Fixes Issue 6262: [Bug]: Error occurred while loading images (#6291)

* ImageInfo.kt: remove call to updateThumbURL()

Before this commit, the updateThumbURL() method would attempt to derive a larger resolution thumbnail URL
from the current thumbnail's width and height. This derived thumbnail URL would sometimes not match
an actual URL. Even creating this thumbnail URL would sometimes fail when doing string manipulation.
Both errors can cause issues, with the second one crashing the thread and preventing images from being
loaded.

This commit simply removes the call to updateThumbURL(). Images with their thumbnails now load correctly,
especially with panoramic images.

* MediaInterface.kt: fix MediaWiki API call to retrieve thumbnail URLs properly

Before this change, the API calls to MediaWiki would request thumbnails with atleast a specific width,
rather than height. These thumbnails would often be extremely low resolution on very wide images,
such as panoramas.

This change instead requests thumbnails with atleast a specific height. Panorama thumbnails are now
at a higher resolution than before. Additionally, the height parameter is now represented as an
integer which can be changed more easily.

* ViewPagerAdapter.java: create new constructor with behavior parameter

Before this commit, ViewPagerAdapter only had one constructor which used the default
behavior where more than the current fragment would be in the Resume state.

This commit adds a constructor where the behavior parameter can be specified.

* ExploreFragment.java: modify onCreateView to use new ViewPagerAdapter constructor

Before this change, onCreateView would use the old ViewPagerAdapter constructor, which
had a default behavior where fragments not currently visible would be in the Resume
state.

After this change, the new ViewPagerAdapter constructor is used with a non-default
behavior where only the visible fragment would be in the Resume state. This has
performance benefits for most users since the Fragments will only be active
when they want to view them.

* ExploreMapFragment.java: remove redundant method call

Before this commit, performMapReadyActions() was called in both onViewCreated and onResume.
In effect, the method is called twice before the user can even see the map, leading to
performance issues.

After this commit, the call in onViewCreated is removed. The method is now called only once
when the user switches to the ExploreMapFragment.

* ExploreMapFragment.java: remove method call that causes recursive loop

Before this commit, there was a call loop that included onScroll and animateTo
on the map. These two method calls caused performance issues in
ExploreMapFragment.

This commit breaks the call loop by removing moveCameraToPosition from getMapCenter.
Also, the removed code did not fit the purpose of getMapCenter.

* ExploreMapFragment.java: fix performMapReadyActions to center to user's last known location

Before this commit, fixing a previous bug caused performMapReadyActions to center the map
on a default location rather than the available last known location.

This commit adds code which will attempt to get the last known user location. If it cannot
be retrieved, the default location is used. The map now centers properly.

* MediaInterface.kt: adjust thumbnail height parameter

Before this commit, the thumbnail height parameter was too small, causing low resolution thumbnails to render.

This commit more than doubles the parameter, increasing the thumbnail resolution.

---------

Co-authored-by: Ritika Pahwa <[email protected]>
Co-authored-by: Nicolas Raoul <[email protected]>

Author: 3 people

app/src/main/java/fr/free/nrw/commons/ViewPagerAdapter.java

@@ -18,6 +18,17 @@ public ViewPagerAdapter(FragmentManager manager) {
         super(manager);
     }
 
+    /**
+     * Constructs a ViewPagerAdapter with a specified Fragment Manager and Fragment resume behavior.
+     *
+     * @param manager The FragmentManager
+     * @param behavior An integer which represents the behavior of non visible fragments. See
+     *                 FragmentPagerAdapter.java for options.
+     */
+    public ViewPagerAdapter(FragmentManager manager, int behavior) {
+        super(manager, behavior);
+    }
+
     /**
      * This method returns the fragment of the viewpager at a particular position
      * @param position

app/src/main/java/fr/free/nrw/commons/explore/ExploreFragment.java

@@ -12,6 +12,7 @@
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentPagerAdapter;
 import androidx.viewpager.widget.ViewPager.OnPageChangeListener;
 import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.ViewPagerAdapter;
@@ -69,7 +70,9 @@ public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
         loadNearbyMapData();
         binding = FragmentExploreBinding.inflate(inflater, container, false);
 
