Develop Reference

How to draw a route from current location to a markerpoint on Android Google Maps?

I'm new creating apps and I want to show a drawn route in a Google Map starting from the current location. I've just found how to get the current location, but now I'm stuck in the second part, which is drawing the route from the current location to another marker point.
Here is my code:
`public class Trazo_Rutas extends FragmentActivity implements
OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
GoogleApiClient googleApiClient;
LocationRequest locationRequest;
Location lastLocation;
Marker userLocation;
private static final int Request_User_Location_Code = 99;
PlaceAutocompleteFragment placeAutoComplete;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_trazo__rutas);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkUserLocationPermission();
}
//Check if Google Play Services Available or not
if (!CheckGooglePlayServices()) {
Log.d("onCreate", "Finishing test case since Google Play Services are not available");
finish();
}
else {
Log.d("onCreate","Google Play Services available.");
}
//AutoComplete search bar
placeAutoComplete = (PlaceAutocompleteFragment) getFragmentManager().findFragmentById(R.id.place_autocomplete);
placeAutoComplete.setOnPlaceSelectedListener(new PlaceSelectionListener() {
#Override
public void onPlaceSelected(Place place) {
Log.d("Maps", "Place selected: " + place.getName());
}
#Override
public void onError(Status status) {
Log.d("Maps", "An error occurred: " + status);
}
});
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
private boolean CheckGooglePlayServices() {
GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
int result = googleAPI.isGooglePlayServicesAvailable(this);
if(result != ConnectionResult.SUCCESS) {
if(googleAPI.isUserResolvableError(result)) {
googleAPI.getErrorDialog(this, result,
0).show();
}
return false;
}
return true;
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.getUiSettings().setZoomControlsEnabled(true);
//get latlong for corners for specified place
LatLng corner1 = new LatLng(25.64379, -103.60966);
LatLng corner2 = new LatLng(25.64317, -103.20935);
LatLng corner3 = new LatLng(25.43872, -103.61104);
LatLng corner4 = new LatLng(25.43748, -103.20866);
LatLngBounds.Builder builder = new LatLngBounds.Builder();
builder.include(corner1);
builder.include(corner2);
builder.include(corner3);
builder.include(corner4);
LatLngBounds bounds = builder.build();
//add them to builder
int width = getResources().getDisplayMetrics().widthPixels;
int height = getResources().getDisplayMetrics().heightPixels;
// 20% padding
int padding = (int) (width * 0.20);
//set latlng bounds
mMap.setLatLngBoundsForCameraTarget(bounds);
//move camera to fill the bound to screen
mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, width, height, padding));
//set zoom to level to current so that you won't be able to zoom out viz. move outside bounds
mMap.setMinZoomPreference(mMap.getCameraPosition().zoom);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
} else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
public boolean checkUserLocationPermission() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)){
ActivityCompat.requestPermissions(this, new String[] {
Manifest.permission.ACCESS_FINE_LOCATION
}, Request_User_Location_Code);
} else {
ActivityCompat.requestPermissions(this, new String[] {
Manifest.permission.ACCESS_FINE_LOCATION
}, Request_User_Location_Code);
}
return false;
} else {
return true;
}
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
switch (requestCode) {
case Request_User_Location_Code:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
if (googleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
Toast.makeText(this, "Se requieren Permisos de Google", Toast.LENGTH_SHORT).show();
finish();
}
return;
}
}
protected synchronized void buildGoogleApiClient() {
googleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
googleApiClient.connect();
}
#Override
public void onLocationChanged(Location location) {
lastLocation = location;
if (userLocation != null) {
userLocation.remove();
}
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.draggable(true);
markerOptions.title("Tu ubicación");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
userLocation = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 16));
if (googleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient, this);
}
}
#Override
public void onConnected(#Nullable Bundle bundle) {
locationRequest = new LocationRequest();
locationRequest.setInterval(1100);
locationRequest.setFastestInterval(1100);
locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
}
}`
My concern is that I don't know how to implement the other marker and draw the route.
Thank you.

