Develop Reference

Camera moves back to original position everytime I scroll/pan/drag

I am creating an Android application and have set up a standard Google Maps activity. The application so far just displays the location of the user. The camera is set to focus on the users location initally. I am running into a problem when I try to scroll or drag to a new position on the emulator. I drag and once i lift up the mouse the camera resets to its original position.
onMapReady Code
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
mMap.clear();
LatLng currentLocation = new LatLng(location.getLatitude(), location.getLongitude());
mMap.addMarker(new MarkerOptions().position(currentLocation).title("You Are Here"));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(currentLocation)
.zoom(25)
.bearing(200)
.tilt(90)
.build();
mMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
Geocoder geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());
try {
List<Address> listAddresses = geocoder.getFromLocation(location.getLatitude(), location.getLongitude(), 1);
if (listAddresses.get(0).getAdminArea() != null) {
String address += listAddresses.get(0).getAdminArea();
}
Toast.makeText(MapsActivity.this, address, Toast.LENGTH_SHORT).show();
Log.i("Address", address);
} catch (Exception e) {
e.printStackTrace();
}
}
if (ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);
} else {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
mMap.clear();
LatLng userLocation = new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude());
mMap.addMarker(new MarkerOptions().position(userLocation).title("Your Location"));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(userLocation)
.zoom(25)
.bearing(0)
.tilt(90)
.build();
mMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
}
}
This is the code I have to display a marker at current location. I also have code to get AdminArea of current location.
I believe the problem is that my code is runnning constantly so that when I attempt to drag the screen, it just resets to where the camera was originally set. The same occurs for the Toast displaying the current location. This does not update wth new information when i change new location

You are correct. You are setting the camera location in your onLocationChange method, which fires constantly (the user's location doesn't have to change much for this method to fire). So, by setting the camera location to the currentLocation, it will keep scrolling the map. Try commenting that out and see what happens.
public void onLocationChanged(Location location) {
mMap.clear();
LatLng currentLocation = new LatLng(location.getLatitude(), location.getLongitude());
mMap.addMarker(new MarkerOptions().position(currentLocation).title("You Are Here"));
//CameraPosition cameraPosition = new CameraPosition.Builder()
// .target(currentLocation)
// .zoom(25)
// .bearing(200)
// .tilt(90)
// .build();
//mMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

Adding Default Location if User Doesn't Allow Permission for a Fine Location for a Map in Android

I am starting to learn about the runtime permissions. I have a map and I made a permission. If user allows fine location - map zooms to his current location, and if he doesn't allow it, the map stays in the place. What I want to do instead of map staying in the place is this: if the user doesn't allow permission for accessing his location, map should zoom in to my custom location (Greenwich).
My maps fragment:
mapView.getMapAsync(new OnMapReadyCallback() {
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)) {
} else {
ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, MY_LOCATION_REQUEST_CODE);
}
return;
}
mMap.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
// if (ContextCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION)
// == PackageManager.PERMISSION_GRANTED) {
// mMap.setMyLocationEnabled(true);
// } else {
// // Show rationale and request permission.
// }
//Disable Map Toolbar:
mMap.getUiSettings().setMapToolbarEnabled(false);
// Get the name of the best provider and current location
String provider = null;
if (locationManager != null) {
provider = locationManager.getBestProvider(criteria, true);
}
// Get current location
Location myLocation = null;
if (locationManager != null) {
myLocation = locationManager.getLastKnownLocation(provider);
}
// Set default latitude and longitude to Greenwich
double latitude = 51.4825766;
double longitude = -0.0076589;
// Get latitude and longitude of the current location and a LatLng object
if (myLocation != null) {
latitude = myLocation.getLatitude();
longitude = myLocation.getLongitude();
}
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(latitude, longitude)).zoom(14).build();
mMap.animateCamera(CameraUpdateFactory
.newCameraPosition(cameraPosition));
}

You can zoom to location manually with this code :
CameraUpdate center=CameraUpdateFactory.newLatLng(new LatLng(latitude,
longitude));
CameraUpdate zoom=CameraUpdateFactory.zoomTo(15);
map.moveCamera(center);
map.animateCamera(zoom);

Couldn't find solution so I put the permission inside the parent activity. I think it is a known bug.

when user turn On location show marker on current location

i create one map in this i show one marker on current location its working fine
when location turn on already but when Activity is on and i turn On location it does not show any marker i want to show marker when location is on
any help?..
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
getCurrentLocation();
// latLngCurrentLocation is my current location which is update using getCurrentLocation() method.
if(latLngCurrentLocation != null) {
// add marker on current location
markerCurrent = mMap.addMarker(new MarkerOptions()
.position(latLngCurrentLocation)
.draggable(true)
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN))
.title("Current Location"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLngCurrentLocation));
mMap.animateCamera(CameraUpdateFactory.zoomTo(8));
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.setOnMarkerDragListener(this);
}
}

Through GpsTracker class or googleClient api you can get latitude and longtitude and then get it as gpstracker.getlatitude and getlongtitude and set this values to global variables and access it whereever you want.

