* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 10:22 gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler Alain De Vos
@ 2019-11-02 11:00 ` Alain De Vos
2019-11-02 11:03 ` Dmitry A. Kazakov
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Alain De Vos @ 2019-11-02 11:00 UTC (permalink / raw)
On Saturday, November 2, 2019 at 11:22:49 AM UTC+1, Alain De Vos wrote:
> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>
> procedure hello is
> Top : Gtk.Window.Gtk_Window;
> Button : Gtk_Button;
> Label : Gtk_Label;
> VBox : Gtk_Box;
> procedure Create_Window is
> begin
> Gtk.Window.Gtk_New
> (Window => Top,
> The_Type => Gtk.Enums.Window_Toplevel);
> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
> Gtk_New(Button);
> Button.On_Clicked (Call => On_Button_Click'Access,
> Slot => Top);
> Gtk_New(Label);
> Gtk_New_Vbox(VBox);
> Add (VBox,Button);
> Add (VBox,Label);
> Add (Top,VBox);
> Gtk.Window.Show_All (Top);
> end Create_Window;
> begin
> Gtk.Main.Init;
> Create_Window;
> Gtk.Main.Main;
> end hello;
>
> I pass the topwindow to the eventhandler(slot).
> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
> {The label is not directly visible in the handler ...}
>
> package body buttonhandler is
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
> begin
> Put_line ("Hallo");
> -- I need to go from Top to Vbox to Label and set text ... ????
> end On_Button_Click;
> end buttonhandler;
Or should I subclass Gtk.Window.Gtk_Window ?
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 10:22 gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler Alain De Vos
2019-11-02 11:00 ` Alain De Vos
@ 2019-11-02 11:03 ` Dmitry A. Kazakov
2019-11-02 15:27 ` Alain De Vos
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Dmitry A. Kazakov @ 2019-11-02 11:03 UTC (permalink / raw)
On 2019-11-02 11:22, Alain De Vos wrote:
> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>
> procedure hello is
> Top : Gtk.Window.Gtk_Window;
> Button : Gtk_Button;
> Label : Gtk_Label;
> VBox : Gtk_Box;
> procedure Create_Window is
> begin
> Gtk.Window.Gtk_New
> (Window => Top,
> The_Type => Gtk.Enums.Window_Toplevel);
> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
> Gtk_New(Button);
> Button.On_Clicked (Call => On_Button_Click'Access,
> Slot => Top);
> Gtk_New(Label);
> Gtk_New_Vbox(VBox);
> Add (VBox,Button);
> Add (VBox,Label);
> Add (Top,VBox);
> Gtk.Window.Show_All (Top);
> end Create_Window;
> begin
> Gtk.Main.Init;
> Create_Window;
> Gtk.Main.Main;
> end hello;
>
> I pass the topwindow to the eventhandler(slot).
> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
> {The label is not directly visible in the handler ...}
>
> package body buttonhandler is
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
> begin
> Put_line ("Hallo");
> -- I need to go from Top to Vbox to Label and set text ... ????
> end On_Button_Click;
> end buttonhandler;
It is possible to enumerate children of a container, but that is not the
recommended way as it is weakly typed and fragile. A better way is a
derived widget. It is very easy to drive customized widgets in GtkAda. E.g.
