Android Tutorial GPS / GNSS tutorial

The GNSS library replaces the old GPS library. The GNSS library is available here: https://www.b4x.com/android/forum/threads/gnss-library-an-updated-gps-library.109110/#content

Using it is quite simple:
1. Checking whether location services are available. If not take the user to the settings.
2. Request permission.

If the purpose is to get the user location then the FusedLocationProvider might be a better option: https://www.b4x.com/android/forum/threads/fusedlocationprovider-resolution-dialog.111652/#content

 

[Erel]

It sounds like a problem on your device. You cannot reset the GPS. There is no API for that. You can try to call GPS.Stop and then GPS.Start. Though it will probably not help in this case.

 

[Kevin L. Johnson]

It sounds like a problem on your device. You cannot reset the GPS. There is no API for that. You can try to call GPS.Stop and then GPS.Start. Though it will probably not help in this case.

Ok, Thanks Erel.

I did notice that when I upgraded to KitKat, my "GPS" Icon in the pull-down "Settings" section changed to a "Location" icon. If I turn off "Location" Services prior to re-running the code and let the tutorial code ask the user to enable GPS (via the "Location" services Icon) then everything runs as before. I just don't like the idea of needing to turn off "Location" services every time before running a GPS dependent app. I would like to know if anyone else might be experiencing this.

Thanks

 

[GMan]

I have several App using GPS (also as BT etc.)
SOME Apps Stops the GPS when finishing (GPS.Stop), others not: if a Apps is used i.e. once a day, the Service will be stopped, if the App is used several time the GPS keep running in the background.
At all, the Service is only used if an App needs it.

So you may set it as a Setup- or Option-parameter to let the user decide

 

[Erel]

You don't need to disable Location in order to use the GPS. Maybe the location settings are set to low accuracy mode.

 

[Kevin L. Johnson]

You don't need to disable Location in order to use the GPS. Maybe the location settings are set to low accuracy mode.

In fact, I have been using the 'GPS only' Mode (which is not the 'High Accuracy' Mode and therefore presumably considered 'Low accuracy'). Additionally, the symptom is as follows ... if I don't manually disable "Location" AND let the app prompt the user to enable "GPS" (which is done by enabling "Location") THEN the app takes takes an unusually long time (10 to 15 min) before the GPS data begins streaming.

UPDATE: I've just run my location services in High Accuracy Mode two times in a row and communication with the GPS was picked up almost immediately. I need to run some more tests for now.

 

[AndyW999]

Hi

I am running the GPS as a service and starting it off with a timer :-

Sub tmrGPS_Tick
GPSService.Start(0, 0) 'Listen to GPS with no filters.
ServiceCounter = 2

End Sub

I then have :-

Sub GPSService_LocationChanged(Location1 As Location)

If ServiceLocation.Accuracy <=16 Then
do stuff...
GPSService.Stop
end if
End Sub

But it does not stop!

Any ideas?

 

[Erel]

Please use [ code ] [ /code ] tags (without spaces) when posting code.

Make sure that you don't call Start multiple times (without calling stop).

 

[AndyW999]

Please use [ code ] [ /code ] tags (without spaces) when posting code.

Make sure that you don't call Start multiple times (without calling stop).

You might well be onto something there!

Thanks

Andy.

 

[vincentehsu]

Dear Sir:
I've download the sourcecode,but when i built up the project and run as acturally mobile device,I can't get the lat and lon data?

 

[klaus]

Have you tried it outsides ?
In the house GPS will probably not work.

 

[vincentehsu]

But I use the google map,It can be locate me in a second

 

[klaus]

What source code did you download ?
If it's the project in the first post in this thread it uses GPS.

 

[vincentehsu]

yes,just the first post,is there another way to locate? like base station?

 

[klaus]

Enter 'location' in the search box.
The fifth result is LocationManager.
I haven't tested it.

 

[vincentehsu]

tks,I'll check it out

 

[stefanoxjx]

Hi guys, I've a strange problem
I'm testing the sample app of this post, but the app returns me wrong coordinates.
It returns me for latitude 45:37,76xxxx and longitude 12:1,68xxxx instead real coordinate 45:62,xxxx / 12:0,2xxxx.
I've tested this app in two different device and have same problem
Anyone have some ideas?
Thanks.
Best regards.

Stefano

 

[stefanoxjx]

Hi guys, I already found the solution here: https://www.b4x.com/android/forum/threads/gps-lat-long-returning-wrong-values.12836/#post-72586

Many thanks

Stefano

 

[achtrade]

Today, the GPS stopped working.

I have an app with GPS and everything was working fine til now, I'm using galaxy s 3 and galaxy tab 3 7.0 without problem and suddenly today they 2 are not working. I'm not getting any error, just lat and long with value 0.

I tried google map and it's working fine, only my app can't find my location. Also, I installed this example and it doesn't get any lat/long, just this msg "Satellites: 16.20 False 159.30xxxxxxxxxxxxxxxxx.5

What's going on ?

 

[Erel]

Google Maps uses other sources to find the location if GPS is not available.

Are you testing it outdoors?

 

[achtrade]

Google Maps uses other sources to find the location if GPS is not available.

Are you testing it outdoors?

I'm only using wifi, those devices don't have cellphone service. Is possible that GPS does not work well only with wifi ?. The strange thing is that Google Map App is working fine only with wifi

Note: After left open my app for several minutes, like 5 or 7 minutes, finally the GPS found my location. What can be happening ?