1 - Just out of curiosity ... why do you want your own keyboard?
2- Let's figure that you want to make an application for those who only speak "Klingon" ... then you do an "activity" called "my keyboard" with its respective "layout" and define the "symbols" and you go capturing the "symbols" selected by the user. ..
At the end you save all symbols in a "global" variable.
Note:
every time the user clicks on a field, you call the activity "my keyboard"
The reason is because the user will input data in an edittext and he has to be able to type(click) any key related to the edittext. In this sample is related to a production process in a manufacturing company and the value belong to this process. Thats why.
I starting get in you...So I need to build my keyboard with buttons and each clic is a letter for example.
I'm not quite sure open a new activity and then go back to the activity where was called. I think its not friendly to the user.
I knew that there are software that can create their own keyboards. That's why I asking if B4A can handle this function!.