so guys....the google project to work on rockbox as an application is exactly what is needed to start it from android.http://www.anddev.org/native_c_-und-quothello_world-und-quot_working_in_emulator-t61.html
but thats only console.....we need to start a real C application..
i have read a book about android development the past 3 weeks and there is one problem i am not sure about....android boots to "activities" which use "views" for displaying the gui...if we want rockbox to run on android some way then we need to quit the java gui, start the native rockbox application and if quiting rockbox we need to start the java gui again. rockbox needs to take over control over the screen and later release it again. ah and btw there maybe should be a way to still receive calls/sms/mms while rockbox is on...so there should be a way from the outside to trigger this switch.
the vendors of the android handsets have to write drivers for the linux kernel in a standardized way because the dalvik virtual machine would always perform the same calls to the linux kernel.....the vendors themselves have to compile the dalvik virtual machine and everything underlying fresh so it works on the cpu architecture....it would be crazy if they now still would use custom hacks to make something working after google removed the constraint to develop an OS...they only have to create support in the linuxkernel - and the main git tree is at android.git.kernel.org ..... and thats damn great. i think vendors will concentrate on provider the drivers for sensors/gps/touchscreen/whatever ....
what does this mean for rockbox? rockbox as an application for android would mean:
1) it needs to be compiled for every supported android device as they might use a different cpu architecture (but thats the same for all other devices as well)
2) the drivers for the sensors/gps/whatever i think will be standardized....if rockbox would be ported once to run as an application on unix/linux OS then i think it would be relatively easy to get a different smartphone supported....probably again only a recompile?
i plan to buy an android phone as soon as there are some smaller formfactors available...for now i want to write some small android apps / android games with the help of the emulator.....i guess that will be enough to give you reliable advice soon...and maybe i can help later when i digged deeper in this issue.