Develop Reference

Why Location manager returns null?

I am developing an app where users will be reporting field Incidences.
The Incident location(longitude and latitude) is important for mapping purposes.
For better, i want to use GPS provider only.
In my activity, i have a nested class for getting location information.
private class myGPSTracker extends Service implements LocationListener {
public myGPSTracker() {
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) context
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
//isNetworkEnabled = locationManager
// .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled ) {
// no network provider is enabled
showSettingsAlert();
canGetLocation = true;
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if ( ActivityCompat.checkSelfPermission(ReportIncident.this, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
ActivityCompat.requestPermissions(ReportIncident.this, new String[] { android.Manifest.permission.ACCESS_FINE_LOCATION }, ACCESS_FINE_LOCATION );
}
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
} else {
canGetLocation = true;
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if ( ContextCompat.checkSelfPermission(ReportIncident.this, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
ActivityCompat.requestPermissions(ReportIncident.this, new String[] { android.Manifest.permission.ACCESS_FINE_LOCATION }, ACCESS_FINE_LOCATION );
}
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
public double getAltitude()
{
if(location != null){
altitude = location.getAltitude();
}
// return longitude
return altitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
public String getAddress()
{
Geocoder geocoder =
new Geocoder(context, Locale.getDefault());
// Create a list to contain the result address
List<Address> addresses = null;
try {
/*
* Return 1 address.
*/
addresses = geocoder.getFromLocation(this.getLatitude(),
this.getLongitude(), 1);
} catch (Exception e1) {
e1.printStackTrace();
return ("Un Known place!");
}
// If the reverse geocode returned an address
if (addresses != null && addresses.size() > 0) {
// Get the first address
Address address = addresses.get(0);
/*
* Format the first line of address (if available),
* city, and country name.
*/
String addressText = String.format(
"%s, %s, %s",
// If there's a street address, add it
address.getMaxAddressLineIndex() > 0 ?
address.getAddressLine(0) : "",
// Locality is usually a city
address.getLocality(),
// The country of the address
address.getCountryName());
// Return the text
return addressText;
} else {
return "Un known place";
}
}
}
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(ReportIncident.this);
// Setting Dialog Title
alertDialog.setTitle("GPS settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
context.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
In my Activity, i try to get location information by
gpstracker=new myGPSTracker();
Incidents incidents =new Incidents();
incidents.setId(new Date().getTime());
incidents.setIncidentdate(new Date().getTime());
incidents.setPlaceName("Some Thing");
incidents.setAltitude(gpstracker.getAltitude());
incidents.setMyLat(gpstracker.getLatitude());
incidents.setMyLongtitude(gpstracker.getLongitude());
When i run the app, i get 0 for longitude and latitude, and i also debugged and found out the location manager is null.
Here is the complete code for the activity.
public class ReportIncident extends Activity {
Button bb;
double mylat;
double mylong;
String myplace;
double myalt;
EditText editText;
private Context context;
//private Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
private myGPSTracker gpstracker;
Location location; // location
double latitude; // latitude
double longitude; // longitude
double altitude;
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
private static final int ACCESS_FINE_LOCATION = 200;
//private Activity activity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_incident);
context=getApplicationContext();
gpstracker=new myGPSTracker();
editText=(EditText)findViewById(R.id.txtReportIncident);
bb=(Button)findViewById(R.id.btnReport);
bb.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String mydescription=editText.getText().toString().trim();
if(TextUtils.isEmpty(mydescription))
{
editText.setError("Field can not be blank");
return;
}
Incidents incidents =new Incidents();
incidents.setId(new Date().getTime());
incidents.setIncidentdate(new Date().getTime());
incidents.setPlaceName("Some Thing");
incidents.setAltitude(gpstracker.getAltitude());
incidents.setMyLat(gpstracker.getLatitude());
incidents.setMyLongtitude(gpstracker.getLongitude());
incidents.setIncidentDescription(mydescription);
new AddIncidentAsyncTask(getApplicationContext()).execute(incidents);
editText.setText("");
}
});
}
What is missing?
Any help will be highly appreciated.
Ronald

