fix(android): implement missing scroll events for ListView and TableView

android/modules/ui/src/java/ti/modules/titanium/ui/widget/listview/TiListView.java

@@ -33,6 +33,7 @@
 import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.ItemTouchHelper;
 import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
 
 import ti.modules.titanium.ui.widget.TiSwipeRefreshLayout;
 import ti.modules.titanium.ui.widget.searchbar.TiUISearchBar.OnSearchChangeListener;
@@ -66,6 +67,49 @@ public TiListView(ListViewProxy proxy)
 		this.recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
 		this.recyclerView.setFocusableInTouchMode(false);
 
+		// Add listener to fire scroll events.
+		this.recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
+		{
+			@Override
+			public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)
+			{
+				super.onScrollStateChanged(recyclerView, newState);
+
+				if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+					proxy.fireSyncEvent(TiC.EVENT_SCROLLEND, generateScrollPayload());
+				}
+			}
+
+			@Override
+			public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy)
+			{
+				super.onScrolled(recyclerView, dx, dy);
+
+				proxy.fireSyncEvent(TiC.EVENT_SCROLLSTART, generateScrollPayload());
+			}
+		});
+		this.recyclerView.setOnFlingListener(new RecyclerView.OnFlingListener()
+		{
+			@Override
+			public boolean onFling(int velocityX, int velocityY)
+			{
+				final KrollDict payload = new KrollDict();
+
+				// Determine scroll direction.
+				if (velocityY > 0) {
+					payload.put(TiC.PROPERTY_DIRECTION, "down");
+				} else if (velocityY < 0) {
+					payload.put(TiC.PROPERTY_DIRECTION, "up");
+				}
+
+				// Set scroll velocity.
+				payload.put(TiC.EVENT_PROPERTY_VELOCITY, velocityY);
+
+				proxy.fireSyncEvent(TiC.EVENT_SCROLLING, payload);
+				return true;
+			}
+		});
+
 		// Disable list animations.
 		this.recyclerView.setItemAnimator(null);
 
@@ -192,6 +236,41 @@ public void filterBy(String query)
 		this.isFiltered = true;
 	}
 
+	/**
+	 * Generate payload for `scrollstart` and `scrollend` events.
+	 *
+	 * @return KrollDict
+	 */
+	public KrollDict generateScrollPayload()
+	{
+		final KrollDict payload = new KrollDict();
+		final LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
+
+		// Obtain first visible list item view.
+		final View firstVisibleView =
+			layoutManager.findViewByPosition(layoutManager.findFirstVisibleItemPosition());
+		final ListViewHolder firstVisibleHolder =
+			(ListViewHolder) recyclerView.getChildViewHolder(firstVisibleView);
+
+		// Obtain first visible list item proxy.
+		final ListItemProxy firstVisibleProxy = (ListItemProxy) firstVisibleHolder.getProxy();
+		payload.put(TiC.PROPERTY_FIRST_VISIBLE_ITEM, firstVisibleProxy);
+
+		// Obtain first visible list item index in section.
+		final int firstVisibleItemIndex = firstVisibleProxy.getIndexInSection();
+		payload.put(TiC.PROPERTY_FIRST_VISIBLE_ITEM_INDEX, firstVisibleItemIndex);
+
+		// Obtain first visible section proxy.
+		final ListSectionProxy firstVisibleSection = (ListSectionProxy) firstVisibleProxy.getParent();
+		payload.put(TiC.PROPERTY_FIRST_VISIBLE_SECTION, firstVisibleSection);
+
+		// Obtain first visible section index.
+		final int firstVisibleSectionIndex = proxy.getIndexOfSection(firstVisibleSection);
+		payload.put(TiC.PROPERTY_FIRST_VISIBLE_SECTION_INDEX, firstVisibleSectionIndex);
+
+		return payload;
+	}
+
 	/**
 	 * Get list adapter.
 	 *

android/modules/ui/src/java/ti/modules/titanium/ui/widget/listview/TiNestedRecyclerView.java