Map Fragment loops back to current location after searching a new place in SupportPlaceAutocompleteFragment

I have added a Support Place Autocomplete fragment inside a Map Fragment, and it does not seem to work properly for some reason. Whenever I search for a place, the map moves to the correct location for a split second, and automatically returns back to the user's current location for some reason.
This is the code of my map fragment:
public class MyMapFragment extends SupportMapFragment
implements OnMapReadyCallback {
GoogleMap mGoogleMap;
SupportMapFragment mapFrag;
LocationRequest mLocationRequest;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
FusedLocationProviderClient mFusedLocationClient;
PlaceAutocompleteFragment mPlaceAutocompleteFragment;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
RelativeLayout layout = (RelativeLayout) inflater.inflate(R.layout.fragment_map,
container, false);
View v = super.onCreateView(inflater, container, savedInstanceState);
layout.addView(v, 0);
getChildFragmentManager().beginTransaction()
.replace(R.id.place_autocomplete, new SupportPlaceAutocompleteFragment())
.addToBackStack(SupportPlaceAutocompleteFragment.class.getName())
.commit();
mFusedLocationClient =
LocationServices.getFusedLocationProviderClient(getContext());
return layout;
}
#Override
public void onAttachFragment(Fragment childFragment) {
super.onAttachFragment(childFragment);
if (childFragment instanceof SupportPlaceAutocompleteFragment) {
((SupportPlaceAutocompleteFragment) childFragment).setOnPlaceSelectedListener(
new PlaceSelectionListener() {
#Override
public void onPlaceSelected(Place place) {
LatLng latLng = place.getLatLng();
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 12));
}
#Override
public void onError(Status status) {
}
});
}
}
#Override
public void onResume() {
super.onResume();
setUpMapIfNeeded();
mapFrag = ((SupportMapFragment) getChildFragmentManager()
.findFragmentById(R.id.map));
mapFrag.getMapAsync(this);
}
private void setUpMapIfNeeded() {
if (mGoogleMap == null) {
getMapAsync(this);
}
}
#Override
public void onPause() {
super.onPause();
//stop location updates when Activity is no longer active
if (mFusedLocationClient != null) {
mFusedLocationClient.removeLocationUpdates(mLocationCallback);
}
}
#SuppressLint("RestrictedApi")
#Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap;
mGoogleMap.setPadding(0,200, 0,0);
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(120000); // two minute interval
mLocationRequest.setFastestInterval(120000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(getActivity(),
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
//Location Permission already granted
mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
mGoogleMap.setMyLocationEnabled(true);
} else {
//Request Location Permission
checkLocationPermission();
}
}
else {
mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
mGoogleMap.setMyLocationEnabled(true);
}
}
LocationCallback mLocationCallback = new LocationCallback() {
#Override
public void onLocationResult(LocationResult locationResult) {
List<Location> locationList = locationResult.getLocations();
if (locationList.size() > 0) {
//The last location in the list is the newest
Location location = locationList.get(locationList.size() - 1);
Log.i("MapsActivity", "Location: " + location.getLatitude() + " " + location.getLongitude());
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");
//move map camera
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 12));
}
}
};
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
private void checkLocationPermission() {
if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(),
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
new android.app.AlertDialog.Builder(getActivity())
.setTitle("Location Permission Needed")
.setMessage("This app needs the Location permission, please accept to use location functionality")
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(getActivity(),
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION );
}
})
.create()
.show();
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(getActivity(),
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION );
}
}
}
#Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// location-related task you need to do.
if (ContextCompat.checkSelfPermission(getActivity(),
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
mGoogleMap.setMyLocationEnabled(true);
}
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
Toast.makeText(getActivity(), "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other
// permissions this app might request
}
}

i am getting zero values of longitude and latitude in google maps in android studio

