What do I expect the Android to do: Process the information in whichever way it wants
OK. I still don't understand, and perhaps shouldn't have asked, particularly as I recall there is some kind of taboo on unsigned chars. All I do is send data to Android. The reason why I asked specifically about the Android is that all the Android apps that receive from Arduino are more or less the same, they just get data, so perhaps your real exercise is a new Android app. The only exception I am aware of is Bluetooth graphics terminal, which demands data in a string. It is also the only Android app I know of that actually processes anything.
If you need to work in chars, then the code you wrote may be "normal" but I'm afraid I don't see anything normal in it. I guess it is also incomplete. Taking a deep breath and explaining your project might actually be a good idea.