Home » Forums » Open Motif 2.3 Discussion » Open Motif 2.3 Discussion

dynamically changing a label

Submitted by Anonymous on Mon, 04/05/2004 - 20:58.

Hi,
I am a newbie to motif programming.

After i intialize the GUI with " XtAppMainLoop" I want to change the label. The application is very simple it involves displaying some numbers on a text field. The numbers update at about 10-Hz. I see that all the callbacks (that i have seen) are triggered via. some user controlled event.

If you can send me a sample code to do this that would be great.

‹ Pixmaps in Menu's... Tables in XmHTML ›
 



  

    
    
    
  

  

    
    
    
Tue, 04/06/2004 - 13:35#1

    

    

        Anonymous    

    
Anonymous's picture
    

    

    
Try this...

        
You should be able to use XtVaSetValues and set the XmNlabelString property to the text that you want.


Example:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Widget o_Label;

XmString s_String;


s_String = XmStringCreateLocalized("MyLabel");

XtVaSetValues(o_Label, XmNlabelString, s_String, NULL);

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


NOTE: XmStringCreateLocalized accepts a char as input and creates a XmString item  that can then be used to modify the text of the label.  When working with text Motif uses XmString's as input a lot (Combobox, Lists, Labels, Buttons); however, for some reason with textboxes they don't


Hope this help.

C. Lamb



    

    

    		
    
  

  

    
    
    
  









  

    
    
    
  

  

    
    
    
Fri, 04/09/2004 - 06:48#2

    

    

        Anonymous    

    
Anonymous's picture
    

    

    
A sample

        
Hello, here is a sample you requested.


<br />
#include <Xm/Xm.h><br />
#include <Xm/Label.h><br />
#include <Xm/LabelG.h><br />
#include <time.h><br />
#include <sys/time.h></p>
<p>char time_string_buf[13];</p>
<p>char *<br />
get_time_string()<br />
{<br />
	struct timeval tv;<br />
	struct tm *tm;<br />
	gettimeofday(&tv, NULL);<br />
	tm = localtime(&(tv.tv_sec));<br />
	snprintf(time_string_buf, sizeof(time_string_buf),<br />
	    "%02d:%02d:%02d.%03ld",<br />
	    tm->tm_hour, tm->tm_min, tm->tm_sec, tv.tv_usec);<br />
        return time_string_buf;<br />
}</p>
<p>void<br />
show_time(XtPointer closure, XtIntervalId *id)<br />
{<br />
        Widget label = (Widget)closure;<br />
	XmString s = XmStringCreateLocalized(get_time_string());<br />
	XtVaSetValues(label, XmNlabelString, s, NULL);<br />
	XmStringFree(s);<br />
	XtAppAddTimeOut(XtWidgetToApplicationContext(label),<br />
                100, show_time, (XtPointer)label);<br />
}</p>
<p>int<br />
main (int argc, char** argv)<br />
{<br />
	Widget toplevel, label;<br />
	XtAppContext app;<br />
	XmString s;</p>
<p>	XtSetLanguageProc(NULL, NULL, NULL);<br />
	toplevel = XtVaOpenApplication(&app, "Demos", NULL, 0,<br />
                &argc, argv,<br />
		NULL, sessionShellWidgetClass, NULL);</p>
<p>	s = XmStringCreateLocalized(get_time_string());</p>
<p>	label = XtVaCreateManagedWidget("time_label",<br />
                xmLabelWidgetClass, toplevel,<br />
		XmNlabelString, s,<br />
		NULL);</p>
<p>	XtAppAddTimeOut(XtWidgetToApplicationContext(label),<br />
                100, show_time, (XtPointer)label);</p>
<p>	XmStringFree(s);</p>
<p>	XtRealizeWidget(toplevel);<br />
	XtAppMainLoop(app);</p>
<p>	return 0;<br />
}<br />