Here is my MapsActivity.java code, I am getting zero values for longitude and latitude after placing a marker on map and after calling getCurrentlocation(). What is going wrong?
public class MapsActivity extends FragmentActivity implements
OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
GoogleMap.OnMarkerDragListener,
GoogleMap.OnMapLongClickListener,
View.OnClickListener {
//Our Map
private GoogleMap mMap;
//To store longitude and latitude from map
private double longitude;
private double latitude;
//Buttons
private ImageButton buttonSave;
private ImageButton buttonCurrent;
private ImageButton buttonView;
//Google ApiClient
private GoogleApiClient googleApiClient;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
//Initializing googleapi client
googleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
//Initializing views and adding onclick listeners
buttonSave = (ImageButton) findViewById(R.id.buttonSave);
buttonCurrent = (ImageButton) findViewById(R.id.buttonCurrent);
buttonView = (ImageButton) findViewById(R.id.buttonView);
buttonSave.setOnClickListener(this);
buttonCurrent.setOnClickListener(this);
buttonView.setOnClickListener(this);
}
#Override
protected void onStart() {
googleApiClient.connect();
super.onStart();
}
#Override
protected void onStop() {
googleApiClient.disconnect();
super.onStop();
}
//Getting current location
private void getCurrentLocation() {
mMap.clear();
//Creating a location object
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;
}
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 location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
if (location != null) {
//Getting longitude and latitude
longitude = location.getLongitude();
latitude = location.getLatitude();
//moving the map to location
moveMap();
}
}
//Function to move the map
private void moveMap() {
//String to display current latitude and longitude
String msg = latitude + ", "+longitude;
//Creating a LatLng Object to store Coordinates
LatLng latLng = new LatLng(latitude, longitude);
//Adding marker to map
mMap.addMarker(new MarkerOptions()
.position(latLng) //setting position
.draggable(true) //Making the marker draggable
.title("Current Location")); //Adding a title
//Moving the camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
//Animating the camera
mMap.animateCamera(CameraUpdateFactory.zoomTo(15));
//Displaying current coordinates in toast
Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
LatLng latLng = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(latLng).draggable(true));
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.setOnMarkerDragListener(this);
mMap.setOnMapLongClickListener(this);
}
#Override
public void onConnected(Bundle bundle) {
getCurrentLocation();
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
#Override
public void onMapLongClick(LatLng latLng) {
//Clearing all the markers
mMap.clear();
//Adding a new marker to the current pressed position
mMap.addMarker(new MarkerOptions()
.position(latLng)
.draggable(true));
String msg = latitude + ", "+longitude;
Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
}
#Override
public void onMarkerDragStart(Marker marker) {
}
#Override
public void onMarkerDrag(Marker marker) {
}
#Override
public void onMarkerDragEnd(Marker marker) {
//Getting the coordinates
latitude = marker.getPosition().latitude;
longitude = marker.getPosition().longitude;
//Moving the map
moveMap();
}
#Override
public void onClick(View v) {
if(v == buttonCurrent){
getCurrentLocation();
moveMap();
}
}
}

GetLastLocation only returns a location if one is available. 99% of the time it won't be. Use requestLocationUpdates or requestSingleUpdate to ensure a location is acquired (note both of these are asynchronous functions, as getting a location takes time).

Use Request Location Updates better
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
#Override
public void onConnected(#Nullable Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(15 * 1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setSmallestDisplacement(0);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, locationListener);
}
}
LocationListener locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
mLastLocation = location;
//do whatever you want here
}
}
};
Don't Forget to add onDestory Method
#Override
protected void onDestroy() {
super.onDestroy();
if (mGoogleApiClient != null && mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, locationListener);
mGoogleApiClient.disconnect();
}
}

