help changing first responder

[Jamal Bernhard]

NSTextField is really kicking my ass... :-)

If the user edits a text field and the value is invalid, I want to pop
up an alert, restore the previous value, and keep the field as first
responder. I can do the first two just fine in the text field action,
but I can't figure out how to stop first responder from changing. First
I tried makeFirstResponder. Then I figured the text field action is
being sent before the event that caused it (tab, for example) is being
processed, so I tried flushBufferedKeyEvents but that didn't work either
(and anyway that wouldn't work for mouse clicks?). Out of ideas right
now...

Also, is using a formatter the only way to limit the number of
characters in a text field?

Thanks in advance,

[Michael Ash]

In article
<jamalbspambegone-E85813.02581916082003@news.sf.sbcglobal.net>,
Jamal Bernhard <jamalbspambegone@pacbell.goawayspam.net> wrote:

> NSTextField is really kicking my ass... :-)
>
> If the user edits a text field and the value is invalid, I want to pop
> up an alert, restore the previous value, and keep the field as first
> responder. I can do the first two just fine in the text field action,
> but I can't figure out how to stop first responder from changing. First
> I tried makeFirstResponder. Then I figured the text field action is
> being sent before the event that caused it (tab, for example) is being
> processed, so I tried flushBufferedKeyEvents but that didn't work either
> (and anyway that wouldn't work for mouse clicks?). Out of ideas right
> now...

If that truly is the problem, then try something like this:

[window performSelector:@selector(makeFirstResponder:)
withObject:textField afterDelay:0.0];

This will send makeFirstResponder: after your program gets back to the
main event loop.

[Simon Slavin]

In article <jamalbspambegone-E85813.02581916082003@news.sf.sbcglobal.net>,
Jamal Bernhard <jamalbspambegone@pacbell.goawayspam.net> wrote:

>If the user edits a text field and the value is invalid, I want to pop
>up an alert, restore the previous value, and keep the field as first
>responder. I can do the first two just fine in the text field action,
>but I can't figure out how to stop first responder from changing.

Your code to revert to the original value should be put into
the 'textShouldEndEditing:' delegate for the text field or
handled via the default code for it. This automatically
handles cases where the new text is not acceptable for that
field. See 'NSTextField' for documentation.

Note that reverting to the earlier version of the text if the
new text is unacceptable is /not/ the Macintosh way. You're
meant to leave the new text exactly the way it is so that the
user can modify it further. If they decide they want to
revert to the original text they can use the 'Undo' menu item
all by themselves.