[Jetnews] Fix swipe to refresh using nested scrolling

JetNews/app/src/main/java/com/example/jetnews/ui/SwipeToRefresh.kt

@@ -20,15 +20,21 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.offset
 import androidx.compose.material.ExperimentalMaterialApi
 import androidx.compose.material.FractionalThreshold
+import androidx.compose.material.SwipeableState
 import androidx.compose.material.rememberSwipeableState
 import androidx.compose.material.swipeable
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.onCommit
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.gesture.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.gesture.nestedscroll.NestedScrollSource
+import androidx.compose.ui.gesture.nestedscroll.nestedScroll
 import androidx.compose.ui.gesture.scrollorientationlocking.Orientation
 import androidx.compose.ui.platform.AmbientDensity
 import androidx.compose.ui.unit.IntOffset
+import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.unit.dp
 import kotlin.math.roundToInt
 
@@ -50,15 +56,17 @@ fun SwipeToRefreshLayout(
     }
 
     Box(
-        modifier = Modifier.swipeable(
-            state = state,
-            anchors = mapOf(
-                -refreshDistance to false,
-                refreshDistance to true
-            ),
-            thresholds = { _, _ -> FractionalThreshold(0.5f) },
-            orientation = Orientation.Vertical
-        )
+        modifier = Modifier
+            .nestedScroll(state.PreUpPostDownNestedScrollConnection)
+            .swipeable(
+                state = state,
+                anchors = mapOf(
+                    -refreshDistance to false,
+                    refreshDistance to true
+                ),
+                thresholds = { _, _ -> FractionalThreshold(0.5f) },
+                orientation = Orientation.Vertical
+            )
     ) {
         content()
         Box(
@@ -79,3 +87,57 @@ fun SwipeToRefreshLayout(
         }
     }
 }
+
+/**
+ * Temporary workaround for nested scrolling behavior. See b/174756744
+ */
+@ExperimentalMaterialApi
+private val <T> SwipeableState<T>.PreUpPostDownNestedScrollConnection: NestedScrollConnection
+    get() = object : NestedScrollConnection {
+        override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
+            val delta = available.toFloat()
+            return if (delta < 0 && source == NestedScrollSource.Drag) {
+                performDrag(delta).toOffset()
+            } else {
+                Offset.Zero
+            }
+        }
+
+        override fun onPostScroll(
+            consumed: Offset,
+            available: Offset,
+            source: NestedScrollSource
+        ): Offset {
+            return if (source == NestedScrollSource.Drag) {
+                performDrag(available.toFloat()).toOffset()
+            } else {
+                Offset.Zero
+            }
+        }
+
+        override fun onPreFling(available: Velocity): Velocity {
+            val toFling = available.pixelsPerSecond.toFloat()
+            return if (toFling < 0) {
+                performFling(velocity = toFling) {}
+                // since we go to the anchor with tween settling, consume all for the best UX
+                available
+            } else {
+                Velocity.Zero
+            }
+        }
+
+        override fun onPostFling(
+            consumed: Velocity,
+            available: Velocity,
+            onFinished: (Velocity) -> Unit
+        ) {
+            performFling(velocity = available.pixelsPerSecond.toFloat()) {
+                // since we go to the anchor with tween settling, consume all for the best UX
+                onFinished.invoke(available)
+            }
+        }
+
+        private fun Float.toOffset(): Offset = Offset(0f, this)
+
+        private fun Offset.toFloat(): Float = this.y
+    }