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

get current Location with GPS

I want to get my current latitude and longitutude each 30 second but I can get same coordinates in each 30 second its doesn't change I use Gps services class it is below.How can I change location when I moved to device.
public class GPSService extends Service implements LocationListener {
// saving the context for later use
private final Context mContext;
// if GPS is enabled
boolean isGPSEnabled = false;
// if Network is enabled
boolean isNetworkEnabled = false;
// if Location co-ordinates are available using GPS or Network
public boolean isLocationAvailable = false;
// Location and co-ordinates coordinates
Location mLocation;
double mLatitude;
double mLongitude;
// Minimum time fluctuation for next update (in milliseconds)
private static final long TIME = 30000;
// Minimum distance fluctuation for next update (in meters)
private static final long DISTANCE = 20;
// Declaring a Location Manager
protected LocationManager mLocationManager;
public GPSService(Context context) {
this.mContext = context;
mLocationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
}
/**
* Returs the Location
*
* #return Location or null if no location is found
*/
public Location getLocation() {
try {
// Getting GPS status
isGPSEnabled = mLocationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// If GPS enabled, get latitude/longitude using GPS Services
if (isGPSEnabled) {
mLocationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, TIME, DISTANCE, this);
if (mLocationManager != null) {
mLocation = mLocationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (mLocation != null) {
mLatitude = mLocation.getLatitude();
mLongitude = mLocation.getLongitude();
isLocationAvailable = true; // setting a flag that
// location is available
return mLocation;
}
}
}
// If we are reaching this part, it means GPS was not able to fetch
// any location
// Getting network status
isNetworkEnabled = mLocationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (isNetworkEnabled) {
mLocationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, TIME, DISTANCE, this);
if (mLocationManager != null) {
mLocation = mLocationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (mLocation != null) {
mLatitude = mLocation.getLatitude();
mLongitude = mLocation.getLongitude();
isLocationAvailable = true; // setting a flag that
// location is available
return mLocation;
}
}
}
// If reaching here means, we were not able to get location neither
// from GPS not Network,
if (!isGPSEnabled) {
// so asking user to open GPS
askUserToOpenGPS();
}
} catch (Exception e) {
e.printStackTrace();
}
// if reaching here means, location was not available, so setting the
// flag as false
isLocationAvailable = false;
return null;
}
/**
* Gives you complete address of the location
*
* #return complete address in String
*/
public String getLocationAddress() {
if (isLocationAvailable) {
Geocoder geocoder = new Geocoder(mContext, Locale.getDefault());
// Get the current location from the input parameter list
// Create a list to contain the result address
List<Address> addresses = null;
try {
/*
* Return 1 address.
*/
addresses = geocoder.getFromLocation(mLatitude, mLongitude, 1);
} catch (IOException e1) {
e1.printStackTrace();
return ("IO Exception trying to get address:" + e1);
} catch (IllegalArgumentException e2) {
// Error message to post in the log
String errorString = "Illegal arguments "
+ Double.toString(mLatitude) + " , "
+ Double.toString(mLongitude)
+ " passed to address service";
e2.printStackTrace();
return errorString;
}
// 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 "No address found by the service: Note to the developers, If no address is found by google itself, there is nothing you can do about it.";
}
} else {
return "Location Not available";
}
}
/**
* get latitude
*
* #return latitude in double
*/
public double getLatitude() {
if (mLocation != null) {
mLatitude = mLocation.getLatitude();
}
return mLatitude;
}
/**
* get longitude
*
* #return longitude in double
*/
public double getLongitude() {
if (mLocation != null) {
mLongitude = mLocation.getLongitude();
}
return mLongitude;
}
/**
* close GPS to save battery
*/
public void closeGPS() {
if (mLocationManager != null) {
mLocationManager.removeUpdates(GPSService.this);
}
}
/**
* show settings to open GPS
*/
public void askUserToOpenGPS() {
AlertDialog.Builder mAlertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
mAlertDialog.setTitle("Location not available, Open GPS?")
.setMessage("Activate GPS to use use location services?")
.setPositiveButton("Open Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
})
.setNegativeButton("Cancel",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
}).show();
}
/**
* Updating the location when location changes
*/
#Override
public void onLocationChanged(Location location) {
mLatitude = location.getLatitude();
mLongitude = location.getLongitude();
}
#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;
}
}
and I call getLocation method for Myclass
double latitudem2, longitudem2;
String cnvrt_latitude2,cnvrt_longitude2;
if (mGPSService2.isLocationAvailable == false) {
cnvrt_latitude2 = "0";
cnvrt_longitude2 = "0";
// Or you can continue without getting the location, remove the return; above and uncomment the line given below
// address = "Location not available";
} else {
mGPSService2.getLocation();
// Getting current location co-ordinates
latitudem2 = mGPSService2.getLatitude();
longitudem2 = mGPSService2.getLongitude();
//Toast.makeText(getApplicationContext(), "Latitude:" + latitudem + " | Longitude: " + longitudem, Toast.LENGTH_LONG).show();
cnvrt_latitude2 = String.valueOf(latitudem2);
cnvrt_longitude2 = String.valueOf(longitudem2);
}

