Re: Updating displayed spinbutton value from a text file

[Allin Cottrell <cottrell wfu edu>]

On Wed, 4 Jul 2018, Roger Matthews via gtk-app-devel-list wrote:

>     I'm using gtk+3.10 on Ubuntu 14.04 and am writing an application in C, with the user interface 
> constructed with a builder.ui file. I am using spinbuttons to create and change Cairo drawings of some 
> mathematical functions. The spinbuttons’ adjustment value is initialised from the builder.ui file and can 
> then can be changed with the spinbutton, I also read values from a text file to create and change the 
> drawings, which after being read from the file (containing many drawing parameters) these parameters are then 
> written to seperate files for each parameter which are then read into the drawing function in drawing.c, 
> which is compiled together with mymain.c.
>     This works ok (the drawings change), except that when reading the values from the file I would also like 
> to update the values displayed in the spinbuttons so that they match those in the file and with the correctly 
> updated drawings.
>     I have tried using the following, taken from Foundations of GTK+ Development, by Andrew Krause (gtk+2):
>
> gtk_spin_button_set_value (GtkSpinButton *spin_drawingparameter1, 
> int drawingparameter1);
>
> in the callback for the spinbutton *spin_readfile (which makes the 
> choice between reading/not reading the file).
>
> When attempting to compile I receive this error message:
>
> mymain.c: In function ‘callback_readfile’:
> mymain.c:1124:28: error: expected expression before ‘GtkSpinButton’
>
> gtk_spin_button_set_value (GtkSpinButton *spin_drawingparameter1, 
> int drawingparameter1);

Try

gtk_spin_button_set_value(GTK_SPIN_BUTTON(spin_drawingparameter1),...

You have a broken attempt at a cast.

--
Allin Cottrell
Department of Economics
Wake Forest University