@@ -31,6 +31,9 @@ public class TiNestedRecyclerView extends RecyclerView implements NestedScrollin
 
 	private boolean isScrollEnabled = true;
 
+	private float lastTouchX;
+	private float lastTouchY;
+
 	public TiNestedRecyclerView(@NonNull Context context)
 	{
 		super(new ContextThemeWrapper(context, R.style.RecyclerView));
@@ -46,6 +49,9 @@ public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEv
 				switch (action) {
 
 					case MotionEvent.ACTION_DOWN: {
+						lastTouchX = e.getX();
+						lastTouchY = e.getY();
+
 						if (scrollState == RecyclerView.SCROLL_STATE_SETTLING) {
 							rv.stopScroll();
 						}
@@ -86,6 +92,16 @@ public void setScrollEnabled(boolean enabled)
 		this.isScrollEnabled = enabled;
 	}
 
+	public float getLastTouchX()
+	{
+		return this.lastTouchX;
+	}
+
+	public float getLastTouchY()
+	{
+		return this.lastTouchY;
+	}
+
 	@Override
 	public boolean dispatchTouchEvent(MotionEvent ev)
 	{

android/modules/ui/src/java/ti/modules/titanium/ui/widget/tableview/TiTableView.java

@@ -12,6 +12,7 @@
 import org.appcelerator.kroll.KrollDict;
 import org.appcelerator.titanium.TiApplication;
 import org.appcelerator.titanium.TiC;
+import org.appcelerator.titanium.TiDimension;
 import org.appcelerator.titanium.util.TiUIHelper;
 
 import android.app.Activity;
@@ -33,6 +34,7 @@
 import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.ItemTouchHelper;
 import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
 
 import ti.modules.titanium.ui.TableViewProxy;
 import ti.modules.titanium.ui.TableViewRowProxy;
@@ -57,6 +59,8 @@ public class TiTableView extends TiSwipeRefreshLayout implements OnSearchChangeL
 	private final SelectionTracker tracker;
 
 	private boolean isFiltered = false;
+	private int scrollOffsetX = 0;
+	private int scrollOffsetY = 0;
 
 	public TiTableView(TableViewProxy proxy)
 	{
@@ -70,6 +74,45 @@ public TiTableView(TableViewProxy proxy)
 		this.recyclerView.setBackgroundColor(Color.TRANSPARENT);
 		this.recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
 
+		// Add listener to fire scroll events.
+		this.recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
+		{
+			@Override
+			public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)
+			{
+				super.onScrollStateChanged(recyclerView, newState);
+
+				if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+					final KrollDict payload = generateScrollPayload();
+					final TiNestedRecyclerView nestedRecyclerView = getRecyclerView();
+
+					// Obtain last touch position for `scrollend` event.
+					final TiDimension xDimension =
+						new TiDimension(nestedRecyclerView.getLastTouchX(), TiDimension.TYPE_WIDTH);
+					final TiDimension yDimension =
+						new TiDimension(nestedRecyclerView.getLastTouchY(), TiDimension.TYPE_HEIGHT);
+					payload.put(TiC.EVENT_PROPERTY_X, xDimension.getAsDefault(nestedRecyclerView));
+					payload.put(TiC.EVENT_PROPERTY_Y, yDimension.getAsDefault(nestedRecyclerView));
+
+					proxy.fireSyncEvent(TiC.EVENT_SCROLLEND, payload);
+				}
+			}
+
+			@Override
+			public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy)
+			{
+				super.onScrolled(recyclerView, dx, dy);
+
+				// Update scroll offsets.
+				scrollOffsetX += dx;
+				scrollOffsetY += dy;
+
+				final KrollDict payload = generateScrollPayload();
+
+				proxy.fireSyncEvent(TiC.EVENT_SCROLL, payload);
+			}
+		});
+
 		// Disable table animations.
 		this.recyclerView.setItemAnimator(null);
 
@@ -193,6 +236,59 @@ public void filterBy(String query)
 		this.isFiltered = true;
 	}
 
