define classes in Interface Builder (Classes -> Subclass 
<SomeClass>). Doesn't doesn't really define a class, but creates a note 
in the NIB file that the program that will load the NIB will contain a 
definition of the class. E.g. you promise IB that you will implement 
the class in your program.

IB can create empty Objective-C implementation files for the classes 
you "define" in IB, but that will overwrite any existing implementation 
files for those classes. These are not usefull for python anyway (wrong 
language).

You can use NibClassBuilder as a script and then it will behave the 
same as 'Classes -> Create Files for <SomeClass>' in Interface Builder.

This is useful for creating the initial (empty) implementation of 
classes, but cannot be used when you change the class in Interface 
Builder (add another action or outlet) because the script will always 
create an empty implementation (just like the Create Files command of 
IB). If you add a new outlet to the class you must therefore manually 
add this to your class definition.

This is where NibClassBuilder.AutoBaseClass and 
NibClassBuilder.extractClasses come into play. These two are used to 
extract information about the classes you declared in IB from the NIB 
file and automaticly add outlet definitions to your class. You must 
still add actions to your class, but you would have to do that anyway 
because the NIB doesn't contain imformation about the behaviour of the 
action.

Say to define MyController inside IB, with outlet myWindow and action 
myAction:.

	NibClassBuilder.extractClasses("MyNib")
	
	class MyController (NibClassBuilder.AutoBaseClass):

		def myAction_(self, sender):
			print self.myWindow


NibClassBuilder.AutoBaseClass is a magic base class that will look up 
'MyController' in the information extracted from the NIB file(s). It 
will then replace itself by the actual base class (as defined in the 
NIB) and add an outlet definition for the outlets.

You could also have written:

	class MyController (NSObject):
		myWindow = objc.IBOutlet("myWindow")

		def myAction_(self, sender):
			print self.myWindow


I hope this helps you understand what is going on,

	Ronald