Develop Reference

NullPointerException error on an Android-GeoFire project

This is the error I'm getting: java.lang. Attempt to call the virtual method 'double android.location.Location.getLatitude()' on a null object reference results in a NullPointerException.Can anyone guide me on how to achieve this?
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks ,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
private ActivityMapsBinding binding;
private static final int MY_PERMISSION_REQUEST_CODE =71922 ;
private static final int PLAY_SERVICES_RESOLUTION_REQUEST = 300193;
private LocationRequest locationRequest;
private GoogleApiClient googleApiClient;
private Location mLastLocation ;
private static int UPDATE_INTERVAL =5000;
private static int FARTEST_INTERVAL =5000;
private static int DISPLACEMENT =10;
Marker marker;
DatabaseReference ref ;
GeoFire geoFire;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMapsBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
// 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);
ref = FirebaseDatabase.getInstance().getReference("Test");
setupLocation();
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
{
case MY_PERMISSION_REQUEST_CODE:
if(grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
{
if(checkPlayServices())
{
buildGoogleApiCLient();
createLocationRequest();
displayLocation();
}
}
break;
}
}
private void setupLocation() {
try {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED )
{
ActivityCompat.requestPermissions(this, new String[]{
Manifest.permission.ACCESS_COARSE_LOCATION,
Manifest.permission.ACCESS_FINE_LOCATION
}, MY_PERMISSION_REQUEST_CODE);
}
else {
if(checkPlayServices())
{
buildGoogleApiCLient();
createLocationRequest();
displayLocation();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void displayLocation() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED )
{
return;
}
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
if(mLastLocation != null)
{
double latitude = mLastLocation.getLatitude();
double longitude = mLastLocation.getLongitude();
Log.d("EDMDEV",String.format("your location was changed: %f %f ",latitude,longitude));
// upDate to firebase
geoFire.setLocation("You", new GeoLocation(latitude, longitude), new GeoFire.CompletionListener() {
#Override
public void onComplete(String key, DatabaseError error) {
if(marker != null){
marker.remove(); //remove old marker
marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(latitude,longitude))
.title("Ele"));
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude,longitude),12.0f));
}
}
});
}
else {
Log.d("EDMDEV","cannot get ur location");
}
}
private void createLocationRequest() {
locationRequest = new LocationRequest();
locationRequest.setInterval(UPDATE_INTERVAL);
locationRequest.setFastestInterval(FARTEST_INTERVAL);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
private void buildGoogleApiCLient() {
googleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
googleApiClient.connect();
}
private boolean checkPlayServices() {
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (resultCode != ConnectionResult.SUCCESS)
{
if(GooglePlayServicesUtil.isUserRecoverableError(resultCode))
GooglePlayServicesUtil.getErrorDialog(resultCode,this,PLAY_SERVICES_RESOLUTION_REQUEST).show();
else {
Toast.makeText(this, "this device is not support", Toast.LENGTH_SHORT).show();
finish();
}
return false ;
}
return true;
}
/**
* 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;
// LatLng syd = new LatLng( -34,151);
// mMap.addMarker(new MarkerOptions().position(syd).title("mar in syd"));
// mMap.moveCamera(CameraUpdateFactory.newLatLng(syd));
//Create area
LatLng village = new LatLng(35.7533,-122.4056);
mMap.addCircle(new CircleOptions()
.center(village)
.radius(500) // in meter
.strokeColor(Color.BLUE)
.fillColor(0x220000FF)
.strokeWidth(5.0f)
);
// 0.5f = 0.5km = 500 m
GeoQuery geoQuery = geoFire .queryAtLocation(new GeoLocation(village.latitude,village.longitude),0.5f);
geoQuery.addGeoQueryEventListener(new GeoQueryEventListener() {
#Override
public void onKeyEntered(String key, GeoLocation location) {
sendNotification("EDKDD",String.format("%s entered village area ",key ));
}
#Override
public void onKeyExited(String key) {
sendNotification("EDKDD",String.format("%s no longer village area ",key ));
}
#Override
public void onKeyMoved(String key, GeoLocation location) {
sendNotification("Move",String.format("%s moved within the village area [%f/%f]",key,location.latitude, location.longitude ));
}
#Override
public void onGeoQueryReady() {
}
#Override
public void onGeoQueryError(DatabaseError error) {
Log.e("Error","" + error);// 36.46
}
});
}
private void sendNotification(String title, String content) {
Notification.Builder builder = new Notification.Builder(this)
.setSmallIcon(R.mipmap.ic_launcher_round)
.setContentTitle(title)
.setContentText(content);
NotificationManager notificationManager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
Intent intent = new Intent(this,MapsActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(this,0,intent,PendingIntent.FLAG_IMMUTABLE);
builder.setContentIntent(contentIntent);
Notification notification = builder.build();
notification.flags = Notification.DEFAULT_SOUND;
notificationManager.notify(new Random().nextInt(),notification);
}
#Override
public void onConnected(#Nullable Bundle bundle) {
displayLocation();
startLocationUpdate();
}
private void startLocationUpdate() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED )
{
return;
}
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient,locationRequest,this);
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onConnectionFailed(#NonNull ConnectionResult connectionResult) {
}
#Override
public void onLocationChanged(Location location) {
mLastLocation = location;
displayLocation();
}
}
java.lang.NullPointerException Error
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.newapp.elephantapplication, PID: 3267
java.lang.NullPointerException: Attempt to invoke virtual method 'com.firebase.geofire.GeoQuery com.firebase.geofire.GeoFire.queryAtLocation(com.firebase.geofire.GeoLocation, double)' on a null object reference
at com.newapp.elephantapplication.MapsActivity.onMapReady(MapsActivity.java:224)
at com.google.android.gms.maps.zzat.zzb(com.google.android.gms:play-services-maps##18.0.0:1)
at com.google.android.gms.maps.internal.zzaq.zza(com.google.android.gms:play-services-maps##18.0.0:5)
at com.google.android.gms.internal.maps.zzb.onTransact(com.google.android.gms:play-services-maps##18.0.0:3)
at android.os.Binder.transact(Binder.java:387)
at eg.aZ(:com.google.android.gms.dynamite_mapsdynamite#220920047#22.09.20 (040308-0):2)
at com.google.maps.api.android.lib6.impl.bk.run(:com.google.android.gms.dynamite_mapsdynamite#220920047#22.09.20 (040308-0):1)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Just getting used to Java and Android and I've got the above error.
Can anyone guide me on how to achieve this?

