This thread here about iPad is getting Android -answers that belong to other thread.
I am interested in things such as real-time TeXing, LaTeX recognition, writing math by styluses/keyboards, teaching — anything that can be useful for mathematicians and students alike to work.
So can you use Android devices for reading textbooks and writing math by hand?
Because most Android devices lack proper screens, precision writing with things such as Jot Pro do not work. Your best bet for precision writing with Android is to get a Thinkpad x220 tablet or similar. More about this here. I use Maglus stylus in Android devices because the precision tools do not work. Then I use finger-writing tools below, free and good enough to have an old Android phone for casual uses such as finding certain Greek alphabets.
Apps with Finger-writing
The apps below do not work with precision writing with Jot because most Android devices do not have good-enough display. Currently, the only way to test whether Jot works with a display is to test it: even certain better-than-retina-displays do not work with Jot.
I. Detexify here
II. OCR MyScript -calculator here
I use Gooseneck 1/4, Balljoint 1/4 and camera-phone-mount here to have my hands free while working with things. Sometimes, I use a macro flash for near-photographs with a DSL camera for very precise photographs. Phone-camera works however for casual photos such as note-taking.
P.s. For future, there is a software called Screenshot UX here for sharing sheetshots in Android devices but it requires rooted phone. By this tool, you can easily show and recommend apps.