Fix cancelling nested scroll across Pager axis

Upstreaming #1154 fix Bug: 327687953 Test: run `nestedScrollContent_shouldPropagateCrossAxisUnconsumedFlings` test (cherry picked from https://android-review.googlesource.com/q/commit:9083dbe9cb097ef39adaa5ff23533b526fd70309) Merged-In: I39287f09161f9775665fb45ad4075954cfac5032 Change-Id: I39287f09161f9775665fb45ad4075954cfac5032
JetBrains · Mar 5, 2024 · 8d23611 · 8d23611
1 parent 22b329d
commit 8d23611
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diff --git a/...InstrumentedTest/kotlin/androidx/compose/foundation/pager/PagerNestedScrollContentTest.kt b/...InstrumentedTest/kotlin/androidx/compose/foundation/pager/PagerNestedScrollContentTest.kt
@@ -45,6 +45,7 @@ import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.input.nestedscroll.NestedScrollSource
 import androidx.compose.ui.platform.LocalViewConfiguration
 import androidx.compose.ui.test.onNodeWithTag
 import androidx.compose.ui.test.performTouchInput
@@ -163,8 +164,18 @@ class PagerNestedScrollContentTest(
     @Test
     fun nestedScrollContent_shouldPropagateCrossAxisUnconsumedFlings() {
         // Arrange
+        var scrollAvailable = Offset.Zero
         var postFlingVelocity = Velocity.Zero
         val dataCapturingConnection = object : NestedScrollConnection {
+            override fun onPostScroll(
+                consumed: Offset,
+                available: Offset,
+                source: NestedScrollSource
+            ): Offset {
+                scrollAvailable += available
+                return Offset.Zero
+            }
+
             override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
                 postFlingVelocity = available
                 return Velocity.Zero
@@ -207,6 +218,11 @@ class PagerNestedScrollContentTest(
         val crossAxisVelocity = if (vertical) postFlingVelocity.x else postFlingVelocity.y
         assertThat(mainAxisVelocity.absoluteValue).isEqualTo(0f)
         assertThat(crossAxisVelocity.absoluteValue).isNotEqualTo(0f)
+
+        val mainAxisScrollAvailable = if (vertical) scrollAvailable.y else scrollAvailable.x
+        val crossAxisScrollAvailable = if (vertical) scrollAvailable.x else scrollAvailable.y
+        assertThat(crossAxisScrollAvailable.absoluteValue).isNotEqualTo(0f)
+        assertThat(mainAxisScrollAvailable.absoluteValue).isEqualTo(0f)
     }
 
     @OptIn(ExperimentalFoundationApi::class)

diff --git a/...se/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/pager/Pager.kt b/...se/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/pager/Pager.kt
@@ -895,7 +895,7 @@ private class DefaultPagerNestedScrollConnection(
         available: Offset,
         source: NestedScrollSource
     ): Offset {
-        if (source == NestedScrollSource.Fling && available != Offset.Zero) {
+        if (source == NestedScrollSource.Fling && available.mainAxis() != 0f) {
             throw CancellationException()
         }
         return Offset.Zero
@@ -904,6 +904,9 @@ private class DefaultPagerNestedScrollConnection(
     override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
         return available.consumeOnOrientation(orientation)
     }
+
+    private fun Offset.mainAxis(): Float =
+        if (orientation == Orientation.Horizontal) this.x else this.y
 }
 
 @OptIn(ExperimentalFoundationApi::class)