Hi there,

I've been coding up some screens and dialogs and im totally unsure how I am supposed to be
validating user input. For instance if I have a dialog box with 3 JFormattedTextFields and an OK and
Cancel button am I supposed to check the data when the OK button is pressed or when each textfields
data is changed. I don't like the first approach and have been trying to implement the 2nd approach
however this seems harder than it first appeared :-

1) I started using a NumberFormatter (still am) plus setting up a enter key map to check the
validity of the entered data. If the data was ok it would be accepted for the field otherwise I got
a popup dialog to be opened which forced the operator to press an edit button or a undo button. The
edit selected all  field and they re-typed it in (same checks again after). If the undo button was
pressed the field was reset to its original value. This worked fine but I couldn't seem to get it to
work when the mouse was clicked elsewhere or the tab key was pressed to go to another field.
Basically I couldn't get the actionmap on enter and the tab and focus lost to all do the same check
and same action (popup a dialog if the data was wrong). In the focuslost case there seemed to be
some interference between the enter key opening a dialog and this causes focus to be lost on the
field !!!

2) I tried using an InputValidator on each field which stopped focus from changing if the data isn't
correct. I also fill in a error panel when this occurs telling what the problem is. This seems to
work ok but I haven't really seen it used elsewhere and I'm not really that keen on it.

So basically Im looking for some info on the preferred approach to how these things are done and
also if they are secure and don't have holes like my first try where there doesn't seem to be a way
of doing the same checks and actions on enter being pressed, focus being lost.

I personally think the best approach is to stop focus from being lost until the data is correct and
also popup a dialog telling them what the problem is giving the option of re-edit or undo. But as I
said I couldn't seem to get it to work properly for all possible events (enter, tab, lost focus
.... ).

There MUST be some simple way of doing a consistent check and action atleast for
JFormattedTextFields surely :( ??

Thanks for any info

Steve