Sending a keyboard event from java to any application (on-screen-keyboard)

Question

I am working on developing an on-screen keyboard with java. This keyboard has a JComponent for every possible key. When a mouse down is detected on the button, I want to send a specific keyboard code to the application currently on focus. The keyboard itself is within a JFrame with no decorations and set to always-on-top.

I found that the Robot class can be used to simulate these keyboard events on the native queue. However, in this case, selecting the JComponent would mean that the key-press is received on the JFrame, and I wouldn't be able to receive it in the other application

How can I keep my on-screen keyboard "Always-without-focus"? Is it maybe possible to use another approach to send the key-press?

Batman0730 · Accepted Answer · 2012-01-12 16:41:39Z

3

I found jnativehook when I was trying to control a gamebot with actual keyboard and mouse commands (to be more "human-like").

answered Jan 12, 2012 at 16:41

Batman0730

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1 Comment

Simon Forsberg Over a year ago

From the description of JNativeHook, it seems like it's for listening for keyboard and mouse events, not for sending events to another application.

Mario Ortegón · Accepted Answer · 2008-10-09 22:37:00Z

2

The only solution I could find so far, is to make every key a JComponent (so it can not have focus), and set the following properties on the JFrame:

    setUndecorated(true);
    setFocusableWindowState(false);
    setFocusable(false);
    enableInputMethods(false);

Now when using the robot class I can send events to any focused window by clicking on the keys. The only limitation, is that it only seems to work for windows that belong to the same virtual machine, and it doesn't work at all with any other system window.

edited Oct 9, 2008 at 22:37

answered Oct 9, 2008 at 14:24

Mario Ortegón

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1 Comment

Alex Jone Over a year ago

Worked perfectly on windows 10, should be number 1 answer, no need for jni

Mario Ortegón · Accepted Answer · 2008-10-20 15:25:17Z

2

Apparently the only way to do this is to have a JNI layer that will make the conversion from java to native. Java has no easy way to provide such funcionality.

This could be an interesting concept for a small, third party library for someone who wants to learn JNI...

answered Oct 20, 2008 at 15:25

Mario Ortegón

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Comments

Tom · Accepted Answer · 2008-10-01 11:15:08Z

0

have you tried to call native setfocus() or setactivewindow() functions to move focus before you use robot class?

answered Oct 1, 2008 at 11:15

Tom

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iny · Accepted Answer · 2008-10-11 15:14:18Z

0

I am not aware of any way of doing this in OS independent way. I don't know about Windows, but it would be possible talk with X server over the X protocol.

answered Oct 11, 2008 at 15:14

iny

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