Be as device-independent as possible. Whatever the device's font setting, your app's font sizes should scale smoothly with it as long as you don't set them to pixels.
Always favour scale-independent pixels(sp
) over pixels (px
) for your units when setting font sizes, e.g. 12sp instead of 12px.
EDIT: You may need to adjust the layouts for large screens to better match the behaviour you are now seeing so as to avoid being invasive to your users by forcing them back to the setting they changed from. Use appropriate layout qualifiers for proper size selection at run-time.
Refer to this: Supporting Multiple Screens on the android developer site.