I used a different way. I think you should use Google play.
dependencies {
..
compile 'com.google.android.gms:play-services:8.4.0'
..
}
and in your activity:
private void initGoogleClient() {
googleClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
and then register your app:
LocationRequest req = new LocationRequest();
req.setInterval(60 * 60 * 1000);
req.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
LocationServices.FusedLocationApi.requestLocationUpdates(googleClient, req, this);
You can change the priority according to your requirements.
Don't forget to implement the listeners in your Activity
public class MainActivity extends AppCompatActivity
implements GoogleApiClient.OnConnectionFailedListener,
GoogleApiClient.ConnectionCallbacks,
LocationListener {
...
}
I made something similar to know UV index according to the current position. You can give a look at my post.

GPS Icon wont dissapear when remove updates is called from onPause Android

Hi i am having a issue where the location icon wont dissaprear after calling location.removeUpdates. I have followed this solution.
public class GPSTracker extends Service implements LocationListener {
// Get Class Name
private static String TAG = GPSTracker.class.getName();
private final Context mContext;
// flag for GPS Status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS Tracking is enabled
boolean isGPSTrackingEnabled = false;
Location location;
double latitude;
double longitude;
// How many Geocoder should return our GPSTracker
int geocoderMaxResults = 1;
// 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;
// Store LocationManager.GPS_PROVIDER or LocationManager.NETWORK_PROVIDER information
private String provider_info;
public GPSTracker(Context context) {
this.mContext = context;
//getLocation();
}
/**
* Try to get my current location by GPS or Network Provider
*/
public void 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);
// Try to get location if you GPS Service is enabled
if (isGPSEnabled) {
this.isGPSTrackingEnabled = true;
Log.d(TAG, "Application use GPS Service");
/*
* This provider determines location using
* satellites. Depending on conditions, this provider may take a while to return
* a location fix.
*/
provider_info = LocationManager.GPS_PROVIDER;
} else if (isNetworkEnabled) { // Try to get location if you Network Service is enabled
this.isGPSTrackingEnabled = true;
Log.d(TAG, "Application use Network State to get GPS coordinates");
/*
* This provider determines location based on
* availability of cell tower and WiFi access points. Results are retrieved
* by means of a network lookup.
*/
provider_info = LocationManager.NETWORK_PROVIDER;
}
// Application can use GPS or Network Provider
if (!provider_info.isEmpty()) {
locationManager.requestLocationUpdates(
provider_info,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES,
this
);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(provider_info);
updateGPSCoordinates();
}
}
}
catch (Exception e)
{
//e.printStackTrace();
Log.e(TAG, "Impossible to connect to LocationManager", e);
}
}
/**
* Update GPSTracker latitude and longitude
*/
public void updateGPSCoordinates() {
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
/**
* GPSTracker latitude getter and setter
* #return latitude
*/
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
return latitude;
}
/**
* GPSTracker longitude getter and setter
* #return
*/
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
return longitude;
}
/**
* GPSTracker isGPSTrackingEnabled getter.
* Check GPS/wifi is enabled
*/
public boolean getIsGPSTrackingEnabled() {
return this.isGPSTrackingEnabled;
}
/**
* Stop using GPS listener
* Calling this method will stop using GPS in your app
*/
public void stopUsingGPS() {
if (locationManager != null) {
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to show settings alert dialog
*/
