Replace onMainScroll with MainScrollProvider

src/lib/ScrollContext.tsx

@@ -0,0 +1,35 @@
+import React, {createContext, useContext, useMemo} from 'react'
+import {ScrollHandlers} from 'react-native-reanimated'
+
+const ScrollContext = createContext<ScrollHandlers<any>>({
+  onBeginDrag: undefined,
+  onEndDrag: undefined,
+  onScroll: undefined,
+})
+
+export function useScrollHandlers(): ScrollHandlers<any> {
+  return useContext(ScrollContext)
+}
+
+type ProviderProps = {children: React.ReactNode} & ScrollHandlers<any>
+
+// Note: this completely *overrides* the parent handlers.
+// It's up to you to compose them with the parent ones via useScrollHandlers() if needed.
+export function ScrollProvider({
+  children,
+  onBeginDrag,
+  onEndDrag,
+  onScroll,
+}: ProviderProps) {
+  const handlers = useMemo(
+    () => ({
+      onBeginDrag,
+      onEndDrag,
+      onScroll,
+    }),
+    [onBeginDrag, onEndDrag, onScroll],
+  )
+  return (
+    <ScrollContext.Provider value={handlers}>{children}</ScrollContext.Provider>
+  )
+}

src/view/com/feeds/FeedPage.tsx

@@ -7,7 +7,7 @@ import {useNavigation} from '@react-navigation/native'
 import {useAnalytics} from 'lib/analytics/analytics'
 import {useQueryClient} from '@tanstack/react-query'
 import {RQKEY as FEED_RQKEY} from '#/state/queries/post-feed'
-import {useOnMainScroll} from 'lib/hooks/useOnMainScroll'
+import {MainScrollProvider} from '../util/MainScrollProvider'
 import {usePalette} from 'lib/hooks/usePalette'
 import {useWebMediaQueries} from 'lib/hooks/useWebMediaQueries'
 import {useSetMinimalShellMode} from '#/state/shell'
@@ -54,7 +54,6 @@ export function FeedPage({
   const queryClient = useQueryClient()
   const {openComposer} = useComposerControls()
   const [isScrolledDown, setIsScrolledDown] = React.useState(false)
-  const onMainScroll = useOnMainScroll()
   const setMinimalShellMode = useSetMinimalShellMode()
   const {screen, track} = useAnalytics()
   const headerOffset = useHeaderOffset()
@@ -168,20 +167,22 @@ export function FeedPage({
 
   return (
     <View testID={testID} style={s.h100pct}>
-      <Feed
-        testID={testID ? `${testID}-feed` : undefined}
-        enabled={isPageFocused}
-        feed={feed}
-        feedParams={feedParams}
-        pollInterval={POLL_FREQ}
-        scrollElRef={scrollElRef}
-        onScrolledDownChange={setIsScrolledDown}
-        onHasNew={setHasNew}
-        renderEmptyState={renderEmptyState}
-        renderEndOfFeed={renderEndOfFeed}
-        ListHeaderComponent={ListHeaderComponent}
-        headerOffset={headerOffset}
-      />
+      <MainScrollProvider>
+        <Feed
+          testID={testID ? `${testID}-feed` : undefined}
+          enabled={isPageFocused}
+          feed={feed}
+          feedParams={feedParams}
+          pollInterval={POLL_FREQ}
+          scrollElRef={scrollElRef}
+          onScrolledDownChange={setIsScrolledDown}
+          onHasNew={setHasNew}
+          renderEmptyState={renderEmptyState}
+          renderEndOfFeed={renderEndOfFeed}
+          ListHeaderComponent={ListHeaderComponent}
+          headerOffset={headerOffset}
+        />
+      </MainScrollProvider>
       {(isScrolledDown || hasNew) && (
         <LoadLatestBtn
           onPress={onPressLoadLatest}

src/view/com/util/List.tsx

@@ -1,6 +1,7 @@
 import React, {useState} from 'react'
 import {FlatListProps} from 'react-native'
 import {FlatList_INTERNAL} from './Views'
+import {useScrollHandlers} from '#/lib/ScrollContext'
 import {runOnJS} from 'react-native-reanimated'
 import {useAnimatedScrollHandler} from '#/lib/hooks/useAnimatedScrollHandler_FIXED'
 
@@ -17,19 +18,26 @@ function ListImpl<ItemT>(
   ref: React.Ref<ListMethods>,
 ) {
   const [isScrolledDown, setIsScrolledDown] = useState(false)
+  const scrollHandlers = useScrollHandlers()
 
   function handleScrolledDownChange(didScrollDown: boolean) {
     setIsScrolledDown(didScrollDown)
     onScrolledDownChange?.(didScrollDown)
   }
 
