Android Question B4A IDE running under Android?

I dont think this will happen.

The IDE is not designed to run on Android.

Additionally your dont have the SDK installed (especially the buildtools (windows apps) on Android devices which are needed to compile

I could be possible, in theory (http://www.makeuseof.com/answers/can-compile-run-java-android/), at least to a degree, but would it be practical at all?
I don't see it even happening, unless someone with way too much time in their hands, highly fluent in B4A/Java/Android, would engage in such a colossal fan project.

Windows PC/Laptop + Usb Cable + Tablet/Phone (debug mode) is the best and fastest combo for now.