There are many apps available in the Google Play Store that can read and display GPX files.  Some can also record them for uplaod to the Walkr website.

A well known app for viewing and navigatig using GPX files is Track Navigator - https://play.google.com/store/apps/details?id=com.thunkmonkey.tracknav&h...

Tyoe GPX into Google Play search bar for the full range.