type My_Box_Record is new Gtk_VBox with -- Derive from VBox
Button : Gtk_Button;
Label : Gtk_Label;
end record;
type My_Box is access all My_Box_Record;
procedure Gtk_New (Box : out My_Box);
Creation:
procedure Gtk_New (Box : out My_Box) is
begin
Box := new My_Box_Record;
Initialize_Vbox (Box); -- Parent's initialization from Gtk_Box
Gtk_New (Box.Button);
Box.Add (Box.Button);
Gtk_New (Box.Label);
Box.Add (Box.Label);
-- Connect signal handlers here, pass My_Box to them
end Get_New;
Put declaration of the custom widget in a separate package. All handlers
go into the package body. [This will reduce the inevitable mess GTK
imposes on any otherwise cleanly designed Ada application]
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 10:22 gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler Alain De Vos
2019-11-02 11:00 ` Alain De Vos
2019-11-02 11:03 ` Dmitry A. Kazakov
@ 2019-11-02 15:27 ` Alain De Vos
2019-11-02 16:18 ` Dmitry A. Kazakov
2019-11-02 19:07 ` Alain De Vos
2019-11-02 22:03 ` Alain De Vos
4 siblings, 1 reply; 8+ messages in thread
From: Alain De Vos @ 2019-11-02 15:27 UTC (permalink / raw)
On Saturday, November 2, 2019 at 11:22:49 AM UTC+1, Alain De Vos wrote:
> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>
> procedure hello is
> Top : Gtk.Window.Gtk_Window;
> Button : Gtk_Button;
> Label : Gtk_Label;
> VBox : Gtk_Box;
> procedure Create_Window is
> begin
> Gtk.Window.Gtk_New
> (Window => Top,
> The_Type => Gtk.Enums.Window_Toplevel);
> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
> Gtk_New(Button);
> Button.On_Clicked (Call => On_Button_Click'Access,
> Slot => Top);
> Gtk_New(Label);
> Gtk_New_Vbox(VBox);
> Add (VBox,Button);
> Add (VBox,Label);
> Add (Top,VBox);
> Gtk.Window.Show_All (Top);
> end Create_Window;
> begin
> Gtk.Main.Init;
> Create_Window;
> Gtk.Main.Main;
> end hello;
>
> I pass the topwindow to the eventhandler(slot).
> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
> {The label is not directly visible in the handler ...}
>
> package body buttonhandler is
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
> begin
> Put_line ("Hallo");
> -- I need to go from Top to Vbox to Label and set text ... ????
> end On_Button_Click;
> end buttonhandler;
In the main program I can have,
MyVBox.Button.On_Clicked (Call => On_Button_Click'Access, Slot => Top);
MyVBox.Button.On_Clicked (Call => On_Button_Click'Access, Slot => MyVBox);
with
Top : Gtk.Window.Gtk_Window;
MyVBox : MyVBoxT;
Both work fine,
In handler i can have,
procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class),
this works fine,
But when i try :
procedure On_Button_Click (MyVBox : access Gtk_Button_Record'Class)
the error received is :
hello.adb:33:56: expected type "Cb_GObject_Void" defined at gtk-button.ads:445
hello.adb:33:56: found type access to procedure "On_Button_Click" defined at...
In the docs procedure On_Clicked is defined as :
(Self : not null access Gtk_Button_Record;
Call : Cb_Gtk_Button_Void;
After : Boolean := False);
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 15:27 ` Alain De Vos
@ 2019-11-02 16:18 ` Dmitry A. Kazakov
0 siblings, 0 replies; 8+ messages in thread
From: Dmitry A. Kazakov @ 2019-11-02 16:18 UTC (permalink / raw)
On 2019-11-02 16:27, Alain De Vos wrote:
> In the main program I can have,
> MyVBox.Button.On_Clicked (Call => On_Button_Click'Access, Slot => Top);
> MyVBox.Button.On_Clicked (Call => On_Button_Click'Access, Slot => MyVBox);
> with
> Top : Gtk.Window.Gtk_Window;
> MyVBox : MyVBoxT;
> Both work fine,
>
> In handler i can have,
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class),
> this works fine,
> But when i try :
> procedure On_Button_Click (MyVBox : access Gtk_Button_Record'Class)
Because Gtk_Button_Record'Class and GObject_Record'Class are two
different types. On_Clicked with Slot parameter require downcasting,
which is why you should use Gtk.Handlers.User_Callback instead.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 10:22 gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler Alain De Vos
` (2 preceding siblings ...)
