手机屏幕锁定时 onLocationChanged 不起作用

Question

I've created an app which tracks the user and draws polyline. In some cellphones when the phone is locked, the onlocationchanged listener stops working and doesn't take the locations where the user passed, so the polylines are not drawn.

can someone tell me how to resolve my problem? why when the phone is locked, the location listener stops working?

here is a my code in fragment:

package ir.fragments;

public class OneFragment extends Fragment implements
    PermissionsListener,
    MapboxMap.OnMapClickListener,
    OnMapReadyCallback,
    LocationListener, SensorEventListener, StepListener {

    private List<LatLng> points = new ArrayList<>();
    private LocationComponent locationComponent;
    private PermissionsManager permissionsManager;
    private LocationEngine locationEngine;
    private MapboxMap mapboxMap_global;


    public OneFragment() {
        // Required empty public constructor
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        cx = getActivity();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        Mapbox.getInstance(getActivity(), getString(R.string.mapbox_access_token));
        view = inflater.inflate(R.layout.fragment_one, container, false);
        my_configMap(savedInstanceState);

        return view;
    }


    //-----------------------------------------//
    //-----------START NAVIGATION--------------//
    //-----------------------------------------//


    @SuppressLint("MissingPermission")
    @Override
    public void onMapReady(@NonNull MapboxMap mapboxMap) {

        mapboxMap_global = mapboxMap;

        obj_myMAPBOX = new MY_MAPBOX_CLASS(mapboxMap_global, "waiting", "1");
        mapboxMap_global.addOnMapClickListener(this);
        mapboxMap_global.setStyle(Style.MAPBOX_STREETS, style -> {
            if (PermissionsManager.areLocationPermissionsGranted(getActivity())) {
                locationComponent = mapboxMap.getLocationComponent();
                locationComponent.activateLocationComponent(getActivity(), style);
                locationComponent.setRenderMode(RenderMode.GPS);
                locationComponent.setLocationComponentEnabled(true);
                locationComponent.setCameraMode(CameraMode.TRACKING_COMPASS);

                this.map_style = style;

                //--------------****peida kardane location avaliye****--------////
                LocationEngine locationEngine1 = LocationEngineProvider.getBestLocationEngine(getActivity());
                locationEngine1.getLastLocation(new LocationEngineCallback<LocationEngineResult>() {
                    @Override
                    public void onSuccess(LocationEngineResult result) {

                        //Toast.makeText(getActivity(),"Place Your First Option Code",Toast.LENGTH_SHORT).show();
                        if (fill_My_Primary_Location(result)) {

                           //get_activity_info();


                            CameraPosition position = new CameraPosition.Builder()
                                    .target(userCurrentLocation_latLng)
                                    .zoom(15)
                                    .tilt(20)
                                    .build();
                            mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(position), 500);


                        }


                    }

                    @Override
                    public void onFailure(@NonNull Exception exception) {

                    }
                });

                //--------------****end of peida kardane location avaliye****--------////



                lm = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
                lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
                //lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this);
                this.onLocationChanged(null);

            } else {
                permissionsManager = new PermissionsManager(this);
                permissionsManager.requestLocationPermissions(getActivity());
            }

        });
    }


    @Override
    public void onLocationChanged(Location location) {
        //Toast.makeText(getActivity(),"im changing"+location,Toast.LENGTH_LONG).show();
        if (location != null)
        {
            Location s1 = new Location("");
            s1.setLatitude(stations.get(race_station).getLatitude());
            s1.setLongitude(stations.get(race_station).getLongitude());

            drawPolyline(s1);
        }

    }




    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }

    @Override
    public void onSensorChanged(SensorEvent event) {

    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int i) {
    }

    @Override
    public void step(long timeNs) {
        if (status.equals("start")) {
            numSteps++;
            F1_TextView_1.setText(numSteps + "");
        }
    }

    //-----------------------------------------//
    //-----------END NAVIGATION--------------//
    //-----------------------------------------//

    @Override
    public void onExplanationNeeded(List<String> permissionsToExplain) {

    }

    @Override
    public void onPermissionResult(boolean granted) {

    }

    @Override
    public boolean onMapClick(@NonNull LatLng point) {
        return false;
    }


    public void my_configMap(Bundle savedInstanceState) {
        mapView.onCreate(savedInstanceState);
        mapView.getMapAsync(this);


    }




    // Add the mapView's own lifecycle methods to the activity's lifecycle methods
    @Override
    public void onStart() {
        super.onStart();
        mapView.onStart();
    }

    @Override
    public void onResume() {
        super.onResume();
        mapView.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
        mapView.onPause();
    }

    @Override
    public void onStop() {
        super.onStop();
        mapView.onStop();
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mapView.onLowMemory();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mapView.onDestroy();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mapView.onSaveInstanceState(outState);
    }
}

Answer 1

when you lock the phone your activity gets paused, to get location in background you need to use service there are so many resources to get location in background.