Develop Reference

How can I get greater than 1m position accuracy with android FusedLocationProviderClient?

I'm trying to create an android app that gives accurate location (1m or less) indoors. It seems the recommended way is to use the
a FusedLocationProviderClient
However the current horizontal accuracy I'm getting is between 5m and 15m for longitude and latitude while the vertical accuracy is often up to 50m out.
Not sure if it makes a difference but the the test device is an HTC U11?
I've updated google play service location com.google.android.gms:play-services-location:17.0.0
I've included android.permission.ACCESS_FINE_LOCATION in my app manifest and locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY); in the location request.
I've got some code in there which turns the GPS on.
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(3 * 1000); // 3 seconds
locationRequest.setFastestInterval(1 * 1000); // 3 seconds
new GpsUtils(this).turnGPSOn(new GpsUtils.onGpsListener() {
#Override
public void gpsStatus(boolean isGPSEnable) {
// turn on GPS
isGPS = isGPSEnable;
}
});
locationCallback = new LocationCallback() {
#Override
public void onLocationResult(LocationResult locationResult) {
if (locationResult == null) {
return;
}
for (Location location : locationResult.getLocations()) {
if (location != null) {
wayLatitude = location.getLatitude();
wayLongitude = location.getLongitude();
Lat.setText(Double.toString(location.getLatitude()));
Longs.setText(Double.toString(location.getLongitude()));
Acc.setText(String.format("%.2f", location.getAccuracy()));
if(location.hasAltitude()) {
Alt.setText(String.format("%.2f",location.getAltitude() - 108));
VAcc.setText(String.format("%.2f",location.getVerticalAccuracyMeters()));
}
else {
Alt.setText("Lost");
VAcc.setText("Lost");
}
SendToBackend(wayLatitude,wayLongitude, location);
if (!isContinue && mFusedLocationClient != null) {
mFusedLocationClient.removeLocationUpdates(locationCallback);
}
}
}
}
};
According to google it should be possible to get below 1m accuracy indoors. a link.
Thanks in advance :-)

Using mFusedLocationClient to get current location within a firebase service

I'm new to java/android dev so my code may be dumb.
I have a website which uses google maps, I have a button on the website which sends a push cURL message to a specific device using firebase. I want the device to then get the current location and update my database.
I'm using MyFirebaseMessagingService and onMessageReceived to grab the cURL message and that all works fine, it breaks when I start going into the location code. I had various errors so I tried creating a class for getting the location then calling a method of that class within my service.
The class:
public class LocationMedium {
private FusedLocationProviderClient mFusedLocationClient;
private Context mContext;
public LocationMedium(Context context) {
mContext=context;
}
public void getLocation()
{
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(mContext);
if (ActivityCompat.checkSelfPermission(mContext, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
//currently pointless
//return;
}
mFusedLocationClient.getLastLocation()
.addOnSuccessListener((Activity)mContext, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
Log.d("mytag", "2222");
// Got last known location. In some rare situations this can be null.
if (location != null) {
// Logic to handle location object
double x = location.getLatitude();
double y = location.getLongitude();
Log.d("mytag1", String.valueOf(x));
Log.d("mytag2", String.valueOf(y));
String user = PreferenceManager.getDefaultSharedPreferences(mContext).getString("USERNAME", "none");
MyFirebaseInstanceIDService firebase = new MyFirebaseInstanceIDService();
firebase.onDeadline(user, x, y);
} else //no location found
{
String user = PreferenceManager.getDefaultSharedPreferences(mContext).getString("USERNAME", "none");
MyFirebaseInstanceIDService firebase = new MyFirebaseInstanceIDService();
firebase.onDeadline(user, 0, 0);
Log.d("mytag", "hmm");
}
}
});
//END OF LOCATION
Log.d("mytag", "theend");
}//end of run
}
And I call it with this from the MyFirebaseMessagingService
if (Objects.equals(user, " location ")) {
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
public void run() {
LocationMedium task = new LocationMedium(context);
task.getLocation();
}
});
}
The error with this I get is:
MyFirebaseMessagingService cannot be cast to android.app.Activity
And it appears to be on this line:
mFusedLocationClient.getLastLocation()
I tried removing the (Activity) bit from:
.addOnSuccessListener((Activity) mContext, new OnSuccessListener<Location>()
and changing it to:
.addOnSuccessListener(mContext, new OnSuccessListener<Location>()
but then I get the error:
Cannot resolve method 'addOnSuccessListener...'
Perhaps I'm going about this completely the wrong way. Any help/suggestions would be appreciated. Thanks.

