Merge "Improve tap to scroll support to be ready for rollout" into main

2 files changed, 125 insertions, 72 deletions

diff --git a/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ModifierExt.kt b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ModifierExt.kt
new file mode 100644
index 00000000..a9d8b9dc
--- /dev/null
+++ b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ModifierExt.kt
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.intentresolver.contentpreview.payloadtoggle.ui.composable
+
+import androidx.compose.foundation.gestures.ScrollableState
+import androidx.compose.foundation.gestures.animateScrollBy
+import androidx.compose.foundation.gestures.awaitEachGesture
+import androidx.compose.foundation.gestures.awaitFirstDown
+import androidx.compose.foundation.gestures.waitForUpOrCancellation
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.layout.onGloballyPositioned
+import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.LayoutDirection
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.launch
+
+/** Calls [whenTrue] on this [Modifier] if [condition] is true. */
+@Composable
+inline fun Modifier.conditional(
+    condition: Boolean,
+    crossinline whenTrue: @Composable Modifier.() -> Modifier,
+): Modifier = if (condition) this.whenTrue() else this
+
+/**
+ * Overlays tap regions at the beginning and end of the scrollable region.
+ *
+ * When tap regions are tapped, [scrollableState] will be scrolled by the size of the modified
+ * scrollable multiplied by the [scrollRatio].
+ *
+ * Note: [scrollableState] must be shared with the scrollable being modified and [vertical] must be
+ * true only if the modified scrollable scrolls vertically.
+ */
+@Composable
+fun Modifier.tapToScroll(
+    scrollableState: ScrollableState,
+    vertical: Boolean = false,
+    tapRegionSize: Dp = 48.dp,
+    scrollRatio: Float = 0.5f,
+): Modifier {
+    val scope = rememberCoroutineScope()
+    var viewSize by remember { mutableStateOf(0) }
+    val isLtrLayoutDirection = LocalLayoutDirection.current == LayoutDirection.Ltr
+    val normalizedScrollVector = remember {
+        derivedStateOf {
+            if (vertical || isLtrLayoutDirection) {
+                viewSize * scrollRatio
+            } else {
+                -viewSize * scrollRatio
+            }
+        }
+    }
+    return onGloballyPositioned { viewSize = if (vertical) it.size.height else it.size.width }
+        .pointerInput(Unit) {
+            val tapRegionSizePx = tapRegionSize.roundToPx()
+
+            awaitEachGesture {
+                // Tap to scroll is disabled if the modified composable is not large enough to fit
+                // both tap regions.
+                if (viewSize < tapRegionSizePx * 2) return@awaitEachGesture
+
+                val down = awaitFirstDown(pass = PointerEventPass.Initial)
+                if (down.isConsumed) return@awaitEachGesture
+
+                val downPosition = if (vertical) down.position.y else down.position.x
+                val scrollVector =
+                    when {
+                        // Start taps scroll toward start
+                        downPosition <= tapRegionSizePx -> -normalizedScrollVector.value
+
+                        // End taps scroll toward end
+                        downPosition >= viewSize - tapRegionSizePx -> normalizedScrollVector.value
+
+                        // Middle taps are ignored
+                        else -> return@awaitEachGesture
+                    }
+
+                val up =
+                    waitForUpOrCancellation(pass = PointerEventPass.Initial)
+                        ?: return@awaitEachGesture
+
+                // Long presses are ignored
+                if (up.uptimeMillis - down.uptimeMillis >= viewConfiguration.longPressTimeoutMillis)
+                    return@awaitEachGesture
+
+                // Swipes are ignored
+                if ((up.position - down.position).getDistance() >= viewConfiguration.touchSlop)
+                    return@awaitEachGesture
+
+                down.consume()
+                up.consume()
+                scope.launch { scrollableState.animateScrollBy(scrollVector) }
+            }
+        }
+}
diff --git a/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ShareouselComposable.kt b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ShareouselComposable.kt
index 9a9a0821..015a0490 100644
--- a/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ShareouselComposable.kt
+++ b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/ui/composable/ShareouselComposable.kt
@@ -22,8 +22,7 @@ import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
-import androidx.compose.foundation.gestures.animateScrollBy
-import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -61,7 +60,6 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.scale
 import androidx.compose.ui.graphics.ColorFilter
 import androidx.compose.ui.graphics.asImageBitmap
-import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.layout.MeasureScope
 import androidx.compose.ui.layout.Placeable
@@ -77,7 +75,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.android.intentresolver.Flags.announceShareouselItemListPosition
 import com.android.intentresolver.Flags.shareouselScrollOffscreenSelections
 import com.android.intentresolver.Flags.shareouselSelectionShrink
-import com.android.intentresolver.Flags.shareouselTapToScroll
+import com.android.intentresolver.Flags.shareouselTapToScrollSupport
 import com.android.intentresolver.Flags.unselectFinalItem
 import com.android.intentresolver.R
 import com.android.intentresolver.contentpreview.payloadtoggle.domain.model.ValueUpdate
@@ -178,7 +176,10 @@ private fun PreviewCarouselItems(
                 start = measurements.horizontalPaddingDp,
                 end = measurements.horizontalPaddingDp,
             ),
-        modifier = Modifier.fillMaxSize(),
+        modifier =
+            Modifier.fillMaxSize().conditional(shareouselTapToScrollSupport()) {
+                tapToScroll(scrollableState = state)
+            },
     ) {
         itemsIndexed(
             items = previews.previewModels,
@@ -226,9 +227,6 @@ private fun PreviewCarouselItems(
             }
 
