Re: JTextField validation

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#11698

From: Jason Burton
Date: Tue, 20 Apr 1999 00:00

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> If you get a focus lost event, note that you *ALREADY* lost focus.  Focus
> is *GONE*.  Another component *ALREADY* has the focus.  To move focus
> back, the new component gets a focus lost event.  Will you then validate
> the new component as well losing focus back to the original?
> See how complicated all this is?  I personally highly advise *AGAINST*
> doing things on a focus lost.  One good way to do validation is on each
> keystroke by writing your own Document.  It's quite easy.

A simple "user changed field" flag can be used to determine whether or not
to perform validation.  This will prevent validation from occuring in the
newly focused field when it is determined that the input in the last field
is invalid.  Validating on key strokes can be a bad choice for things like
database lookups based on current field value.

Jason Burton

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From: "Jason Burton" <Jason.Burton@McLeodSoftware.com>
Subject: Re: JTextField validation
Date: 1999/04/20
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