Android Geocoder doesn't work on API 23

i have develop app that when run take the city name by lat and long using a GPSTracker.java class and add this city name to url for retrive json data.
My code works very fine from API 18 to API 22 but now when i run my code on API 23 the geocoder doesn't work and city name is null
This is my code on Main Activity for retrive city name:
// To get City-Name from coordinates
GPSTracker gpsTracker = new GPSTracker(getActivity());
String cityName = null;
Geocoder gcd = new Geocoder(getContext(), Locale.ENGLISH);
List<Address> addresses = null;
try {
addresses = gcd.getFromLocation(gpsTracker.getLatitude(), gpsTracker.getLongitude(), 1);
if (addresses.size() > 0) {
System.out.println(addresses.get(0).getLocality());
cityName = addresses.get(0).getLocality();
Log.d("nome_cit", "debug_cit " + cityName);
// Controllo formattazione nomi Car2Go
if(cityName.equals("Rome")) {
nome_citta = "Roma";
}else if (cityName.equals("Florence")){
nome_citta = "Firenze";
}
else if (cityName.equals("Milan")){
nome_citta = "Milano";
}
else if (cityName.equals("Turin")){
nome_citta = "Torino";
}else if (cityName.equals("New York")){
nome_citta = "NewYorkCity";
}else if (cityName.equals("Los Angeles")){
nome_citta = "LosAngeles";
}
else if (cityName.equals("San Diego")){
nome_citta = "SanDiego";
}
else if (cityName.equals("Twin Cities")){
nome_citta = "TwinCities";
}
else if (cityName.equals("Vienna")) {
nome_citta = "wien";
}
else if (cityName.equals("Munich")) {
nome_citta = "München";
}
else if (cityName.equals("Osler")) {
nome_citta = "Rheinland";
}
// Controllo formattazione JCDecaux
else if (cityName.equals("Valencia")) {
nome_citta_test = "Valence";
}
else if (cityName.equals("Parigi")) {
nome_citta_test = "Paris";
}
else if (cityName.equals("Besançon")){
nome_citta_test = "Besancon";
}
else if (cityName.equals("Créteil")) {
nome_citta_test = "Creteil";
}
else {
nome_citta = cityName;
nome_citta_test = cityName;
}
}
else {
}
} catch (IOException e) {
e.printStackTrace();
}
on my map for my position i have set this permission:
if (ActivityCompat.checkSelfPermission(getContext(),
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager
.PERMISSION_GRANTED && ActivityCompat
.checkSelfPermission(getContext(),
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager
.PERMISSION_GRANTED) {
/*Toast.makeText(getActivity(),
"Need location permission for map.setMyLocationEnabled(true);",
Toast.LENGTH_LONG).show();*/
MultiplePermissionsListener snackbarMultiplePermissionsListener =
SnackbarOnAnyDeniedMultiplePermissionsListener.Builder
.with((ViewGroup) getView(), "La app ha bisogno di ablitare i permessi di localizzaione per mostrare la mappa")
.withOpenSettingsButton("Settings")
.withCallback(new Snackbar.Callback() {
#Override
public void onShown(Snackbar snackbar) {
// Event handler for when the given Snackbar has been dismissed
}
#Override
public void onDismissed(Snackbar snackbar, int event) {
// Event handler for when the given Snackbar is visible
}
})
.build();
Dexter.checkPermissions(snackbarMultiplePermissionsListener, Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.READ_PHONE_STATE, Manifest.permission.GET_ACCOUNTS);
return;
}
and this is my GPSTracker.java class:
public final class GPSTracker implements LocationListener {
private final Context mContext;
// flag for GPS status
public boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
/**
* Function to get the user's current location
*
* #return
*/
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(Context.LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
Log.v("isGPSEnabled", "=" + isGPSEnabled);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
Log.v("isNetworkEnabled", "=" + isNetworkEnabled);
if (isGPSEnabled == false && isNetworkEnabled == false) {
// no network provider is enabled
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
location=null;
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
location=null;
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
// DecimalFormat latitude = new DecimalFormat("00.00");
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener Calling this function will stop using GPS in your
* app
* */
public void stopUsingGPS() {
if (locationManager != null) {
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
*
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog On pressing Settings button will
* lauch Settings Options
* */
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle(R.string.title);
// Setting Dialog Message
alertDialog
.setMessage(R.string.subtitle);
// On pressing Settings button
alertDialog.setPositiveButton(R.string.impostazioni,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(
Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton(R.string.cancella,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
alertDialog.setCancelable(false);
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
Also i have notice that using place picker on API 23 i recive this error:
Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
for this code:
if (resultCode == getActivity().RESULT_OK) {
Place place = PlaceAutocomplete.getPlace(getActivity(), data);
String addresses = place.getAddress().toString();
if (addresses != null) {
puntoA.setText(addresses);
}if (addresses.isEmpty()){
addresses = "(" + place.getLatLng().latitude + "," + place.getLatLng().longitude + ")";
puntoA.setText("nessun indirizzo disponibile " + addresses);
}
//puntoA.setText(addresses);
// Recupero coordinate
Geocoder geocoder = new Geocoder(getActivity());
List<Address> address = null;
try {
address = geocoder.getFromLocationName(addresses, 1);
} catch (IOException e) {
e.printStackTrace();
}
if(address.size() > 0) {
Lat = address.get(0).getLatitude();
Lon = address.get(0).getLongitude();
}
else if (address.size() == 0) {
Lat = place.getLatLng().latitude;
Lon = place.getLatLng().longitude;
}
but also this function works very well on other API version
Any help please?

