Task: GUI component interaction








VB: VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   2265
   ClientLeft      =   60
   ClientTop       =   600
   ClientWidth     =   2175
   LinkTopic       =   "Form1"
   ScaleHeight     =   2265
   ScaleWidth      =   2175
   StartUpPosition =   3  
   Begin VB.CommandButton cmdRnd 
      Caption         =   "Random"
      Height          =   495
      Left            =   120
      TabIndex        =   2
      Top             =   1680
      Width           =   1215
   End
   Begin VB.CommandButton cmdInc 
      Caption         =   "Increment"
      Height          =   495
      Left            =   120
      TabIndex        =   1
      Top             =   1080
      Width           =   1215
   End
   Begin VB.TextBox txtValue 
      Height          =   495
      Left            =   120
      TabIndex        =   0
      Text            =   "0"
      Top             =   240
      Width           =   1215
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

Private Sub Form_Load()
    Randomize Timer
End Sub

Private Sub cmdRnd_Click()
    If MsgBox("Random?", vbYesNo) Then txtValue.Text = Int(Rnd * 11)
End Sub

Private Sub cmdInc_Click()
    If Val(txtValue.Text) < 10 Then txtValue.Text = Val(txtValue.Text) + 1
End Sub

Private Sub txtValue_KeyPress(KeyAscii As Integer)
    Select Case KeyAscii
        Case 8, 43, 45, 48 To 57
            
        Case Else
            KeyAscii = 0
    End Select
End Sub




Ada: with Ada.Numerics.Discrete_Random;
with Ada.Strings.Fixed;
with Gtk.Main;
with Gtk.Handlers;
with Gtk.Button;
with Gtk.Window;
with Gtk.GEntry;
with Gtk.Editable;
with Gtk.Box;
with Gtk.Widget;
with Glib.Values;
with Gtkada.Dialogs;

procedure Interaction is

   The_Value : Natural := 0;

   package Natural_Random is new Ada.Numerics.Discrete_Random (Natural);
   RNG : Natural_Random.Generator;

   Main_Window      : Gtk.Window.Gtk_Window;
   Content          : Gtk.Box.Gtk_Vbox;
   Increment_Button : Gtk.Button.Gtk_Button;
   Random_Button    : Gtk.Button.Gtk_Button;
   Entry_Field      : Gtk.GEntry.Gtk_Entry;

   package Entry_Callbacks is new Gtk.Handlers.Callback
     (Gtk.GEntry.Gtk_Entry_Record);

   package Button_Callbacks is new Gtk.Handlers.Callback
     (Gtk.Button.Gtk_Button_Record);

   package Window_Callbacks is new Gtk.Handlers.Return_Callback
     (Gtk.Window.Gtk_Window_Record, Boolean);

   
   procedure Update_Entry is
   begin
      Gtk.GEntry.Set_Text
        (The_Entry => Entry_Field,
         Text      =>
           Ada.Strings.Fixed.Trim
             (Source => Natural'Image (The_Value),
              Side   => Ada.Strings.Both));
   end Update_Entry;

   
   procedure Update_Value is
   begin
      The_Value := Natural'Value (Gtk.GEntry.Get_Text (Entry_Field));
   exception
      when Constraint_Error =>
         The_Value := 0;
   end Update_Value;

   
   procedure On_Insert_Text
     (Object : access Gtk.GEntry.Gtk_Entry_Record'Class;
      Params : Glib.Values.GValues)
   is
      Length : constant Glib.Gint :=
        Glib.Values.Get_Int (Glib.Values.Nth (Params, 2));
      Text   : constant String    :=
        Glib.Values.Get_String (Glib.Values.Nth (Params, 1), Length);
   begin
      declare
         Number : Natural;
      begin
         Number := Natural'Value (Text);
      exception
         when Constraint_Error =>
            
            Gtk.Handlers.Emit_Stop_By_Name
              (Object => Object,
               Name   => Gtk.Editable.Signal_Insert_Text);
      end;
   end On_Insert_Text;

   
   procedure On_Increment_Click
     (Object : access Gtk.Button.Gtk_Button_Record'Class)
   is
   begin
      Update_Value;
      The_Value := The_Value + 1;
      Update_Entry;
   end On_Increment_Click;

   
   procedure On_Random_Click
     (Object : access Gtk.Button.Gtk_Button_Record'Class)
   is
      use type Gtkada.Dialogs.Message_Dialog_Buttons;
   begin
      if Gtkada.Dialogs.Message_Dialog
        (Msg            => "Really reset to random value?",
         Dialog_Type    => Gtkada.Dialogs.Confirmation,
         Buttons        => Gtkada.Dialogs.Button_Yes or
           Gtkada.Dialogs.Button_No,
         Default_Button => Gtkada.Dialogs.Button_Yes) =
        Gtkada.Dialogs.Button_Yes
      then
         The_Value := Natural_Random.Random (RNG);
         Update_Entry;
      end if;
   end On_Random_Click;

   
   function On_Main_Window_Delete
     (Object : access Gtk.Window.Gtk_Window_Record'Class)
      return   Boolean
   is
   begin
      Gtk.Main.Main_Quit;
      return True;
   end On_Main_Window_Delete;

begin
   
   Natural_Random.Reset (RNG);

   Gtk.Main.Init;

   Gtk.GEntry.Gtk_New (Widget => Entry_Field);
   Update_Entry;
   Entry_Callbacks.Connect
     (Widget => Entry_Field,
      Name   => Gtk.Editable.Signal_Insert_Text,
      Cb     => On_Insert_Text'Access);

   Gtk.Button.Gtk_New (Button => Increment_Button, Label => "Increment");
   Gtk.Button.Gtk_New (Button => Random_Button, Label => "Random");

   Button_Callbacks.Connect
     (Widget => Increment_Button,
      Name   => Gtk.Button.Signal_Clicked,
      Marsh  => Button_Callbacks.To_Marshaller (On_Increment_Click'Access));
   Button_Callbacks.Connect
     (Widget => Random_Button,
      Name   => Gtk.Button.Signal_Clicked,
      Marsh  => Button_Callbacks.To_Marshaller (On_Random_Click'Access));

   Gtk.Box.Gtk_New_Vbox (Box => Content);
   Gtk.Box.Add (Container => Content, Widget => Entry_Field);
   Gtk.Box.Add (Container => Content, Widget => Increment_Button);
   Gtk.Box.Add (Container => Content, Widget => Random_Button);

   Gtk.Window.Gtk_New (Window => Main_Window);
   Gtk.Window.Add (Container => Main_Window, Widget => Content);

   Window_Callbacks.Connect
     (Widget => Main_Window,
      Name   => Gtk.Widget.Signal_Delete_Event,
      Cb     => On_Main_Window_Delete'Access);
   Gtk.Window.Show_All (Widget => Main_Window);

   Gtk.Main.Main;
end Interaction;