Fix buggy BottomSheet nested scroll connection

Thanks, Albert Chang!

app/src/main/kotlin/it/vfsfitvnm/vimusic/ui/components/BottomSheet.kt

@@ -38,7 +38,6 @@ import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.Velocity
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.launch
 
 @Composable
@@ -72,36 +71,7 @@ fun BottomSheet(
                     onDragEnd = {
                         val velocity = -velocityTracker.calculateVelocity().y
                         velocityTracker.resetTracking()
-
+                        state.performFling(velocity, onDismiss)
-                        if (velocity > 250) {
-                            state.expand()
-                        } else if (velocity < -250) {
-                            if (state.value < state.collapsedBound && onDismiss != null) {
-                                state.dismiss()
-                                onDismiss.invoke()
-                            } else {
-                                state.collapse()
-                            }
-                        } else {
-                            val l0 = state.dismissedBound
-                            val l1 = (state.collapsedBound - state.dismissedBound) / 2
-                            val l2 = (state.expandedBound - state.collapsedBound) / 2
-                            val l3 = state.expandedBound
-
-                            when (state.value) {
-                                in l0..l1 -> {
-                                    if (onDismiss != null) {
-                                        state.dismiss()
-                                        onDismiss.invoke()
-                                    } else {
-                                        state.collapse()
-                                    }
-                                }
-                                in l1..l2 -> state.collapse()
-                                in l2..l3 -> state.expand()
-                                else -> Unit
-                            }
-                        }
                     }
                 )
             }
@@ -173,11 +143,11 @@ class BottomSheetState(
         }
     }
 
-    fun collapse() {
+    private fun collapse() {
         collapse(SpringSpec())
     }
 
-    fun expand() {
+    private fun expand() {
         expand(SpringSpec())
     }
 
@@ -202,21 +172,53 @@ class BottomSheetState(
         }
     }
 
-    fun nestedScrollConnection(initialIsTopReached: Boolean = true): NestedScrollConnection {
+    fun performFling(velocity: Float, onDismiss: (() -> Unit)?) {
-        return object : NestedScrollConnection {
+        if (velocity > 250) {
-            var isTopReached = initialIsTopReached
+            expand()
+        } else if (velocity < -250) {
+            if (value < collapsedBound && onDismiss != null) {
+                dismiss()
+                onDismiss.invoke()
+            } else {
+                collapse()
+            }
+        } else {
+            val l0 = dismissedBound
+            val l1 = (collapsedBound - dismissedBound) / 2
+            val l2 = (expandedBound - collapsedBound) / 2
+            val l3 = expandedBound
+
+            when (value) {
+                in l0..l1 -> {
+                    if (onDismiss != null) {
+                        dismiss()
+                        onDismiss.invoke()
+                    } else {
+                        collapse()
+                    }
+                }
+                in l1..l2 -> collapse()
+                in l2..l3 -> expand()
+                else -> Unit
+            }
+        }
+    }
+
+    val preUpPostDownNestedScrollConnection
+        get() =  object : NestedScrollConnection {
+            var isTopReached = false
 
             override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
                 if (isExpanded && available.y < 0) {
                     isTopReached = false
                 }
 
-                if (isTopReached) {
+                return if (isTopReached && available.y < 0 && source == NestedScrollSource.Drag) {
                     dispatchRawDelta(available.y)
-                    return available
+                    available
+                } else {
+                    Offset.Zero
                 }
-
-                return Offset.Zero
             }
 
             override fun onPostScroll(
@@ -228,44 +230,30 @@ class BottomSheetState(
                     isTopReached = consumed.y == 0f && available.y > 0
                 }
 
-                return Offset.Zero
+                return if (isTopReached && source == NestedScrollSource.Drag) {
+                    dispatchRawDelta(available.y)
+                    available
+                } else {
+                    Offset.Zero
+                }
             }
 
             override suspend fun onPreFling(available: Velocity): Velocity {
-                if (isTopReached) {
+                return if (isTopReached) {
                     val velocity = -available.y
-                    coroutineScope {
+                    performFling(velocity, null)
-                        if (velocity > 250) {
-                            expand()
-                        } else if (velocity < -250) {
-                            collapse()
-                        } else {
-                            val l0 = dismissedBound
-                            val l1 = (collapsedBound - dismissedBound) / 2
-                            val l2 = (expandedBound - collapsedBound) / 2
-                            val l3 = expandedBound
 
