Can't save settings on Android

[mljes]

Steps to reproduce:
In settings page, modify any setting (I changed the rules and hash file URLs), then scroll to bottom of page and tap "Save and refresh add-on".

Expected result:
Settings are saved. Leaving page and returning shows settings that user just updated.

Actual result:
Button remains in "pressed" mode. Leaving settings page and returning shows old settings and desired changes are not reflected in add-on behavior.