Java: use Robot while running fullscreen app

Question

I have a problem with Robot class in Java: it sometimes doesn't work when i run a fullscreen game. Here's my code:

Toolkit tlkt = Toolkit.getDefaultToolkit();
Robot bot = new Robot();
while(true) {
    Thread.sleep(3000);
    tlkt.beep(); //make sure that program still runs
    bot.mousePress(MouseEvent.BUTTON1_DOWN_MASK);
    bot.mouseRelease(MouseEvent.BUTTON1_DOWN_MASK);
}

I want to left-click every 3 seconds and beep for sure. It work fine but when I run some full-screen application, then it just beeps but not click.

I already tried to move the Robot declaration into the loop, so new Robot is created every time, but with no sucess.

I have tried it on 5 different games, on 3 of them it worked fine even with fullscreen, but on 2 it didnt work but only beeped. Any help?

Answer 1

Assuming you are on a Windows machine, the call to java.awt.Robot calls are redirected to sun.awt.windows.WRobotPeer, which in turn calls native code in awt_Robot.cpp. You can check the source code of the awt_Robot.cpp here : http://www.koders.com/cpp/fidFFE004659A9CAB3DA2B3302C457E624AF6F3EEDF.aspx?s=GetDIBits#L232

Here you can see that the mouse events are realized with win32 call mouse_event(...) (defined in winuser.h)

So your Robot mouse click calls are limited by the limitations of mouse_event(...).

Then a little googling on this, reveals that some games have some sort of macro protection mechanism. They ignore mouse_event(...) routed methods and talk directly with the driver. Hackshield, for instance, provides such protection mechanisms to a number of games. So this is the reason why some games do not receive your Robot mouse clicks.