on Sun, 28 May 2006 16:55:52, Alice Hartley <email@hidden> wrote:
> Some time ago our application switched from using a home grown
> implementation of alert dialogs to using
> CreateStandardAlert plus RunStandardAlert.
> In the process we lost a feature.
> Formerly one could select a button by typing
> the first character of it's name,
> that is if the buttons were named
> "No" "Cancel" "Yes"
> then typing the character n would act as a click in the "No" button,
> c the "Cancel" button etc.
> Typing escape, return, or enter worked as expected.
> With the change, typing escape, return, or enter still
> work as expected, but I am having a problem handling
> the typing of other characters. Some users have
> requested that the ability to type e.g. n to choose the
> "No" button be reinstated.
>
> It seems as if calling RunStandardAlert with
> a filterproc created with NewModalFilterUPP should be
> helpful in doing so.
>
> However when the filterproc is called and I do
> GetEventClass and GetEventKind of the event,
> the class is nonsense (corresponds to no known
> event class and varies) and the kind is always 0.
> I would have expected to find kEventClassKeyboard
> and kEventRawKeyDown when a character is typed.
> Never happens.
> Also when the filterproc is used, typing escape return or enter
> cease to function.
>
> So either:
> a) I doing something wrong
> b) I shouldn't expect this approach to work
> c) There another way to handle keystrokes in StandardAlert
> d) its not possible
Below is source code of event filter that does almost what
you say (it specifically filters out default/cancel buttons
on the grounds they are already accessible by enter/escape
keys; comment the corresponding lines in GetDialogButtonShortcut
if you don't like this). Beware: it is not unicode-savvy.
Enjoy.
Mike
static UInt8 GetDialogButtonShortcut(DialogRef dialog, DialogItemIndex item)
{
ControlRef c;
DialogItemType type;
Rect r;
Str255 title;
if (item == GetDialogDefaultItem(dialog)) return 0;
if (item == GetDialogCancelItem(dialog)) return 0;
GetDialogItem(dialog, item, &type, (Handle *)&c, &r);
if ((type & ~kItemDisableBit) != kButtonDialogItem) return 0;
if (!c) return 0;
if (r.left > 0x2000) return 0; // invisible
if (!IsControlVisible(c)) return 0;
GetControlTitle(c, title);
if (!title[0] || !title[1]) return 0;
return toupper(title[1]);
}
static pascal Boolean TheAlertEventFilter(DialogRef dialog,
EventRecord *event, short *itemHit)
{
ControlRef c;
UInt32 L;
DialogItemType type;
Rect r;
UInt8 ch;
DialogItemIndex button;
do {
if (event->what != keyDown) break;
if ((event->modifiers & cmdKey) == 0) break;
ch = event->message & charCodeMask;
if (!ch) break;
ch = toupper(ch);
for (button = 1; button <= 3; button++) {
if (GetDialogButtonShortcut(dialog, button) == ch) {
GetDialogItem(dialog, button, &type, (Handle *)&c, &r);
HiliteControl(c, kControlButtonPart);
QDFlushPortBuffer(GetWindowPort(GetDialogWindow(dialog)),
NULL);
Delay(8, &L);
HiliteControl(c, kControlNoPart);
QDFlushPortBuffer(GetWindowPort(GetDialogWindow(dialog)),
NULL);
*itemHit = button;
return true;
}
}
} while (false);
return StdFilterProc(dialog, event, itemHit);
}
Mike
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