.addOnSuccessListener(mContext, new OnSuccessListener<Location>()
Replace the above code with this,
.addOnSuccessListener(new OnSuccessListener<Location>()
Worked for me.

getLatitude and getLongitude throws NullPointerException [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 3 years ago.
Would you please explain me why getLongitude and getLatitude returns a NullPointerException?
The truth is the problem already has been solved, but there's one thing that is bugging me for this might be asked by our thesis coordinator. The situation is that I have to get the user's current coordinates (latitude and longitude). I've decided to use FusedLocationClient.getLastLocation() in order to get the coordinates.
mFusedLocationClient = getFusedLocationProviderClient(this);
//app already crashes once the line below is executed
mFusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
if(location != null){
//myLocation is an instance variable of this class
myLocation = location;
}else{
Toast.makeText(PlaceCategoriesActivity.this, "Location fetch failed!", Toast.LENGTH_SHORT).show();
}
}
});
latitude = myLocation.getLatitude(); //this line throws NullPointerException
longitude = myLocation.getLongitude();
The app seems to compile fine but then it crashes, upon inspecting by adding a breakpoint for debugging on myLocation.getLatiude() and myLocation.getLongititude(), it turns out that this method invokes a null pointer exception, which for me is weird because myLocation already has referenced the location object brought by the onSuccess method of the addOnSuccessListener.
I've already solved the problem by moving the last two lines of code and putting in within the listener like this:
mFusedLocationClient = getFusedLocationProviderClient(this);
mFusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
if(location != null){
myLocation = location;
//moved the 2 lines of code and it now works
latitude = myLocation.getLatitude();
longitude = myLocation.getLongitude();
}else{
Toast.makeText(PlaceCategoriesActivity.this, "Location fetch failed!", Toast.LENGTH_SHORT).show();
}
}
});
//Toast returns a value of 0 on latitude and 0 on longitude
Toast.makeText(this, "Lat: " + latitude + "Long: + " + longitude, Toast.LENGTH_SHORT).show();
The funny thing is that the longitude and latitude is shown on the Toast and both has a value of 0.

which for me is weird because myLocation already has referenced the location object brought by the onSuccess method of the addOnSuccessListener
Let's simplify your first code listing:
mFusedLocationClient = getFusedLocationProviderClient(this);
latitude = myLocation.getLatitude(); //this line throws NullPointerException
longitude = myLocation.getLongitude();
Here, myLocation has not been assigned a value. If you have not assigned a value to myLocation in preceding lines, myLocation will be null, and you will get a NullPointerException.
Now, let's restore some lines to that code snippet:
mFusedLocationClient = getFusedLocationProviderClient(this);
//app already crashes once the line below is executed
mFusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
}
});
latitude = myLocation.getLatitude(); //this line throws NullPointerException
longitude = myLocation.getLongitude();
The last word in addOnSuccessListener() is "listener". This suggests that you are registering an event listener. Usually — though not always — such a listener is only invoked on future events. It is likely that onSuccess() will not be called until sometime later. However, your program keeps running, and you then try calling getLatitude() on myLocation. Since we still have not done anything to assign a value to myLocation, it will be null, and you will crash with a NullPointerException.
And so while your first code snippet does assign a value to myLocation, you as a programmer have to assume that it will not do so until some time in the future (e.g., when we get a new location fix). Do not attempt to use myLocation until onSuccess() has assigned it a value.

you should not add these lines after addOnSuccessListener:
latitude = myLocation.getLatitude(); //this line throws NullPointerException
longitude = myLocation.getLongitude();
because you have to wait until mFusedLocationClient successfully gets LastLocation
i.e. move these lines into onSuccess method!
As for the reason of the nullPointerException it's because myLocation has not yet been initialized !

You simply need to display the location when you get it, not before. That's said, just put the display code in the listener.
mFusedLocationClient = getFusedLocationProviderClient(this);
// Register a listener, that will be called when the location will be available
mFusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
if (location != null) {
// We have a location!
myLocation = location;
// So print it now
latitude = myLocation.getLatitude();
longitude = myLocation.getLongitude();
Toast.makeText(PlaceCategoriesActivity.this, "Lat: " + latitude + "Long: + " + longitude, Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(PlaceCategoriesActivity.this, "Location fetch failed!", Toast.LENGTH_SHORT).show();
}
}
});
// Loading, as we wait for listener to be called
Toast.makeText(this, "Loading...", Toast.LENGTH_SHORT).show();

Example:
class LocationApi : Service(), GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener, LocationListener {
private var myGoogleApiClient: GoogleApiClient? = null
private val myLocationRequest = LocationRequest.create()
override fun onBind(intent: Intent?): IBinder? {
return null
}
override fun onCreate() {
super.onCreate()
myGoogleApiClient = GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addOnConnectionFailedListener(this)
.addConnectionCallbacks(this)
.build()
}
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
myGoogleApiClient?.connect()
return super.onStartCommand(intent, flags, startId)
}
override fun onDestroy() {
myGoogleApiClient?.disconnect()
if (myGoogleApiClient != null && myGoogleApiClient?.isConnected!!) {
LocationServices.getFusedLocationProviderClient(this).removeLocationUpdates(locationCallBack)
}
super.onDestroy()
}
override fun onConnected(bundle: Bundle?) {
//here u can define your interval and priority
// request locations, check permissions ok
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
LocationServices.getFusedLocationProviderClient(this).requestLocationUpdates(myLocationRequest, locationCallBack, Looper.myLooper())
}
}
override fun onConnectionSuspended(p0: Int) {
}
override fun onConnectionFailed(p0: ConnectionResult) {
}
override fun onLocationChanged(location: Location?) {
//saving location on DB
LocationInteractor(location)
}
private val locationCallBack = object : LocationCallback() {
override fun onLocationResult(location: LocationResult) {
super.onLocationResult(location)
onLocationChanged(location.lastLocation)
}
}
}

