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androidlocationandroid-gps

Android Location GPS Track

I have a small test App that with an Android GPS API map fragment. I use FusedLocationProvider. TarketSDK=29. Using Java.

As long as the app is active it works beautifully. On locationUpdates, I add a new point to the track and everything looks great and stays accurate. The goal is to track my hike, total distance and track and show it on the map. Works great.

As soon I lock my phone or loses focus, then the updates stop and I no longer get location updates.

Solution seems to be:

  • Background Service (discouraged)
  • Foreground Service
  • PendingIntent

I have poured over the docs, StackOverflow, all examples/tutorials I can find, developer.android.com, etc. I have downloaded examples of the latter 2 from GitHub; they seem incredibly obtuse (probably just me).

  1. What are the dis/advantages of ForegroundService vs PendingIntent?
  2. How about a bare-bones example illustrating the min features of each to implement location updates while your phone is locked in your pocket or some other app is active? Just the template minimum.
  3. I need to save the locationUpdates that occur while my app is not active or phone is locked; in order to fill in Track when activity is restored to the app.

Some simple end-to-end guidance from my working app to something that will maintain locationUpdates and save the data would be great.

Solution

  • Ok - I have answered my question in a roundabout way.

    I had been Searching on "retrieving location updates when app is not active". This lead to the various solutions of background service, foreground service, pendingIntents, etc.

    I eventually found that if you just start a Foreground Service with a Notification, even if your phone is locked or you switch active apps, your App continues to receive LocationUpdates; as the Foreground Service runs in the same thread and therefore activates your app code (if I understand the reasons why correctly).

    So, I started searching on just how to start a Foreground Service. As anyone knows that has tried to figure this out lately, this has changed more than a couple times over recent versions. The online docs at developer.android.com are not up to date. You will spend a lot of time wondering why things do not work following these docs.

    Eventually, with just searching on how to start a foreground service, I came across this simple and straightforward (non-youtube-video - don't you just hate those things) tutorial. https://androidwave.com/foreground-service-android-example/

    I just added this code to my existing Mapping code that works when the app is active, and tested with locking the phone and putting it in my pocket and switching apps and doing the same. It appears to solve the problem.

    Update: Added code to count number of location updates and average accuracy of each update holding the phone in hand, screen on and app active as the baseline. Phone locked, or App not active no difference in number of updates nor accuracy. Phone locked and in pocket, no difference in number of updates, but accuracy suffered by from an average of 10m to an average of 13m; to be expected I assume whilst in the pocket.