2019-11-02 15:27 ` Alain De Vos
@ 2019-11-02 19:07 ` Alain De Vos
2019-11-02 19:21 ` Dmitry A. Kazakov
2019-11-02 22:03 ` Alain De Vos
4 siblings, 1 reply; 8+ messages in thread
From: Alain De Vos @ 2019-11-02 19:07 UTC (permalink / raw)
On Saturday, November 2, 2019 at 11:22:49 AM UTC+1, Alain De Vos wrote:
> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>
> procedure hello is
> Top : Gtk.Window.Gtk_Window;
> Button : Gtk_Button;
> Label : Gtk_Label;
> VBox : Gtk_Box;
> procedure Create_Window is
> begin
> Gtk.Window.Gtk_New
> (Window => Top,
> The_Type => Gtk.Enums.Window_Toplevel);
> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
> Gtk_New(Button);
> Button.On_Clicked (Call => On_Button_Click'Access,
> Slot => Top);
> Gtk_New(Label);
> Gtk_New_Vbox(VBox);
> Add (VBox,Button);
> Add (VBox,Label);
> Add (Top,VBox);
> Gtk.Window.Show_All (Top);
> end Create_Window;
> begin
> Gtk.Main.Init;
> Create_Window;
> Gtk.Main.Main;
> end hello;
>
> I pass the topwindow to the eventhandler(slot).
> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
> {The label is not directly visible in the handler ...}
>
> package body buttonhandler is
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
> begin
> Put_line ("Hallo");
> -- I need to go from Top to Vbox to Label and set text ... ????
> end On_Button_Click;
> end buttonhandler;
Ok, so now I try to force a casting, but I'm still not there,
package body buttonhandler is
type MyVBoxR is new Gtk_VBox_Record with record
Button : Gtk_Button;
Label : Gtk_Label;
end record;
type MyVBoxT is access all MyVBoxR'Class;
procedure On_Button_Click (T : access Glib.Object.GObject_Record'Class) is
MyVBox : MyVBoxT;
begin
Put_line ("You pressed");
MyVBox :=MyVBoxT (T); -- Dangerous
Gtk.Button.Set_Label (MyVBox.Button,"You pressed");
end On_Button_Click;
end buttonhandler;
No compile time warning but a runtime error on "MyVBox :=MyVBoxT (T);" ,
the error is :
Hallo
raised CONSTRAINT_ERROR : buttonhandler.adb:15 tag check failed
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 19:07 ` Alain De Vos
@ 2019-11-02 19:21 ` Dmitry A. Kazakov
0 siblings, 0 replies; 8+ messages in thread
From: Dmitry A. Kazakov @ 2019-11-02 19:21 UTC (permalink / raw)
On 2019-11-02 20:07, Alain De Vos wrote:
> On Saturday, November 2, 2019 at 11:22:49 AM UTC+1, Alain De Vos wrote:
>> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>>
>> procedure hello is
>> Top : Gtk.Window.Gtk_Window;
>> Button : Gtk_Button;
>> Label : Gtk_Label;
>> VBox : Gtk_Box;
>> procedure Create_Window is
>> begin
>> Gtk.Window.Gtk_New
>> (Window => Top,
>> The_Type => Gtk.Enums.Window_Toplevel);
>> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
>> Gtk_New(Button);
>> Button.On_Clicked (Call => On_Button_Click'Access,
>> Slot => Top);
>> Gtk_New(Label);
>> Gtk_New_Vbox(VBox);
>> Add (VBox,Button);
>> Add (VBox,Label);
>> Add (Top,VBox);
>> Gtk.Window.Show_All (Top);
>> end Create_Window;
>> begin
>> Gtk.Main.Init;
>> Create_Window;
>> Gtk.Main.Main;
>> end hello;
>>
>> I pass the topwindow to the eventhandler(slot).
>> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
>> {The label is not directly visible in the handler ...}
>>
>> package body buttonhandler is
>> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
>> begin
>> Put_line ("Hallo");
>> -- I need to go from Top to Vbox to Label and set text ... ????
