you willl have to learn how to write softwrae in Android as x86 and x64 code will not work there.
You have to use Java, wich is platform independent (and easy

)
Even if Android is just a flavour of Linux, applications must have some kind of stub in Java.
i had in mind cross Development editor
To program directly in tablet or phone you can use Termux. Then you have a terminal in Android, with vi, vim, emacs, micro, nano and all kind of editors and tools usual in Linux. Also you can install C, Java, Python and more.
The true problem is the keyboard