Getting longitude and latitude takes a very long time

I am getting the longitude and latitude of my device, but it takes at 30 seconds to a minute to do so. Any suggestions to cut the time down?
public class MainActivity extends Activity
{
public String zipcode;
public double latG;
public double lonG;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
boolean enabled = service.isProviderEnabled(LocationManager.GPS_PROVIDER);
if (!enabled)
{
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.getLastKnownLocation(Context.LOCATION_SERVICE);
LocationListener locationListener = new LocationListener()
{
public void onLocationChanged(Location location)
{
if (location != null)
{
latG = location.getLatitude();
lonG = location.getLongitude();
Toast.makeText(MainActivity.this,
latG + " " + lonG,
Toast.LENGTH_LONG).show();
}
}
public void onProviderDisabled(String provider)
{
}
public void onProviderEnabled(String provider)
{
}
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
};
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
Geocoder geocoder = new Geocoder(this, Locale.getDefault());
List<Address> addresses = null;
try
{
addresses = geocoder.getFromLocation(latG, lonG, 1);
}
catch (IOException e)
{
Context context = this;
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
alertDialogBuilder.setTitle("Error");
alertDialogBuilder.setMessage("Error in getting address information.");
alertDialogBuilder.setCancelable(true);
}
for (Address address : addresses)
{
if(address.getPostalCode() != null)
{
zipcode = address.getPostalCode();
Toast.makeText(MainActivity.this, zipcode, Toast.LENGTH_LONG).show();
break;
}
}
}
}

You are using GPS_PROVIDER for fetching the GPS data. GPS_PROVIDER fetches details directly from the satellite so it takes time for the first time you load this. Moreover GPS_PROVIDER takes more than 30 seconds if your are not below the open sky. GPS_PROVIDER may return NULL when you are inside the office or in basement.
There is an alternative way for this is to use NETWORK_PROVIDER. This provider will give you GPS details based on your current Network state. This will not be much accurate like GPS_PROVIDER but it works faster.

hi you are using GPS PROVIDER which can take some time as it depends on several constraints like yours building position, physical position, weather as gps data is available from the satellite so use a network provider which may faster in yours case please have a look on the given code snippet at
http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/

Best option is to use Google Play Services and its LocationClient.
http://developer.android.com/google/play-services/location.html
This gives you a provider that automatically picks the best available information from all the provider types and can return the location immediately in some cases using getLastLocation()

try to run it in device rather than running it in the emulator.

try this
try {
gps_enabled = locManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception ex) {
}
try {
network_enabled = locManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception ex) {}
if (gps_enabled) {
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locListener);
}
if (network_enabled) {
locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener);
It will give the response what ever the service is available.Even you can place your priority

Use this code to fetch faster,
String provider;
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
if (provider != null && !provider.equals("")) {
Location location = locationManager.getLastKnownLocation(provider);
locationManager.requestLocationUpdates(provider, 20000, 1, this);
if (location != null)
{
onLocationChanged(location);
//your remaining code
}

Location returns NULL

I am writing an Android app that returns longitude and latitude, however location holds a Null value.
Please see if you can see why, Its been bugging me all day. Code below:
public class example extends Activity {
public static double latitude;
public static double longitude;
LocationManager lm;
LocationListener ll;
Location location;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.questions);
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
ll = new MyLocationListener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
//location = lm.getLastKnownLocation(lm.getBestProvider(criteria, true));
Button b = (Button) findViewById(R.id.button2);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
int index1 = provider.indexOf("gps");
if(index1 < 0)
// gps not enabled, call msgbox
showMsgBox("GPS is off", "GPS is off. Turn it on?", "Turn on");
else
areWeThereYet(); }});
}
private void areWeThereYet()
{
if(weAreThere())
{
toastMsg("in correct place");
}
else if(location!=null)
toastMsg("not there yet");
}
private boolean weAreThere() {
location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location!=null)
{
longitude = location.getLongitude();
latitude = location.getLatitude();
toastMsg(latitude + " " + longitude);
return inCorrectPlace(question);
}
else
{
toastMsg("Location not ready yet");
return false;
}
}
private void toastMsg(String msg) {
Toast toast = Toast.makeText(this, msg, 2000);
toast.setGravity(Gravity.BOTTOM, 0, 0);
toast.show();
}
}

If the GPS has not ever gotten a location since the device was booted, the location object will be null. One thing you can do is attempt to get a GPS location and a network location, and check to two to see if either of them are good (or which one is better) and use that location.

If you're using the emulator, then see here for advice on setting up the emulator to provide a location. If you're testing it on your device, it may be because you've never had a gps location on it. Try using the Google maps application before testing your app.