Develop Reference

requestLocationUpdates with Criteria doesn't work

Here's the code:
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setPowerRequirement(Criteria.POWER_LOW);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setSpeedRequired(false);
LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
manager.requestLocationUpdates(0,0, criteria, locationListener, null); // doesn't work
The Listener never gets an update if i pass criteria as argument. However, if i get provider from cirteria and pass to different arguments of request locationUpdates, it works
manager.requestLocationUpdates(manager.getBestProvider(criteria, true), 0, 0, locationListener); // works
Is the manager.requestLocationUpdates(0,0, criteria, listener, looper) method broken in the API?

How to get current location when proximity alert fires

I am using the following code to determine the current location when a proximity alert fires:
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location == null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location == null) {
// We'll just write an empty location
location = new Location("");
}
}
When I look at the locations that I get back I get entering alerts in locations where I should't get them. I was under the impression since proximity alerts internally poll the GPS and network provider - thus updating the LastKnownLocation - that this code would yield the current location. Is this assumption correct?

I am using the following code to determine the current location and its working too. Check out dis code...
LocationManager locationManager;
String context = Context.LOCATION_SERVICE;
locationManager = (LocationManager) getSystemService(context);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = locationManager.getBestProvider(criteria, true);
if (null != provider)
{
Location location = locationManager.getLastKnownLocation(provider);
if (null != location) {
GpsFound=true;
currentLat = location.getLatitude();
currentLon = location.getLongitude();
System.out.println("Current Lat,Long :"+currentLat+" ,"+currentLon);
}
else
{
//GpsFound=false;
gpsMsg="Current Location can not be resolved!";
}
}
else
{
gpsMsg="Provider is not available!";
//GpsFound=false;
}

java.lang.NullPointerException about gps api?

as the title i have a question about the gps api
follow is my code
LocationManager loctionManager;
String contextService=Context.LOCATION_SERVICE;
loctionManager=(LocationManager) getSystemService(contextService);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = loctionManager.getBestProvider(criteria, true);
Location location = loctionManager.getLastKnownLocation(provider);
double a=location.getLatitude();
double b=location.getLongitude();
Log.d(""+a,""+b);
then the error is java.lang.NullPointerException
anyone can help me?thx

getLastKnownLocation() can return null you need to ensure it does not.
In order to get a Location you need at first to set permission in your Manifest.
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Then in your code you need to listen for location avalability. You do that by registering a LocationListener. The activity will display, and when Android will have a location for you it will call you back.
private final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
latitude = location.getLatitude();
longitude = location.getLongitude();
//Do what you want with your coordinates
}
loctionManager.requestLocationUpdates(LocationManager.GPS, 100, 1, locationListener);
If you are using the emulator and not a real device you need to force a location, you can use DDMS inside Eclipse to send a fake location:

How to get CurrentLocation from GPS FirstTime quickly?

Iam using
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, true);
locationManager.requestLocationUpdates(bestProvider, 0, 0, this);
location = locationManager.getLastKnownLocation(bestProvider);
but first time it is not giving location object.Always giving me null.I read in developer.android.com ,
"Cached Location is dismissed if it is
too old"
But second time it is giving location updates.How to solve my problem.
Regards,
Android Developer

There are few options... if getLastKnownLocation() is null because it's to old you only can wait to get a newer position fix.
However if you don't need a very accurate location you can use the networkProvider which is faster.

mLocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
mLocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
mLocManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this);
CellLocation.requestLocationUpdate();
Call these all statement together..
and there is no way to simply seek device LAT and LONG statically ..
You have to wait for update..... Use any progress bar or do any other waiting stuff...
In the onLocationChanged method .. recieve the location object and save its reference to any of your class...

criteria for both GPS and network

I would like to know how can I get location from the best provider
do I have to make two separate criteria 1 for the GPS and 1 for the network or is there a way to put them all together ?
this is my code when I add the COARSE criteria the GPS does not go on (no GPS flashing logo on the top of the screen) and when I use the FINE criteria I dont get any thing from the network.......so do I have to write criteria for both and switch between them for what ever is available or can they both be in the same criteria ?
because I have the "getBestProvider(criteria, true);" in my code so it should get the location from the best provider....right..??!
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
//// criteria.setAccuracy(Criteria.ACCURACY_COARSE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_HIGH);
String provider = locationManager.getBestProvider(criteria, true);

Using a getBestProvider with Criteria.ACCURACY_FINE will never return the NETWORK_PROVIDER, even though wifi position is usually quite accurate.
In my application, I use getProviders to get all providers matching my criteria, then add the NETWORK_PROVIDER if it is activated and not yet in the list.
Then I launch a requestLocationUpdates for each of these providers, making sure to call removeUpdates when I get a location accurate enough.
This way, if the location provided by the network is accurate enough, the gps provider will be turned off

#nicopico getBestProvider with Criteria.ACCURACY_FINE can return the NETWORK_PROVIDER if gps is not enabled
i use the following code in my app
public void getLocation() {
// Getting Google Play availability status
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(context);
// boolean network_enabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
// Showing status
if (status != ConnectionResult.SUCCESS) { // Google Play Services are not available
Log.e(TAG, "getLocation fired Google Play Services are not available");
mHandler.post(new UiToastCommunicaton(context.getApplicationContext(),
context.getResources().getString(R.string.gpserv_notfound)));
}
// Getting LocationManager object from System Service LOCATION_SERVICE
locationManager = (LocationManager) context.getSystemService(IntentService.LOCATION_SERVICE);
if (!locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {//check if network location provider context on
Log.e(TAG, "network location provider not enabled");
} else {
criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
//criteria.setPowerRequirement(Criteria.POWER_LOW);
// Getting the name of the best provider
provider = locationManager.getBestProvider(criteria, true);
// Check provider exists then request for location
if (provider != null) {
requestLocation(locationManager, provider);
} else {
//start wifi, gps, or tell user to do so
}
}
}
public void requestLocation(LocationManager locationManager, String provider) {
Log.e(TAG, "requestLocation fired getting location now");
if (provider != null) {
locationManager.requestLocationUpdates(provider, 0, 0, this);
//locationManager.requestLocationUpdates(provider, 0, 0, this, Looper.getMainLooper());
} else {
//tell user what has happened
}
}
this code is in a class that implements locationListener
you can edit this line
locationManager.requestLocationUpdates(provider, 0, 0, this);
to reflect your implementation of locationListener