Port ItemPagerFragment to ViewPager2

app/src/main/java/de/danoeh/antennapod/fragment/ItemPagerFragment.java

@@ -7,29 +7,30 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.view.ViewCompat;
 import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentStatePagerAdapter;
-import androidx.viewpager.widget.ViewPager;
+import androidx.viewpager2.adapter.FragmentStateAdapter;
+import androidx.viewpager2.widget.ViewPager2;
+
+import org.greenrobot.eventbus.EventBus;
+import org.greenrobot.eventbus.Subscribe;
+import org.greenrobot.eventbus.ThreadMode;
+
 import de.danoeh.antennapod.R;
-import de.danoeh.antennapod.activity.CastEnabledActivity;
 import de.danoeh.antennapod.activity.MainActivity;
 import de.danoeh.antennapod.core.event.FeedItemEvent;
 import de.danoeh.antennapod.core.feed.FeedItem;
 import de.danoeh.antennapod.core.storage.DBReader;
-import de.danoeh.antennapod.core.util.Flavors;
 import de.danoeh.antennapod.menuhandler.FeedItemMenuHandler;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.Disposable;
 import io.reactivex.schedulers.Schedulers;
-import org.greenrobot.eventbus.EventBus;
-import org.greenrobot.eventbus.Subscribe;
-import org.greenrobot.eventbus.ThreadMode;
 
 /**
  * Displays information about a list of FeedItems.
@@ -41,7 +42,7 @@ public class ItemPagerFragment extends Fragment {
     /**
      * Creates a new instance of an ItemPagerFragment.
      *
-     * @param feeditems The IDs of the FeedItems that belong to the same list
+     * @param feeditems   The IDs of the FeedItems that belong to the same list
      * @param feedItemPos The position of the FeedItem that is currently shown
      * @return The ItemFragment instance
      */
@@ -76,31 +77,21 @@ public class ItemPagerFragment extends Fragment {
         feedItems = getArguments().getLongArray(ARG_FEEDITEMS);
         int feedItemPos = getArguments().getInt(ARG_FEEDITEM_POS);
 
-        ViewPager pager = layout.findViewById(R.id.pager);
+        ViewPager2 pager = layout.findViewById(R.id.pager);
         // FragmentStatePagerAdapter documentation:
         // > When using FragmentStatePagerAdapter the host ViewPager must have a valid ID set.
         // When opening multiple ItemPagerFragments by clicking "item" -> "visit podcast" -> "item" -> etc,
         // the ID is no longer unique and FragmentStatePagerAdapter does not display any pages.
         int newId = ViewCompat.generateViewId();
         pager.setId(newId);
-        pager.setAdapter(new ItemPagerAdapter());
+        pager.setAdapter(new ItemPagerAdapter(this));
         pager.setCurrentItem(feedItemPos);
         loadItem(feedItems[feedItemPos]);
-        pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
-            @Override
-            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
-
-            }
-
+        pager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
             @Override
             public void onPageSelected(int position) {
                 loadItem(feedItems[position]);
             }
-
-            @Override
-            public void onPageScrollStateChanged(int state) {
-
-            }
         });
 
         EventBus.getDefault().register(this);
@@ -173,20 +164,20 @@ public class ItemPagerFragment extends Fragment {
         ((MainActivity) getActivity()).loadChildFragment(fragment);
     }
 
-    private class ItemPagerAdapter extends FragmentStatePagerAdapter {
+    private class ItemPagerAdapter extends FragmentStateAdapter {
 
-        ItemPagerAdapter() {
-            super(getFragmentManager(), BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
+        ItemPagerAdapter(@NonNull Fragment fragment) {
+            super(fragment);
         }
 
         @NonNull
         @Override
-        public Fragment getItem(int position) {
+        public Fragment createFragment(int position) {
             return ItemFragment.newInstance(feedItems[position]);
         }
 
         @Override
-        public int getCount() {
+        public int getItemCount() {
             return feedItems.length;
         }
     }

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

@@ -14,7 +14,7 @@
             app:navigationIcon="?homeAsUpIndicator"
             android:id="@+id/toolbar"/>
 
-    <androidx.viewpager.widget.ViewPager
+    <androidx.viewpager2.widget.ViewPager2
             android:id="@+id/pager"
             android:layout_width="match_parent"
             android:layout_height="match_parent"/>

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

@@ -14,7 +14,7 @@
         app:tabGravity="fill"
         app:tabMode="fixed" />
 
-    <androidx.viewpager.widget.ViewPager2
+    <androidx.viewpager2.widget.ViewPager2
         android:id="@+id/viewpager"
         android:layout_width="match_parent"
         android:layout_height="0px"