Re: [Pyobjc-dev] implementing objective C interface in python

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

On 31 Jan, 2008, at 7:19, John Stoner wrote:

> in WiiRemoteDiscovery.h;
>
> @interface NSObject( WiiRemoteDiscoveryDelegate )
>
> - (void) WiiRemoteDiscovered:(WiiRemote*)wiimote;
> - (void) WiiRemoteDiscoveryError:(int)code;
>
> @end;
> in python;
>
>     wd = WiiRemoteDiscovery.new()
>     class wii_remote_discovery_delegate(WiiRemoteDiscoveryDelegate):
>         def wiiRemoteDiscovered_(self, wiiRemote):
>             self.wiiRemote=wiiRemote
>             print "discovered"
>         def WiiRemoteDiscoveryError_(self, returnCode):
>             print "not discovered"
>     x=wii_remote_discovery_delegate()
>     wd.setDelegate_(x)
>     wd.start()
>
> Traceback (most recent call last):
>   File "/Users/jstoner/Documents/projects/boogiepants/wii.py", line  
> 29, in <module>
>     class wii_remote_discovery_delegate(WiiRemoteDiscoveryDelegate):
> NameError: name 'WiiRemoteDiscoveryDelegate' is not defined
> >>>
>
> Do I need to do a stub implementation of WiiRemoteDiscoveryDelegate  
> or does PyObjC have a way to handle this?

WiiRemoteDiscoveryDelegate is not a class, but a category (which is  
the ObjC way of adding new methods to an existingclass). You have to  
define an objc.informal_protocol that defines which methods are  
present in the WiiRemoteDiscoveryDelegate informal protocol (the  
category in the header file). You can then define your delegate as a  
subclass of NSObject, PyObjC will automaticly detect that you're  
implementing an informal protocol and use the right type information  
for your methods.

This is a sample protocol definition from the Foundation wrappers in  
PyObjC 1.4:

NSArchiverCallback = _objc.informal_protocol(
     "NSArchiverCallback",
     [
# (Class)classForArchiver
         _objc.selector(
             None,
             selector='classForArchiver',
             signature='#@:',
             isRequired=0,
         ),
# (id)replacementObjectForArchiver:(NSArchiver *)archiver
         _objc.selector(
             None,
             selector='replacementObjectForArchiver:',
             signature='@@:@',
             isRequired=0,
         ),
     ]
)


The hardest part is defining the 'signature' strings, Apple's ADC  
website contains an Objective-C runtime manual that explains how to  
construct these strings.

Ronald

>
> -- 
> blog:
> http://www.generosity.org/stoner/
> 'In knowledge is power, in  wisdom, humility.'  
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2008.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/_______________________________________________
> Pyobjc-dev mailing list
> Pyo...@li...
> https://lists.sourceforge.net/lists/listinfo/pyobjc-dev