AndroWish and undroidwish are conceptually similar to what is called a
GUI program in Win32 (what a Win32 wish is, too, btw). These do not have
the concept of an interactive stdin channel in form of a console or xterm.
But they have a special console channel/command described in

  https://www.tcl.tk/man/tcl8.6/TkCmd/console.htm

And that's the reason why "gets stdin" won't work in these environments.
So you have to transform your business logic to GUI (event driven) style
and to use some entry or text widget for user input plus bindings and/or
buttons in order to trigger some action on that input.