[SOLVED] Keep an action repeating while a TButton is pressed.

[CM630]

The task is to change the values of a an element  (a variable or a visual control, like for example SpinEdit) while a button is pressed. One of the buttons shall increase the value and the other one should decrease it.
So for an example I created a TSpinEdit, two buttons (ButtonUp and ButtonDown) and a Timer1, disabled by default, and I declared a SpinInc: Integer;

First obstacle is that I could not find how to detect if the button is pressed.
I did :

Code: [Select]

procedure TForm1.ButtonUpClick(Sender: TObject);
begin
  SpinEdit1.Value:=SpinEdit1.Value+1;
end;

procedure TForm1.ButtonUpMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
    SpinInc:=1;
    Timer1.Enabled:=True;
end;

procedure TForm1.ButtonUpMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
   Timer1.Enabled:=False;
end;

procedure TForm1.ButtonDownClick(Sender: TObject);
begin
    SpinEdit1.Value:=SpinEdit1.Value-1;
end;

procedure TForm1.ButtonDownMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  SpinInc:=-1;
  Timer1.Enabled:=True;
end;

procedure TForm1.ButtonDownMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Timer1.Enabled:=False;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  SpinEdit1.Value:=SpinEdit1.Value + SpinInc;
end;
It sort of works, with the exception when the button is clicked by the keyboard (TAB to it and press spacebar).
In order to do it, I have to use also OnKeyDown and OnKeyUp, checking if the key is Spacebar.
Maybe there is a simpler solution?
I tried BitButton and SpeedButton, but they have no pressed property neither.

[wp]

Isn't this behavior built into TSpinEdit and TFloatSpinEdit?

[CM630]

I actually mean to use this for something else (moving a point in TAChart), but SpinEdit was the first numeric control that occurred to me.

[howardpc]

The Common Controls page also offers TTrackBar and TUpDown, either of which might suit your purpose.

[CM630]

Now I realize that my example is too specific, while I am searching a more general purpose solution, so I edited my first post
Maybe another example will explain things more globally.
I have 9 buttons, for each direction and I have a button with an asterisk on it (see image attached). How am I to move the button with the asterisk while a button for the corresponding direction is pressed (button is pressed- asterisk moves, an it will stop moving when the button is released).

I cannot use track bar, because it is something else, and I cannot use TUpDown, because I need to change the image on the button.
EDIT: Now I checked to find that I am using TArrows (so it occurs it cannot handle keyboard clicks), but I'd prefer to switch to TSpeedButtons.

[wp]

TSpeedButton doesn't handle the keyboard either...

The only solution that I see is using a Timer which activates at MouseDown on a button and which moves the target with each OnTimer event. Taking the Sender parameter of the MouseDown event of the button allows you to determine the button clicked and the direction to go. This shouldn't be too hard.

Maybe there are buttons with "autofire" capabilities somewhere (Rx?), but this usually comes with the burdon of installing an entire library needed for nothing else.

[howardpc]

The attached project is one you can adapt using speedbuttons in the way I think you are looking for.

[CM630]

Thanks for the ideas, they are quite similar to my code, so I know I'm on the right way.
Still I can't get how it is possible for the TButton not to have a pressed property, but I will put the blame on Delphi.

[wp]

Why do you need a "pressed" property? You have the events OnMouseDown and OnMouseUp...

See this example where the Label1 counts up while the Mouse is held down on the button, but stops when it is released:

Code: [Select]

var
  Counter: Integer = 0;

procedure TForm1.Button1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Timer1.Enabled := true;
end;

procedure TForm1.Button1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Timer1.Enabled := false;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  Label1.Caption := IntToStr(Counter);
  inc(Counter);
end;


[CM630]

@WP, you code is exactly the same as mine.
Pressed would be useful, because I could simply use a timer like

Code: [Select]

procedure TForm1.Timer1Timer(Sender: TObject);
begin
      if ButtonLeft.pressed then ...
       if ButtonRight.pressed then ...
end;
Maybe I'm used to other IDEs.

I will decide how exactly to I do it, I can emulate a pressed property, if I find it easier.

[wp]

      if ButtonLeft.pressed then ...
       if ButtonRight.pressed then ...

I still don't see the problem in typing 2-3 lines: It would be the first thing to log the button pressed in the MouseDown event

Code: [Select]

var
  StoredShift: TShiftState;

procedure TForm1.Button1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  StoredShift := Shift;
  Timer1.Enabled := true;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  if StoredShift = ssLeft then ...
  if StoredShift = ssRight then...
end


[CM630]

There is no problem in storing the shifts- you have emulated a pressed state. For some reason I expected that a more native existed. Everything can be solve by adding a few (thousand of) line, just too many times I've reimplemented existing features.
Anyway, here's my final solution, it works, so I won't touch it:
I had

Code: [Select]

TArrowStar= Record
ArrowLeftPressed: Boolean;
  ArrowUpPressed: Boolean;
  ArrowRightPressed: Boolean;
  ArrowDownPressed: Boolean;
end;   


so I just added a few lines
 

Code: [Select]

TArrowStar= Record
  ArrowLeft:  TArrow;
  ArrowUp:    TArrow;
  ArrowRight: TArrow;
  ArrowDown:  TArrow;
  ArrowLeftPressed: Boolean;
  ArrowUpPressed: Boolean;
  ArrowRightPressed: Boolean;
  ArrowDownPressed: Boolean;
end;