>> end On_Button_Click;
>> end buttonhandler;
>
> Ok, so now I try to force a casting, but I'm still not there,
>
> package body buttonhandler is
> type MyVBoxR is new Gtk_VBox_Record with record
> Button : Gtk_Button;
> Label : Gtk_Label;
> end record;
> type MyVBoxT is access all MyVBoxR'Class;
> procedure On_Button_Click (T : access Glib.Object.GObject_Record'Class) is
> MyVBox : MyVBoxT;
> begin
> Put_line ("You pressed");
> MyVBox :=MyVBoxT (T); -- Dangerous
> Gtk.Button.Set_Label (MyVBox.Button,"You pressed");
> end On_Button_Click;
> end buttonhandler;
>
> No compile time warning but a runtime error on "MyVBox :=MyVBoxT (T);" ,
> the error is :
> Hallo
> raised CONSTRAINT_ERROR : buttonhandler.adb:15 tag check failed
Which is why the idea is bad.
The proper conversion would look like this:
MyVBoxR'Class (T.all)'Unchecked_Access
However in Ada it is done rather this way:
procedure On_Button_Click (T : access GObject_Record'Class) is
MyVBox : MyVBoxR'Class renames MyVBoxR'Class (T.all);
begin
MyVBox.Button.Set_Label ("You pressed");
...
Note that in GtkAda you must catch and suppress exceptions. If Ada
exceptions propagate into C code they kill all application. The right
way is this:
with GLib.Messages; use GLib.Messages;
procedure On_Button_Click (T : access GObject_Record'Class) is
begin
declare
MyVBox : MyVBoxR'Class renames MyVBoxR'Class (T.all);
begin
MyVBox.Button.Set_Label ("You pressed");
...
end;
exception
when Error : others =>
Log
( "MyApp",
Log_Level_Critical,
( "Fault: "
& Exception_Information (Error)
& " in On_Button_Click "
) );
end On_Button_Click;
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler
2019-11-02 10:22 gtkada evenhandler on_procedure method , how to access children of topwindow in the eventhandler Alain De Vos
` (3 preceding siblings ...)
2019-11-02 19:07 ` Alain De Vos
@ 2019-11-02 22:03 ` Alain De Vos
4 siblings, 0 replies; 8+ messages in thread
From: Alain De Vos @ 2019-11-02 22:03 UTC (permalink / raw)
On Saturday, November 2, 2019 at 11:22:49 AM UTC+1, Alain De Vos wrote:
> I have a window with obe button and one label and want to change the text on the label when the button is pressed in the eventhandler, I pass the top window.
>
> procedure hello is
> Top : Gtk.Window.Gtk_Window;
> Button : Gtk_Button;
> Label : Gtk_Label;
> VBox : Gtk_Box;
> procedure Create_Window is
> begin
> Gtk.Window.Gtk_New
> (Window => Top,
> The_Type => Gtk.Enums.Window_Toplevel);
> Gtk.Window.Set_Title (Window => Top, Title => "Hello from ADA");
> Gtk_New(Button);
> Button.On_Clicked (Call => On_Button_Click'Access,
> Slot => Top);
> Gtk_New(Label);
> Gtk_New_Vbox(VBox);
> Add (VBox,Button);
> Add (VBox,Label);
> Add (Top,VBox);
> Gtk.Window.Show_All (Top);
> end Create_Window;
> begin
> Gtk.Main.Init;
> Create_Window;
> Gtk.Main.Main;
> end hello;
>
> I pass the topwindow to the eventhandler(slot).
> In the eventhandler I need go from the Top to the Vbox to the Label and set the text on the label ... button pressed. I probably need to set a property in the main and query it in the handler and cast the correct type ...
> {The label is not directly visible in the handler ...}
>
> package body buttonhandler is
> procedure On_Button_Click (Top : access Glib.Object.GObject_Record'Class) is
> begin
> Put_line ("Hallo");
> -- I need to go from Top to Vbox to Label and set text ... ????
> end On_Button_Click;
> end buttonhandler;
Now it worked. It was imperative to put the custom-widget-MVBox type declaration in only one place , the eventhandler .ads file.
^ permalink raw reply [flat|nested] 8+ messages in thread