Android app (Serbian Keyboard) not working on my BBz10, why?

Android app( "Serbian Input Mehod" and any other "Serbian Keyboard" app) can't work on my z10 or can't even be installed on him, but all other Andorid apps have no problem working. How can I fix this, and how can I make them work?
Please help,
Thanks!

First off, an Android keyboard will only work with your Android apps. It will not work with anything else.

Second, you need an Android launcher (like Apex) to change your keyboard within the Runtime.

Z30STA100-5/10.3.2.2339