How to connect a callback function to its signal - ada

Question

i created two buttons a that display a Gtk_Radio_Button and a button that display a GtK_label but when i click on buttons nothing happens. I don't understand why it doesn't work yet the code compiles and runs without finding any error.
main_Program.adb
With Gtk.Window; Use Gtk.Window;
With Gtk.Button; Use Gtk.Button;
With Gtk.Grid; Use Gtk.Grid;
With file; Use file;
Procedure main_program is
Bouton : Gtk_Button;
Bouton2 : Gtk_Button;
Win : Gtk_Window;
Test : Test_Record;
begin
Gtk.Main.Init;
Init_Grid (Container => Test);
Gtk_New (Win);
Win.Add (Test.Grid);
Win.Set_Default_Size (Width => 600,
Height => 400);
Gtk_New (Bouton,Label => "Bouton");
Test.Grid.Attach (Bouton,0,0);
P.Connect (Widget => Bouton,
Name => Signal_Clicked,
Marsh => Test2.P.To_Marshaller (Init_Button'Access),
After => False);
Gtk_New (Bouton2,Label => "Bouton2");
Test.Grid.Attach (Bouton2,50,4);
P.Connect (Widget => Bouton2,
Name => Signal_Clicked,
Marsh => Test2.P.To_Marshaller (Init_Text'Access),
After => False);
Win.Show_All;
Main;
end Main_Program;
file.ads
With Gtk.Label; Use Gtk.Label;
With Gtk.Radio_Button; Use Gtk.Radio_Button;
With Gtk.Grid; Use Gtk.Grid;
With Gtk.Handlers;
Package file is
type Test_Record is record
Text : Gtk_Label;
Grid : Gtk_Grid;
Button_Radio : Gtk_Radio_Button;
end record;
Procedure Init_Text ( Self : access Gtk_Widget_Record'Class );
-- Callback for create the text
Procedure Init_Button (Self : access Gtk_Widget_Record'Class );
-- Callback for Initialize the Radio Button;
Procedure Init_Grid (Container : out Test_Record);
-- Initialize the Gtk.Grid.Gtk_Grid
Package P is new Gtk.Handlers.Callback (Gtk_Widget_Record);
Use P;
end file;
file.adb
With file; Use file;
Package body file is
Procedure Init_Grid ( Container : out Test_Record ) is
begin
Gtk_New (Container.Grid);
end Init_Grid;
Procedure Init_Button ( Self : access Gtk_Widget_Record'Class ) is
V : Test_Record;
begin
Init_Grid (Container => V);
Gtk_New (V.Button_Radio,
Group => null,
Label => "Button Radio");
V.Grid.Attach (V.Button_Radio,0,50);
V.Grid.Show;
end Init_Button;
Procedure Init_Text (Self : access Gtk_Widget_Record'Class) is
V : Test_Record;
begin
Init_Grid (Container => V);
Gtk_New (V.Text);
V.Text.Set_Label ("Hello,World");
V.Grid.Attach (V.Text,150,0);
V.Grid.Show;
end Init_Text;
end file;
I want that when I click on the first button it shows me a radio button and when I click on the second button it shows me a label.

