CODEWITHSUNDEEP
androidgoogle-mapscrashgps
user3708158
user3708158

Reputation: 143

Google Maps Crashes when GPS is Off(requesting location)

I've tried to manage a thing like this:

If the GPS is off, DO nothing, if it's on, zoom in the camera to the location of the user. Then, on the location button, if it's clicked and GPS is off, link it to the setting activity(of Android of course); then if clicked again it zooms in.

Otherwise, if it's on, then zoom in.

The problem is, if I open the application and the GPS is off, it crashes right away, but if GPS is on it works fine.

What do I need to change/add to my code to make it work properly?

MainActivity:

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.Menu;
import android.widget.Toast;

import com.google.android.gms.location.LocationListener;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMyLocationButtonClickListener;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;

public class MainActivity extends Activity implements LocationListener {
    GoogleMap map;
    public double longitude;
    public double latitude;

    Location location;

    @SuppressWarnings("unused")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
        map.setMyLocationEnabled(true);

        final Criteria criteria = new Criteria();

        final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        lm.getBestProvider(criteria, true);

        final Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        latitude = location.getLatitude();
        longitude = location.getLongitude();

        if (location != null) {
            LatLng UserLoc = new LatLng(latitude, longitude);
            map.animateCamera(CameraUpdateFactory.newLatLngZoom(UserLoc, 7));
        } else {
            Toast.makeText(getApplicationContext(), "cant get loc", Toast.LENGTH_LONG).show();
        }


        map.setOnMyLocationButtonClickListener(new OnMyLocationButtonClickListener() {
            @Override
            public boolean onMyLocationButtonClick() {
                // if the Gps is off it openes a dialog to turn it off
                if (!lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
                    buildAlertMessageNoGps();
                } else if (location == null) {
                    Toast.makeText(getApplicationContext(), "cant get loc", Toast.LENGTH_LONG).show();
                } else {
                    // if it on, animates to the current position
                    map.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 15));
                    return false;
                }
                return false;
            }
        });
    }

    public void TurnOnGps(){
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        setUpMapIfNeeded();
        super.onResume();
    }

    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the
        // map.
        if (map == null) {
            map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
            if (map != null) {
            }
        }
    }

    // function that opened an activity to turn on the GPS
    private void buildAlertMessageNoGps() {
        final AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("GPS is off ")
                .setCancelable(true)
                .setPositiveButton("Yes",
                        new DialogInterface.OnClickListener() {
                            public void onClick(final DialogInterface dialog, final int id) {
                                startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
                            }
                        })
                .setNegativeButton("No", new DialogInterface.OnClickListener() {
                    public void onClick(final DialogInterface dialog, final int id) {
                        dialog.cancel();
                    }
                });
        final AlertDialog alert = builder.create();
        alert.show();
    }

    @Override
    public void onLocationChanged(Location location) {
        longitude = location.getLongitude();
        latitude = location.getLatitude();
    }

}

my LogCat:

06-04 20:48:44.811: E/AndroidRuntime(11489): FATAL EXCEPTION: main
06-04 20:48:44.811: E/AndroidRuntime(11489): java.lang.RuntimeException: Unable to start activity ComponentInfo{nir.rauch.flantir/nir.rauch.flantir.MainActivity}: java.lang.NullPointerException
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread.access$700(ActivityThread.java:159)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.os.Looper.loop(Looper.java:137)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread.main(ActivityThread.java:5419)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at java.lang.reflect.Method.invokeNative(Native Method)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at java.lang.reflect.Method.invoke(Method.java:525)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at dalvik.system.NativeStart.main(Native Method)
06-04 20:48:44.811: E/AndroidRuntime(11489): Caused by: java.lang.NullPointerException
06-04 20:48:44.811: E/AndroidRuntime(11489):    at nir.rauch.flantir.MainActivity.onCreate(MainActivity.java:45)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.Activity.performCreate(Activity.java:5372)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
06-04 20:48:44.811: E/AndroidRuntime(11489):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
06-04 20:48:44.811: E/AndroidRuntime(11489):    ... 11 more

I've tried to do if else statement(if GPS enabled or not) in the OnCreate function, but then it doesn't find the location.

Upvotes: 3

Views: 1294

Answers (1)

matiash
matiash

Reputation: 55350

final Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);

latitude = location.getLatitude(); // <--
longitude = location.getLongitude(); // <--

if (location != null) {

Shouldn't those two lines go inside the if statement?

Upvotes: 4

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