Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!csus.edu!ucdavis!ucbvax!alfalfa.com!nazgul
From: nazgul@alfalfa.com (Kee Hinckley)
Newsgroups: comp.windows.x.motif
Subject: Re: Troubles using popup menus from PushButtonWidgets
Message-ID: <910206114208.1219@alphalpha>
Date: 6 Feb 91 16:42:08 GMT
References: <842@igor.Rational.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 159

> 
> The goal: Make a push button that when selected (button 1 pressed,
> *not* button 3) popups up a menu.  Having the button arm while the

I considered doing this but decided not to since the visuals are wrong.
I don't expect things to pop down when I press a button.  On the other
hand, the visuals for an optionmenu are just right, except for that
pesky little label.  Enter the following grotesque hacks.  You'll have
to bear with the C++, but the concepts should stand.

The goal here is to have a cascade button.  That thing with the cute
little box on the right.  However the label shouldn't be there and
the text of the button should be constant.



//
// OmXCascadeMenu Class
//

// clean up the string on delete

OmXCascadeMenu::~OmXCascadeMenu() {
    if (labelString) XmStringFree(labelString);
}

// This gets called everytime a child button is activated, since we
// need to reset the label and menuHistory.  There's some other garbage
// here to, you can try it without it, but this is the result of a lot
// of "damn it doesn't work, lets try this", so I'm not going to try and
// explain it all, I don't even know myself.

void OmXCascadeMenu::resetCascade(Widget, XtPointer ud, XtPointer) {
    OmXCascadeMenu	*cw = (OmXCascadeMenu *) ud;
    Widget	cascade;
    Arg		args[4];

    cascade = XmOptionButtonGadget(cw->widget);
    if (cw->buttons.size()) XtSetArg(args[0], XmNmenuHistory, (*(cw->buttons.at(0)))->widget);
    else XtSetArg(args[0], XmNmenuHistory, cascade);
    XtSetValues(cw->widget, args, 1);
    XtSetValues(cw->pulldown, args, 1);
    XtSetArg(args[0], XmNlabelString, cw->labelString);
    XtSetArg(args[1], XmNmarginWidth, 2);
    XtSetArg(args[2], XmNmarginHeight, 2);
    XtSetValues(cascade, args, 3);
}

// In case we want to change the string

void OmXCascadeMenu::setLabel(XmString str) {
    Boolean	wasManaged = True;
    Widget	cascade;
    
    if (XtIsManaged(widget)) XtUnmanageChild(widget);
    else wasManaged = False;
    
    if (labelString) XmStringFree(labelString);
    labelString = XmStringCopy(str);
    if (widget) resetCascade(NULL, this, NULL);

    if (wasManaged) {
	cascade = XmOptionButtonGadget(widget);
	XtUnmanageChild(cascade);
	XtManageChild(widget);
	XtManageChild(cascade);
    }
}

// Create the silly thing.

Widget OmXCascadeMenu::create(Widget parent, String name, Arg *args, Cardinal argc) {
    Widget	label, cascade;
    XmString	str;
    
    OmXOptionMenu::create(parent, name, args, argc);
    arglist.add(XmNnumColumns, 1, XmNpacking, XmPACK_NONE, NULL);
    XtSetValues(widget, arglist.args, arglist.clear());
    label = XmOptionLabelGadget(widget);
    arglist.add(XmNlabelString, &labelString, NULL);
    XtGetValues(label, arglist.args, arglist.clear());
    str = XmStringCreateSimple("");
    arglist.add(XmNlabelString, str, XmNwidth, 1, XmNheight, 1, NULL);
    XtSetValues(label, arglist.args, arglist.clear());
    XmStringFree(str);
    cascade = XmOptionButtonGadget(widget);
    XtUnmanageChild(cascade);
    arglist.add(XmNmarginWidth, 2, XmNmarginHeight, 2, NULL);
    XtSetValues(cascade, arglist.args, arglist.clear());
    XtManageChild(cascade);
    addCallback(XmNmapCallback, OmXCascadeMenu::resetCascade, this);
    return widget;
}    
    
// How to manage it

void OmXCascadeMenu::manage() {
    Widget	cascade = XmOptionButtonGadget(widget);
    resetCascade(NULL, this, NULL);
    OmXOptionMenu::manage();
}

// These are the routines to add child buttons.  Since there can be
// two kinds of buttons, and the stupid things have different callbacks,
// you have to figure out which callback to use (to add resetCascade).
// I should note that this is the same logic used inside of Motif.  Ugh.
//
OmXMenuItem *OmXCascadeMenu::addMenuItem(OmXMenuItem *menuItem, Arg *args, Cardinal argc) {
    OmXMenuItem	*mi;
    extern char *WhichCallback(Widget w);
    char	*which;
    
    mi = OmXOptionMenu::addMenuItem(menuItem, args, argc);

    if (which = WhichCallback(mi->widget)) {
	mi->addCallback(which, OmXCascadeMenu::resetCascade, this);
    }
    return mi;
}
OmXMenuItem *OmXCascadeMenu::addMenuItem(long itemId, Arg *args, Cardinal argc) {
    OmXMenuItem	*mi;
    extern char *WhichCallback(Widget w);
    char	*which;
    
    mi = OmXOptionMenu::addMenuItem(itemId, args, argc);

    if (which = WhichCallback(mi->widget)) {
	mi->addCallback(which, OmXCascadeMenu::resetCascade, this);
    }
    return mi;
}     




 

/* Here's the C file to figure out which button callback to use */

#include <Xm/XmP.h>


char *whichCallback(
#if NeedFunctionPrototypes
		Widget w)
#else
		w)
Widget w;
#endif
{
    if (XmIsPushButtonGadget(w) || XmIsPushButton(w) || 
        XmIsCascadeButton(w) || XmIsCascadeButtonGadget(w) ||
	XmIsDrawnButton(w))
      return (XmNactivateCallback);

    if (XmIsToggleButtonGadget(w) || XmIsToggleButton(w))
       return (XmNvalueChangedCallback);
    return NULL;
}