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
//Setting Dialog Title
alertDialog.setTitle(R.string.GPSAlertDialogTitle);
//Setting Dialog Message
alertDialog.setMessage(R.string.GPSAlertDialogMessage);
//On Pressing Setting button
alertDialog.setPositiveButton(R.string.action_settings, new DialogInterface.OnClickListener() {
#Override
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.cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel();
}
});
alertDialog.show();
}
/**
* Get list of address by latitude and longitude
* #return null or List<Address>
*/
public List<Address> getGeocoderAddress(Context context) {
if (location != null) {
Geocoder geocoder = new Geocoder(context, Locale.ENGLISH);
try {
/**
* Geocoder.getFromLocation - Returns an array of Addresses
* that are known to describe the area immediately surrounding the given latitude and longitude.
*/
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, this.geocoderMaxResults);
return addresses;
} catch (IOException e) {
//e.printStackTrace();
Log.e(TAG, "Impossible to connect to Geocoder", e);
}
}
return null;
}
/**
* Try to get AddressLine
* #return null or addressLine
*/
public String getAddressLine(Context context) {
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0) {
Address address = addresses.get(0);
String addressLine = address.getAddressLine(0);
return addressLine;
} else {
return null;
}
}
/**
* Try to get Locality
* #return null or locality
*/
public String getLocality(Context context) {
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0) {
Address address = addresses.get(0);
String locality = address.getLocality();
return locality;
}
else {
return null;
}
}
/**
* Try to get Postal Code
* #return null or postalCode
*/
public String getPostalCode(Context context) {
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0) {
Address address = addresses.get(0);
String postalCode = address.getPostalCode();
return postalCode;
} else {
return null;
}
}
/**
* Try to get CountryName
* #return null or postalCode
*/
public String getCountryName(Context context) {
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0) {
Address address = addresses.get(0);
String countryName = address.getCountryName();
return countryName;
} else {
return null;
}
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public IBinder onBind(Intent intent) {
return null;
}
}
When i call the stopUsingGPS function it calls it but doesnt stop the location service, it still shows the icon in the action bar.
#Override
public void onPause() {
super.onPause();
GPSTracker gpsTracker = new GPSTracker(getActivity());
gpsTracker.stopUsingGPS();
}
Any suggestion would be gratefully appreciated. Thank you.

You can't really create a new instance of GPSTracker and call functions there. Because you've already started the Service. To achieve this, you should implement a ServiceConnection with a Binder.
In your Service add,
private final IBinder locationBinder = new LocationBinder();
#Override
public IBinder onBind(Intent intent) {
return locationBinder;
}
public class LocationBinder extends Binder {
public GPSTracker getService() {
Log.v("Test", "GPSTracker: getService() called");
return GPSTracker.this;
}
}
And in your activity,
private GPSTracker gpsTracker;
private ServiceConnection serviceConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder baBinder) {
gpsTracker = ((GPSTracker.LocationBinder) baBinder).getService();
}
public void onServiceDisconnected(ComponentName className) {
gpsTracker = null;
}
};
And the in your activity's onCreate(),
Intent locationIntent = new Intent(this, GPSTracker.class);
startService(locationIntent);
bindService(locationIntent, serviceConnection, Context.BIND_AUTO_CREATE);
And then onPause(),
#Override
public void onPause() {
super.onPause();
gpsTracker.stopUsingGPS();
}
And then onDestroy(),
#Override
public void onDestroy() {
super.onDestroy();
unbindService(serviceConnection);
}

