Detecting a New Cartwall Page

English Scripts
1

I’d like to take some actions whenever a new CartWall page is opened. But there doesn’t seem to be a background script event that does that.
The nearest is OnCartWallPlayerStateChange. It does fire when a specific cart slot on the new page is different - e.g. changes from blank to occupied, so it alters from “empty” to “stopped”. But that’s not always the case.

Is there a more reliable way I could do this?

Thanks, Greg

2

I should clarify this. OnCartWallPlayerStateChange basically does what it should with respect to changes in player states, as I mentioned before.
The comment (in 6.02) says it also fires when “…the user switches to another page.” I’m not sure that’s always true. I’ve found it doesn’t work :-

  • If switching between pages with exactly the same players occupied / unoccupied (as they’re all the same state).
  • If adding a new empty “Untitled” page when the CartWall itself is empty.
  • When adding multiple empty pages to the above situation.

Perhaps what’s needed is an additional event, something like “OnCartWallPageChange” that specifically looks at pages rather than players.

Thanks, Greg

3

Hi Greg,

the main purpose of OnCartwallPlayerStateChange is to push out the state of the players/slots on the current page to external devices, e.g. LEDs on a MIDI controller. So yes, it will not trigger if you switch between pages and the player state remains the same.

Right now, the workaround is to use a timer that looks at Cartwall.GetActivePage:

var
  curPage: ICartwallPageControl;

procedure OnTimer;
var
  p: ICartwallPageControl;
begin
  p := Cartwall.GetActivePage;
  if p <> curPage then begin
    curPage := p;
    // page has changed, do something here
  end;
end;

procedure OnLoad;
begin
  curPage := nil;
  EnableTimer(100); // milliseconds
end;

PS: Received your e-mail while I was away from office, will reply shortly.
end;

4

Hi Torben,

No problem, polling with a timer was always going be plan B. I’ll do that for now.

Regards,

Greg