• disable every line edit but the first
• once the first line edit has acceptable input, enable the next line edit
• when the content changes to inacceptable input, disable all line edits following the current one
• and so on

This way your users have a clear presentation of which controls are usable at a given moment.

I personally would be really embarrassed by an UI that makes me widgets appear as active, which actually are not. This is against all UI design principles. Such an application is plain not acceptable from a UI point of view.

I was finally able to obtain a consistent result, after reading Qt source code and understanding what the different events do.

So in the focusOut event I keep track that the object needs to have focus back and in the focusIn of the next widget, the first thing I do is to set focus back and returning true (so that doesn't start the blinking cursor).

I have not tried with other widgets, probably there will be no other widgets other than QLineEdit since this is a porting of a text-mode application: forms are defined in a database and so we need to comply with the text-mode forms.

Alternatively I already created a couple of tests, doing something similar to what you propose.

Thank you

But, indeed, I would stick to disabling the "Next" or "Save" or whatever your action button is, and just put a hint to the user what is wrong, and what he needs to do to enable it.

Another point to take into account: you may succeed to disable the focus, but you will not disable the other widgets, so your user can change a spinbox, check/uncheck checkboxes, select from a combobox etc. with the mouse.

focusNextPrevChild finds the next/prev widget and calls setFocus on it.

setFocus emits focusOut and focusIn and there is no way to avoid this (well, I may override setFocus...)

I'm looking in Qt source code where focus is set after mouse click

[quote author="cincirin" date="1321538915"]I'm not sure. Maybe your idea, with single shot timer
@
QTimer::singleShot(0, yourLineEdit, SLOT(setFocus()))
@[/quote]

Thanks for the answer, this will save me writing a test program.

Do you know about the use of setFocus inside a focusOut/In event ?

using setFocus in a focusOut/in event creates, in my test programs (that may be wrong) confusing situations:

• multiple blinking cursors
• cursor blinking in one QLineEdit but focus on another...

and other strangenesses..

thanks
Francesco

About validators I post the question directly:
if I'm editing a QLineEdit and for the current text the validator returns Invalid, if I press TAB/BACKTAB the focus is moved away from the QLineEdit ?

Then back to the "general" question: is it possible and if yes how, to setFocus to a QLineEdit during a focusOut/In event ?

Example, in a field I can enter the iso country codes, so I can set maximum length and force alpha chars. But I can't allow to move focus to other QLineEdits until the country code is validated !

Probably in a brand new program, following GUI guidelines, I would build the form differently, but in this case, I need to do in this way.

thanks