feat: allow doubleTapToSwipe in discoverfragment

mastodon/src/main/java/org/joinmastodon/android/fragments/discover/DiscoverFragment.java

@@ -12,6 +12,7 @@ import android.widget.ImageButton;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 
+import org.joinmastodon.android.GlobalUserPreferences;
 import org.joinmastodon.android.R;
 import org.joinmastodon.android.fragments.IsOnTop;
 import org.joinmastodon.android.fragments.ScrollableToTop;
@@ -208,6 +209,11 @@ public class DiscoverFragment extends AppKitFragment implements ScrollableToTop,
 	@Override
 	public void scrollToTop(){
 		if(!searchActive){
+			if (((IsOnTop)getFragmentForPage(pager.getCurrentItem())).isOnTop() && GlobalUserPreferences.doubleTapToSwipe){
+				int nextPage=(pager.getCurrentItem()+1)%tabViews.length;
+				pager.setCurrentItem(nextPage, true);
+				return;
+			}
 			((ScrollableToTop)getFragmentForPage(pager.getCurrentItem())).scrollToTop();
 		}else{
 			searchFragment.scrollToTop();

mastodon/src/main/java/org/joinmastodon/android/fragments/discover/DiscoverNewsFragment.java

@@ -11,6 +11,7 @@ import android.widget.TextView;
 
 import org.joinmastodon.android.R;
 import org.joinmastodon.android.api.requests.trends.GetTrendingLinks;
+import org.joinmastodon.android.fragments.IsOnTop;
 import org.joinmastodon.android.fragments.ScrollableToTop;
 import org.joinmastodon.android.model.Card;
 import org.joinmastodon.android.model.viewmodel.CardViewModel;
@@ -43,7 +44,7 @@ import me.grishka.appkit.utils.SingleViewRecyclerAdapter;
 import me.grishka.appkit.utils.V;
 import me.grishka.appkit.views.UsableRecyclerView;
 
-public class DiscoverNewsFragment extends BaseRecyclerFragment<CardViewModel> implements ScrollableToTop{
+public class DiscoverNewsFragment extends BaseRecyclerFragment<CardViewModel> implements ScrollableToTop, IsOnTop{
 	private String accountID;
 	private DiscoverInfoBannerHelper bannerHelper;
 	private MergeRecyclerAdapter mergeAdapter;
@@ -111,6 +112,11 @@ public class DiscoverNewsFragment extends BaseRecyclerFragment<CardViewModel> im
 		smoothScrollRecyclerViewToTop(list);
 	}
 
+	@Override
+	public boolean isOnTop(){
+		return isRecyclerViewOnTop(list);
+	}
+
 	private class LinksAdapter extends UsableRecyclerView.Adapter<BaseLinkViewHolder> implements ImageLoaderRecyclerAdapter{
 		private final List<CardViewModel> data;
 

mastodon/src/main/java/org/joinmastodon/android/fragments/discover/TrendingHashtagsFragment.java

@@ -7,6 +7,7 @@ import android.widget.TextView;
 
 import org.joinmastodon.android.R;
 import org.joinmastodon.android.api.requests.trends.GetTrendingHashtags;
+import org.joinmastodon.android.fragments.IsOnTop;
 import org.joinmastodon.android.fragments.ScrollableToTop;
 import org.joinmastodon.android.model.Hashtag;
 import org.joinmastodon.android.ui.DividerItemDecoration;
@@ -23,7 +24,7 @@ import me.grishka.appkit.fragments.BaseRecyclerFragment;
 import me.grishka.appkit.utils.BindableViewHolder;
 import me.grishka.appkit.views.UsableRecyclerView;
 
-public class TrendingHashtagsFragment extends BaseRecyclerFragment<Hashtag> implements ScrollableToTop{
+public class TrendingHashtagsFragment extends BaseRecyclerFragment<Hashtag> implements ScrollableToTop, IsOnTop{
 	private String accountID;
 
 	public TrendingHashtagsFragment(){
@@ -58,6 +59,11 @@ public class TrendingHashtagsFragment extends BaseRecyclerFragment<Hashtag> impl
 		smoothScrollRecyclerViewToTop(list);
 	}
 
+	@Override
+	public boolean isOnTop(){
+		return isRecyclerViewOnTop(list);
+	}
+
 	private class HashtagsAdapter extends RecyclerView.Adapter<HashtagViewHolder>{
 		@NonNull
 		@Override