How to get current location update every 10 steps moved

I have implemented this code to get current location update every 10 steps moved but I'm not getting current lat lng as i move 10 steps or more, I have question is it realistic to set minimum distance 10 steps?
Also every time when my code runs I get different different lat lng in terms of digits after decimal and if i compare these lat lng that i get every time my application runs with current location on google maps website, its roughly 400 meters away from my current location, why is it happening.
private FusedLocationProviderClient mFusedLocationClient;
private GoogleApiClient mGoogleApiClient;
private GoogleMap mMap;
private TextView tvLat;
private TextView tvLng;
Map<String, Double> latlng = new HashMap<>();
DatabaseReference data;
private double lat;
private double lng;
CameraPosition CurrentLocation;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SingletonConnectClass instence = SingletonConnectClass.getInstance();
data = instence.firebaseSetup();
setContentView(R.layout.activity_maps);
initView();
setUpMapIfNeeded();
}
private void setUpMapIfNeeded() {
mFusedLocationClient
= LocationServices.getFusedLocationProviderClient(this);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setMyLocationEnabled(true);
mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
getCurrentLocation();
buildClient();
}
private void getCurrentLocation(){
mFusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(final Location location) {
CurrentLocation = new CameraPosition.Builder().target(new
LatLng(location.getLatitude(),
location.getLongitude()))
.zoom(15.5f)
.bearing(0)
.tilt(25)
.build();
//changed camera position to current location and added marker there
}
Here is the code for getting current location update if i move 10 steps after connecting to play services in onConnected callback
public void onConnected(Bundle bundle) {
mFusedLocationClient.requestLocationUpdates(requestLocation(),
new LocationCallback() {
#Override
public void onLocationResult(LocationResult locationResult) {
for (final Location location : locationResult.getLocations()) {
//not getting changing current lat lng if i move 10 steps
tvLat.setText(Double.toString(location.getLatitude()));
tvLng.setText(Double.toString(location.getLongitude()));
lat = location.getLatitude();
lng = location.getLongitude();
//as result not camera position is not changed
changeCameraPosition(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLong)
}}, Looper.myLooper());

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
#Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
#Override
public void onConnectionSuspended(int i) {
}
#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_MAGENTA));
mCurrLocationMarker = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission(){
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
#Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted. Do the
// contacts-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other permissions this app might request.
// You can add here other case statements according to your requirement.
}
}
}

