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From: jordan@tcs.com (Jordan Hayes)
Newsgroups: comp.windows.x.motif
Subject: weird behavior with ScrolledList
Message-ID: <9105131738.AA03313@dwight.tcs.com>
Date: 13 May 91 17:38:30 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 105

1.1.1, SunOs 4.1.1, MIT/18, etc.

In the example below, I create an applicationShell, and put an XmButton
in it.  When the button is pushed, XtAppWarning is called.  Also, I
create a topLevelShell with an XmScrolledList in it.  Then I install a
warning handler, which takes the string and makes an entry in the
list.

Here's what happens when I run it:  the first time I push the button,
the message appears.  Subsequent times I push the button, nothing shows
up (the list area doesn't get redrawn).  When there are enough lines
such that it would scroll, the list gets redrawn (when the scrollbars
show up).

Before the scrollbars show up, if I resize the window, the messages
appear, and it begins to work correctly.

Any guesses?

Code follows ...

=====

#include <stdio.h>
#include <Xm/Xm.h>
#include <Xm/List.h>
#include <Xm/PushB.h>

static Widget		_ErrList;
static XtAppContext	app;

static void
ErrBoxWarnFunc(s)
	char	*s;
{
	char		*cp, *cp1;
	XmString	str;

	if (s == NULL || *s == NULL)
		return;
	for (cp = s; *cp != NULL; cp = cp1) {
		for (cp1 = cp; *cp1 != NULL && *cp1 != '\n'; cp1++)
			;
		if (*cp1 == '\n')
			*cp1++ = NULL;
		str = XmStringCreateLtoR(s, XmSTRING_DEFAULT_CHARSET);
		XmListAddItem(_ErrList, str, 0);
		XmStringFree(str);
	}
}

static void
_AddMore(w, client, call)
	Widget		w;
	XtPointer	client;
	XtPointer	call;
{
	char		buf[BUFSIZ];
	static int	i;

	(void)sprintf(buf, "Push number %d\n", i++);
	XtAppWarning(app, buf);
}

main(argc, argv)
	int	argc;
	char	**argv;
{
	Display	*display;
	Widget	shell, button, errBox;

	/* setup */
	XtToolkitInitialize();
	app = XtCreateApplicationContext();
	if ((display = XtOpenDisplay(app, NULL, NULL, "Testing", NULL,
	    0, (Cardinal *)&argc, argv)) == (Display *)NULL) {
		fprintf(stderr, "Cannot open display \"%s\"\n",
		    XDisplayName(NULL));
		exit(-1);
	}

	/* make a shell with a button */
	shell = XtAppCreateShell(NULL, NULL, applicationShellWidgetClass,
	    display, NULL, 0);
	button = XmCreatePushButton(shell, "PushMe", NULL, 0);
	XtAddCallback(button, XmNactivateCallback, _AddMore, NULL);
	XtManageChild(button);
	XtRealizeWidget(shell);

	/* make the error window */
	errBox = XtAppCreateShell("ErrBox", NULL, topLevelShellWidgetClass,
	    display, NULL, 0);
	_ErrList = XmCreateScrolledList(errBox, "errList", NULL, 0);
	XtManageChild(_ErrList);
	XtRealizeWidget(errBox);

	/* set the warning handler */
	XtAppSetWarningHandler(app, ErrBoxWarnFunc);

	XtAppMainLoop(app);
}

=====

/jordan