For now, The Black Toolkit has ports for Windows and Linux, in native PC achitecture.
Its source code is in Object Pascal using Lazarus IDE, but it doesn't mean that some units cannot be compiled as a java library.
The FPCJVM compiler can compile a Object Pascal source code and output to Java (and Dalvik) Virtual Machine format. It has some restrictions, but it can be made.
Since The Black Toolkit 1.4 (May 2014) I have made some tests with FPCJVM and the source code of the tool.
I have seen the docs of androidlcl too, but writing for a native CPU achitecture instead of Java is not good for compatibility :(
My choice was not to use androidlcl, but a pure FPCJVM app using some units of the PC version of The Black Toolkit. Others units, like activities need to be new Java Classes, with a new interface and more useful for small screen resolutions.
Some parts of source need to be reallocated or rewrited for a concurrent build (PC and Android). It will take a lot of work, but it is very possible to goes well.