Error invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
As Jon Skeet mentioned in the comments, the getLastKnownLocation()
method can and will return null. The main problem is that it doesn't prompt a request to the OS for a new location lock, instead it just checks if there was a last known location from some other app's location request. If no other app had recently made a location request, then you get a null location returned to you.
The only way to guarantee that you actually get a location is to request one, and this is done with a call to requestLocationUpdates()
.
The location passed into the onLocationChanged()
callback method will not be null, since the callback only occurs on a successful location lock.
Just to note, the entire time your app is registered for location updates, it will be causing extra battery drain, so be sure to un-register for location updates as soon as possible. Here it looks like you can un-register as soon as the first location comes in.
Also, you might want to consider showing a progress dialog in this Activity while it waits for a location lock in order to give the user some feedback that the app is waiting on something.
Here is the general structure of what your code should look like:
public class MainActivity extends Activity
implements LocationListener {
Intent intentThatCalled;
public double latitude;
public double longitude;
public LocationManager locationManager;
public Criteria criteria;
public String bestProvider;
String voice2text; //added
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
intentThatCalled = getIntent();
voice2text = intentThatCalled.getStringExtra("v2txt");
getLocation();
}
public static boolean isLocationEnabled(Context context)
{
//...............
return true;
}
protected void getLocation() {
if (isLocationEnabled(MainActivity.this)) {
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
criteria = new Criteria();
bestProvider = String.valueOf(locationManager.getBestProvider(criteria, true)).toString();
//You can still do this if you like, you might get lucky:
Location location = locationManager.getLastKnownLocation(bestProvider);
if (location != null) {
Log.e("TAG", "GPS is on");
latitude = location.getLatitude();
longitude = location.getLongitude();
Toast.makeText(MainActivity.this, "latitude:" + latitude + " longitude:" + longitude, Toast.LENGTH_SHORT).show();
searchNearestPlace(voice2text);
}
else{
//This is what you need:
locationManager.requestLocationUpdates(bestProvider, 1000, 0, this);
}
}
else
{
//prompt user to enable location....
//.................
}
}
@Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
@Override
public void onLocationChanged(Location location) {
//Hey, a non null location! Sweet!
//remove location callback:
locationManager.removeUpdates(this);
//open the map:
latitude = location.getLatitude();
longitude = location.getLongitude();
Toast.makeText(MainActivity.this, "latitude:" + latitude + " longitude:" + longitude, Toast.LENGTH_SHORT).show();
searchNearestPlace(voice2text);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
public void searchNearestPlace(String v2txt) {
//.....
}
}