[Tutor] The case of the scrolling label....

[Magnus Lycka]

At 23:53 2002-12-06 -0500, andy surany wrote:
>I am putting up a label when an improper entry is received.
>
>Label(text='Invalid Entry').pack() # Tk
>
>Works fine. But how do I get rid of it?

Don't throw away the reference to it!

It irritates me (I've written about this before) that a lot
of GUI code relies on magic hand-hold that let people use
object instanciations as if they were some kind of procedure
calls. It gives the wrong idea.

I would do
   attention = Label(text='')
   attention.pack() # Can't do these in one line (think about it)
as a part of program init, and then
   attention['text'] = 'Invalid Entry'
when things go wrong, and
   attention['text'] = ''
when I don't want to show that any longer.

The variable must persist to be useful. If you're in a class,
use "self.attention = Label(text='Invalid Entry')" and so on.

Another option could be to do
   attention = Label(text='Invalid Entry')
   attention.pack()
when needed, and
   attention.destroy()
when you want the text to go away.

I would NOT use that. How on earth are you going to have any
control over your UI when you realize that you have to add more
things in your frame. I'd layout my windows in the beginning,
and then fill in values as appropriate.



-- 
Magnus Lycka, Thinkware AB
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