gpstracker | Open Hardware , 100 % hackable GPS tracker | Map library

I created an open source library that uses the Bluettoth LE to communicate with other devices (you can send both text and raw data), I link you the github page of the library: https://github.com/niedev/BluetoothCommunicator

You can directly use the library or see the code to get an example of a working bluetooth le, there aren't many out there.

If you see that the code is too long don't worry, most of it is to improve the connection (reconnection in case of unintentional loss of a device signal, error checking, splitting and rebuilding of long messages, etc.) it is not essential to have a working bluetooth le.

I did some tests and it works better than nearby connections (only if the devices are not under the same wifi network) and wifi direct, the only flaw is that bluetooth has problems in case of more than 4/5 devices connected between them (maybe with a star topology you can increase the number) and that my library does not have message encryption, but you can always add it yourself, the code is open source :)

You can format your string like this

From the code it looks correct, but I cannot see the location vs. the expected location. By default, MapOverlays are drawn centered on the coordinates. You can set an anchor point to move the overlay in relation to the coordinates. This could help if there is always an offset between the coordinates in your database and the location on the map.

Maybe, can you try to render a small MapCircle item onto the map at the expected location? Then you can more easily see where that location lies on the map. You can compare the results with https://www.latlong.net/.

I´ve worked a lot in this field (in getting frequent location updates "forever"). If you need several location updates per hour, the only way to do this is to make your service to be in Foreground (with START_STICKY - see sample for this). The service can live almost "forever" if it keeps in the foreground (even in Doze Mode). In Doze Mode is possible that the location updates stops because some sensors "sleep" but the service must not be affected in Doze Mode.

You can refer to the next google sample: Location Updates in Foreground Sample

NOTE: Keep in mind that a foreground service can also be killed by Android if it needs too (low memory, etc), but a foreground will be one last things to be shutdown by Android.

Server replies 200 does not mean the upload is succuessful. Try to output the php echo. See Get PHP Echo in Android.

Edit: Do you have permission on that directory? See PHP move_uploaded_file() error?

The easiest way is that you throw a `System.Web.Http.HttpResponseException' from your action method with an appropriate HTTP status code.

Something along these lines might work, more of an idea than a promise of fully functioning code for your df.

According to official document of Android 8.0 Background Execution Limits

Android 8.0 introduces the new method startForegroundService() to start a new service in the foreground. After the system has created the service, the app has five seconds to call the service's startForeground() method to show the new service's user-visible notification. If the app does not call startForeground() within the time limit, the system stops the service and declares the app to be ANR.

So, make sure you have started ongoing notification by calling startForeground (int id, Notification notification) in the onCreate() method of your service.

Note: Apps targeting API Build.VERSION_CODES.P or later must request the permission Manifest.permission.FOREGROUND_SERVICE in order to use this API.

In order to fix the NullPointerException, just initialize the LocationManager reference. Also, move the logic to request location updates to the onStartCommand() method override, and return START_STICKY in order to restart the service automatically.