can't find the exact current location in android

I have use this below code for find the current location but i got that some devices(samsung 7' and 10'inch and nexus 10'inch) exact current locations,but unfoirtunately i can't find the locations in samsung s3.
I don't have any idea ,what is issue.no find the locations.
here is my code:
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;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
//The minimum distance to change updates in metters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; //10 metters
//The minimum time beetwen 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);
updateGPSCoordinates();
}
}
//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);
updateGPSCoordinates();
}
}
}
}
}
catch (Exception e)
{
//e.printStackTrace();
Log.e("Error : Location", "Impossible to connect to LocationManager", e);
}
return location;
}
public void updateGPSCoordinates()
{
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
/**
* 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;
}
/**
* Function to get longitude
*/
public double getLongitude()
{
if (location != null)
{
longitude = location.getLongitude();
}
return longitude;
}
/**
* Function to check GPS/wifi enabled
*/
public boolean canGetLocation()
{
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
*/
public void showSettingsAlert()
{
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
//Setting Dialog Title
alertDialog.setTitle(R.string.GPSAlertDialogTitle);
//Setting Dialog Message
alertDialog.setMessage(R.string.GPSAlertDialogMessage);
//On Pressing Setting button
alertDialog.setPositiveButton(R.string.settings, new DialogInterface.OnClickListener()
{
#Override
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.cancel, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel();
}
});
alertDialog.show();
}
/**
* Get list of address by latitude and longitude
* #return null or List<Address>
*/
public List<Address> getGeocoderAddress(Context context)
{
if (location != null)
{
Geocoder geocoder = new Geocoder(context, Locale.ENGLISH);
try
{
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
return addresses;
}
catch (IOException e)
{
//e.printStackTrace();
Log.e("Error : Geocoder", "Impossible to connect to Geocoder", e);
}
}
return null;
}
/**
* Try to get AddressLine
* #return null or addressLine
*/
public String getAddressLine(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String addressLine = address.getAddressLine(0);
return addressLine;
}
else
{
return null;
}
}
/**
* Try to get Locality
* #return null or locality
*/
public String getLocality(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String locality = address.getLocality();
return locality;
}
else
{
return null;
}
}
/**
* Try to get Postal Code
* #return null or postalCode
*/
public String getPostalCode(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String postalCode = address.getPostalCode();
return postalCode;
}
else
{
return null;
}
}
/**
* Try to get CountryName
* #return null or postalCode
*/
public String getCountryName(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String countryName = address.getCountryName();
return countryName;
}
else
{
return null;
}
}
#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 intent)
{
return null;
}
}

When the location comes in check for accuracy. If its not accurate enough then don't process it.
#Override
public void onLocationChanged(Location location) {
if (!location.hasAccuracy()) {
return;
}
if (location.getAccuracy() > 5) {
return;
}
// do something with location accurate to 5 meters here.
}

Do this, Load the application in your device, move to open sky, run the application, wait for 2 minutes. Come back to office inside, and then execute above code
It worked for me.
Hope it helps you.

We worked in Samsung devices and had issues too. Just ensure the following:
GPS is on (Street Level should also be enabled)
Mobile Network is enabled (If required, also enable Use packet data option)
Download and install some 3rd party widgets in your phone and wait till the location coordinates appear/refresh in the widget. (This is because the widgets have timeout concept integrated in them and keep trying repeatedly to get coordinates)
Goto Google-maps from the device and check if your location is being identified. (Sometimes, we have observed that Google Maps would be able to identify coordinates where as we would not be able to!!)
Ensure that the GPS Satellite signal on the notification header bar is blinking.
If required, set a timer for refresh and add toast messages to display lat long once obtained.
For samsung device alone, for the first time, the GPS Coordinates do not get reflected immediately (It is null and can last upto half an hour :( How Annoying!! ). So, we used to wait outside the office for some time till the GPS coordinate is recieved.

