How can I remap certain keys?

Question

I want to create a virtual numeric keyboard, so that when I press U I get a 4, I produces a 5, O produces a 6, and so on:

789            789
uio   becomes  456  
jkl            123
m              0

But I need the rest of the keyboard to continue working as usual. I have tried this and some other solutions, but they are not useful to me, because on my JTextField I get 4U5I6O (or U4I5O6 depending on which solution I implement).

I need to get rid of the letter, and produce only the number.

Does anybody know a proper solution?

Thanks.

Answer 1

If you are typing directly to JTextField, then I recommend to use DocumentFilter.

As an example of DocumentFilter, see:

• Only allowing numbers and a symbol (-) to be typed into a JTextField