B4A Library GeoLocation

JohnC

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@DonManfred,

Any chance you can update your sample app in OP to include these changes:

1) To set the event signature properly.
B4X: 
Sub GeoLocation_Location(success As Boolean, Lattitude As Double, Longitude As Double, info As String, isMockLocation As Boolean)
    Log($"GeoLocation_Location(${success}, ${Lattitude}, ${Longitude}, ${info}, ${isMockLocation})"$)
End Sub

2) Remove these lines from the Activity_Create sub (and move them to sub #3 below) because it will crash trying to do geoAddress if GetLocation failed (or if the geolocation event didn't fire yet):
B4X: 
GeoLoc.geoAddress
Log(GeoLoc.Address)
Log(GeoLoc.City)
Log(GeoLoc.Country)
Log(GeoLoc.KnownName)
Log(GeoLoc.PostalCode)
Log(GeoLoc.State)

3) And as in Post #8 to fix the crashing bug if GetLocation failed (and to also make sure this event sub's signature matches):
B4X: 
Sub GeoLocation_Location(success As Boolean, Lattitude As Double, Longitude As Double, info As String, isMockLocation As Boolean)
    Log($"GeoLocation_Location(${success}, ${Lattitude}, ${Longitude}, ${info}, ${isMockLocation})"$)

    If success Then
        GeoLoc.geoAddress
        Log(GeoLoc.Address)
        Log(GeoLoc.City)
        Log(GeoLoc.Country)
        Log(GeoLoc.KnownName)
        Log(GeoLoc.PostalCode)
        Log(GeoLoc.State)
    End If
End Sub

I ask because another user ran into these same issues and it would just save time all-around in the future:

GeoLocation works but constantly fails

I am using the Geolocation 1.11 library and it works intermittently, hours spend working fine as well as hours that don't work, any suggestions? I took it from here: https://www.b4x.com/android/forum/threads/geolocation.99710/
www.b4x.com
 
Last edited:

joaquinortiz

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Don, I have a question. The address(for example Zip Code) from where it's extracting this information?.

Also I realize, that in some cases, I run it, several times, and it doesn't bring the aproximatelly address, or in this case, the same Zip Code...for instance. I received at this momento my zipcode 64170....but after some time after (liek an 1 hour) I receive zipcode 64159.

I think that this could be for the GPS antenna, that it's not exactly. Or I'm wrong?
 

joaquinortiz

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DonManfred said:
From the Android Geocoder Object. Don´t know where GeoCoder get his infos from.
Click to expand...

@DonManfred Thanks. I currently tested your sample, and I'm realize that it doesn't update the GPS location. I took your sample in 2 cellphones, and I drove my car, early 15mins ago, from my house to my work, its like 5kms long, and I test it the sample, and it doesn't refresh the address. To do the update, I have tu turno off "Location" antenna in both cells, kill the app, and start it again. And it shows me the current address (by the new gps location i have).

What do you think that could be happen?

PD. And some times it's not precise location.
 

TILogistic

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See:

android.location.Geocoder · Issue #1 · AravindVijay7/GeoLocator-Android

After reviewing the library code, I would like to warn you that you are using the geocoder which on some devices may return an empty value. Learn more
github.com

Android Geocoder behaves different on some devices

I have the below code, it works perfectly on some devices and in others the function getFromLocationName return a list with size 0. For example, in Nexus 6p it returns the correct result and in M...
stackoverflow.com
 

TILogistic

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better occupy services:

Nominatim

Open source geocoding with OpenStreetMap data
nominatim.org


taking into account the policies of the service:

Daily quotas are not limited like google api
 

joaquinortiz

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This is very surprising. But how do you think Uber or Didi manages to get a more accurate GPS position? Regardless of device

This is the million dollar question....hahahahahaha!!!!!
 

TILogistic

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Uber and Didi use various location services.

check where is uber partner:

example:

LocationIQ - Free Reverse Geocoding API, Geocoding API, Autocomplete API

Affordable Google Maps alternative for Reverse Geocoding, Geocoding, Maps and Routing APIs. Generous free tier, offering Enterprise-grade APIs for everyone!
locationiq.com

Customer Showcases | Mapbox

Mapbox powers location for more than a million live location developers. Today, 600 million people worldwide touch Mapbox maps every month.
www.mapbox.com
etc.

and it will give you an idea.
 

TILogistic

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As for the location of your phone, it is better to use:

FusedLocationProvider

FusedLocationProvider is Android's latest attempt to improve the location services available to your applications. Official documentation can be found here: https://developer.android.com/google/play-services/location.html. This library depends on the Google Play Services library...
www.b4x.com

and your geocoder service uses an external API

 

JohnC

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OK,

I don't have a lot of experience navigating a github project, so I can't seem to find any detailed info about the methods and events from the original developer.

