Develop Reference

Get User Current City in Android

I want to fetch user's current city name in my Android application but as per some of my research (this, this, and this) it is a pretty complicated task and require switching between network providers and fetch location updates after some time.
My application is not some location-based app to require an accurate and up-to-date location of a user using the app. I just need a city name from NETWORK_PROVIDER (or any other provider for that matter) but if it is unable to fetch the city name, that's fine, too. It's just one feature in the application and doesn't matter if it fails to fetch the city name in some cases.
I'm using following code but it always shows both latitude and longitude to be 0.0.
Location location = new Location(LocationManager.NETWORK_PROVIDER);
Geocoder geocoder = new Geocoder(context, Locale.getDefault());
try {
Log.d("Lat-Lng", location.getLatitude()+","+location.getLongitude());
// Doesn't really return anything as both latitude and longitude is 0.0.
List<Address> address = geocoder.getFromLocation(location.getLatitude(), location.getLongitude(), 1);
} catch(Exception e) {
}

Well all you are doing here is creating a new Location object whose initial values for latitude and longitude are zero by default.
What you need to do is connect that location to the GPS information of the user.
// Getting LocationManager object from System Service LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location From GPS
Location location = locationManager.getLastKnownLocation(provider);
if(location != null) {
Log.d("Lat-Lng", location.getLatitude()+","+location.getLongitude());
getUserGeoInfo(location.getLatitude(), location.getLongitude());
}
// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
Log.d("Lat-Lng", location.getLatitude()+","+location.getLongitude());
getUserGeoInfo(location.getLatitude(), location.getLongitude());
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Set how often you want to request location updates and where you want to receive them
locationManager.requestLocationUpdates(provider, 20000, 0, locationListener);
// ...
void getUserGeoInfo(double lat, double lon) {
Geocoder geoCoder = new Geocoder(context, Locale.getDefault());
if (Geocoder.isPresent()) {
List<Address> addresses = geoCoder.getFromLocation(lat, lon, 1);
if (addresses.size() > 0) {
// obtain all information from addresses.get(0)
}
}
}
The LocationListener interface can, for example, also be implemented by the Activity that holds this code and then you would only pass that activity's context as the third parameter in locationManager.requestLocationUpdates(provider, 20000, 0, context);. Of course, as with any interface implementation, you will have to override all the methods same way as in above code.
As far as the requestLocationUpdates() method, you can read more about it here
As far as general techniques for obtaining user location on Android, this is a definite read

Trying to get latitude and latitude with Network provider

I am trying to get my current coordinates with network provider and not gps provider.
I was able to figure out the solution for that but I am a bit confused with the concept in this scenario.
Working Code
Here's my code for getting my coordinates:
public void getLocation(){
locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
if(appUtils.isOnline()){
try{
Geocoder geocoder = new Geocoder(
MainActivity.this.getApplicationContext(),
Locale.getDefault());
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
List<Address> list;
if(locationNetwork!=null){
Toast.makeText(context,"Network Available!!",Toast.LENGTH_LONG).show();
list = geocoder.getFromLocation(locationNetwork.getLatitude(),locationNetwork.getLongitude(),3);
if(list!=null&&list.size()>0){
latitude = list.get(0).getLatitude();
longitude = list.get(0).getLongitude();
Toast.makeText(context,String.valueOf(latitude) + " (....) " + String.valueOf(longitude),Toast.LENGTH_LONG).show();
int count = 0;
while (latitude==null||longitude==null){
latitude = list.get(count).getLatitude();
longitude = list.get(count).getLongitude();
count++;
Toast.makeText(context,String.valueOf(latitude) + " --- " + String.valueOf(longitude),Toast.LENGTH_LONG).show();
}
}
}else{
Toast.makeText(context,"No response!!",Toast.LENGTH_LONG).show();
}
}catch (IOException e){
e.printStackTrace();
}
}else{
Toast.makeText(context,"Server not responding",Toast.LENGTH_LONG).show();
}
}
This piece of code is working perfectly fine when the gps is enabled. If gps is disabled, it doesn't work.
Now, if we are setting the location to NETWORK_PROVIDER:
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
Why do we still require gps ?
Now if I change it to PASSIVE PROVIDER:
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
It works fine with the passive provider. Why is it that ?
Can someone explain what is the major difference here and what would be the right way to get the coordinates with network provider ?
I know this question is been asked several times and I did went through it. I just want to get cleared with this concept.
Thank's in advance.. :)

