Resolves #2239 by adding a compass arrow for direction of nearest item (#5433)

* Resolves issue #2239 by adding an arrow for direction

* Removed unnecessary change in styles.xml

* spacing

* javadoc

---------

Co-authored-by: Nicolas Raoul <nicolas.raoul@gmail.com>

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

@@ -1,15 +1,21 @@
 package fr.free.nrw.commons.contributions;
 
+import static android.content.Context.SENSOR_SERVICE;
 import static fr.free.nrw.commons.contributions.Contribution.STATE_FAILED;
 import static fr.free.nrw.commons.contributions.Contribution.STATE_PAUSED;
 import static fr.free.nrw.commons.nearby.fragments.NearbyParentFragment.WLM_URL;
 import static fr.free.nrw.commons.profile.ProfileActivity.KEY_USERNAME;
+import static fr.free.nrw.commons.utils.LengthUtils.computeBearing;
 import static fr.free.nrw.commons.utils.LengthUtils.formatDistanceBetween;
 
 import android.Manifest;
 import android.Manifest.permission;
 import android.annotation.SuppressLint;
 import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -83,6 +89,7 @@ public class ContributionsFragment
         OnBackStackChangedListener,
         LocationUpdateListener,
     MediaDetailProvider,
+    SensorEventListener,
     ICampaignsView, ContributionsContract.View, Callback{
     @Inject @Named("default_preferences") JsonKvStore store;
     @Inject NearbyController nearbyController;
@@ -122,6 +129,10 @@ public class ContributionsFragment
 
     String userName;
     private boolean isUserProfile;
+
+    private SensorManager mSensorManager;
+    private Sensor mLight;
+    private float direction;
     private ActivityResultLauncher<String[]> nearbyLocationPermissionLauncher = registerForActivityResult(new ActivityResultContracts.RequestMultiplePermissions(), new ActivityResultCallback<Map<String, Boolean>>() {
         @Override
         public void onActivityResult(Map<String, Boolean> result) {
@@ -162,6 +173,8 @@ public class ContributionsFragment
             userName = getArguments().getString(KEY_USERNAME);
             isUserProfile = true;
         }
+        mSensorManager = (SensorManager) getActivity().getSystemService(SENSOR_SERVICE);
+        mLight = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
     }
 
     @Nullable
@@ -428,6 +441,7 @@ public class ContributionsFragment
         super.onPause();
         locationManager.removeLocationListener(this);
         locationManager.unregisterLocationManager();
+        mSensorManager.unregisterListener(this);
     }
 
     @Override
@@ -464,6 +478,7 @@ public class ContributionsFragment
                 fetchCampaigns();
             }
         }
+        mSensorManager.registerListener(this, mLight, SensorManager.SENSOR_DELAY_UI);
     }
 
     private void checkPermissionsAndShowNearbyCardView() {
@@ -521,7 +536,8 @@ public class ContributionsFragment
             Place closestNearbyPlace = nearbyPlacesInfo.placeList.get(0);
             String distance = formatDistanceBetween(curLatLng, closestNearbyPlace.location);
             closestNearbyPlace.setDistance(distance);
-            nearbyNotificationCardView.updateContent(closestNearbyPlace);
+            direction = (float) computeBearing(curLatLng, closestNearbyPlace.location);
+            nearbyNotificationCardView.updateContent(closestNearbyPlace, direction);
         } else {
             // Means that no close nearby place is found
             nearbyNotificationCardView.setVisibility(View.GONE);
@@ -793,6 +809,17 @@ public class ContributionsFragment
       }
   };
 
-
+    /**
+     * When the device rotates, rotate the Nearby banner's compass arrow in tandem.
+     */
+    @Override
+    public void onSensorChanged(SensorEvent event) {
+        float rotateDegree = Math.round(event.values[0]);
+        nearbyNotificationCardView.rotateCompass(rotateDegree, direction);
     }
 
+    @Override
+    public void onAccuracyChanged(Sensor sensor, int accuracy) {
+        // Nothing to do.
+    }
+}

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

@@ -27,6 +27,7 @@ public class NearbyNotificationCardView extends SwipableCardView {
     private TextView notificationTitle;
     private TextView notificationDistance;
     private ImageView notificationIcon;
+    private ImageView notificationCompass;
     private ProgressBar progressBar;
 
     public CardViewVisibilityState cardViewVisibilityState;
@@ -64,6 +65,7 @@ public class NearbyNotificationCardView extends SwipableCardView {
         notificationDistance = rootView.findViewById(R.id.nearby_distance);
 
         notificationIcon = rootView.findViewById(R.id.nearby_icon);
+        notificationCompass = rootView.findViewById(R.id.nearby_compass);
 
         progressBar = rootView.findViewById(R.id.progressBar);
 
@@ -111,10 +113,11 @@ public class NearbyNotificationCardView extends SwipableCardView {
     }
 
     /**
-     * Pass place information to views.
+     * Pass place information to views and set compass arrow direction
      * @param place Closes place where we will get information from
+     * @param direction Direction in which compass arrow needs to be set
      */
-    public void updateContent(Place place) {
+    public void updateContent(Place place, float direction) {
         Timber.d("Update nearby card notification content");
         this.setVisibility(VISIBLE);
         cardViewVisibilityState = CardViewVisibilityState.READY;
@@ -129,7 +132,7 @@ public class NearbyNotificationCardView extends SwipableCardView {
         notificationIcon.setVisibility(VISIBLE);
         notificationTitle.setText(place.name);
         notificationDistance.setText(place.distance);
-
+        notificationCompass.setRotation(direction);
     }
 
