Android check permission for LocationManager

Question

I'm trying to get the GPS coordinates to display when I click a button in my activity layout. The following is the method that gets called when I click the button:

public void getLocation(View view) {
    TextView tv = (TextView) findViewById(R.id.gps_coord_view);
    LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE);
    Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
    tv.setText("Latitude: " + loc.getLatitude() + "\nLongitude: " + loc.getLongitude());
}

I'm getting an error that says

Call requires permission which may be rejected by user. Code should explicitly check to see if permission is available.

I have already granted these permissions in my AndroidManifest. The error is taken care of and the app compiles when I add the following before calling lm.getLastKnownLocation:

if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
        && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
    return;
}

However, the app crashes when I press the button that calls getLocation when it's clicked. What is going on? Is there better/simpler way to grab the GPS coordinates of the device?

Answer 1

With Android API level (23), we are required to check for permissions. https://developer.android.com/training/permissions/requesting.html

I had your same problem, but the following worked for me and I am able to retrieve Location data successfully:

(1) Ensure you have your permissions listed in the Manifest:

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

(2) Ensure you request permissions from the user:

if ( ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_COARSE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {

            ActivityCompat.requestPermissions( this, new String[] {  android.Manifest.permission.ACCESS_COARSE_LOCATION  },
                                                LocationService.MY_PERMISSION_ACCESS_COURSE_LOCATION );
        }

(3) Ensure you use ContextCompat as this has compatibility with older API levels.

(4) In your location service, or class that initializes your LocationManager and gets the last known location, we need to check the permissions:

if ( Build.VERSION.SDK_INT >= 23 &&
             ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED &&
             ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return  ;
        }

(5) This approach only worked for me after I included @TargetApi(23) at the top of my initLocationService method.

(6) I also added this to my gradle build:

compile 'com.android.support:support-v4:23.0.1'

Here is my LocationService for reference:

public class LocationService implements LocationListener  {

    //The minimum distance to change updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 0; // 10 meters

    //The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 0;//1000 * 60 * 1; // 1 minute

    private final static boolean forceNetwork = false;

    private static LocationService instance = null;

    private LocationManager locationManager;
    public Location location;
    public double longitude;
    public double latitude; 


    /**
     * Singleton implementation
     * @return
     */
    public static LocationService getLocationManager(Context context)     {
        if (instance == null) {
            instance = new LocationService(context);
        }
        return instance;
    }

    /**
     * Local constructor
     */
    private LocationService( Context context )     {

        initLocationService(context); 
        LogService.log("LocationService created");
    }



    /**
     * Sets up location service after permissions is granted
     */
    @TargetApi(23)
    private void initLocationService(Context context) {


        if ( Build.VERSION.SDK_INT >= 23 &&
             ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED &&
             ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return  ;
        }

        try   {
            this.longitude = 0.0;
            this.latitude = 0.0;
            this.locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

            // Get GPS and network status
            this.isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
            this.isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (forceNetwork) isGPSEnabled = false;

            if (!isNetworkEnabled && !isGPSEnabled)    {
                // cannot get location
                this.locationServiceAvailable = false;
            }
            //else
            {
                this.locationServiceAvailable = true;

                if (isNetworkEnabled) {
                    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    if (locationManager != null)   {
                        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        updateCoordinates();
                    }
                }//end if

                if (isGPSEnabled)  {
                    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

                    if (locationManager != null)  {
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        updateCoordinates();
                    }
                }
            }
        } catch (Exception ex)  {
            LogService.log( "Error creating location service: " + ex.getMessage() );

        }
    }       


    @Override
    public void onLocationChanged(Location location)     {
        // do stuff here with location object 
    }
}

I tested with an Android Lollipop device so far only. Hope this works for you.