-  // TODO: This ignores the passed-in onScroll completely.
   const scrollHandler = useAnimatedScrollHandler({
-    onScroll(e) {
+    onBeginDrag(e, ctx) {
+      scrollHandlers.onBeginDrag?.(e, ctx)
+    },
+    onEndDrag(e, ctx) {
+      scrollHandlers.onEndDrag?.(e, ctx)
+    },
+    onScroll(e, ctx) {
       const didScrollDown = e.contentOffset.y > SCROLLED_DOWN_LIMIT
       if (isScrolledDown !== didScrollDown) {
         runOnJS(handleScrolledDownChange)(didScrollDown)
       }
+      scrollHandlers.onScroll?.(e, ctx)
     },
   })
 

src/view/com/util/MainScrollProvider.tsx

@@ -1,20 +1,17 @@
-import {useCallback, useMemo} from 'react'
+import React, {useCallback} from 'react'
+import {ScrollProvider} from '#/lib/ScrollContext'
 import {NativeScrollEvent} from 'react-native'
 import {useSetMinimalShellMode, useMinimalShellMode} from '#/state/shell'
 import {useShellLayout} from '#/state/shell/shell-layout'
 import {isWeb} from 'platform/detection'
-import {
-  useSharedValue,
-  interpolate,
-  ScrollHandlers,
-} from 'react-native-reanimated'
+import {useSharedValue, interpolate} from 'react-native-reanimated'
 
 function clamp(num: number, min: number, max: number) {
   'worklet'
   return Math.min(Math.max(num, min), max)
 }
 
-export function useOnMainScroll(): ScrollHandlers<any> {
+export function MainScrollProvider({children}: {children: React.ReactNode}) {
   const {headerHeight} = useShellLayout()
   const mode = useMinimalShellMode()
   const setMode = useSetMinimalShellMode()
@@ -89,14 +86,12 @@ export function useOnMainScroll(): ScrollHandlers<any> {
     [headerHeight, mode, setMode, startDragOffset, startMode],
   )
 
-  const scrollHandler: ScrollHandlers<any> = useMemo(
-    () => ({
-      onBeginDrag,
-      onEndDrag,
-      onScroll,
-    }),
-    [onBeginDrag, onEndDrag, onScroll],
+  return (
+    <ScrollProvider
+      onBeginDrag={onBeginDrag}
+      onEndDrag={onEndDrag}
+      onScroll={onScroll}>
+      {children}
+    </ScrollProvider>
   )
-
-  return scrollHandler
 }

src/view/screens/Notifications.tsx

@@ -11,7 +11,7 @@ import {Feed} from '../com/notifications/Feed'
 import {TextLink} from 'view/com/util/Link'
 import {ListMethods} from 'view/com/util/List'
 import {LoadLatestBtn} from 'view/com/util/load-latest/LoadLatestBtn'
-import {useOnMainScroll} from 'lib/hooks/useOnMainScroll'
+import {MainScrollProvider} from '../com/util/MainScrollProvider'
 import {usePalette} from 'lib/hooks/usePalette'
 import {useWebMediaQueries} from 'lib/hooks/useWebMediaQueries'
 import {s, colors} from 'lib/styles'
@@ -36,7 +36,6 @@ type Props = NativeStackScreenProps<
 export function NotificationsScreen({}: Props) {
   const {_} = useLingui()
   const setMinimalShellMode = useSetMinimalShellMode()
-  const onMainScroll = useOnMainScroll()
   const [isScrolledDown, setIsScrolledDown] = React.useState(false)
   const scrollElRef = React.useRef<ListMethods>(null)
   const checkLatestRef = React.useRef<() => void | null>()
@@ -132,11 +131,13 @@ export function NotificationsScreen({}: Props) {
   return (
     <View testID="notificationsScreen" style={s.hContentRegion}>
       <ViewHeader title={_(msg`Notifications`)} canGoBack={false} />
-      <Feed
-        onScrolledDownChange={setIsScrolledDown}
-        scrollElRef={scrollElRef}
-        ListHeaderComponent={ListHeaderComponent}
-      />
+      <MainScrollProvider>
+        <Feed
+          onScrolledDownChange={setIsScrolledDown}
+          scrollElRef={scrollElRef}
+          ListHeaderComponent={ListHeaderComponent}
+        />
+      </MainScrollProvider>
       {(isScrolledDown || hasNew) && (
         <LoadLatestBtn
           onPress={onPressLoadLatest}