It doesn't require GPS to use the network provider, I've done it many times. However, getLastKnowLocation may not return a value if either it has never had an app request updates for that provider, or if the last time that happened was too long ago. You cannot count on that function always returning non-NULL. If you want to ensure that you get a location, use requestSingleUpdate instead. This will always get you a location (assuming the provider you use is enabled), but may take some time- a result may not be immediately available.
(There is one other time that function may never return- if you use the GPS provider and it can't get a lock on enough sattelites to find a location. Such as if you're in an underground parking garage).

This is the bit of code that I use to quickly get the current location, by checking all available network options.
private double[] getGPS(){
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
List<String> providers = lm.getProviders(true);
/* Loop over the array backwards, and if you get an accurate location, then break out the loop*/
Location l = null;
for (int i=providers.size()-1; i>=0; i--) {
l = lm.getLastKnownLocation(providers.get(i));
if (l != null) break;
}
double[] gps = new double[2];
if (l != null) {
gps[0] = l.getLatitude();
gps[1] = l.getLongitude();
}
return gps;
}

Does LocationManager:NETWORK_PROVIDER work without GPS enabled?

I'm wondering why my app still finds location although the GPS is disabled. So I asked myselft why this is possible and I have too less knowledge about this. Maybe the NETWORK_PROVIDER needs no GPS?
I promise, GPS is really disabled.
Can anyone tell me how this is possible?
I have this in my App:
in oncreate():
locationManager = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
Method:
public void getGpsLocation(){
locationManager.requestSingleUpdate(LocationManager.NETWORK_PROVIDER, myLocationListener, this.getMainLooper());
}
Listener:
LocationListener myLocationListener = new LocationListener() {
// When location has changed
public void onLocationChanged(Location location) {
locationManager.removeUpdates(this);
locationAll = location;
// positionOnceFound = true --> location was already found and no further update necessary
//if (location != null && positionOnceFound == false)
if (location != null)
{
// location is found, no more update necessary --> true
positionOnceFound = true;
// get Lat/Lon of my current position
myPosLat = location.getLatitude();
myPosLon = location.getLongitude();
// For calculating the point B(right top corner) and point C(left bottom corner
// Lat/Lon of B and C needed for getting the prices from this area around my position
double dy = 5.0 / 110.54; // 5.0 -> 5km to vertical
double dx = 5.0 / (111.320 * Math.cos(myPosLat / 180 * Math.PI)); // 5km to horizontal
// Get point B
rightTopCornerLon = myPosLon + dx;
rightTopCornerLat = myPosLat + dy;
// Get point C
leftBottomCornerLon = myPosLon - dx;
leftBottomCornerLat = myPosLat - dy;
System.out.println("Alat: " + myPosLat + " Alon: " + myPosLon + " Blat: " + rightTopCornerLat + " Blon: " + rightTopCornerLon +
" Clat: " + leftBottomCornerLat + " Clon: " + leftBottomCornerLon);
getCityName(isItStartOrStop);
}
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
};

The network provider requires the permission of ACCESS_COARSE_LOCATION, so it will work and provide you location updates using the WIFI networks, or Mobile networks, this may not be so accurate but is faster than getting a location update using the GPS.

Yes, NETWORK_PROVIDER needs no GPS, but NETWORK_PROVIDER fetches location with low precision by wireless network site.

