Re: [Pyobjc-dev] simple animation w/ NSTimer

[John B. <nho...@go...>]

Hi Carl,

You don't pass in the function object when specifying Objective-C  
methods, but a method "selector", which in Python land is just a  
string (in Objective-C selectors have the type SEL, which may or may  
not also be a string). Be careful to fully specify the selector by  
including the colon for each argument e.g.

NSTimer 
.scheduledTimerWithTimeInterval_target_selector_userInfo_repeats_ 
(1.0,self,'tick:',None,True)

Note that in the Python method definition the colon is replaced by an  
underscore. So in Objective-C your 'tick' method would look like:

- (void)tick:(NSTimer*)timer
{
	// Implemenation here
}

In Python this must be translated to:

def tick_(self, timer):
	# implementation here

However the "selector" string must always use the Objective-C version  
i.e. with the colon.

Regards,

John
____________________

Dr. John Buckley
nho...@gm...

www.olivetoast.com

Mac OS X Leopard
____________________

On 31 Mar 2008, at 00:03, Carl Bauer wrote:

> I'm a physics grad student (not a coder) wanting to put together a  
> slick realtime physics simulation for my statistical mechanics  
> class. (Simulating the 2D Ising model for ferromagnets in case  
> anyone cares).
>
> Anyway, to start, I'm just trying to get a rectangle to change  
> colors periodically. Why doesn't this work?
>
> import objc
> from Foundation import *
> from AppKit import *
> from PyObjCTools import NibClassBuilder, AppHelper
> from Quartz import NSColor
>
> NibClassBuilder.extractClasses("MainMenu")
>
> # class defined in MainMenu.nib
> class Lattice(NibClassBuilder.AutoBaseClass):
>     # the actual base class is NSView
>     color = NSColor.redColor()
>     toggle = 0
>     rect = NSMakeRect(40,40,40,40)
>
>     def drawRect_(self,frameRect):
>         NSEraseRect(self.rect)
>         self.color.setFill()
>         NSRectFill(self.rect)
>
>     def start_(self, sender):
>          
> self 
> .timer 
> = 
> NSTimer 
> .scheduledTimerWithTimeInterval_target_selector_userInfo_repeats_ 
> (1.0,self,self.tick,None,True)
>
>     def tick(self,timer):
>         self.toggle = (self.toggle+1)%2
>         if self.toggle:
>             self.color = NSColor.blueColor()
>         else:
>             self.color = NSColor.redColor()
>         self.display()
>
> if __name__ == "__main__":
>     AppHelper.runEventLoop()
>
> The rectangle is drawn just fine at the beginning, but the timer  
> doesn't seem to actually invoke drawRect_. I'm probably just not  
> understanding how to properly use display()? Let me know if I'm  
> being annoying and should just post to a different mailing list.
>
> Thanks,
> Carl
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