[Tutor] tk entry focus

jfouhy@paradise.net.nz jfouhy at paradise.net.nz
Thu Jul 14 04:46:57 CEST 2005

Quoting Ron Weidner <xecronix at yahoo.com>:

> What's wrong with this code? Or more to the point,
> how do you set the focus to an Entry widget?

Look at what the error message is saying:
>  self.cmd.focus()
> AttributeError: 'NoneType' object has no attribute
> 'focus'

Translation: self.cmd is a 'NoneType' object.  There is only one NoneType
object: None.  So, somehow, you have (effectively) done:
 self.cmd = None

Let's see ...

> 		self.cmd = Entry( self.frame,
> textvariable=self.cmd_text ).grid( row = 1, column = 2 )

Aha.  Here, you are creating an Entry widget, calling the grid() method on the
entry widget, and then assigning to self.cmd the return value _of the grid()
call_.  This is extremely different from assigning to self.cmd the Entry widget
just created.
(can you guess what .grid() returns?)

You need to break your code up into two lines:
 self.cmd = Entry(...)

Then give it a try :-)


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