-                            when (value) {
+                    available
-                                in l0..l1 -> collapse()
+                } else {
-                                in l1..l2 -> collapse()
+                    Velocity.Zero
-                                in l2..l3 -> expand()
-                                else -> Unit
-                            }
-                        }
-                    }
-
-                    return available
                 }
-
-                return Velocity.Zero
             }
 
             override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
                 isTopReached = false
-                return super.onPostFling(consumed, available)
+                return Velocity.Zero
             }
         }
-    }
 }
 
 const val expandedAnchor = 2

app/src/main/kotlin/it/vfsfitvnm/vimusic/ui/screens/player/Lyrics.kt

@@ -37,8 +37,6 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ColorFilter
-import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
-import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalDensity
@@ -53,9 +51,9 @@ import it.vfsfitvnm.vimusic.LocalPlayerServiceBinder
 import it.vfsfitvnm.vimusic.R
 import it.vfsfitvnm.vimusic.query
 import it.vfsfitvnm.vimusic.ui.components.LocalMenuState
+import it.vfsfitvnm.vimusic.ui.components.ShimmerHost
 import it.vfsfitvnm.vimusic.ui.components.themed.Menu
 import it.vfsfitvnm.vimusic.ui.components.themed.MenuEntry
-import it.vfsfitvnm.vimusic.ui.components.ShimmerHost
 import it.vfsfitvnm.vimusic.ui.components.themed.TextFieldDialog
 import it.vfsfitvnm.vimusic.ui.components.themed.TextPlaceholder
 import it.vfsfitvnm.vimusic.ui.styling.DefaultDarkColorPalette
@@ -89,7 +87,6 @@ fun Lyrics(
     mediaMetadataProvider: () -> MediaMetadata,
     durationProvider: () -> Long,
     onLyricsUpdate: (Boolean, String, String) -> Unit,
-    nestedScrollConnectionProvider: () -> NestedScrollConnection,
     modifier: Modifier = Modifier
 ) {
     AnimatedVisibility(
@@ -274,7 +271,6 @@ fun Lyrics(
                             text = lyrics,
                             style = typography.xs.center.medium.color(PureBlackColorPalette.text),
                             modifier = Modifier
-                                .nestedScroll(remember { nestedScrollConnectionProvider() })
                                 .verticalFadingEdge()
                                 .verticalScroll(rememberScrollState())
                                 .fillMaxWidth()

app/src/main/kotlin/it/vfsfitvnm/vimusic/ui/screens/player/Player.kt

@@ -36,6 +36,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.drawBehind
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
@@ -239,8 +240,8 @@ fun Player(
                 onShowLyrics = { isShowingLyrics = it },
                 isShowingStatsForNerds = isShowingStatsForNerds,
                 onShowStatsForNerds = { isShowingStatsForNerds = it },
-                nestedScrollConnectionProvider = layoutState::nestedScrollConnection,
                 modifier = modifier
+                    .nestedScroll(layoutState.preUpPostDownNestedScrollConnection)
             )
         }
 

app/src/main/kotlin/it/vfsfitvnm/vimusic/ui/screens/player/Queue.kt

@@ -140,9 +140,7 @@ fun Queue(
                         .only(WindowInsetsSides.Horizontal + WindowInsetsSides.Top).asPaddingValues(),
                     horizontalAlignment = Alignment.CenterHorizontally,
                     modifier = Modifier
-                        .nestedScroll(remember {
+                        .nestedScroll(layoutState.preUpPostDownNestedScrollConnection)
-                            layoutState.nestedScrollConnection(reorderingState.lazyListState.firstVisibleItemIndex == 0 && reorderingState.lazyListState.firstVisibleItemScrollOffset == 0)
-                        })
 
                 ) {
                     items(

app/src/main/kotlin/it/vfsfitvnm/vimusic/ui/screens/player/Thumbnail.kt

@@ -21,7 +21,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
-import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.unit.dp
@@ -48,7 +47,6 @@ fun Thumbnail(
     onShowLyrics: (Boolean) -> Unit,
     isShowingStatsForNerds: Boolean,
     onShowStatsForNerds: (Boolean) -> Unit,
-    nestedScrollConnectionProvider: () -> NestedScrollConnection,
     modifier: Modifier = Modifier
 ) {
     val binder = LocalPlayerServiceBinder.current
@@ -145,7 +143,6 @@ fun Thumbnail(
                 size = thumbnailSizeDp,
                 mediaMetadataProvider = mediaItem::mediaMetadata,
                 durationProvider = player::getDuration,
-                nestedScrollConnectionProvider = nestedScrollConnectionProvider,
             )
 
             StatsForNerds(