[Gambas-user] Trying to do a "confirm" window (hopefully worded better)

[Benoit Minisini]

On Friday 07 October 2005 07:39, Kchula-Rrit wrote:
>   I'm trying to do a "confirm" window to ask the user if they really want
> to exit a program.  I'm not sure what I'm doing wrong, but it doesn't work.
>
>         Right now, the program is just one window (FMain.form) with two
> buttons, created by the Gambas "New Project" command with "Standard Dialog"
> option.  I changed the name of the "OK" button to say "Exit", the "Cancel"
> button was left alone.
>
>         When the user selects the "Exit" button, I want the main window to
> minimize and a "Confirm" window to show.  I have defined the "Confirm"
> window (FExit.form) to also have two buttons, called "Yes" and "No".
>  Selecting either button should close the "Confirm" window and return to
> the main program.  Selecting "Yes" should set an exit-flag in the main
> program, which then exits.  Selecting "No" should just return to the main
> program, which should restore the main window.
>
>         The main window minimizes like it should but the confirm-window
> never shows.  
> When I "un-minimize" the main window, the buttons are blank 
> and do not respond.
>
>         Can anyone tell me what I'm doing wrong?  I'm using Gambas 1.9.20
> in Debian Sarge from the www.linex.org packages, with "gb", "gb.debug", and
> "gb.qt" checked in the "components" property of the project file.
>
>         I'm using a couple of blank WHILE loops to wait for the user to
> respond- is this appropriate?  I'm kind of new to event-driven programs and
> this has me stymied.
>
>         Here's my main class file.
> ' Gambas class file  (FMain.class)
>
> ' TRUE = Exit, FALSE = Don't Exit
> STATIC PUBLIC ExitFlag AS Boolean
>
> STATIC PUBLIC SUB _init()
>
>     ExitFlag = FALSE
>
> END
>
> STATIC PUBLIC SUB _exit()
>
> END
>
> PUBLIC SUB _new()
>
> END
>
> PUBLIC SUB _free()
>
> END
>
> STATIC PUBLIC FUNCTION Run() AS Boolean
>
>     ' This function was created by Gambas
>     DIM hForm AS Form
>
>     hForm = NEW FMain
>
>     RETURN hForm.ShowModal()
>
> END
>
> PUBLIC SUB btnExit_Click()
>
>     ' Minimize Main Window
>     ME.Minimized = TRUE
>
>     ' Show "Confirm" Window
>     FExit.Confirm()
>
>     WHILE FExit.InExitScreen = TRUE
>         ' Wait for user to respond to "Confirm" window

This is an infinite loop, it never ends. You must understand that GUI 
programming is event loop driver, and what an event loop is exactly.

In other words, nothing happens in the GUI while you are executing Gambas 
code, *unless* you call the WAIT instruction.

But do not implement your own event loop by looping around the WAIT 
instruction. Just use Form.Show, Form.ShowModal and Form.Close.

So you must do FExit.ShowModal(), so that the FExit form is shown as a dialog. 
This function returns when FExit is closed.

>     WEND
>
>     IF ExitFlag <> FALSE THEN
>         ' User really wants to exit- do so.
>         ME.Close
>     ENDIF
>
>     ' User goofed.  Return to main program.
>     ' Restore Main Window
>     ME.Minimized = FALSE
>     ME.Refresh
>
> END
>
> PUBLIC SUB btnCancel_Click()
>
>     ' Exit
>     ME.Close()
>
> END
> ==========================================
>
> Here's my "Exit-class" file:
> ' Gambas class file (FExit.class)
>
> ' Exit window - just contains two buttons
> PUBLIC ExitForm AS FExit
>
> ' "Yes" button - user really wants to exit.
> PUBLIC btnYes AS Button
>
> ' "No" button - Oops, return to main.
> PUBLIC btnNo AS Button
>
> ' TRUE = Wait for user to respond to "Confirm" window.
> PRIVATE StayInLoop AS Boolean
>
> ' TRUE = User is in "Confirm" window.
> PUBLIC InExitScreen AS Boolean
>
>
> PUBLIC SUB _new()
>
>
>     ' Filler
>     InExitScreen = TRUE
>
> END
>
>
> PUBLIC SUB _free()
>
>
> END
>
> PUBLIC SUB Confirm()
>
>
>     ' Display new window.
>     ExitForm = NEW FExit
>     FExit.Caption = "Confirm"
>     ' (Try to) Display window.
>     FExit.Show
>     FExit.Refresh
>
>     ' Create buttons.
>     btnYes = NEW Button(ME)
>     btnNo = NEW Button(ME)
>
>     FExit.Refresh
>
>     ' Set loop flag.
>     StayInLoop = TRUE
>
>     WHILE StayInLoop = TRUE
>         ' Wait for user to respond.

This is a loop that never ends too.

>     WEND
>
>     ' Close window.
>     FExit.Close
>
>     ' Clear Exit-window flag.
>     InExitScreen = FALSE
>
> END
>
> PUBLIC SUB Yes_Click()
>
>
>     ' Set Program-Exit flag in main routine.
>     FMain.ExitFlag = TRUE
>
>     ' Clear loop-flag.
>     StayInLoop = FALSE
>
> END
>
> PUBLIC SUB No_Click()
>
>     ' Clear loop-flag.
>     StayInLoop = FALSE
>
> END
>
> ================================================
>

Regards,

-- 
Benoit Minisini