Prevent memory leak(s) in LocationServiceManager.

This was causing a memory leak in at least API 19, and possibly others.

Author: dbrant

app/src/main/java/fr/free/nrw/commons/contributions/ContributionsFragment.java

@@ -87,6 +87,7 @@ public class ContributionsFragment
     @Inject NearbyController nearbyController;
     @Inject OkHttpJsonApiClient okHttpJsonApiClient;
     @Inject CampaignsPresenter presenter;
+    @Inject LocationServiceManager locationManager;
 
     private ArrayList<DataSetObserver> observersWaitingForLoad = new ArrayList<>();
     private UploadService uploadService;
@@ -105,8 +106,6 @@ public class ContributionsFragment
     private LatLng curLatLng;
 
     private boolean firstLocationUpdate = true;
-    public LocationServiceManager locationManager;
-
     private boolean isFragmentAttachedBefore = false;
     private View checkBoxView;
     private CheckBox checkBox;
@@ -496,7 +495,6 @@ public void onSaveInstanceState(Bundle outState) {
     @Override
     public void onResume() {
         super.onResume();
-        locationManager = new LocationServiceManager(getActivity());
 
         firstLocationUpdate = true;
         locationManager.addLocationListener(this);
@@ -546,7 +544,7 @@ private void checkGPS() {
 
     private void checkLocationPermission() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            if (locationManager.isLocationPermissionGranted()) {
+            if (locationManager.isLocationPermissionGranted(requireContext())) {
                 nearbyNotificationCardView.permissionType = NearbyNotificationCardView.PermissionType.NO_PERMISSION_NEEDED;
                 locationManager.registerLocationManager();
             } else {
@@ -638,8 +636,6 @@ public void onDestroy() {
         getChildFragmentManager().removeOnBackStackChangedListener(this);
         locationManager.unregisterLocationManager();
         locationManager.removeLocationListener(this);
-        // Try to prevent a possible NPE
-        locationManager.context = null;
         super.onDestroy();
 
         if (isUploadServiceConnected) {

app/src/main/java/fr/free/nrw/commons/location/LocationServiceManager.java

@@ -9,6 +9,8 @@
 import android.location.LocationListener;
 import android.location.LocationManager;
 import android.os.Bundle;
+
+import androidx.annotation.NonNull;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 
@@ -26,21 +28,19 @@ public class LocationServiceManager implements LocationListener {
     private static final long MIN_LOCATION_UPDATE_REQUEST_TIME_IN_MILLIS = 2 * 60 * 100;
     private static final long MIN_LOCATION_UPDATE_REQUEST_DISTANCE_IN_METERS = 10;
 
-    public Context context;
     private LocationManager locationManager;
     private Location lastLocation;
     //private Location lastLocationDuplicate; // Will be used for nearby card view on contributions activity
     private final List<LocationUpdateListener> locationListeners = new CopyOnWriteArrayList<>();
     private boolean isLocationManagerRegistered = false;
-    public Set<Activity> locationExplanationDisplayed = new HashSet<>();
+    private Set<Activity> locationExplanationDisplayed = new HashSet<>();
 
     /**
      * Constructs a new instance of LocationServiceManager.
      *
      * @param context the context
      */
     public LocationServiceManager(Context context) {
-        this.context = context;
         this.locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
     }
 
@@ -57,7 +57,7 @@ public boolean isProviderEnabled() {
      * Returns whether the location permission is granted.
      * @return true if the location permission is granted
      */
-    public boolean isLocationPermissionGranted() {
+    public boolean isLocationPermissionGranted(@NonNull Context context) {
         return ContextCompat.checkSelfPermission(context,
                 Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED;
     }
@@ -101,8 +101,8 @@ public boolean isPermissionExplanationRequired(Activity activity) {
      * @return last known LatLng
      */
     @SuppressLint("MissingPermission")
-    public LatLng getLKL() {
-        if (isLocationPermissionGranted()) {
+    public LatLng getLKL(@NonNull Context context) {
+        if (isLocationPermissionGranted(context)) {
             Location lastKL = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
             if (lastKL == null) {
                 lastKL = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
@@ -225,6 +225,7 @@ private boolean isSameProvider(String provider1, String provider2) {
      */
     public void unregisterLocationManager() {
         isLocationManagerRegistered = false;
+        locationExplanationDisplayed.clear();
         try {
             locationManager.removeUpdates(this);
         } catch (SecurityException e) {

app/src/main/java/fr/free/nrw/commons/nearby/NearbyFragment.java

@@ -572,7 +572,7 @@ private void hideProgressBar() {
      */
     private void registerLocationUpdates() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            if (locationManager.isLocationPermissionGranted()) {
+            if (locationManager.isLocationPermissionGranted(requireContext())) {
                 locationManager.registerLocationManager();
             } else {
                 // Should we show an explanation?
@@ -666,7 +666,7 @@ private void checkGps() {
     private void checkLocationPermission() {
         Timber.d("Checking location permission");
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            if (locationManager.isLocationPermissionGranted()) {
+            if (locationManager.isLocationPermissionGranted(requireContext())) {
                 refreshView(LOCATION_SIGNIFICANTLY_CHANGED);
             } else {
                 // Should we show an explanation?