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javaeventsswingkeyboardjava-native-interface

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


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?


Solution

  • 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...