I had the same problem. The point is: You need a time-gap between your "requestLocationUpdates" and "getLastKnownLocation"
Try to start requestLocationUpdates in the "onStart" or "onCreate" method.
protected void onStart() {
super.onStart();
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
}
This activates your GPS. You have to wait some seconds until it found some locations.
So i put the "getlastKnownLocation" - method in an OnClickEvent. If no location is found it just displays a Toast.
public void onClick(View v) {
m_CurrentLocation = m_LocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (m_CurrentLocation != null)
// Your action with the last known location
else
Toast.makeText(YourActivity.this, "No GPS Location found", Toast.LENGTH_SHORT).show();
}

There are numerous bugs with LocationManager, why don't you try using fused location provider with LocationClient instead. The devs at Google have recommended this as well during the last Google I/O.
Unless the device runs on versions older than Froyo which do not have play services, there is no reason to use LocationManager.

how to enable GPS on long key press of power button while screen is locked in Android?

I'm Developing an application to send User's current location on selected contact number when user long presses power key button while the device is actually locked as pattern/screen lock mode. so how can i enable GPS so that it gets auto enable and gets current longitude and latitude.

First, you need to take care of the key press, and there is some good information here.
Here is an example of getting longitude and latitude:
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;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
//The minimum distance to change updates in metters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; //10 metters
//The minimum time beetwen 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);
updateGPSCoordinates();
}
}
//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);
updateGPSCoordinates();
}
}
}
}
}
catch (Exception e)
{
//e.printStackTrace();
Log.e("Error : Location", "Impossible to connect to LocationManager", e);
}
return location;
}
public void updateGPSCoordinates()
{
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
/**
* 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;
}
/**
* Function to get longitude
*/
public double getLongitude()
{
if (location != null)
{
longitude = location.getLongitude();
}
return longitude;
}
/**
* Function to check GPS/wifi enabled
*/
public boolean canGetLocation()
{
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
*/
public void showSettingsAlert()
{
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
//Setting Dialog Title
alertDialog.setTitle(R.string.GPSAlertDialogTitle);
//Setting Dialog Message
alertDialog.setMessage(R.string.GPSAlertDialogMessage);
//On Pressing Setting button
alertDialog.setPositiveButton(R.string.settings, new DialogInterface.OnClickListener()
{
#Override
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.cancel, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel();
}
});
alertDialog.show();
}
/**
* Get list of address by latitude and longitude
* #return null or List<Address>
*/
public List<Address> getGeocoderAddress(Context context)
{
if (location != null)
{
Geocoder geocoder = new Geocoder(context, Locale.ENGLISH);
try
{
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
return addresses;
}
catch (IOException e)
{
//e.printStackTrace();
Log.e("Error : Geocoder", "Impossible to connect to Geocoder", e);
}
}
return null;
}
/**
* Try to get AddressLine
* #return null or addressLine
*/
public String getAddressLine(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String addressLine = address.getAddressLine(0);
return addressLine;
}
else
{
return null;
}
}
/**
* Try to get Locality
* #return null or locality
*/
public String getLocality(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String locality = address.getLocality();
return locality;
}
else
{
return null;
}
}
/**
* Try to get Postal Code
* #return null or postalCode
*/
public String getPostalCode(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String postalCode = address.getPostalCode();
return postalCode;
}
else
{
return null;
}
}
/**
* Try to get CountryName
* #return null or postalCode
*/
public String getCountryName(Context context)
{
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
{
Address address = addresses.get(0);
String countryName = address.getCountryName();
return countryName;
}
else
{
return null;
}
}
#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 intent)
{
return null;
}
}