How to pass the current lat long values from one class to another activity in Android?

I am using googleAPIClient to get the current lat long values using Location. I am getting the values of both my current lat and long in a separate class. I need to pass these current lat and long values inside my MapsActivity ( GoogleMap Activity), Since I have already created the object for the another class, from which I need to get the values, I don't know how to pass the values to this activity from the class.
Here's what I have tried. This is the class which I have created to get the current lat long values:
CurrentValues.java:
public class CurrentValues implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {
private static final String TAG = CurrentValues.class.getSimpleName();
private Context context;
private GoogleApiClient mGoogleApiClient;
private Location mLocation;
private LocationManager mLocationManager;
private LocationRequest mLocationRequest;
private long UPDATE_INTERVAL = 2 * 1000; /* 10 secs */
private long FASTEST_INTERVAL = 2000; /* 2 sec */
public CurrentValues( Context context){
mGoogleApiClient = new GoogleApiClient.Builder(context)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mLocationManager = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
checkLocation();
}
#Override
public void onConnected(#Nullable Bundle bundle) {
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, 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;
}
startLocationUpdates();
mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if(mLocation == null){
startLocationUpdates();
}
if (mLocation != null) {
// mLatitudeTextView.setText(String.valueOf(mLocation.getLatitude()));
//mLongitudeTextView.setText(String.valueOf(mLocation.getLongitude()));
} else {
Toast.makeText(context, "Location not Detected", Toast.LENGTH_SHORT).show();
}
}
#Override
public void onConnectionSuspended(int i) {
Log.i(TAG, "Connection Suspended");
mGoogleApiClient.connect();
}
#Override
public void onConnectionFailed(#NonNull ConnectionResult connectionResult) {
Log.i(TAG, "Connection failed. Error: " + connectionResult.getErrorCode());
}
#Override
public void onLocationChanged(Location location) {
String msg = "Updated Location: " +
Double.toString(location.getLatitude()) + "," +
Double.toString(location.getLongitude());
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
}
private boolean checkLocation() {
if(!isLocationEnabled())
showAlert();
return isLocationEnabled();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
private boolean isLocationEnabled() {
mLocationManager = (LocationManager)context. getSystemService(Context.LOCATION_SERVICE);
return mLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
mLocationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}
private void showAlert() {
final AlertDialog.Builder dialog = new AlertDialog.Builder(context);
dialog.setTitle("Enable Location")
.setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " +
"use this app")
.setPositiveButton("Location Settings", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface paramDialogInterface, int paramInt) {
Intent myIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
context.startActivity(myIntent);
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface paramDialogInterface, int paramInt) {
}
});
dialog.show();
}
protected void startLocationUpdates() {
// Create the location request
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(UPDATE_INTERVAL)
.setFastestInterval(FASTEST_INTERVAL);
// Request location updates
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, 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;
}
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
mLocationRequest, (com.google.android.gms.location.LocationListener) context);
Log.d("reque", "--->>>>");
}
}
Now I need to pass the lat long values I got from this class to MapsActivity. Since I had already created object for the currentvalues class here in this activity, I don't know how to pass the value from there to here.
Here's my MapActivity (GoogleMap Activity)
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private CurrentValues currentValues;
private Location location;
#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);
}
/**
* 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;
// // Add a marker in Sydney and move the camera
// LatLng sydney = new LatLng(-34, 151);
// mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
//
// LatLng chennai = new LatLng(13.06,80);
// mMap.addMarker(new MarkerOptions().position(chennai).title("Marker in Chennai"));
LatLng latLng = new LatLng(location.getLatitude(),location.getLongitude());
googleMap.addMarker(new MarkerOptions().position(latLng));
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 8f));
// creating object for currentValues class
CurrentValues currentValues = new CurrentValues(this);
}
}
I don't know how to proceed after this to pass the lat long values here. How can I proceed?

