I tried to study on my phone recently and when I set it to only readings I got a message "reading mode is not supported on Android". This seems a little extreme. Since you now have the grading buttons for readings, why not turn the reading prompts into pure flash cards on Android (i.e. they wouldn't have the prompt to type into) and people would have to self-grade? Then at least we could get something done on the go.
Another issue is that, when you select only some parts, the message box that pops up can't be closed (at least on my phone) because the little 'X' is too tiny, and it covers up the "Settings" button so you can't go back in and change it to a different set of parts. The only way out is to restart adding.
James