refactor: simplify scrolling logic

app/src/main/java/com/github/libretube/ui/extensions/RecyclerView.kt

@@ -0,0 +1,9 @@
+package com.github.libretube.ui.extensions
+
+import androidx.recyclerview.widget.RecyclerView
+
+fun RecyclerView.addOnBottomReachedListener(onBottomReached: () -> Unit) {
+    viewTreeObserver.addOnScrollChangedListener {
+        if (!canScrollVertically(1)) onBottomReached()
+    }
+}

app/src/main/java/com/github/libretube/ui/fragments/ChannelFragment.kt

@@ -30,6 +30,7 @@ import com.github.libretube.ui.adapters.SearchChannelAdapter
 import com.github.libretube.ui.adapters.VideosAdapter
 import com.github.libretube.ui.base.DynamicLayoutManagerFragment
 import com.github.libretube.ui.dialogs.ShareDialog
+import com.github.libretube.ui.extensions.addOnBottomReachedListener
 import com.github.libretube.ui.extensions.setupSubscriptionButton
 import com.github.libretube.ui.sheets.AddChannelToGroupSheet
 import com.github.libretube.util.deArrow
@@ -102,10 +103,8 @@ class ChannelFragment : DynamicLayoutManagerFragment() {
             fetchChannel()
         }
 
-        binding.channelRecView.viewTreeObserver.addOnScrollChangedListener {
+        binding.channelRecView.addOnBottomReachedListener {
-            val binding = _binding ?: return@addOnScrollChangedListener
+            if (_binding == null || isLoading) return@addOnBottomReachedListener
-
-            if (binding.channelRecView.canScrollVertically(1) || isLoading) return@addOnScrollChangedListener
 
             loadNextPage()
         }

app/src/main/java/com/github/libretube/ui/fragments/PlaylistFragment.kt

@@ -17,7 +17,6 @@ import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.RecyclerView
-import com.github.libretube.NavDirections
 import com.github.libretube.R
 import com.github.libretube.api.PlaylistsHelper
 import com.github.libretube.api.RetrofitInstance
@@ -31,15 +30,14 @@ import com.github.libretube.enums.PlaylistType
 import com.github.libretube.extensions.TAG
 import com.github.libretube.extensions.ceilHalf
 import com.github.libretube.extensions.dpToPx
-import com.github.libretube.extensions.toID
 import com.github.libretube.extensions.toastFromMainDispatcher
 import com.github.libretube.helpers.ImageHelper
 import com.github.libretube.helpers.NavigationHelper
 import com.github.libretube.helpers.PreferenceHelper
-import com.github.libretube.ui.activities.MainActivity
 import com.github.libretube.ui.adapters.PlaylistAdapter
 import com.github.libretube.ui.base.BaseActivity
 import com.github.libretube.ui.base.DynamicLayoutManagerFragment
+import com.github.libretube.ui.extensions.addOnBottomReachedListener
 import com.github.libretube.ui.models.PlayerViewModel
 import com.github.libretube.ui.sheets.BaseBottomSheet
 import com.github.libretube.ui.sheets.PlaylistOptionsBottomSheet
@@ -312,18 +310,16 @@ class PlaylistFragment : DynamicLayoutManagerFragment() {
             }
         })
 
-        binding.playlistRecView.viewTreeObserver.addOnScrollChangedListener {
+        binding.playlistRecView.addOnBottomReachedListener {
-            if (_binding?.playlistRecView?.canScrollVertically(1) == false &&
+            if (isLoading) return@addOnBottomReachedListener
-                !isLoading
+
-            ) {
+            // append more playlists to the recycler view
-                // append more playlists to the recycler view
+            if (playlistType != PlaylistType.PUBLIC) {
-                if (playlistType != PlaylistType.PUBLIC) {
+                isLoading = true
-                    isLoading = true
+                playlistAdapter?.showMoreItems()
-                    playlistAdapter?.showMoreItems()
+                isLoading = false
-                    isLoading = false
+            } else {
-                } else {
+                fetchNextPage()
-                    fetchNextPage()
-                }
             }
         }
 

app/src/main/java/com/github/libretube/ui/fragments/SubscriptionsFragment.kt

@@ -34,6 +34,7 @@ import com.github.libretube.ui.adapters.LegacySubscriptionAdapter
 import com.github.libretube.ui.adapters.SubscriptionChannelAdapter
 import com.github.libretube.ui.adapters.VideosAdapter
 import com.github.libretube.ui.base.DynamicLayoutManagerFragment
+import com.github.libretube.ui.extensions.addOnBottomReachedListener
 import com.github.libretube.ui.models.EditChannelGroupsModel
 import com.github.libretube.ui.models.PlayerViewModel
 import com.github.libretube.ui.models.SubscriptionsViewModel
@@ -134,24 +135,20 @@ class SubscriptionsFragment : DynamicLayoutManagerFragment() {
             binding.subFeed.isGone = isCurrentTabSubChannels
         }
 
-        binding.subChannels.viewTreeObserver.addOnScrollChangedListener {
+        binding.subChannels.addOnBottomReachedListener {
-            val binding = _binding
+            val binding = _binding ?: return@addOnBottomReachedListener
-            if (binding?.subChannels?.canScrollVertically(1) == false &&
+
-                viewModel.subscriptions.value != null && // scroll view is at bottom
+            if (viewModel.subscriptions.value != null && isCurrentTabSubChannels) {
-                isCurrentTabSubChannels
-            ) {
                 binding.subRefresh.isRefreshing = true
                 channelsAdapter?.updateItems()
                 binding.subRefresh.isRefreshing = false
             }
         }
 
-        binding.subFeed.viewTreeObserver.addOnScrollChangedListener {
+        binding.subFeed.addOnBottomReachedListener {
-            val binding = _binding
+            val binding = _binding ?: return@addOnBottomReachedListener
-            if (binding?.subFeed?.canScrollVertically(1) == false &&
+
-                viewModel.videoFeed.value != null && // scroll view is at bottom
+            if (viewModel.videoFeed.value != null && !isCurrentTabSubChannels) {
-                !isCurrentTabSubChannels
-            ) {
                 binding.subRefresh.isRefreshing = true
                 feedAdapter?.updateItems()
                 binding.subRefresh.isRefreshing = false