I am interested in using the GPS on my Android phone to measure how far I walk but am not keen on sharing that data with the company providing the app that measures it. I did find an app that seems to not send my data to anyone - “Walk Meter”. Unfortunately, if I go indoors for any length of time it seems to make a bad guess at where I am and therefore deduces that instead of sitting down in a coffee shop I have walked eg a mile and back - in other words it is unreliable if I go indoors.
I would envisage the app having a start and stop button and obtaining the GPS coordinates eg every 15 secs and calculating the distance travelled and adding that to as running total but disregarding the value if the distance is an unrealistic one.
Google led me to https://developer.android.com/training/basics/firstapp but I found the videos of unnaturally perky individuals getting over excited about issuing “earnable badges” really annoying (since successfully completing my potty training some years ago I hasve no need for meaningless stars/badges).
The other problem with Googling the question or searching on here is that there is a lot of out of date information out there.
(I have no interest in creating anything for sale or in craeting iPhone apps).