Getting null from 'getLastKnownLocation' on SDK

I have a problem related to the Location API.

I tried the following code:

LocationManager lm = (Loc开发者_运维百科ationManager)getSystemService(Context.LOCATION_SERVICE);
Location loc = getLastKnownLocation(LocationManager.GPS_PROVIDER);

loc is always null, when getLastKnownLocation() is called.

What is wrong?

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Along with the permissions in your AndroidManifest.xml file, have you registered a location listener?

LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location loc = getLastKnownLocation(LocationManager.GPS_PROVIDER);
lm.requestLocationUpdates(LocationManager.GPS, 100, 1, locationListener); 

Then have a method, in this case locationListener, to complete your task

private final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
    latitude = location.getLatitude();
    longitude = location.getLongitude();
}

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If you're running the code in the emulator, any calls to get the GPS location will return null until you explicitly update the location (via Eclipse or ADB).

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I had the same problem as you, I always receive a null Location object, But finally it was solved in an easy way. You must have a valid GPS location, so, if the GPS is not enabled and you dont't have enough signal, the Location object will be ALWAYS null.

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Have you set the permissions in your AndroidManifest.xml? You need these permissions in order to access the user's location with an application:

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />

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Here's something you can use:

LocationManager lm = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = lm.getBestProvider(criteria, false);
Location loc = lm.getLastKnownLocation(bestProvider);

last_lat = loc.getLatitude();
last_lng = loc.getLongitude();

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You need the instance Of LocationManager like this:

First Instance:

   LocationManager lm = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

Wrong:

Location loc = getLastKnownLocation(LocationManager.GPS_PROVIDER);

Correct:

Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);