How do I check if the caps lock key is pressed?

Question

Alright, before this gets flagged as a possible duplicate, I\'ve already tried the following code:

Toolkit.getDefaultToolkit().getLockingKeyState(KeyEvent.VK         


        

Answer 1

Looks like this was always broken or at least since Java 1.3 (see Bug 4414164).

Not sure for other platforms, but for Windows I can say this: State change of Caps Lock can be detected, but only if your awt client has the focus. However, there is this workaround which works for me:

boolean isCapsLockOn() {
    java.awt.Robot robot = new java.awt.Robot();
    robot.keyPress(KeyEvent.VK_CONTROL);
    robot.keyRelease(KeyEvent.VK_CONTROL);
    return Toolkit.getDefaultToolkit().getLockingKeyState(KeyEvent.VK_CAPS_LOCK);  
}

Contraint: Your awt app must have the focus before calling isCapsLockOn.

Note: Your robot might press any other key which is not harmful to your app. Might depend on your use case.