     @Override
@@ -151,6 +154,7 @@ public class NearbyNotificationCardView extends SwipableCardView {
                     notificationTitle.setVisibility(VISIBLE);
                     notificationDistance.setVisibility(VISIBLE);
                     notificationIcon.setVisibility(VISIBLE);
+                    notificationCompass.setVisibility(VISIBLE);
                     break;
                 case LOADING:
                     permissionRequestButton.setVisibility(GONE);
@@ -160,6 +164,7 @@ public class NearbyNotificationCardView extends SwipableCardView {
                     notificationTitle.setVisibility(GONE);
                     notificationDistance.setVisibility(GONE);
                     notificationIcon.setVisibility(GONE);
+                    notificationCompass.setVisibility(GONE);
                     permissionRequestButton.setVisibility(GONE);
                     break;
                 case ASK_PERMISSION:
@@ -192,4 +197,14 @@ public class NearbyNotificationCardView extends SwipableCardView {
         ENABLE_LOCATION_PERMISSION, // For only after Marshmallow
         NO_PERMISSION_NEEDED
     }
+
+    /**
+     * Rotates the compass arrow in tandem with the rotation of device
+     *
+     * @param rotateDegree Degree by which device was rotated
+     * @param direction Direction in which arrow has to point
+     */
+    public void rotateCompass(float rotateDegree, float direction){
+        notificationCompass.setRotation(-(rotateDegree-direction));
+    }
 }

app/src/main/java/fr/free/nrw/commons/utils/LengthUtils.java

@@ -123,4 +123,23 @@ public class LengthUtils {
         double sinHalf = Math.sin(x * 0.5D);
         return sinHalf * sinHalf;
     }
+
+    /**
+     * Computes bearing between the two given points
+     *
+     * @see <a href="https://www.movable-type.co.uk/scripts/latlong.html">Bearing</a>
+     * @param point1 Coordinates of first point
+     * @param point2 Coordinates of second point
+     * @return Bearing between the two end points in degrees
+     * @throws NullPointerException if one or both the points are null
+     */
+    public static double computeBearing(@NonNull LatLng point1, @NonNull LatLng point2) {
+        double diffLongitute = Math.toRadians(point2.getLongitude() - point1.getLongitude());
+        double lat1 = Math.toRadians(point1.getLatitude());
+        double lat2 = Math.toRadians(point2.getLatitude());
+        double y = Math.sin(diffLongitute) * Math.cos(lat2);
+        double x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(diffLongitute);
+        double bearing = Math.atan2(y, x);
+        return (Math.toDegrees(bearing) + 360) % 360;
+    }
 }

app/src/main/res/drawable/baseline_arrow_upward_24.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="?attr/tabTextColor"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="?attr/tabTextColor" android:pathData="M4,12l1.41,1.41L11,7.83V20h2V7.83l5.58,5.59L20,12l-8,-8 -8,8z"/>
+</vector>

app/src/main/res/layout/nearby_card_view.xml

@@ -93,6 +93,13 @@
 
             </TextView>
 
+            <ImageView
+              android:id="@+id/nearby_compass"
+              android:layout_width="40dp"
+              android:layout_height="40dp"
+              android:layout_marginEnd="16dp"
+              app:srcCompat="@drawable/baseline_arrow_upward_24"/>
+
         </LinearLayout>
 
     </LinearLayout>

app/src/test/kotlin/fr/free/nrw/commons/utils/LengthUtilsTest.kt

@@ -106,6 +106,29 @@ class LengthUtilsTest {
         assertDistanceBetween(20015115.07, pointA, pointB)
     }
 
+    // Test LengthUtils.formatDistanceBetween()
+
+    @Test
+    fun testBearingPoleToPole() {
+        val pointA = LatLng(90.0, 0.0, 0f)
+        val pointB = LatLng(-90.0, 0.0, 0f)
+        assertBearing(180.00, pointA, pointB)
+    }
+
+    @Test
+    fun testBearingRandomPoints() {
+        val pointA = LatLng(27.17, 78.04, 0f)
+        val pointB = LatLng(-40.69, 04.13, 0f)
+        assertBearing(227.46, pointA, pointB)
+    }
+
+    @Test
+    fun testBearingSamePlace() {
+        val pointA = LatLng(90.0, 0.0, 0f)
+        val pointB = LatLng(90.0, 0.0, 0f)
+        assertBearing(0.0, pointA, pointB)
+    }
+
     // Test assertion helper functions
 
     private fun assertFormattedDistanceBetween(expected: String, pointA: LatLng, pointB: LatLng) =
@@ -117,4 +140,8 @@ class LengthUtilsTest {
     private fun assertDistanceBetween(expected: Double, pointA: LatLng, pointB: LatLng) =
     // Acceptable error: 1cm
             assertEquals(expected, LengthUtils.computeDistanceBetween(pointA, pointB), 0.01)
+
+    private fun assertBearing(expected: Double, pointA: LatLng, pointB: LatLng) =
+        // Acceptable error: 1 degree
+        assertEquals(expected, LengthUtils.computeBearing(pointA,pointB), 1.0)
 }