now my code works fine on API 23 and i use this code:
// To get City-Name from coordinates
GPSTracker gpsTracker = new GPSTracker(getActivity());
Double LatFab = gpsTracker.getLatitude();
Double LonFab = gpsTracker.getLongitude();
List<Address> geocodeMatchess = null;
String Country_;
try {
geocodeMatchess = new Geocoder(getActivity(), Locale.ENGLISH).getFromLocation(gpsTracker.getLatitude(), gpsTracker.getLongitude(), 1);
if (geocodeMatchess.isEmpty()) {
}else {
Country_ = geocodeMatchess.get(0).getLocality();
citta_fab = Country_;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
hope this hel you

Android GPS tracks wrong location

In my app I want to show user's current location and if location is changed it will show an alert message to change the location. The problem is that it shows location chahnge message even when the phone's GPS is off. What might be the reason?
Here's my code:
protected void onResume() {
/**
* get saved Location from shared preference
*
*/
SharedPreferences sPrefs = PreferenceManager
.getDefaultSharedPreferences(Activity_Home.this);
String getL = sPrefs.getString(Utility.KEY_USER_LAT, "0.000000");
String getLo = sPrefs.getString(Utility.KEY_USER_LONG, "0.000000");
getLat = Double.parseDouble(getL);
getLog = Double.parseDouble(getLo);
gps = new GpsTracker(Activity_Home.this);
/**
* Get user current latitude and longitude and match them to stored
* latitude and longitude if distance between these latitude then Pop up
* will be show
*
* #author Ankit
*/
if (gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
System.out.println("Latitude is " + getLat);
if (getLat > 0.0) {
Location locationA = new Location("point A");
locationA.setLatitude(getLat);
locationA.setLongitude(getLog);
Location locationB = new Location("point B");
locationB.setLatitude(latitude);
locationB.setLongitude(longitude);
distance = locationA.distanceTo(locationB);
// Toast.makeText(Activity_Home.this,
// "Distance is :"+Double.toString(distance),
// Toast.LENGTH_LONG).show();
distance = distance / 1000000;
int getDistance = (int) (distance * 1000000);
System.out.println("Distance is " + getDistance);
if (getDistance > 100) {
showWarningMessage();
}
}
String lat = String.valueOf(latitude);
String lon = String.valueOf(longitude);
SharedPreferences sPref = PreferenceManager
.getDefaultSharedPreferences(Activity_Home.this);
SharedPreferences.Editor sEdit = sPref.edit();
sEdit.putString(Utility.KEY_USER_LAT, lat);
sEdit.putString(Utility.KEY_USER_LONG, lon);
sEdit.commit();
} else {
gps.showSettingsAlert();
}
super.onResume();
}
// Method for show an Alert dialog for user if user's location changed''
public void showWarningMessage() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(
Activity_Home.this);
alertDialog.setCancelable(false);
// Setting Dialog Title
alertDialog.setTitle("Location Changed");
// Setting Dialog Message
alertDialog
.setMessage("It seems your location has changed, would you like to change the Branch now?");
// On pressing Settings button
alertDialog.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Activity_Home.this,
Activity_Settings.class);
startActivity(intent);
dialog.cancel();
}
});
// on pressing cancel button
alertDialog.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
public class GpsTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 100; // 100 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GpsTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
System.out.println("=====isGPSEnabled:
"+isGPSEnabled+"====isNetworkEnabled: "+isNetworkEnabled);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
System.out.println("=====notgps");
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GpsTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
alertDialog.setCancelable(false);
// Setting Dialog Title
alertDialog.setTitle("Enable GPS");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to
settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new
DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new
Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new
DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
// alertDialog.;
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}