+	/**
+	 * Generate payload for `scroll` and `scrollend` events.
+	 *
+	 * @return KrollDict
+	 */
+	public KrollDict generateScrollPayload()
+	{
+		final KrollDict payload = new KrollDict();
+		final LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
+
+		// Obtain index for first visible row.
+		final View firstVisibleView =
+			layoutManager.findViewByPosition(layoutManager.findFirstVisibleItemPosition());
+		final TableViewHolder firstVisibleHolder =
+			(TableViewHolder) recyclerView.getChildViewHolder(firstVisibleView);
+		final TableViewRowProxy firstVisibleProxy = (TableViewRowProxy) firstVisibleHolder.getProxy();
+		final int firstVisibleIndex = firstVisibleProxy.getIndexInSection();
+		payload.put(TiC.PROPERTY_FIRST_VISIBLE_ITEM, firstVisibleIndex);
+
+		// Obtain scroll offset for content.
+		final KrollDict contentOffset = new KrollDict();
+		final TiDimension scrollOffsetXDimension = new TiDimension(scrollOffsetX, TiDimension.TYPE_WIDTH);
+		final TiDimension scrollOffsetYDimension = new TiDimension(scrollOffsetY, TiDimension.TYPE_HEIGHT);
+		contentOffset.put(TiC.EVENT_PROPERTY_X, scrollOffsetXDimension.getAsDefault(recyclerView));
+		contentOffset.put(TiC.EVENT_PROPERTY_Y, scrollOffsetYDimension.getAsDefault(recyclerView));
+		payload.put(TiC.PROPERTY_CONTENT_OFFSET, contentOffset);
+
+		// Approximate content size.
+		// NOTE: Due to recycling of views, we cannot calculate the true
+		// content size without loading all rows. The best we can do is an
+		// approximation based on first visible row.
+		final KrollDict contentSize = new KrollDict();
+		final TiDimension contentWidthDimension =
+			new TiDimension(firstVisibleView.getMeasuredWidth(), TiDimension.TYPE_WIDTH);
+		final TiDimension contentHeightDimension =
+			new TiDimension(firstVisibleView.getMeasuredHeight() * rows.size(), TiDimension.TYPE_HEIGHT);
+		contentSize.put(TiC.PROPERTY_WIDTH, contentWidthDimension.getAsDefault(recyclerView));
+		contentSize.put(TiC.PROPERTY_HEIGHT, contentHeightDimension.getAsDefault(recyclerView));
+		payload.put(TiC.PROPERTY_CONTENT_SIZE, contentSize);
+
+		// Obtain view size.
+		final KrollDict size = new KrollDict();
+		final TiDimension widthDimension =
+			new TiDimension(recyclerView.getMeasuredWidth(), TiDimension.TYPE_WIDTH);
+		final TiDimension heightDimension =
+			new TiDimension(recyclerView.getMeasuredHeight(), TiDimension.TYPE_HEIGHT);
+		size.put(TiC.PROPERTY_WIDTH, widthDimension.getAsDefault(recyclerView));
+		size.put(TiC.PROPERTY_HEIGHT, heightDimension.getAsDefault(recyclerView));
+		payload.put(TiC.PROPERTY_SIZE, size);
+
+		return payload;
+	}
+
 	/**
 	 * Get table adapter.
 	 *

android/titanium/src/java/org/appcelerator/titanium/TiC.java

@@ -1742,6 +1742,26 @@ public class TiC
 	 */
 	public static final String PROPERTY_FIRSTNAME = "firstName";
 
+	/**
+	 * @module.api
+	 */
+	public static final String PROPERTY_FIRST_VISIBLE_ITEM = "firstVisibleItem";
+
+	/**
+	 * @module.api
+	 */
+	public static final String PROPERTY_FIRST_VISIBLE_ITEM_INDEX = "firstVisibleItemIndex";
+
+	/**
+	 * @module.api
+	 */
+	public static final String PROPERTY_FIRST_VISIBLE_SECTION = "firstVisibleSection";
+
+	/**
+	 * @module.api
+	 */
+	public static final String PROPERTY_FIRST_VISIBLE_SECTION_INDEX = "firstVisibleSectionIndex";
+
 	/**
 	 * @module.api
 	 */