You will get location in onLocationChanged(Location location) once your position is changed. You will get Latitude and Longitude in location object, so you can set your marker into onLocationChanged(Location location) method
#Override
public void onLocationChanged(Location location)
{
mLastLocation = location;
if (mCurrLocationMarker != null)
{
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ORANGE));
mCurrLocationMarker = mGoogleMap.addMarker(markerOptions);
//move map camera
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(11));
}
OR if you want to refresh your marker once GPS turns on then you can use BroadcastReceiver. BroadcastReciever triggers when GPS turns/off so you can check whether GPS is turned on or off, You can find example in following link, Broadcast receiver for GPS

Location change glitches on map using polyline options

Im facing some problem with my application, specifically with route plot/draw on my google maps. Ive made test route around my house and found out, that GPS providers are not as accurate as similar applications like runtastic or endomondo.
Sometimes Location listener makes incomprehensible changes on my map and the polyline then draws any lines on the map near my location even with perfect GPS signal.
Some other time, it just doesnot work. It does not listen to location change.
Can anybody explain me (like Im five) how does other fitness application get their current position and the plot route onto the google map? Thanks!
//Map Fragment
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.fragment1)).getMap();
map.setMyLocationEnabled(true);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String provider = locationManager.getBestProvider(criteria, true);
//Permission gain
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) {
ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_COARSE_LOCATION},
MY_PERMISSION_ACCESS_COURSE_LOCATION);
return;
}
isLocationEnabled(getApplicationContext());
Location myLocation = locationManager.getLastKnownLocation(provider);
if (myLocation != null) {
latitude = myLocation.getLatitude();
longitude = myLocation.getLongitude();
float zoom = (float) 17.0;
map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, longitude), zoom));
Log.e("TAG", "GPS is on");
Toast.makeText(MainActivity.this, "latitude:" + latitude + " longitude:" + longitude, Toast.LENGTH_SHORT).show();
} else {
locationManager.requestLocationUpdates(provider, 5000, 0, this);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 5000, 10, this);
}
public void onLocationChanged(Location mylocation) {
if (lastLocationloc == null) {
lastLocationloc = mylocation;
}
LatLng lastLatLng = locationToLatLng(lastLocationloc);
LatLng thisLatLng = locationToLatLng(mylocation);
map.addPolyline(new PolylineOptions().add(lastLatLng).add(thisLatLng).width(6).color(Color.RED));
lastLocationloc = mylocation;
Toast.makeText(MainActivity.this, "!!!!Location CHANGE!!!!", Toast.LENGTH_SHORT).show();
}
public static LatLng locationToLatLng(Location loc) {
if (loc != null)
return new LatLng(loc.getLatitude(), loc.getLongitude());
return null;
}
For example, I want to plot it like this:
But my application works its own way..

First of all, you need to take into account the accuracy of the received location. You can get the accuracy using the Location.getAccuracy() method (documentation). The accuracy is measured in meters, so the lower the better:
if (location.getAccuracy() < MINIMUM_ACCURACY) {
// Add the new location to your polyline
}
You can set your MINIMUM_ACCURACY to be 10 meter for example.
On the other hand, you may want to add a new location to your polyline only if your new location is farther than a given distance to your last added location. As an example:
private static final float MINIMUM_ACCURACY = 10;
private static final float MINIMUM_DISTANCE_BETWEEN_POINTS = 20;
private Location lastLocationloc;
// ...
public void onLocationChanged(Location mylocation) {
if (mylocation.getAccuracy() < MINIMUM_ACCURACY) {
if (lastLocationloc == null || lastLocationloc.distanceTo(mylocation) > MINIMUM_DISTANCE_BETWEEN_POINTS) {
// Add the new location to your polyline
lastLocationloc = mylocation;
}
}
}

Marker for location disappears when updating the location Android Studio

In my app I have a button to get the location programmatically. Everything went well until I realized that once I added the location marker, each time I was requesting for the location a new marker was added. Therefore I added an if statement that in my opinion is logical enough but does not work as I would like. When I get the location the first time everything is good and a marker is placed. When I push the location button a second time, the marker is deleted and no new marker is added. The app compiles on my phone with no problem. What am I doing wrong?
public void showCurrentLocation(MenuItem item) {
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) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
Location currentLocation = LocationServices.FusedLocationApi
.getLastLocation(mGoogleApiClient);
if (currentLocation == null){
LayoutInflater inflater = getLayoutInflater();
View layout = inflater.inflate(R.layout.toast_gps_view, null);
Toast toast = new Toast(getApplicationContext());
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.setDuration(Toast.LENGTH_LONG);
toast.setView(layout);
toast.show();
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
} else {
LatLng latLng = new LatLng(
currentLocation.getLatitude(),
currentLocation.getLongitude()
);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(latLng, 16);
mMap.animateCamera(update);
if (myPosition != null){
myPosition.remove();
} else {
myPosition = mMap.addMarker(new MarkerOptions()
.icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_location_icon))
.position(latLng)
.title("I'm here!"));
}
}
}

You are removing the Marker from the map when the Marker already exists but you are not adding it again.
Note that when you remove a marker from the map it is not null, it's state is undefined.
Change your if to update your Marker's position when the Marker exists:
if (myPosition != null){
myPosition.setPosition(latLng);
} else {
myPosition = mMap.addMarker(new MarkerOptions()
.icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_location_icon))
.position(latLng)
.title("I'm here!"));
}