Detect if a application is not in use

Question

How can I detect if an application is not used for more than x minutes in DELPHI

Answer 1

Depends on how you're defining "used" -- if you were monitoring yourself, you could look at the last time you responded to user interaction by logging it when it happened (mouse move/key pressed/menu event fired/etc.). Monitoring another application is tricky as it'll be harder to define that it is "in use".

Answer 2

That really depends on the application and what it does. While users may not interact with it in the sense of new input, they certainly might be viewing the client area that is visible.

Also - you don't say if you want to detect this internal to the app or external to the app.

Simple methods

• see if it has current focus.
• check if the window is visible

lots of others too, but they rely on the app itself.

You must define what you mean by "used" as well. It could mean different things and that would make significant changes to how you determine whether it met your criteria or not.

Answer 3

Here is some code that looks for mouse and keybord activity with the applicatin

procedure TUserActivity.AppMessage(var Msg: TMsg; var Handled: Boolean);
begin
  Handled := False;
  case Msg.message Of
    WM_KEYDOWN,
    WM_LBUTTONDOWN,
    WM_MBUTTONDOWN,
    WM_RBUTTONDOWN:
      Activity := TRUE;
    WM_MOUSEMOVE:
    begin
      if (LastXYPos <> Msg.lParam) then 
        Activity := True;
      LastXYPos := Msg.lParam;
    end;
  end;
end;

Answer 4

If you write Windows app take a look at GetLastInputInfo function.

Answer 5

Use the applications OnDeactivate and onActive events.. That way you can abort the longrunning job if the user activates your program again.

ex:

 Application.OnDeactivate = yourDeactivProcedure;

procedure mainform.YourDecativateProcedure (sender : tObject);
begin
 // do your job.. 
end;

To handle the activate event to abort you either have to do it a bad way with a sleep and after the sleep check if i global vairable has been set. Or you can have a theared object that does the loongrunning job. Which I would say is much better. You can set the loongrunningjobs priority to low and it wont affect your program as much,