Write your own application on your mobile phone and tablet...
QuickBasic and QBasic (Quick Beginners All-purpose Symbolic Instruction Code) are very popular programming languages for beginners.
QBasic is extremely easy to use. Its graphics and math functions are especially good, and it's a great "learners language" for schools and other simila institutions. It resembles BASIC in its statements, but is more structured -and- flexible at the same time. For instance, line numbers are not required but can be used - as well as "line labels" with text names.
It is not possible to use touch screen for such applications. Instead, you can use the on-screen keyboard buttons.