Android get location is null after phone reboot

问题

In my app im getting the phone's location via this function, but when I restart the phone and start the app I get null from this method. Is there something that im missing or doing wrong? What should I do to fix this issue?

Here is the function im using:

public void getAddress() {
        Log.v("--", "get address 1");
        boolean isGPSProviderEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);
        boolean network_enabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
        Log.v("--", "get address 31 " + isGPSProviderEnabled + " gps  -  "
                + isConnectedToNetwork());

        if (isGPSProviderEnabled || network_enabled) {
            Log.v("--", "get address 2");
            Criteria c = new Criteria();
            Log.v("--", "provider " + locationManager.getBestProvider(c, true));
            locationManager.requestSingleUpdate(
                    locationManager.getBestProvider(c, true),
                    mLocationListener, Looper.myLooper());
            location = locationManager.getLastKnownLocation(locationManager
                    .getBestProvider(c, true));
            if (location == null) {
                Log.v("--", "get address 6");
                // TODO check if this is working
                locationManager.requestSingleUpdate(
                        locationManager.getBestProvider(c, true),
                        mLocationListener, Looper.myLooper());
                locationManager.requestLocationUpdates(
                        locationManager.getBestProvider(c, true), 0, 0,
                        mLocationListener);
                Location oldLocation = new Location("");
                oldLocation.setLatitude(new Double(prefs.getString(
                        Constants.LATITUDE, "48.51")));
                oldLocation.setLongitude(new Double(prefs.getString(
                        Constants.LONGITUDE, "2.20")));
                populateList(oldLocation);
                // locationManager.requestLocationUpdates(
                // locationManager.getBestProvider(c, true), 1000, 100,
                // mLocationListener);
            } else {
                Log.v("--", "get address 3");
                if (isConnectedToNetwork()) {
                    new AsyncTask<Void, Void, Void>() {
                        protected Void doInBackground(Void... params) {
                            try {
                                com.quanticapps.athan.utils.Geocoder geocoder = new com.quanticapps.athan.utils.Geocoder(
                                        Main.this);
                                GeocoderModel geocoderModel = geocoder
                                        .getFromLocation(
                                                location.getLatitude(),
                                                location.getLongitude(), 5);
                                city = geocoderModel.getCity();
                                country = geocoderModel.getCountry();
                                prefs.edit().putString(Constants.CITY, city)
                                        .apply();
                                Log.v("--", "get address 4");
                            } catch (IOException e) {
                                Log.v("--", "get address 11");
                                e.printStackTrace();
                            } catch (LimitExceededException e) {
                                Log.v("--", "get address 12");
                                e.printStackTrace();
                            }
                            return null;
                        };

                        protected void onPostExecute(Void result) {
                            prefs.edit().putString(Constants.COUNTRY, country)
                                    .apply();
                            prefs.edit().putString(Constants.CITY, city)
                                    .apply();
                            populateList(location);
                        };
                    }.execute();
                } else {
                    city = null;
                    Log.v("--", "get address 33 " + location.getLatitude());
                    populateList(location);
                }
            }
        } else {
            Log.v("--", "get address 5");
            startGpsEnableDialog();
        }

    }

and my location listener:

private final LocationListener mLocationListener = new LocationListener() {
        @Override
        public void onLocationChanged(final Location location) {
            // TODO
            Log.v("--", "get address 121");
            if (location != null) {
                Main.this.location = location;
                getAddress();
            }
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub
            Log.v("--", "provider enabled");
        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub
            Log.v("--", "provider disabled");
        }
    };

回答1:

When the phone is rebooted the cached last location is lost so if you didnt open up an app that uses GPS like google maps or something then there will be no last location.

There never has to be a location returned to you, you should always assume it could be null

来源：https://stackoverflow.com/questions/28173322/android-get-location-is-null-after-phone-reboot