NullPointerException - Location & LocationManager - double

Question

I'm getting a null pointer exception from the following line of code:

    double longitude = location.getLongitude();

I having an issue figuring out what the problem is.

    LocationManager locManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, waypointActivity);

    //LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
    Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
    double longitude = location.getLongitude();
    double latitude = location.getLatitude();
    String locLat = String.valueOf(latitude)+","+String.valueOf(longitude);

Here is the logcat output:

04-30 10:20:54.988: E/AndroidRuntime(1827): FATAL EXCEPTION: main
04-30 10:20:54.988: E/AndroidRuntime(1827): java.lang.RuntimeException: Unable to instantiate application android.app.Application: java.lang.NullPointerException
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.LoadedApk.makeApplication(LoadedApk.java:504)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4364)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.ActivityThread.access$1300(ActivityThread.java:141)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1294)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.os.Looper.loop(Looper.java:137)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at java.lang.reflect.Method.invokeNative(Native Method)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at java.lang.reflect.Method.invoke(Method.java:511)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at dalvik.system.NativeStart.main(Native Method)
04-30 10:20:54.988: E/AndroidRuntime(1827): Caused by: java.lang.NullPointerException
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:379)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.LoadedApk.getClassLoader(LoadedApk.java:322)
04-30 10:20:54.988: E/AndroidRuntime(1827):     at android.app.LoadedApk.makeApplication(LoadedApk.java:496)
04-30 10:20:54.988: E/AndroidRuntime(1827):     ... 11 more
04-30 10:21:04.048: E/Trace(1863): error opening trace file: No such file or directory (2)

I can't understand why it thinks my location variable is null. Any suggestions would be appreciated.

Solution

The documentation states:

Returns a Location indicating the data from the last known location fix obtained from the given provider.

This can be done without starting the provider. Note that this location could be out-of-date, for example if the device was turned off and moved to another location.

If the provider is currently disabled, null is returned.

Since you're getting null for GPS location, you probably have not turned on your GPS or your phone has no GPS.

Change your code to

Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location!=null){
   double longitude = location.getLongitude();
   double latitude = location.getLatitude();
   String locLat = String.valueOf(latitude)+","+String.valueOf(longitude);
}

Comments

[Fildor]

See stackoverflow.com/questions/1608632/…

[njzk2]

no one thinks your location variable is null. Apparently it has issues with loading your apk for some reason, possibly the name of your application ? unless some of your process is in a static block ?

[Houcine]

where you are trying to get the longitude ?? it should be in onLocationChanged() method

[Alexis C.]

Did you set <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> ?

[user268397]

Yes I did include that permission

[Fildor]

@njzk2 you should add this as an answer. I totally missed that.

[DigCamara]

Your logcat is contradicting your question...

[WarrenFaith]

The shown logcat is the one that is thrown when the app is being installed while still running on the device/emulator (should be only with ICS or above). The OP just pasted the wrong stacktrace. @OP please check below that for another stacktrace!

[WarrenFaith]

it can be null even if the provider is enabled. Mostly if the location wasn't requested before before...

[DigCamara]

@WarrenFaith I imagine you're right, but I'm just stating what the docs say. Do you have a reference that confirms that behavior?

[WarrenFaith]

Nearly every time I start an app :) No real data, just my personal experience.

[DigCamara]

Heh. Yeah, I can confirm it on that level. However, I don't know if all devices will behave accordingly...

[user3104760]

Even though my provider is enabled(I checked with isProviderEnabled() method), my location returns null so I can't get latitude and longitude. What can be the problem?