Here is one sample code for find location check this if it works for you
public static void LocationFind() {
try {
if (Skyhook) {
_xps.getXPSLocation(null,
// note we convert _period to seconds
(int) (_period / 1000), _desiredXpsAccuracy, _callback);
// _xps.getLocation(null, _streetAddressLookup, _callback);
} else {
Criteria criteria = new Criteria();
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
criteria.setAltitudeRequired(false);
criteria.setAccuracy(Criteria.ACCURACY_FINE);
LocationManager locationManager = (LocationManager) mcontext.getSystemService(Context.LOCATION_SERVICE);
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
// Getting network status
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener);
// Log.d("Network", "Network");
if (locationManager != null) {
lastknownlocations = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (lastknownlocations != null) {
lat = lastknownlocations.getLatitude();
lng = lastknownlocations.getLongitude();
}
}
}
if (isGPSEnabled) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener);
// Log.d("Network", "Network");
if (locationManager != null) {
lastknownlocations = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (lastknownlocations != null) {
lat = lastknownlocations.getLatitude();
lng = lastknownlocations.getLongitude();
}
}
}
if (lat == 0.0 && lng == 0.0) {
lng = lastknownlocations.getLongitude();
lat = lastknownlocations.getLatitude();
}
getAddressFromLatLong(lat, lng);
}
} catch (Exception e) {
e.printStackTrace();
}
}

Try out with this service class. This sends updates to method sendLocationDataToProcess(Location location) whenever there is a different of 10 meters with respect to last location
public class AppLocationService extends Service implements GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener{
private LocationRequest locationRequest;
private GoogleApiClient googleApiClient;
private Context appContext;
private boolean currentlyProcessingLocation = false;
private int mInterval=0;
private final int CONNTIMEOUT=50000;
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
appContext=getApplicationContext();
Toast.makeText(getBaseContext(), "Location Service Started", Toast.LENGTH_SHORT)
.show();
if (!currentlyProcessingLocation) {
currentlyProcessingLocation = true;
startTracking();
}
return START_STICKY;
}
private void startTracking() {
if (GooglePlayServicesUtil.isGooglePlayServicesAvailable(this) == ConnectionResult.SUCCESS) {
Log.v(Constants.BLL_LOG, "ConnectionResult SUCCESS");
googleApiClient = new GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
if (!googleApiClient.isConnected() || !googleApiClient.isConnecting()) {
googleApiClient.connect();
}else{
Log.v(Constants.BLL_LOG, "NOT connected googleApiClient.connect()");
}
} else {
Log.v(Constants.BLL_LOG, "unable to connect to google play services.");
}
}
#Override
public IBinder onBind(Intent intent) {
return null;
}
public AppLocationService() {
}
#Override
public void onConnected(Bundle bundle) {
Log.v(Constants.BLL_LOG,"onConnected");
locationRequest = LocationRequest.create();
locationRequest.setInterval(mInterval * 1000); // milliseconds
locationRequest.setFastestInterval(mInterval * 1000);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setSmallestDisplacement(MIN_DISTANCE_CHANGE_FOR_UPDATES);//dostance change
int permissionCheck = ContextCompat.checkSelfPermission(appContext, Manifest.permission.ACCESS_COARSE_LOCATION);
if (permissionCheck!= PackageManager.PERMISSION_DENIED)
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
}
#Override
public void onConnectionSuspended(int i) {
Log.v(Constants.BLL_LOG,"onConnectionSuspended");
}
#Override
public void onLocationChanged(Location location) {
Log.v(Constants.BLL_LOG, "onLocationChanged position: " + location.getLatitude() + ", " + location.getLongitude() + " accuracy: " + location.getAccuracy());
Log.v(Constants.BLL_LOG, "onLocationChanged position: location.getAccuracy()= "+location.getAccuracy());
sendLocationDataToProcess(location);
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Log.v(Constants.BLL_LOG,"onConnectionFailed");
}
void sendLocationDataToProcess(Location location){
//Do your logic with Location data
}
#Override
public void onDestroy() {
super.onDestroy();
if (googleApiClient != null && googleApiClient.isConnected()) {
googleApiClient.disconnect();
}
}
}

