I am implementing a function to find my latitude and longitude but it keeps giving a null value. I declared android.permission.ACCESS_FINE_LOCATION, android.permission.ACCESS_BACKGROUND_LOCATION, android.permission.ACCESS_COARSE_LOCATION, and android.permission.INTERNET.

I granted all permissions and it shows a 'granted' toast but why my location is always null?

MainActivity

class MainActivity : AppCompatActivity() {

private lateinit var binding: ActivityMainBinding
private lateinit var fusedLocationProviderClient : FusedLocationProviderClient

companion object {
    private const val PERMISSION_REQUEST_ACCESS_LOCATION = 100
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this)

    getCurrentLocation()
}

private fun getCurrentLocation() {
    if( checkPermissions() )
    {
        if(isLocationEnabled())
        {
            if (ActivityCompat.checkSelfPermission(
                    this,
                    android.Manifest.permission.ACCESS_FINE_LOCATION
                ) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
                    this,
                    android.Manifest.permission.ACCESS_COARSE_LOCATION
                ) != PackageManager.PERMISSION_GRANTED
            ){
                requestPermission()
                return
            }

            fusedLocationProviderClient.lastLocation.addOnCompleteListener(this) { task ->
                val location : Location? = task.result
                if(location == null)
                {
                    Toast.makeText(this, "Null Received", Toast.LENGTH_SHORT).show()
                }
                else
                {
                    Toast.makeText(this, "Get Success", Toast.LENGTH_SHORT).show()
                    binding.txtLat.text = "" location.latitude
                    binding.txtLong.text = "" location.longitude
                }
            }
        }
        else
        {
            Toast.makeText(this, "Turn on location", Toast.LENGTH_SHORT).show()
            val intent = Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)
            startActivity(intent)
        }
    }
    else
    {
        //request permission here
        requestPermission()
    }
}

private fun isLocationEnabled() : Boolean {
    val locationManager : LocationManager = getSystemService(Context.LOCATION_SERVICE) as LocationManager
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)
            || locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
}

private fun requestPermission() {
    ActivityCompat.requestPermissions(
        this, arrayOf(android.Manifest.permission.ACCESS_COARSE_LOCATION,
        android.Manifest.permission.ACCESS_FINE_LOCATION), PERMISSION_REQUEST_ACCESS_LOCATION
    )
}

private fun checkPermissions() : Boolean
{
    if(ActivityCompat.checkSelfPermission(this,
        android.Manifest.permission.ACCESS_COARSE_LOCATION)
    ==PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,
        android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
    {
        return true
    }
    return false
}

override fun onRequestPermissionsResult(
    requestCode: Int,
    permissions: Array<out String>,
    grantResults: IntArray
) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults)

    if(requestCode ==  PERMISSION_REQUEST_ACCESS_LOCATION){
        if(grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)
        {
            Toast.makeText(applicationContext, "Granted", Toast.LENGTH_SHORT).show()
            getCurrentLocation()
        }

        else {
            Toast.makeText(applicationContext, "Denied", Toast.LENGTH_SHORT).show()
        }
    }
}
}

CodePudding user response：

As Google:

The getLastLocation() method returns a Task that you can use to get a Location object with the latitude and longitude coordinates of a geographic location. The location object may be null in the following situations:

• Location is turned off in the device settings. The result could be null even if the last location was previously retrieved because disabling location also clears the cache.

• The device never recorded its location, which could be the case of a new device or a device that has been restored to factory settings.

• Google Play services on the device has restarted, and there is no active Fused Location Provider client that has requested location after the services restarted.

Solution:

1 Get last know location:

    private Location getLastKnownLocation() {
           List<String> providers = mLocationManager.getProviders(true);
           Location bestLocation = null;
           for (String provider : providers) {
               Location l = mLocationManager.getLastKnownLocation(provider);
               if (l == null) {
                   continue;
               }
               if (bestLocation == null
                       || l.getAccuracy() < bestLocation.getAccuracy())       {
                   Log.d("last known location: %s", l);
                   bestLocation = l;
               }
           }
           if (bestLocation == null) {
               return null;
           }
           return bestLocation;
    }

2 Receiving Location Updates: To avoid this situation you can create a new client and request location updates yourself. For more information, see Receiving Location Updates link

CodePudding user response：

Here I shared how I solved the error for anyone having same problem that I got.

So the reason was there was no cache for the location that it could not access to my last location. I solved this problem by adding this.

1. add the below in if(location == null)

   fusedLocationProviderClient.requestLocationUpdates( locationRequest, locationCallback, Looper.getMainLooper() )

Then, I received an error to initialize locationCallback. So I added this. 2) add the below in onCreate

locationCallback = object : LocationCallback() {
        override fun onLocationResult(locationResult: LocationResult) {
            locationResult ?: return
            for (location in locationResult.locations){            
            }
        }
    }