Font Viewer

Tap any font file with .ttf or .otf extension in your file explorer to preview it.
You can also launch the Font Viewer app directly and browse to open a font file.
Font Viewer includes a slider to change font size and allow zooming on font details.

Written and compiled on an Android phone thanks to RFO BASIC!, the GW library, and the BASIC! Compiler:
RFO BASIC! https://play.google.com/store/apps/details?id=com.rfo.basic
GW lib http://mougino.free.fr/gw.html
BASIC! Compiler http://mougino.free.fr/compiler.html

Open source: http://rfobasic.freeforums.org/apk-extension-registration-t4587-10.html