Answer 1

I would consider to not create/destroy the label and radio button, but just toggle their visibility instead. Furthermore, I would also recommend to derive the main window from the GTK window type and always properly terminate the application when requested (see Destroy_Event_Callback in the example below).
app.ads
package App is
end App;
app-main_window.ads
with Gtk.Window; use Gtk.Window;
with Gtk.Grid; use Gtk.Grid;
with Gtk.Button; use Gtk.Button;
with Gtk.Check_Button; use Gtk.Check_Button;
with Gtk.Label; use Gtk.Label;
package App.Main_Window is
type App_Main_Window_Record is new Gtk_Window_Record with private;
type App_Main_Window is access all App_Main_Window_Record'Class;
------------------
-- Constructors --
------------------
procedure Gtk_New
(Main_Window : out App_Main_Window);
procedure Initialize
(Main_Window : not null access App_Main_Window_Record'Class);
private
Window_Width : constant := 300;
Window_Height : constant := 100;
type App_Main_Window_Record is
new Gtk.Window.Gtk_Window_Record with
record
Grid : Gtk_Grid;
Button_1 : Gtk_Button;
Button_2 : Gtk_Button;
Check_Button : Gtk_Check_Button;
Label : Gtk_Label;
end record;
end App.Main_Window;
app-main_window.adb
with Gtk.Main;
with Gtk.Widget;
with Gtk.Window;
with Gdk.Event;
package body App.Main_Window is
procedure Destroy_Event_Callback
(Widget : access Gtk.Widget.Gtk_Widget_Record'Class);
function On_Button_1_Pressed_Callback
(Self : access Gtk.Widget.Gtk_Widget_Record'Class;
Event : Gdk.Event.Gdk_Event_Button) return Boolean;
function On_Button_2_Pressed_Callback
(Self : access Gtk.Widget.Gtk_Widget_Record'Class;
Event : Gdk.Event.Gdk_Event_Button) return Boolean;
-------------
-- Gtk_New --
-------------
procedure Gtk_New (Main_Window : out App_Main_Window) is
begin
Main_Window := new App_Main_Window_Record;
App.Main_Window.Initialize (Main_Window);
end Gtk_New;
----------------
-- Initialize --
----------------
procedure Initialize
(Main_Window : not null access App_Main_Window_Record'Class)
is
begin
-- Initialize and setup the window.
Gtk.Window.Initialize (Main_Window);
Main_Window.Set_Title ("Demo Window");
Main_Window.Set_Size_Request (Window_Width, Window_Height);
Main_Window.Set_Resizable (False);
-- Attach callback: properly end the GTK application when requested.
Main_Window.On_Destroy
(Call => Destroy_Event_Callback'Access);
-- Add a grid.
Gtk_New (Main_Window.Grid);
Main_Window.Grid.Set_Hexpand (True);
Main_Window.Grid.Set_Vexpand (True);
Main_Window.Grid.Set_Column_Homogeneous (True);
Main_Window.Grid.Set_Row_Homogeneous (True);
Main_Window.Add (Main_Window.Grid);
-- Create the two buttons.
Gtk_New (Main_Window.Button_1, Label => "Button 1");
Gtk_New (Main_Window.Button_2, Label => "Button 2");
-- Insert both buttons into the grid.
--
-- +------+------+
-- | | |
-- +------+------+
-- (0,1) --> | XXXX | XXXX | <-- (1,1)
-- +------+------+
Main_Window.Grid.Attach
(Child => Main_Window.Button_1,
Left => 0,
Top => 1);
Main_Window.Grid.Attach
(Child => Main_Window.Button_2,
Left => 1,
Top => 1);
-- Attach "button pressed" callbacks.
Main_Window.Button_1.On_Button_Press_Event
(Call => On_Button_1_Pressed_Callback'Access);
Main_Window.Button_2.On_Button_Press_Event
(Call => On_Button_2_Pressed_Callback'Access);
-- Create new label and check button.
Gtk_New (Main_Window.Label, Str => "Hello World!");
Gtk_New (Main_Window.Check_Button, Label => "A Check Button");
-- Insert both into the grid.
--
-- +------+------+
-- (0,0) --> | XXXXXXXXXXX | Width: 2 columns
-- +------+------+
-- | | |
-- +------+------+
Main_Window.Grid.Attach
(Child => Main_Window.Label,
Left => 0,
Top => 0,
Width => 2);
Main_Window.Grid.Attach
(Child => Main_Window.Check_Button,
Left => 0,
Top => 0,
Width => 2);
-- Show everything except the check button.
Main_Window.Show;
Main_Window.Grid.Show;
Main_Window.Button_1.Show;
Main_Window.Button_2.Show;
Main_Window.Label.Show;
end Initialize;
----------------------------
-- Destroy_Event_Callback --
----------------------------
procedure Destroy_Event_Callback
(Widget : access Gtk.Widget.Gtk_Widget_Record'Class)
is
begin
Gtk.Main.Main_Quit;
end Destroy_Event_Callback;
----------------------------------
-- On_Button_1_Pressed_Callback --
----------------------------------
function On_Button_1_Pressed_Callback
(Self : access Gtk.Widget.Gtk_Widget_Record'Class;
Event : Gdk.Event.Gdk_Event_Button) return Boolean
is
-- (parent) (parent)
-- Button (Self) -------> Grid -------> Window
Grid : Gtk_Grid := Gtk_Grid (Self.Get_Parent);
Window : App_Main_Window := App_Main_Window (Grid.Get_Parent);
begin
-- Just toggle visibility.
Window.Label.Set_Visible (False);
Window.Check_Button.Set_Visible (True);
return True; -- GDK_EVENT_STOP, do not propagate event to parent.
end On_Button_1_Pressed_Callback;
----------------------------------
-- On_Button_2_Pressed_Callback --
----------------------------------
function On_Button_2_Pressed_Callback
(Self : access Gtk.Widget.Gtk_Widget_Record'Class;
Event : Gdk.Event.Gdk_Event_Button) return Boolean
is
Grid : Gtk_Grid := Gtk_Grid (Self.Get_Parent);
Window : App_Main_Window := App_Main_Window (Grid.Get_Parent);
begin
Window.Label.Set_Visible (True);
Window.Check_Button.Set_Visible (False);
return True; -- GDK_EVENT_STOP, do not propagate event to parent.
end On_Button_2_Pressed_Callback;
end App.Main_Window;
main.adb
with Gtk.Main;
with App.Main_Window;
procedure Main is
use App.Main_Window;
Main_Window : App_Main_Window;
begin
Gtk.Main.Init;
Gtk_New (Main_Window);
Gtk.Main.Main;
end Main;