getLastKnownLocation null - how to get data?

Question

I'm trying to get Location information using getLastKnownLocation but I often get null.

Here is what I do:

1. Turn OFF location in Settings
2. Run my app - getLastKnownLocation returns null - this is expected
3. Turn ON location in Settings
4. Run my app again - getLastKnownLocation returns null !?
5. Run Google Maps
6. Run my app again - getLastKnownLocation returns a valid Location !?

I found this question where the accepted answer suggests to launch Maps first in order to get the location: FusedLocationApi.getLastLocation always null

The questions is: what is Google Maps doing to get the location? And how can I do the same in my code?

Thanks!

Answer 1

Thanks everyone for the help!

I was missing uses-features declarations in my manifest - thanks @CommonsWare for the link: https://developer.android.com/guide/topics/location/strategies.html#java

<!-- Needed only if your app targets Android 5.0 (API level 21) or higher. -->
<uses-feature android:name="android.hardware.location.gps" />
<uses-feature android:name="android.hardware.location.network" />

Also, requesting updates like this is needed as well:

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);

In my case the GPS provider needs a few minutes to connect and start sending data - the Network provider seems to be faster but does not always work - so I'll use both of them.

Update: a few key points

1. It's not really intuitive, but in order to get data from getLastKnownLocation some app on the device - be it Google Maps or our own app - needs to call requestLocationUpdates.
2. Some providers might not be enabled on a particular device - so it's a good idea to use both the GPS_PROVIDER and the NETWORK_PROVIDER - or use all enabled providers: locationManager.getProviders(true)

Here is the code I ended up using:

for ( String provider : locationManager.getProviders(true) ) {
    setLocation( locationManager.getLastKnownLocation(provider) );
    locationManager.requestLocationUpdates(provider, Tools.MIN_5, 0, locationListener);
}
// call setLocation again in locationListener.onLocationChanged

Answer 2

here is a code chunk which may help you.

  if (!::mFusedLocationProviderClient.isInitialized) {
        mFusedLocationProviderClient = FusedLocationProviderClient(mContext)
        mLocationRequest = LocationRequest()
        mLocationRequest.priority = LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY
        mLocationRequest.interval = 10000
        mLocationRequest.fastestInterval = 5000
        mLocationRequest.smallestDisplacement = 1000 * 100f
    }
    if (ActivityCompat.checkSelfPermission(
            AppName.appContext,
            android.Manifest.permission.ACCESS_FINE_LOCATION
        ) != PackageManager.PERMISSION_GRANTED || ActivityCompat.checkSelfPermission(
            AppName.appContext,
            android.Manifest.permission.ACCESS_COARSE_LOCATION
        ) != PackageManager.PERMISSION_GRANTED
    ) {
        // not enough permission
        return
    }
    mFusedLocationProviderClient.requestLocationUpdates(mLocationRequest, object : LocationCallback() {
        override fun onLocationResult(p0: LocationResult?) {
            super.onLocationResult(p0)
            mFusedLocationProviderClient.removeLocationUpdates(this)
            if (p0 != null) {
             //here is your location
            } else {
              // location is null
            }
        }

        override fun onLocationAvailability(p0: LocationAvailability?) {
            if(p0?.isLocationAvailable!= true){
       //location not available.
            }
        }

    }, Looper.getMainLooper())

Answer 3

make sure you give all permission and if you run app above 6.1 device then handle permission..

after that used this code..

add below dependency into app level gradle file..

//Place API
implementation 'com.google.android.gms:play-services-places:16.0.0'
implementation 'com.google.android.gms:play-services-location:16.0.0'

define this into class level as global deceleration.

private lateinit var fusedLocationClient: FusedLocationProviderClient
private var context: Context? = null
private var locationCallback: LocationCallback? = null
private var locationRequest: LocationRequest? = null
private var googleApiClient: GoogleApiClient? = null

after that onCreate method..

        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)

make method for getting location..

fun getCurrentLocation() {
    // Get Current location and do reverse geocoding
    ProgressUtils.showOldProgressDialog(this)


    locationCallback = object : LocationCallback() {
        override fun onLocationResult(locationResult: LocationResult?) {
            locationResult ?: return
            ProgressUtils.closeOldProgressDialog()
            for (location in locationResult.locations) {
                // here you get current lat ,long,etc value.. 
                        stopLocationUpdates()
                    }
                } catch (e: Exception) {
                    e.message.loggerError()
                    stopLocationUpdates()
                }
            }
        }
    }

    locationRequest = LocationRequest().apply {
        interval = 10000
        fastestInterval = 5000
        priority = LocationRequest.PRIORITY_HIGH_ACCURACY
    }


    startLocationUpdates()


}

make location update..

 fun startLocationUpdates() {

    googleApiClient = GoogleApiClient.Builder(this)
            .addApi(LocationServices.API)
            .build()

    googleApiClient!!.connect()


    val builder = LocationSettingsRequest.Builder().addLocationRequest(locationRequest!!)
    builder.setAlwaysShow(true)

    val result = LocationServices.SettingsApi.checkLocationSettings(googleApiClient, builder.build())
    result.setResultCallback { result ->
        val status = result.status
        when (status.statusCode) {
            LocationSettingsStatusCodes.SUCCESS -> {
                Log.i(TAG, "All location settings are satisfied.")
                fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, null)
            }
            LocationSettingsStatusCodes.RESOLUTION_REQUIRED -> {
                Log.i(TAG, "Location settings are not satisfied. Show the user a dialog to upgrade location settings ")

                try {
                    // Show the dialog by calling startResolutionForResult(), and check the result
                    // in onActivityResult().
                    status.startResolutionForResult(this, LOCATION_SETTING_REQUEST_CODE)
                } catch (e: IntentSender.SendIntentException) {
                    Log.i(TAG, "PendingIntent unable to execute request.")
                }

            }
            LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE -> Log.i(TAG, "Location settings are inadequate, and cannot be fixed here. Dialog not created.")
        }
    }

}

make method for stop location..

private fun stopLocationUpdates() {

    if (locationCallback != null) {
        fusedLocationClient?.removeLocationUpdates(locationCallback)
    }
}

override fun onStop() {
    super.onStop()
    stopLocationUpdates()
}

override fun onPause() {
    super.onPause()
    stopLocationUpdates()
}

if handle permission than permission is grant then call back getting onActivity Result method there put below code..

     fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, null)