             ShareouselCard(
-                carouselState = state,
-                measurements = measurements,
-                index = index,
                 viewModel = previewModel,
                 aspectRatio = measurements.coerceAspectRatio(previewModel.aspectRatio),
                 annotateWithPosition = previews.previewModels.size > 1,
@@ -285,9 +283,6 @@ private fun ScrollOffscreenSelectionsEffect(
 
 @Composable
 private fun ShareouselCard(
-    carouselState: LazyListState,
-    measurements: PreviewCarouselMeasurements,
-    index: Int,
     viewModel: ShareouselPreviewViewModel,
     aspectRatio: Float,
     annotateWithPosition: Boolean,
@@ -307,13 +302,7 @@ private fun ShareouselCard(
             modifier =
                 Modifier.semantics { this.contentDescription = contentDescription }
                     .testTag(viewModel.testTag)
-                    .clickableWithTapToScrollSupport(
-                        state = carouselState,
-                        index = index,
-                        measurements = measurements,
-                    ) {
-                        scope.launch { viewModel.setSelected(!selected) }
-                    }
+                    .clickable { scope.launch { viewModel.setSelected(!selected) } }
                     .conditional(shareouselSelectionShrink()) {
                         val selectionScale by animateFloatAsState(if (selected) 0.95f else 1f)
                         scale(selectionScale)
@@ -335,50 +324,6 @@ private fun ShareouselCard(
 }
 
 @Composable
-private fun Modifier.clickableWithTapToScrollSupport(
-    state: LazyListState,
-    index: Int,
-    measurements: PreviewCarouselMeasurements,
-    onClick: () -> Unit,
-): Modifier {
-    val scope = rememberCoroutineScope()
-    return pointerInput(Unit) {
-        detectTapGestures { offset ->
-            with(state.layoutInfo) {
-                val item = visibleItemsInfo.firstOrNull { it.index == index }
-                when {
-                    // If the item is not visible, then this was likely an accidental click event
-                    // while flinging so ignore it.
-                    item == null -> {}
-
-                    // If tap to scroll flag is off, do a normal click
-                    !shareouselTapToScroll() -> onClick()
-
-                    // If click is in the start tap to scroll region
-                    (item.offset + offset.x) - viewportStartOffset <
-                        measurements.scrollByTapWidthPx ->
-                        // Scroll towards the start
-                        scope.launch {
-                            state.animateScrollBy(-measurements.viewportCenterPx.toFloat())
-                        }
-
-                    // If click is in the end tap to scroll region
-                    viewportEndOffset - (item.offset + offset.x) <
-                        measurements.scrollByTapWidthPx ->
-                        // Scroll towards the end
-                        scope.launch {
-                            state.animateScrollBy(measurements.viewportCenterPx.toFloat())
-                        }
-
-                    // If click is between the tap to scroll regions, do a normal click
-                    else -> onClick()
-                }
-            }
-        }
-    }
-}
-
-@Composable
 private fun buildContentDescription(
     annotateWithPosition: Boolean,
     viewModel: ShareouselPreviewViewModel,
@@ -520,12 +465,6 @@ private fun ShareouselAction(
     )
 }
 
-@Composable
-private inline fun Modifier.conditional(
-    condition: Boolean,
-    crossinline whenTrue: @Composable Modifier.() -> Modifier,
-): Modifier = if (condition) this.whenTrue() else this
-
 private data class PreviewCarouselMeasurements(
     val viewportHeightPx: Int,
     val viewportWidthPx: Int,
@@ -533,7 +472,6 @@ private data class PreviewCarouselMeasurements(
     val maxAspectRatio: Float,
     val horizontalPaddingPx: Int,
     val horizontalPaddingDp: Dp,
-    val scrollByTapWidthPx: Int,
 ) {
     constructor(
         placeable: Placeable,
@@ -551,7 +489,6 @@ private data class PreviewCarouselMeasurements(
             },
         horizontalPaddingPx = horizontalPadding.roundToInt(),
         horizontalPaddingDp = with(measureScope) { horizontalPadding.toDp() },
-        scrollByTapWidthPx = with(measureScope) { SCROLL_BY_TAP_WIDTH.roundToPx() },
     )
 
     fun coerceAspectRatio(ratio: Float): Float = ratio.coerceIn(MIN_ASPECT_RATIO, maxAspectRatio)
@@ -572,7 +509,6 @@ private data class PreviewCarouselMeasurements(
         private const val MIN_ASPECT_RATIO = 0.4f
         private const val MAX_ASPECT_RATIO = 2.5f
 
-        val SCROLL_BY_TAP_WIDTH = 48.dp
         val UNMEASURED =
             PreviewCarouselMeasurements(
                 viewportHeightPx = 0,
@@ -580,7 +516,6 @@ private data class PreviewCarouselMeasurements(
                 maxAspectRatio = 0f,
                 horizontalPaddingPx = 0,
                 horizontalPaddingDp = 0.dp,
-                scrollByTapWidthPx = 0,
             )
     }
 }