Wait until GPS location is retrived for ListActivity

I am working on an Android project in which I am using GPS data for showing nearby Restaurants. On the server side, I have implemented the Haversine formula to get nearby Restaurants depending upon the longitude and latitude retrieved. But, I am having a problem as to how should I tell my ListActivity class to wait until a non-zero GPS location is retrieved.
I checked similar questions, but they didn't provide any help for ListActivity. Any help would be nice. Thanks a lot.
ListRestaurants code :
public class RestaurantList extends ListActivity {
private ResponseEntity<RestRestaurant[]> responseEntity;
private OrderAdapter m_adapter;
private ArrayList<RestRestaurant> m_orders = null;
GPSTracker gps;
double longitude, latitude;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.restos);
final RestTemplate restTemplate = StaticRestTemplate.getRest();
final String restaurantList = StaticRestTemplate.baseURL+"getnearbyrestaurants";
gps = new GPSTracker(RestaurantList.this);
long TIMEOUT = 5000l; // 5 seconds
long startTime = new Date().getTime();
while (!gps.canGetLocation()) {
gps.showSettingsAlert();
long difference = new Date().getTime() - startTime;
if (TIMEOUT > difference) break;
}
latitude = gps.getLatitude();
longitude = gps.getLongitude();
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
/* if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longitude = gps.getLongitude();
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
} else {
gps.showSettingsAlert();
}*/
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.add("Cookie", "JSESSIONID=" + StaticRestTemplate.jsessionid);
requestHeaders.setAccept(Collections.singletonList(new MediaType("application", "json")));
HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
responseEntity = restTemplate.exchange(restaurantList+"/"+longitude+"/"+latitude,
HttpMethod.GET, requestEntity, RestRestaurant[].class);
}
});
thread.start();
ProgressDialog progress = new ProgressDialog(this);
progress.setTitle("Loading");
progress.setMessage("Wait while loading...");
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
progress.dismiss();
RestRestaurant[] restRestaurantList = responseEntity.getBody();
m_orders = new ArrayList<RestRestaurant>();
this.m_adapter = new OrderAdapter(this, android.R.layout.simple_list_item_1, m_orders);
for (RestRestaurant restRestaurant1 : restRestaurantList) {
m_adapter.add(restRestaurant1);
}
setListAdapter(this.m_adapter);
Now, as you can see in the thread, I am passing the longitude and latitude. I don't want to pass non-zero data there.
Here is the GPSTracker code I am using :
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}
What I would like to do is ask user to turn on GPS and then only call the thread code and set the adapter. I am new to Android, please take that into consideration. Thank you.

You can use a while to wait until timeout or getting location
long TIMEOUT = 5000l; // 5 seconds
long startTime = new Date().getTime();
while (!gps.canGetLocation()) {
gps.showSettingsAlert();
long difference = new Date().getTime() - startTime;
if (TIMEOUT > difference) break;
}
latitude = gps.getLatitude();
longitude = gps.getLongitude();
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();

The proper way to do this is to properly implement onLocationChanged - this function will be called when you have a location. Once you get location with good precision, you can notify your main activity.
Of course, this should be running in a separate thread.

