You can visit the solutions from www.wiris.com. With WIRIS editor you can convert from MathML to PNG images suitable to be displayed in any browser and in any application, in particular, also for android.
It is not clear what you mean by mathml to ASCII. As part of the accessibility solutions, the WIRIS tools can generate a textual representation of a formula. For example, for ½ the “ascii” version would be “1 over 2“.