Mark posts as read on scroll

src/main/java/org/quantumbadger/redreader/common/PrefsUtility.java

@@ -114,6 +114,7 @@ public static boolean isRefreshRequired(final Context context, final String key)
 				|| key.equals(context.getString(R.string.pref_behaviour_fling_post_right_key))
 				|| key.equals(context.getString(R.string.pref_behaviour_nsfw_key))
 				|| key.equals(context.getString(R.string.pref_behaviour_postcount_key))
+				|| key.equals(context.getString(R.string.pref_behaviour_mark_read_on_scroll_key))
 				|| key.equals(context.getString(R.string.pref_behaviour_comment_min_key))
 				|| key.equals(context.getString(R.string.pref_behaviour_pinned_subredditsort_key))
 				|| key.equals(context.getString(
@@ -1784,6 +1785,12 @@ public static boolean pref_behaviour_keep_screen_awake() {
 				false);
 	}
 
+	public static boolean pref_mark_read_on_scroll() {
+		return getBoolean(
+				R.string.pref_behaviour_mark_read_on_scroll_key,
+				false);
+	}
+
 	@Nullable
 	public static String pref_reddit_client_id_override() {
 		final String value = getString(R.string.pref_reddit_client_id_override_key, null);

src/main/java/org/quantumbadger/redreader/fragments/PostListingFragment.java

@@ -507,6 +507,43 @@ private void onLoadMoreItemsCheck() {
 
 		General.checkThisIsUIThread();
 
+		if(PrefsUtility.pref_mark_read_on_scroll()) {
+
+			final LinearLayoutManager layoutManager
+					= (LinearLayoutManager)mRecyclerView.getLayoutManager();
+
+			if(layoutManager != null) {
+
+				final int firstVisibleItemPosition
+						= layoutManager.findFirstVisibleItemPosition();
+
+				final int firstCompletelyVisibleItemPosition
+						= layoutManager.findFirstCompletelyVisibleItemPosition();
+
+				if(firstVisibleItemPosition >= 1
+					&& firstCompletelyVisibleItemPosition != 0) {
+
+					final RedditPostView view = (RedditPostView) layoutManager.getChildAt(0);
+
+					final int position =
+						(view != null) ? layoutManager.getPosition(view) : RecyclerView.NO_POSITION;
+
+					final RedditPreparedPost post
+							= (position == firstVisibleItemPosition) ? view.getPost() : null;
+
+					// Mark the first visible post read if it is unread
+					if((post != null) && !post.isRead()) {
+						new Thread() {
+							@Override
+							public void run() {
+								post.markAsRead(getActivity());
+							}
+						}.start();
+					}
+				}
+			}
+		}
+
 		if(mReadyToDownloadMore && mAfter != null && !mAfter.equals(mLastAfter)) {
 
 			final LinearLayoutManager layoutManager

src/main/java/org/quantumbadger/redreader/views/RedditPostView.java

@@ -667,4 +667,8 @@ private void showPrefPrompt() {
 					.apply();
 		});
 	}
+
+	@Nullable public RedditPreparedPost getPost() {
+		return mPost;
+	}
 }

src/main/res/values/strings.xml

@@ -1924,4 +1924,8 @@
 
 	<!-- 2025-12-07 -->
 	<string name="no_messages_yet">No messages yet.</string>
-</resources>
+
+	<!-- 2025-12-10 -->
+	<string name="pref_behaviour_mark_read_on_scroll_key" translatable="false">pref_behaviour_mark_read_on_scroll</string>
+	<string name="pref_behaviour_mark_read_on_scroll_title">Mark posts as read on scroll</string>
+</resources>

src/main/res/xml/prefs_behaviour.xml

@@ -185,6 +185,10 @@
                         android:entryValues="@array/pref_behaviour_postcount_items_return"
                         android:defaultValue="ALL"/>
 
+		<CheckBoxPreference android:title="@string/pref_behaviour_mark_read_on_scroll_title"
+				android:key="@string/pref_behaviour_mark_read_on_scroll_key"
+				android:defaultValue="false" />
+
     </PreferenceCategory>
 
     <PreferenceCategory android:title="@string/pref_behaviour_comments_header">