How can I get data from Nearby Places into Listview?

Which methods do I have to include to my code to pass the data to list view?
I want to show the nearby places using ListView. It only show the nearby places on the map by clicking the buttons as shown below. When I click the "Nearby School" button it displays the nearby school on the map, now I want it to display the nearby schools using listview. How can I do that?
public class MapsActivity extends FragmentActivity implements com.google.android.gms.location.LocationListener, OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener {
private GoogleMap mMap;
double latitude;
double longitude;
private int PROXIMITY_RADIUS = 10000;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
ListView lvMap;
ArrayList<HashMap<String, String>> placesListItems = new ArrayList<HashMap<String,String>>();
#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();
}
//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.");
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.maps);
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;
}
/**
* 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_NORMAL);
//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);
}
Button btnRestaurant = (Button) findViewById(R.id.btnRestaurant);
btnRestaurant.setOnClickListener(new View.OnClickListener() {
String Restaurant = "restaurant";
#Override
public void onClick(View v) {
Log.d("onClick", "Button is Clicked");
mMap.clear();
String url = getUrl(latitude, longitude, Restaurant);
Object[] DataTransfer = new Object[2];
DataTransfer[0] = mMap;
DataTransfer[1] = url;
Log.d("onClick", url);
GetNearbyPlacesData getNearbyPlacesData = new GetNearbyPlacesData();
getNearbyPlacesData.execute(DataTransfer);
Toast.makeText(MapsActivity.this,"Nearby Restaurants", Toast.LENGTH_LONG).show();
}
});
Button btnHospital = (Button) findViewById(R.id.btnHospital);
btnHospital.setOnClickListener(new View.OnClickListener() {
String Hospital = "hospital";
#Override
public void onClick(View v) {
Log.d("onClick", "Button is Clicked");
mMap.clear();
String url = getUrl(latitude, longitude, Hospital);
Object[] DataTransfer = new Object[2];
DataTransfer[0] = mMap;
DataTransfer[1] = url;
Log.d("onClick", url);
GetNearbyPlacesData getNearbyPlacesData = new GetNearbyPlacesData();
getNearbyPlacesData.execute(DataTransfer);
Toast.makeText(MapsActivity.this,"Nearby Hospitals", Toast.LENGTH_LONG).show();
}
});
Button btnSchool = (Button) findViewById(R.id.btnSchool);
btnSchool.setOnClickListener(new View.OnClickListener() {
String School = "school";
#Override
public void onClick(View v) {
Log.d("onClick", "Button is Clicked");
mMap.clear();
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
String url = getUrl(latitude, longitude, School);
Object[] DataTransfer = new Object[2];
DataTransfer[0] = mMap;
DataTransfer[1] = url;
Log.d("onClick", url);
GetNearbyPlacesData getNearbyPlacesData = new GetNearbyPlacesData();
getNearbyPlacesData.execute(DataTransfer);
Toast.makeText(MapsActivity.this,"Nearby Schools", Toast.LENGTH_LONG).show();
}
});
}
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);
}
}
private String getUrl(double latitude, double longitude, String nearbyPlace) {
StringBuilder googlePlacesUrl = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
googlePlacesUrl.append("location=" + latitude + "," + longitude);
googlePlacesUrl.append("&radius=" + PROXIMITY_RADIUS);
googlePlacesUrl.append("&type=" + nearbyPlace);
googlePlacesUrl.append("&sensor=true");
googlePlacesUrl.append("&key=" + "AIzaSyATuUiZUkEc_UgHuqsBJa1oqaODI-3mLs0");
Log.d("getUrl", googlePlacesUrl.toString());
return (googlePlacesUrl.toString());
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onLocationChanged(Location location) {
Log.d("onLocationChanged", "entered");
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
latitude = location.getLatitude();
longitude = location.getLongitude();
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));
Toast.makeText(MapsActivity.this,"Your Current Location", Toast.LENGTH_LONG).show();
Log.d("onLocationChanged", String.format("latitude:%.3f longitude:%.3f",latitude,longitude));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
Log.d("onLocationChanged", "Removing Location Updates");
}
Log.d("onLocationChanged", "Exit");
}
#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();
}