Yes, NETWORK_PROVIDER doesn't requires GPS.
Network provider access you location through Wireless network if GPS is not enabled but it is not accurate location. Enabling GPS will provide you with more accurate location results.
The access coarse location and access fine location permissions in you meanifeast file differentiate it. With access coarse location you will get location without GPS but fine location can access GPS location too
NETWORK_PROVIDER works with both permissions

What is the simplest way to get the user's longitude and latitude in Android ? Even without using listener?

My app just need to know user's country, and my app doesn't care where user moves.
All I want to know is :
When user start app, app will send user's approximately location(latitude and longitude) to server.
Here is my code with error. I try to send a string to getlocation function, and I hope it can return original string with adding latitude and longitude information.
private String getlocation (String url){
LocationManager status = (LocationManager) (this.getSystemService(Context.LOCATION_SERVICE));
if (status.isProviderEnabled(LocationManager.GPS_PROVIDER) || status.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
Log.v("print","enable to locate");
} else {
Log.v("print","fail to locate");
}
Location location = status.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if(location!=null){
Log.v("print","succed!!!##");
Double longitude = location.getLongitude();
String loc=Double.toString(longitude);
url=url+loc;
}
else{
Log.v("print","location return null");
}
return url;
}
I use network_provider, and it always print "enable to locate", then print "location return null"
So what's wrong with my code that my location always return null.
I use AVD manerger, and I also try GPS_PROVIDER. I use Emulator control to send Decimal on location control. It doesn't work ,too.
By the way, I set network and GPS permission,too.
So much thanks for help!

I am getting location by below code but enable " use wireless networks " in settings i.e ( through settings - Location services - use wireless networks)
public void getCurrentLocation() {
LocationManager locationManager;
String bestProvider;
// Get the location manager
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
bestProvider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(bestProvider);
Log.e(TAG, "Latitude: "+location.getLatitude()+" , Longitude: "+location.getLongitude());
}

problem in showing latitude longitude location in an android app

Following is the code which i am using to find the latitude longitude and location of a place in my app, but it always show no location found
I have added the permissions in manifest file
{
LocationManager locManager;
setContentView(R.layout.main);
locManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,1000L,500.0f, locationListener);
Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(location != null)
{
String param = (String)locManager.getProviders(true).get(0);
Location loc = locManager.getLastKnownLocation(param);
double latitude = location.getLatitude();
double longitude = location.getLongitude();
}
}
private void updateWithNewLocation(Location location)
{
TextView myLocationText = (TextView)findViewById(R.id.widget52);
String latLongString = " ";
if (location != null)
{
double lat = location.getLatitude();
double lng = location.getLongitude();
latLongString = "Lat:" + lat + "\nLong:" + lng;
}
else
{
latLongString = "No location found";
}
myLocationText.setText("Your Current Position is:\n" +
latLongString);
}
private final LocationListener locationListener = new LocationListener()
{
public void onLocationChanged(Location location)
{
updateWithNewLocation(location);
}
public void onProviderDisabled(String provider)
{
updateWithNewLocation(null);
}
public void onProviderEnabled(String provider)
{
}
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
};
}
pls help me...

I've put your code in an Android project and ran it on the emulator and it seems to be working fine.
I would change the code to first check for a lastknown location, and after that check for location updates.
Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
If that location is null, or too stale (timestamp) for your needs, you can start requesting location updates. (currently, you're first requesting location updates from the GPS, and then decide to retrieve its lastknownlocation). This might cause the location manager to stop querying the GPS.
Also you need to ensure the following is in place :
For GPS Provider, make sure the following permission is put in the manifest
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Ensure the GPS is turned on that you have sufficient GPS coverage.
Do this by checking for the GPS icon in your Notification bar
Test on a real device
Although testing GPS location listeners works partly through the emulator, the behavior of an actual device will always be different.
Debug on the emulator
Basic GPS testing can be done using the emulator. Put a breakpoint in your locationlistener, and use the DDMS perspective to send some GPS coordinates to your AVD image.

#Siva, your problem is with the UI thread, as your updates are from different thread.
To verify if this is the UI problem, put a toast or Log cat the message when you receive an update.
Once you know that UI problem, then try using Handler to postInvalidate() the UI.