Google Maps: New markers are not showing after resuming map activity

I am connecting my app to a sensor, everytime the sensor sends data a marker is placed on a map with data inside info window.
When I am starting the activity the first time. mMap has ID: 21319.
In my onLocationChanged()method I add markers to the map with ID 21319. Then if I press the back button and resume the activity. mMap is created again and has now another ID, let's say ID 22431. With my method addMapPoints() I add the old markers to mMap with ID 22431 with mMap.addMarker(markerOptions) and I can see the markers on the screen. But this time when new data is sent and markers are added inside onLocationChanged() no new markers appear on the screen. When I debug I can see that in onLocationChanged() my mMap has the old ID: 21319 and I do not get any errors. So I guess that the new markers are added to the old map but my screen is showing the new map.
Why is this happening? And how can I solve this problem?
UPDATE I think I have found the problem. At the moment mMap == null when new data is sent. What I now wonder is how can I obtain the map inside OnLocationUpdate() or in OnResume()?
Here is my MapsActivity code
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener
{
public GoogleMap mMap;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
private int co_mV;
private int no2_mV;
LocationRequest mLocationRequest;
private boolean initiateApp;
String currentTime;
TcpClient mTcpClient;
ArrayList<Marker> markerArrayList;
static ArrayList<Double> markerLat = new ArrayList<>();
static ArrayList<Double> markerLng = new ArrayList<>();
static ArrayList<String> markerSnippet = new ArrayList<>();
static ArrayList<String> markerTitle = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
initiateApp = true;
markerArrayList = new ArrayList<>();
}
#Override
protected void onResume() {
super.onResume();
}
#Override
protected void onPause() {
super.onPause();
markerArrayList.clear();
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
mMap.setMyLocationEnabled(true);
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
}
}
else {
buildGoogleApiClient();
}
if (markerLat != null) {
addMapPoints();
}
}
/* Here we create the infoWindow **/
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
#Override
public void onConnected(Bundle bundle) {
getNewLocation();
new ConnectTask().execute("");
}
public void newData(JSONObject d) {
try {
co_mV = d.getInt("co_mV");
no2_mV = d.getInt("no2_mV");
} catch (JSONException e) {
e.printStackTrace();
}
getNewLocation();
}
public void getTime() {
Calendar cal = Calendar.getInstance();
currentTime = new SimpleDateFormat("HH:mm:ss").format(cal.getTime());
}
public void getNewLocation() {
mLocationRequest = new LocationRequest();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
public void addMapPoints() {
markerArrayList = new ArrayList<>();
for (int i = 0; i < markerLat.size(); i++) {
LatLng latLng = new LatLng(markerLat.get(i), markerLng.get(i));
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title(markerTitle.get(i));
markerOptions.snippet(markerSnippet.get(i));
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
Marker marker = mMap.addMarker(markerOptions);
markerArrayList.add(marker);
}
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onLocationChanged(Location location) {
if (markerArrayList.size()>1) {
if(location.distanceTo(mLastLocation) < 30) {
markerArrayList.get(markerArrayList.size()-1).remove();
markerArrayList.remove(markerArrayList.size()-1);
markerSnippet.remove(markerSnippet.size()-1);
markerTitle.remove(markerTitle.size()-1);
markerLat.remove(markerTitle.size()-1);
markerLng.remove(markerTitle.size()-1);
Toast.makeText(
getApplicationContext(),
"Reading to close to last reading, replaces last reading", Toast.LENGTH_SHORT).show();
}
}
if (markerArrayList.size() == 8) {
markerArrayList.get(0).remove();
markerArrayList.remove(0);
markerSnippet.remove(0);
markerTitle.remove(0);
markerLat.remove(0);
markerLng.remove(0);
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
if (co_mV != 0) {
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerLat.add(location.getLatitude());
markerLng.add(location.getLongitude());
markerOptions.title("Time of reading: " + currentTime);
markerTitle.add("Time of reading: " + currentTime);
markerOptions.snippet("co: " + String.valueOf(co_mV) + " mV, " + "no2: " + String.valueOf(no2_mV) + " mV");
markerSnippet.add("co: " + String.valueOf(co_mV) + " mV, " + "no2: " + String.valueOf(no2_mV) + " mV");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mMap.addMarker(markerOptions);
markerArrayList.add(mCurrLocationMarker);
}
mLastLocation = location;
Log.d("ADebugTag", "Value: " + Double.toString(location.getLatitude()));
Log.d("ADebugTag", "Value: " + Double.toString(location.getLongitude()));
//move map camera
if(initiateApp){
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 15));
}
boolean contains = mMap.getProjection()
.getVisibleRegion()
.latLngBounds
.contains(latLng);
if(!contains){
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
}
initiateApp = false;
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission() {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
#Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted. Do the
// contacts-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other permissions this app might request.
// You can add here other case statements according to your requirement.
}
}
public JSONObject getNewJSON(JSONObject json) {
try {
int humidity = json.getInt("humidity_ppm");
int pressure = json.getInt("pressure_Pa");
int noise = json.getInt("noise_dB");
double lat = mLastLocation.getLatitude();
double lng = mLastLocation.getLongitude();
long time = System.currentTimeMillis() / 1000L;
JSONObject c = new JSONObject();
c.put("time",time);
c.put("lat",lat);
c.put("long",lng);
c.put("humidity",humidity);
c.put("pressure",pressure);
c.put("noise_dB",noise);
return c;
} catch (JSONException e) {
e.printStackTrace();
}

I solve this problem by exiting the application in onDestroy method .
I think when fragment is reused marker cannot be placed in map
#Override
public void onDestroy() {
getActivity().finish();
System.exit(0);
super.onDestroy();
}