Android Studio Google Maps cannot get latlng or find the blue dot

I am trying to use Google Maps on my app. So far I am able to load the map onto a SupportMapFragment which is called onto my MainActivity as a fragment. However, I am unable to see a blue dot despite enabling locations. I am not able to get the latitude or longitude to show up in the logs as well. Can someone help me with this? I am quite lost. Could it be the permissions I have set? I have also added the necessary permissions in the manifest.
This is my code
public class MapFragment extends SupportMapFragment implements LocationListener,OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener{
private GoogleMap googleMap;
private GoogleApiClient googleApiClient;
private LocationRequest locationRequest;
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
Location location;
Marker locationMarker;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
protected synchronized void buildGoogleAPIClient(){
googleApiClient = new GoogleApiClient.Builder(getActivity())
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
googleApiClient.connect();
}
#Override
public void onLocationChanged(Location location) {
LatLng currentLocation = new LatLng(location.getLatitude(),location.getLongitude());
Double latitude = currentLocation.latitude;
Double longitude = currentLocation.longitude;
this.location = location;
if(locationMarker!=null){
locationMarker.remove();
}
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(currentLocation);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE));
locationMarker = googleMap.addMarker(markerOptions);
if(googleApiClient!=null){
LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient,this);
}
}
#Override
public void onMapReady(GoogleMap googleMap) {
this.googleMap = googleMap;
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
if(ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)== PackageManager.PERMISSION_GRANTED){
buildGoogleAPIClient();
this.googleMap.setMyLocationEnabled(true);
}else{
checkLocationPermission();
}
}else{
buildGoogleAPIClient();
this.googleMap.setMyLocationEnabled(true);
}
}
#Override
public void onPause() {
super.onPause();
if(googleApiClient!=null){
LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient,this);
}
}
#Override
public void onConnected(#Nullable Bundle bundle) {
locationRequest = new LocationRequest();
locationRequest.setInterval(1000);
locationRequest.setFastestInterval(1000);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
if(ContextCompat.checkSelfPermission(getActivity(),Manifest.permission.ACCESS_FINE_LOCATION)==PackageManager.PERMISSION_GRANTED){
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient,locationRequest,this);
}
}
private void checkLocationPermission(){
if(ContextCompat.checkSelfPermission(getActivity(),Manifest.permission.ACCESS_FINE_LOCATION)!=PackageManager.PERMISSION_GRANTED){
//Ask for permission again once the user sees the explanation
if(ActivityCompat.shouldShowRequestPermissionRationale(getActivity(),Manifest.permission.ACCESS_FINE_LOCATION)){
new AlertDialog.Builder(getActivity())
.setTitle("Location Permission required")
.setMessage("This app requires location permissions in order to function")
.setPositiveButton("Allow", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
ActivityCompat.requestPermissions(getActivity(),new String[]{Manifest.permission.ACCESS_FINE_LOCATION},MY_PERMISSIONS_REQUEST_LOCATION);
}
})
.create()
.show();
}else{
//No explanation required. Just request for permissions
ActivityCompat.requestPermissions(getActivity(),new String[]{Manifest.permission.ACCESS_FINE_LOCATION},MY_PERMISSIONS_REQUEST_LOCATION);
}
}
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode){
case MY_PERMISSIONS_REQUEST_LOCATION: {
if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED){
if(googleApiClient==null){
buildGoogleAPIClient();
}
if(ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)== PackageManager.PERMISSION_GRANTED){
this.googleMap.setMyLocationEnabled(true);
}
}else{
Toast.makeText(getActivity(),"Permission denied",Toast.LENGTH_LONG).show();
}
return;
}
}
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onConnectionFailed(#NonNull ConnectionResult connectionResult) {
}
Hope someone can help me. Thanks

In the code that you are showing you are never calling getMapAsync on your SupportMapFragment so basically you are just showing a map.
Add getMapAsync to your onCreate:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getMapAsync(this);
}

Remember to add the following permissions too:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>