组合式 BottomSheetScaffold 引发 IndexOutOfBoundsException 应用崩溃。

Question

我在寻找与此问题相关的解决方案时没有找到任何内容。我已经解决了这个问题，现在将问题和解决方案发布在这里，希望能够帮助到其他人。

问题描述

在将Jetpack Compose从版本1.2.0-beta02更新到1.2.0-rc02后，我的应用程序中的某些内容导致崩溃。

特定屏幕上的代码在两个版本之间没有更改，因此崩溃必须是由我正在使用的某个Compose组件引起的。我通过试错法找到了崩溃源，并发现问题出在BottomSheetScaffold组件上（其中包含空的content）。

导致崩溃的代码：

BottomSheetScaffold(
        sheetContent = { Text(text = "Some sheet content") }
    ) {
        AlertDialog(
            onDismissRequest = {
                // NO-OP
            },
            buttons = {
                Text(text = "here goes a button")
            }
        )
    }

崩溃日志：

2022-07-01 10:02:07.185 16257-16257/chipcard.android.payment.app E/AndroidRuntime: FATAL EXCEPTION: main
    Process: chipcard.android.payment.app, PID: 16257
    java.lang.IndexOutOfBoundsException: Index 0 is out of bounds. The list has 0 elements.
        at androidx.compose.runtime.collection.MutableVectorKt.checkIndex(MutableVector.kt:1135)
        at androidx.compose.runtime.collection.MutableVectorKt.access$checkIndex(MutableVector.kt:1)
        at androidx.compose.runtime.collection.MutableVector$MutableVectorList.get(MutableVector.kt:940)
        at androidx.compose.material.BottomSheetScaffoldKt$BottomSheetScaffoldLayout$1$1.invoke-0kLqBqw(BottomSheetScaffold.kt:447)
        at androidx.compose.material.BottomSheetScaffoldKt$BottomSheetScaffoldLayout$1$1.invoke(BottomSheetScaffold.kt:430)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState$createMeasurePolicy$1.measure-3p2s80s(SubcomposeLayout.kt:590)
        at androidx.compose.ui.node.InnerPlaceable.measure-BRTryo0(InnerPlaceable.kt:44)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1428)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1427)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:2101)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:110)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:78)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeMeasureSnapshotReads$ui_release(OwnerSnapshotObserver.kt:66)
        at androidx.compose.ui.node.LayoutNode.performMeasure-BRTryo0$ui_release(LayoutNode.kt:1427)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.remeasure-BRTryo0(OuterMeasurablePlaceable.kt:94)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.measure-BRTryo0(OuterMeasurablePlaceable.kt:75)
        at androidx.compose.ui.node.LayoutNode.measure-BRTryo0(LayoutNode.kt:1366)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1.measure-3p2s80s(Box.kt:115)
        at androidx.compose.ui.node.InnerPlaceable.measure-BRTryo0(InnerPlaceable.kt:44)
        at androidx.compose.ui.graphics.SimpleGraphicsLayerModifier.measure-3p2s80s(GraphicsLayerModifier.kt:405)
        at androidx.compose.ui.node.ModifiedLayoutNode.measure-BRTryo0(ModifiedLayoutNode.kt:53)
        at androidx.compose.foundation.layout.FillModifier.measure-3p2s80s(Size.kt:658)
        at androidx.compose.ui.node.ModifiedLayoutNode.measure-BRTryo0(ModifiedLayoutNode.kt:53)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1428)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1427)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:2101)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:110)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:78)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeMeasureSnapshotReads$ui_release(OwnerSnapshotObserver.kt:66)
        at androidx.compose.ui.node.LayoutNode.performMeasure-BRTryo0$ui_release(LayoutNode.kt:1427)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.remeasure-BRTryo0(OuterMeasurablePlaceable.kt:94)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.measure-BRTryo0(OuterMeasurablePlaceable.kt:75)
        at androidx.compose.ui.node.LayoutNode.measure-BRTryo0(LayoutNode.kt:1366)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1.measure-3p2s80s(Box.kt:115)
        at androidx.compose.ui.node.InnerPlaceable.measure-BRTryo0(InnerPlaceable.kt:44)
        at androidx.compose.ui.graphics.BlockGraphicsLayerModifier.measure-3p2s80s(GraphicsLayerModifier.kt:342)
        at androidx.compose.ui.node.ModifiedLayoutNode.measure-BRTryo0(ModifiedLayoutNode.kt:53)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1428)
        at androidx.compose.ui.node.LayoutNode$performMeasure$1.invoke(LayoutNode.kt:1427)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:2101)

- mr. Gauss

Answer 1

BottomSheetScaffold content 只包含导致崩溃的 AlertDialog 组件（我猜它被视为空的 content，而空的 content 会导致崩溃）。

在用 Box 组件包装 AlertDialog 后，崩溃问题得到了解决。我猜测 content 参数中必须至少有一些屏幕内容（AlertDialog 可能不被视为屏幕内容，因为它是凸起的——我不确定）。

修复崩溃的代码：

BottomSheetScaffold(
        sheetContent = { Text(text = "Some sheet content") }
    ) {
        Box {
            AlertDialog(
                onDismissRequest = {
                    // NO-OP
                },
                buttons = {
                    Text(text = "here goes a button")
                }
            )
        }
    }

参考 Google 的问题跟踪器，找到了崩溃的原因： https://issuetracker.google.com/issues/235588730

- mr. Gauss