How to update the user location after enabling the GPS from an in App prompt

I am currently developing an Android app which prompts the user to enable GPS if it's not on and I have used AlertDialog for this purpose. After I enable the GPS from settings and come back to my app by pressing back button, the mapView doesn't reflect my current location. Although If I have my GPS on before running the app, the app properly displays my location. I want to know to which method to use for this refresh user location after enabling GPS purpose. Any relevant article would really help.
Following is my code for the GPS part:
GPSTracker.java
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// Flag for GPS status
boolean isGPSEnabled = false;
// Flag for network status
boolean isNetworkEnabled = false;
// Flag for GPS status
boolean canGetLocation = false;
Location location; // Location
double latitude; // Latitude
double longitude; // Longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
/******/
/****/
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// Getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// Getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// No network provider is enabled
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// If GPS enabled, get latitude/longitude using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app.
*/
public void stopUsingGPS() {
if (locationManager != null) {
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
*/
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
*/
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/Wi-Fi enabled
*
* #return boolean
*/
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog.
* On pressing the Settings button it will launch Settings Options.
*/
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing the Settings button.
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// On pressing the cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}
The following class makes use of above class to display location in a mapView
LocationActivity.java
public class LocationActivity extends Activity {
Button btnGPSShowLocation;
Button btnSendAddress;
Button find_rick;
TextView tvAddress;
AppLocationService appLocationService;
Button btnShowLocation;
// GPSTracker class
GPSTracker gps;
//Google maps implementation
GoogleMap googleMap;
private static final String TAG = LocationActivity.class.getSimpleName();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.location_layout);
createMapView();
btnShowLocation = (Button) findViewById(R.id.btnGPSShowLocation);
btnSendAddress = (Button) findViewById(R.id.btnSendAddress);
gps = new GPSTracker(LocationActivity.this);
// Check if GPS enabled and if enabled after popup then call same fn
MapMyCurrentLoction();
btnShowLocation.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MapMyCurrentLoction();
}
});
btnSendAddress.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String tag_string_req_send_data = "req_send";
StringRequest strReq = new StringRequest(Request.Method.POST,
AppConfig.URL_AUTOWALA_DHUNDO, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d(TAG, "Autowala Response: " + response.toString());
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("error");
if (!error) {
// User successfully stored in MySQL
// Now store the user in sqlite
Log.d("Autowale ka data","success");
} else {
// Error occurred in data sending. Get the error
// message
String errorMsg = jObj.getString("error_msg");
Toast.makeText(getApplicationContext(),
errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Data sending Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_LONG).show();
}
}) {
#Override
protected Map<String, String> getParams() {
// Posting params to register url
Map<String, String> params = new HashMap<String, String>();
params.put("tag", "data_send");
params.put("latitude", Double.toString(gps.getLatitude()));
params.put("longitude", Double.toString(gps.getLongitude()));
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req_send_data);
}
});
}
#Override
protected void onPause(){
super.onPause();
MapMyCurrentLoction();
//super.onResume();
}
#Override
protected void onResume(){
super.onResume();
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
addMarker(latitude,longitude);
//super.onResume();
}
private void createMapView(){
/**
* Catch the null pointer exception that
* may be thrown when initialising the map
*/
try {
if(null == googleMap){
googleMap = ((MapFragment) getFragmentManager().findFragmentById(
R.id.map)).getMap();
googleMap.getUiSettings().setZoomGesturesEnabled(true);
/**
* If the map is still null after attempted initialisation,
* show an error to the user
*/
if(null == googleMap) {
Toast.makeText(getApplicationContext(),
"Error creating map",Toast.LENGTH_SHORT).show();
}
}
} catch (NullPointerException exception){
Log.e("mapApp", exception.toString());
}
}
/**
* Adds a marker to the map
*/
private void addMarker(double lat,double lng){
/** Make sure that the map has been initialised **/
if(null != googleMap){
googleMap.addMarker(new MarkerOptions()
.position(new LatLng(lat,lng))
.title("Your Location")
.draggable(true)
);
//zooming to my location
float zoomLevel = 16.0F; //This goes up to 21
LatLng coordinate = new LatLng(lat, lng);
CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(coordinate, zoomLevel);
googleMap.animateCamera(yourLocation);
}
}
private void MapMyCurrentLoction(){
if (gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
addMarker(latitude,longitude);
/*------- To get city name from coordinates -------- */
String area = null;
Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
List<Address> addressList = null;
try {
addressList = gcd.getFromLocation(latitude, longitude, 1);
} catch (IOException e) {
e.printStackTrace();
}
if (addressList != null && addressList.size() > 0) {
Address address = addressList.get(0);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < address.getMaxAddressLineIndex(); i++) {
sb.append(address.getAddressLine(i)).append("\n");
}
sb.append(address.getLocality()).append("\n");
sb.append(address.getPostalCode()).append("\n");
sb.append(address.getCountryName());
area = sb.toString();
}
// \n is for new line
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude + "\n"+area, Toast.LENGTH_SHORT).show();
} else {
// Can't get location.
// GPS or network is not enabled.
// Ask user to enable GPS/network in settings.
gps.showSettingsAlert();
//Again search and map my location after enabling gps
}
}
}

You just need to initialize this
gps = new GPSTracker(LocationActivity.this);
at onResume() and at onCreate() and if needed then at onRestart() too.
This is not the correct way but for making it working you can do this.

you`re probably interest in 'onResume' method. After getting back to Activity this one is invoked. Sho in there you should update the position