[gtkada] Getting Toplevel for Gtk_Entry

[Rick Duley]

Hi folks

I have a Gtk_Entry within a Box, within a Frame, within a Box, within a Toplevel
Window thus:

+---------- Window ------------+
| +--------- VBox -----------+ |
| | +---- Frame&Label -----+ | |
| | | +----- HBox -------+ | | |
| | | | +--------------+ | | | |
| | | | |    Entry     | | | | |
| | | | +--------------+ | | | |
| | | +------------------+ | | |
| | +----------------------+ | |
| +--------------------------+ |
+------------------------------+

Here is a code segment:

   procedure On_Analyse60_Source_Folder_Entry_Changed
     (Object : access Gtk_Entry_Record'Class)
   is
      Main_Window : Gtk_Window := Get_Parent_Window(Widget => Object);
   begin
      . . .

Any attempt to compile using GPS 2.1.0 (20041129) hosted on pentium-mingw32msv
with GNAT GAP 1.1.0 (20041209-323) fails with the following error message:

analyse60_window_pkg-callbacks.adb:69:29: expected type "Gtk_Window" defined at
gtk-window.ads:64
analyse60_window_pkg-callbacks.adb:69:29: found type "Gdk_Drawable" defined at
gdk.ads:46


*Q.1. Why would Get_Parent_Window return a Gdk_Drawable in this case?*


The only thing I can get to work is:

   procedure On_Analyse60_Source_Folder_Entry_Changed
     (Object : access Gtk_Entry_Record'Class)
   is
      Main_Window : constant Gtk_Widget := Get_Toplevel(Widget => Object);
   begin
      -- debug
      Put_Line("Widget is "
               & Get_Name(Widget => Main_Window));
      Put_Line("Entry contains "
               & Get_Text(The_Entry => Object));
      -- debug
   end On_Analyse60_Source_Folder_Entry_Changed;

This prints the name I set in the Gtk_Window_Record and the text I type into the
entry.  My problem is that, when the content of the Entry is changed, I wish to
save the text in the Entry into an Unbounded String identified as
"Source_Folder" contained in a record called "Arguments" to which I have an
access in the Gtk_Window_Record (now represented by Main_Window).  This access
is allocated memory in the Initialize procedure.

Given the code:

   procedure On_Analyse60_Source_Folder_Entry_Changed
     (Object : access Gtk_Entry_Record'Class)
   is
      Main_Window : constant Gtk_Widget := Get_Toplevel(Widget => Object);
   begin
      Main_Window.Arguments.Source_Folder :=                     -- line 79
        To_Unbounded_String(Get_Text(The_Entry => Object));

      -- debug
      Put_Line(To_String(Main_Window.Arguments.Source_Folder));  -- line 83
      -- debug
   end On_Analyse60_Source_Folder_Entry_Changed;

I get the error messages:

analyse60_window_pkg-callbacks.adb:79:18: no selector "Arguments" for type
"Gtk_Widget_Record'Class" defined at gtk-widget.ads:74
analyse60_window_pkg-callbacks.adb:83:37: no selector "Arguments" for type
"Gtk_Widget_Record'Class" defined at gtk-widget.ads:74

That's fair enough.  Main_Window _is_ declared as a Gtk_Widget.  It has to be -
Get_Toplevel returns a Gtk_Widget - but this particular Widget is a Gtk_Window.
 Not only that, it's a Window I know as a named Gtk_Window_Record which has
something named "Arguments" in it!  Here it is:

   type Analyse60_Window_Record is new Gtk_Window_Record with record

      Arguments : Analyst.Arguments_Access_Type;
      -- Storage access for the user-defined arguments.

      Analyse60_Base_Box : Gtk_Vbox;
      . . .
      Analyse60_Source_Folder_Frame : Gtk_Frame;
      Analyse60_Source_Folder_Hbox : Gtk_Hbox;
      Analyse60_Source_Folder_Entry : Gtk_Entry;
      Analyse60_Source_Folder_Label : Gtk_Label;
      . . .
   end record;

According to my way of thinking the procedure
On_Analyse60_Source_Folder_Entry_Changed above should, when the content of
Object is changed, store the text in Object in the Unbounded String in the
record within the window_record.  Then the debug line should read that
Unbounded String and print it.  But it don't!


*Q.2.  What have I done wrong?*

Please, don't just tell me what's wrong - please show me what's right!

Thanks
-------------------------------------------
"Professional qualitative judgement
   consists in knowing the rules
     for using (or occasionally breaking)
       the rules."
                            D. Royce Sadler
-------------------------------------------
Rick Duley
Murdoch University
School of Engineering Science
Perth, Western Australia
http://eng.murdoch.edu.au/~rick
aussie : 040 910 6049                .-_|\
o'seas : + 61 40 910 6049           /     \
                              perth *_.-._/
                                         v