[lazarus] Get button state

[Michael Van Canneyt]

On Tue, 16 Dec 2003, Sebastian Kraft wrote:

> Hi all,
>
> I have a window with 2 buttons. One Start and one Stop. When clicking on start
> the program begins to write some lines to the commandline. How can I find out
> when the button stop is pressed? Seems the event isn't handled when the
> Program is still hanging in the start-button event...
>
> Should look kind of that...
>
> procedure TTestwin.startClicked(Sender: TObject);
> begin
>  repeat writeln('xxx') until "button stop pressed";
> end;
>
> But I've no idea who to build that in Pascal code...
>
> Can anyone help?

In the form class declaration, Introduce a boolean variable FStopped:

Private
  FStopped : Boolean;

The start button onclick handler works as follows:

procedure TTestwin.StartClicked(Sender: TObject);
begin
 FStopped:=False;
 repeat
    writeln('xxx');
    Application.ProcessMessages; // Process pending messages.
 until FStopped;
end;

The stop button onclick handler works as follows:

procedure TTestwin.StopClicked(Sender: TObject);

begin
  FStopped:=True;
end;

The most important part is the
  Application.ProcessMessages;
This makes sure that the click on the stop button is registered.

Michael.