Simulate keypress in java to write user inputs to another application

Question

I am developing a virtual keyboard application. Everything works fine except that what ever i write is written into the present application only not the one that is running behind.

I fell this is because ROBOT class in java only works for the application context that creates it.

Is there a work around for this?

Here is the code, i am trying to write ls in the terminal that is behind my java application:

        Robot robot = new Robot();

        robot.keyPress(KeyEvent.VK_ALT);
        robot.keyPress(KeyEvent.VK_TAB);
        robot.keyRelease(KeyEvent.VK_TAB);
        robot.keyRelease(KeyEvent.VK_ALT);

        robot.keyPress('l');
        robot.keyRelease('l');
        robot.keyPress('s');
        robot.keyRelease('s');

        robot.keyPress(KeyEvent.VK_ENTER);
        robot.keyRelease(KeyEvent.VK_ENTER);

Answer 1

judging from this example , the Robot class is able to send keystrokes to external applications - but they will arrive at the topmost window so you basically need to focus the window to which you want to have your keystrokes sent, there seems to be a variety of solutions for this, im guessing this one is the easiest :

https://stackoverflow.com/a/4782350/351861 :

Alternatively, you can write a VBScript to activate another application. For example:

Set WshShell = WScript.CreateObject("WScript.Shell") 
WshShell.AppActivate("Firefox")

Then use Runtime.exec from your Java app to execute the script.