Even though Don's info doesn't mention this, I do see a .GeoAddress2(Lattitude As Double, Longitude As Double) method using the object's intellisense.

.GeoAddress2(Lattitude As Double, Longitude As Double) - My guess is that this method provides a way to force the "GeoLocation_Location" event to trigger and return the address of the manually ("Mock") location provided via the lat and long parameters (instead of the device's detected GPS lat/long).

Also, you will notice that this lib doesn't really specify the accuracy of the lat and long it detected. It will specify the "service" that was used to obtain the lat/long (GPS/Wifi/Fused, etc) which can somewhat be used to know the accuracy of the lat/long, but I would not depend on it.

What I would do is use the more robust GPS object of Erel's example (https://www.b4x.com/android/forum/threads/background-location-tracking.99873/) and when that object detects a location, it will provide the accuracy of that location in meters.

So if my assumption on how the GeoAddress2 method works is correct, I would use the GPS object in Erel's example and wait for an acquisition that has an accuracy that meets my needs (like less then 25 meters), then I would use the lat/long reported from Erel's GPS object and call this lib's .GeoAddress2 method to force it to calculate the address based on the mock/manually provided via the lat/long of Erel's GPS object.

You will then notice that the GeoLocation_Location event has a "isMockLocation" parameter, I'm thinking that this value will be False for the times that this lib's geo library detects a location, and will be True when we force the lat/long location using the GeoAddress2 method. If all my assumptions are correct, then you would just need to make sure that this param is True before doing a .GeoAddress, so you'll know that the resulting street address is based on the manually provided lat/long (from Erel's GPS object) and not from this geo libs possibly inaccurate GPS location.
 
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joaquinortiz

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Great !, let me dive into this info and share my testings....to enrich this utilities.
 

joaquinortiz

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I tie with your logic!....let me dive into it and share the conclusions!!!...Thanks John for your involvement & time.
 

AdultWolf

New Member
Hi, Thanks for lib
just run and my error:
DonManfred

Error: 
java.lang.Exception: Sub geolocation_location signature does not match expected signature.

    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:215)

    at anywheresoftware.b4a.BA$2.run(BA.java:387)

    at android.os.Handler.handleCallback(Handler.java:873)

    at android.os.Handler.dispatchMessage(Handler.java:99)

    at android.os.Looper.loop(Looper.java:201)

    at android.app.ActivityThread.main(ActivityThread.java:6861)

    at java.lang.reflect.Method.invoke(Native Method)

    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)

    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)
 

DonManfred

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Alex_Puz

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Hello,
SDK=30, Android 12, Oppo-Reno5
if geolacation is OFF then error invoike
Logger connected to: OPPO CPH2211
--------- beginning of main
** Service (starter) Destroy (ignored)**
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Pause, UserClosed = false **
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = true **
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
Error occurred on line: 46 (Main)
java.lang.Exception: Sub geolocation_location signature does not match expected signature.
public static anywheresoftware.b4a.pc.RemoteObject b4a.example.main_subs_0._geolocation_location(anywheresoftware.b4a.pc.RemoteObject,anywheresoftware.b4a.pc.RemoteObject,anywheresoftware.b4a.pc.RemoteObject,anywheresoftware.b4a.pc.RemoteObject,anywheresoftware.b4a.pc.RemoteObject) throws java.lang.Exception
class anywheresoftware.b4a.pc.RemoteObject, class anywheresoftware.b4a.pc.RemoteObject, class anywheresoftware.b4a.pc.RemoteObject, class anywheresoftware.b4a.pc.RemoteObject,
Geolocation: 
LocationProvidersAllowed = Phone1.GetSettings("location_providers_allowed")
    Starter.rp.CheckAndRequest(Starter.rp.PERMISSION_ACCESS_FINE_LOCATION)
    wait for Activity_PermissionResult (Permission As String, Result As Boolean)
    If Result Then
        Try
             GeoLoc.Initialize("GeoLocation")
        Catch
            Log(LastException)
        End Try   
    Else
        Log("NoPermission")   
    End If
Error manager does not catch error as well
Please any solution?
 

TILogistic

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Use lib GPS and

[B4X] Free Geolocation Nominatim (Geocoding API)

Here's a demo of how to use the nominatim geocoding API for free. Note: There are other geocoding options if you want to know, leave your comments. Demo file attached Sub GeoCoderNominatim(Query As String) As ResumableSub Dim ResultURL As String Dim j As HttpJob Dim Parameter() As...
www.b4x.com
 

Alex_Puz

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Longtime User
Thank you Omar. Iwill try it. But what wil be if that service "https://nominatim.openstreetmap.org/search" will block at one day?
Also why Try ... Catch does not catch error?
 
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