[Qt-interest] QValidator::validate() and QLineEdit ... when is it called?

[Robert Hairgrove]

On Fri, 2011-02-04 at 18:33 -0500, K. Frank wrote:
> Hello Robert!
> 
> I do not have an answer to your question, but I do have a
> user-interface suggestion.
> 
> On Fri, Feb 4, 2011 at 6:10 PM, Robert Hairgrove <evorgriahr at hispeed.ch> wrote:
> > I am having a problem with unwanted recursion in my custom validator's
> > validate() function.
> > ...
> > However, checking should only occur after the user finishes
> > editing (i.e. when the editingFinished() signal would normally be
> > emitted). My validator class keeps record of the previous value (if any)
> > and if the new value is invalid, it should reset the line edit control's
> > text to whatever it was before by assigning the non-const argument
> > references passed to the validate() function.
> 
> It might be preferable _not_ to erase or overwrite what the user
> has typed in.
> 
> Let's say that the preloaded file name is "file0123456789.txt"
> and the user needs to edit it to read "file987654321.txt", but
> inadvertently skips the '6', "file98754321.txt".  In your scheme,
> the user cannot see what he incorrectly typed, gets no detailed
> feedback about what might be wrong (other than that there is
> no exact match), and has to repeat the entire process of editing
> the file name.
> 
> It may not seem like much, but these kinds of "lossy" user
> interfaces that forget what I've done and make me repeat my
> work drive me nuts.
> 
> Just a thought.
> 
> 
> Good luck with your original question.

Thank you ... this is a good idea. Now I have put my own validation code
in the handler for the editingFinished() signal, and the user has the
option to restore the old value or keep the typed entry.