Tkinter callback arguments

Peter Otten __peter__ at web.de
Mon Nov 2 10:26:17 CET 2009


Alf P. Steinbach wrote:

>>     for x in range(0,3):
>>         Button(......, command=lambda x=x: function(x))
> 
> An alternative reusable alternative is to create a button-with-id class.
> 
> This is my very first Python class so I'm guessing that there are all
> sorts of issues, in particular naming conventions.

Pseudo-private attributes, javaesque getter methods, unidiomatic None-
checks, broken naming conventions (**args), spaces in funny places...
 
> And the idea of creating a reusable solution for such a small issue may be
> un-pythonic?

Screw pythonic, the signal/noise ratio is awful in any language.
 
> But just as an example, in Python 3.x,

...for achieving less in more lines?

> <code>
> import tkinter
> # I guess for Python 2.x do "import Tkinter as tkinter" but haven't
> # tested.
> 
> 
> class IdButton( tkinter.Button ):
>      def __init__( self, owner_widget, id = None, command = None, **args
>      ):
>          tkinter.Button.__init__(
>              self, owner_widget, args, command = self.__on_tk_command
>              )
>          self.__id = id
>          self.__specified_command = command
> 
>      def __on_tk_command( self ):
>          if self.__specified_command != None:
>              self.__specified_command( self )
>          else:
>              self.on_clicked()
> 
>      def on_clicked( self ):
>          pass
>      def id( self ):
>          return self.__id
>      def id_string( self ):
>          return str( self.id() );
> 
> 
> def on_button_click( aButton ):
>      print( "Button " + aButton.id_string() + " clicked!" )
> 
> window = tkinter.Tk()
> 
> n_buttons = 3
> for x in range( 1, n_buttons + 1 ):
>      IdButton(
>          window, id = x, text = "Button " + str( x ), command =
>          on_button_click ).pack()
> 
> window.mainloop()
> </code>

I'm not grumpy, I just don't like your code ;) And I don't like the notion 
that you are about to spread this style with your book...

Peter





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