lmgc@gmv.es (Luis Mariano Gonzalez) (08/30/89)
Hello -
1) I want to read the text from the widget
using XtGetValues but it seems not to work.
/* this is the way I create the Text Widget */
.....
char buf[100];
.....
n=0;
XtSetArg(arg[n], XtNheight, 40); n++;
XtSetArg(arg[n], XtNwidth, 200); n++;
XtSetArg(arg[n], XtNtextOptions,editable); n++;
XtSetArg(arg[n], XtNeditType,XttextEdit); n++;
XtSetArg(arg[n], XtNstring, buf ); n++;
w_text = XtCreateManagedWidget("text", asciiStringWidgetClass, form, arg, n);
/* Here I fetch the text */
void Accep_text(widget,call_data,client_data)
Widget widget;
caddr_t call_data,client_data;
{
Arg arg[20];
unsigned int n;
char buff[100];
n =0;
XtSetArg(arg[n], XtNstring,buff) ; n++;
XtGetValues(w_text,arg,n); n++;
}
( I've also tried using - char * buff - instead of - buff[100]-,
but the result was the same : null string).
Do I miss something?.
2) I decided to use an asciiStringWidget to allow the user to
edit one line text. The length of the string the user can
introduce is given by the initial value of XtNstring.Thus
if you initialize XtNstring to null the user won't be able
to edit anything.
( Maybe dialog widget would be better in this case but I had
problems with the initialization : length of text field was
given by label lenght)
Is it correct?. How can the user be allowed to edit one line
without initializing the text?
Another question:
I'm using a widget form to implement a menu. Every menu item is
a command widget.
At any moment I want to make insensitive some command widgets.
I wanted every event that occurs over these widgets to be send to the
form widget. If the mouse button was released over an insensitive menu
item I wanted to perform an specific operation. I select button_release
for the form widgets, but when the button is released over an insensitive
widget nothing occurs.
Thanks in advance for any help!
L.M. Gonzalez Ph. +54 1 234 30 04
Grupo de Mecanica del Vuelo, S.A. (GMV) Fax +54 1 233 32 50
Cristobal Bordiu, 35 Telex 48487 GMEV E
E-28003 MADRID lmgonzalez@gmv.es
SPAIN mcvax!gmv.es!lmgonzalez@uunet.uu.net
uunet!mcvax!gmv.es!lmgonzalezkit@EXPO.LCS.MIT.EDU (Chris D. Peterson) (08/30/89)
> 1) I want to read the text from the widget > using XtGetValues but it seems not to work. > char buf[100]; > XtSetArg(arg[n], XtNstring, buf ); n++; > w_text = XtCreateManagedWidget("text", asciiStringWidgetClass, form, arg, n); This allocates your memory off off of the stack, and when you function returns this memory goes away. The string widget explicitally states that it uses the string in place. Once your functions returns the text widget will be writing into bad memory. The proper way to code this is: char * buf = XtMalloc(sizeof(char) * BUFSIZ); XtSetArg(arg[n], XtNstring, buf ); n++; XtSetArg(arg[n], XtNlength, BUFSIZ ); n++; w_text = XtCreateManagedWidget("text", asciiStringWidgetClass, form, arg, n); When retreiving the values use somethin like this: void Accep_text(widget,call_data,client_data) Widget widget; caddr_t call_data, client_data; { char * buf; Arg arg[1]; Cardinal n = 0; XtSetArg(arg[n], XtNstring, &buff) ; n++; XtGetValues(w_text, arg, n); } > 2) I decided to use an asciiStringWidget to allow the user to > edit one line text. The length of the string the user can > introduce is given by the initial value of XtNstring.Thus > if you initialize XtNstring to null the user won't be able > to edit anything. > ( Maybe dialog widget would be better in this case but I had > problems with the initialization : length of text field was > given by label lenght) > Is it correct?. How can the user be allowed to edit one line > without initializing the text? The example code above will work (you will need to make the text editable, however). The key point to remember is that you need to allocate the string to contain enough space, and then specify the anount of space that was allocated in the XtNlength resource. Since the text widget uses the string in place it must know the length of the buffer. The default lenght is strlen(string) and this is what is causing you the problems that you have seen. > ...but when the button is released over an insensitive widget nothing occurs. That's right. The toolkit does not deliver events to an insensitive widget, this is the definition of insensitive. Any look and feel issues associated with insensitivity are left up to the widget implementor. In the Athena widget set we decided to use stippled text and borders. Chris D. Peterson MIT X Consortium Net: kit@expo.lcs.mit.edu Phone: (617) 253 - 9608 Address: MIT - Room NE43-213