-        viewPagerAdapter = new ViewPagerAdapter(getChildFragmentManager());
+        viewPagerAdapter = new ViewPagerAdapter(getChildFragmentManager(),
+            FragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
+
         binding.viewPager.setAdapter(viewPagerAdapter);
         binding.viewPager.setId(R.id.viewPager);
         binding.tabLayout.setupWithViewPager(binding.viewPager);

app/src/main/java/fr/free/nrw/commons/explore/map/ExploreMapFragment.java

@@ -221,7 +221,6 @@ public void onViewCreated(@NonNull final View view, @Nullable final Bundle saved
             binding.mapView.getController().setZoom(ZOOM_LEVEL);
         }
 
-        performMapReadyActions();
 
         binding.mapView.getOverlays().add(new MapEventsOverlay(new MapEventsReceiver() {
             @Override
@@ -341,7 +340,12 @@ private void performMapReadyActions() {
             !locationPermissionsHelper.checkLocationPermission(getActivity())) {
             isPermissionDenied = true;
         }
-        lastKnownLocation = MapUtils.getDefaultLatLng();
+
+        lastKnownLocation = getLastLocation();
+
+        if (lastKnownLocation == null) {
+            lastKnownLocation = MapUtils.getDefaultLatLng();
+        }
 
         // if we came from 'Show in Explore' in Nearby, load Nearby map center and zoom
         if (isCameFromNearbyMap()) {
@@ -974,9 +978,6 @@ public fr.free.nrw.commons.location.LatLng getMapCenter() {
                     -0.07483536015053005, 1f);
             }
         }
-        if (!isCameFromNearbyMap()) {
-            moveCameraToPosition(new GeoPoint(latLnge.getLatitude(), latLnge.getLongitude()));
-        }
         return latLnge;
     }
 

app/src/main/java/fr/free/nrw/commons/media/MediaInterface.kt

@@ -186,13 +186,25 @@ interface MediaInterface {
     ): Single<MwQueryResponse>
 
     companion object {
+        /**
+         * Retrieved thumbnail height will be about this tall, but must be at least this height.
+         * A larger number means higher thumbnail resolution but more network usage.
+         */
+        const val THUMB_HEIGHT_PX = 450
+
         const val MEDIA_PARAMS =
-            "&prop=imageinfo|coordinates&iiprop=url|extmetadata|user&&iiurlwidth=640&iiextmetadatafilter=DateTime|Categories|GPSLatitude|GPSLongitude|ImageDescription|DateTimeOriginal|Artist|LicenseShortName|LicenseUrl"
+            "&prop=imageinfo|coordinates&iiprop=url|extmetadata|user&&iiurlheight=" +
+                    THUMB_HEIGHT_PX +
+                    "&iiextmetadatafilter=DateTime|Categories|GPSLatitude|GPSLongitude|" +
+                    "ImageDescription|DateTimeOriginal|Artist|LicenseShortName|LicenseUrl"
 
         /**
          * fetches category detail(title, hidden) for each category along with File information
          */
         const val MEDIA_PARAMS_WITH_CATEGORY_DETAILS =
-            "&clprop=hidden&prop=categories|imageinfo&iiprop=url|extmetadata|user&&iiurlwidth=640&iiextmetadatafilter=DateTime|GPSLatitude|GPSLongitude|ImageDescription|DateTimeOriginal|Artist|LicenseShortName|LicenseUrl"
+            "&clprop=hidden&prop=categories|imageinfo&iiprop=url|extmetadata|user&&iiurlheight=" +
+                    THUMB_HEIGHT_PX +
+                    "&iiextmetadatafilter=DateTime|GPSLatitude|GPSLongitude|ImageDescription|" +
+                    "DateTimeOriginal|Artist|LicenseShortName|LicenseUrl"
     }
 }

app/src/main/java/fr/free/nrw/commons/wikidata/model/gallery/ImageInfo.kt

@@ -72,7 +72,6 @@ open class ImageInfo : Serializable {
     }
 
     fun getThumbUrl(): String {
-        updateThumbUrl()
         return thumbUrl ?: ""
     }