“待处理的组合物尚未应用”例外是什么意思以及如何避免？

Question

我有一个正在运行的应用程序，但有时，由于我不知道的原因，应用程序会崩溃并显示以下消息：

java.lang.IllegalStateException：尚未应用挂起的组合

我无法在任何地方找到有关此异常发生的信息，而且我也不明白如何避免它。

编辑#1：经过一些研究和测试，我发现当我在 BottomNavigation 中的选项卡之间快速切换时会引发此异常（选项卡包含 LazyColumn）

Answer 1

由于我没有足够的声誉来撰写评论，因此我将其写在这里。也许对你有帮助

我今天遇到了同样的错误。如果我开始调试，并且我将大量日志行放入我的代码中，以了解到底是什么导致了这个问题。我弄清楚了是什么原因导致了这个错误。我的代码中存在实际问题，引发了异常（数组索引越界），但似乎某个地方的重组捕获了这个实际错误并引发了更通用的错误。

简化我的代码看起来像这样

val items = myViewModel.items.collectAsState().value
val focusRequesters = myViewModel.focusRequesters.collectAsState().value
LazyColumn() {
    items(items = items) { item ->
        // When I added new item then I got error in this line, 
        // because I forgot to add new focusRequester when I was adding new item. 
        // so it was actually array index out of bounds error
        val focusRequester = focusRequesters[item.position]
        ...
        // Code to show item
    }
    item {
         AddItemButton(myViewModel)
    }
}

它在日志中向我显示的实际错误是这个一般错误。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.courtesy.test, PID: 27394
    java.lang.IllegalStateException: pending composition has not been applied
        at androidx.compose.runtime.CompositionImpl.drainPendingModificationsForCompositionLocked(Composition.kt:530)
        at androidx.compose.runtime.CompositionImpl.composeContent(Composition.kt:567)
        at androidx.compose.runtime.Recomposer.composeInitial$runtime_release(Recomposer.kt:811)
        at androidx.compose.runtime.ComposerImpl$CompositionContextImpl.composeInitial$runtime_release(Composer.kt:3583)
        at androidx.compose.runtime.CompositionImpl.setContent(Composition.kt:503)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.subcomposeInto(SubcomposeLayout.kt:408)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.subcompose(SubcomposeLayout.kt:383)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.subcompose(SubcomposeLayout.kt:374)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.subcompose(SubcomposeLayout.kt:363)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState$Scope.subcompose(SubcomposeLayout.kt:648)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1.invoke(Scaffold.kt:316)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1.invoke(Scaffold.kt:243)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.layout.LayoutNodeSubcompositionsState$createMeasurePolicy$1$measure$1.placeChildren(SubcomposeLayout.kt:527)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:980)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:965)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:2063)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:112)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:78)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutSnapshotReads$ui_release(OwnerSnapshotObserver.kt:52)
        at androidx.compose.ui.node.LayoutNode.layoutChildren$ui_release(LayoutNode.kt:965)
        at androidx.compose.ui.node.LayoutNode.onNodePlaced$ui_release(LayoutNode.kt:950)
        at androidx.compose.ui.node.InnerPlaceable.placeAt-f8xVGno(InnerPlaceable.kt:78)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeOuterWrapper-f8xVGno(OuterMeasurablePlaceable.kt:158)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.access$placeOuterWrapper-f8xVGno(OuterMeasurablePlaceable.kt:28)
        at androidx.compose.ui.node.OuterMeasurablePlaceable$placeAt$1.invoke(OuterMeasurablePlaceable.kt:146)
        at androidx.compose.ui.node.OuterMeasurablePlaceable$placeAt$1.invoke(OuterMeasurablePlaceable.kt:145)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:2063)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:112)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:78)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutModifierSnapshotReads$ui_release(OwnerSnapshotObserver.kt:59)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeAt-f8xVGno(OuterMeasurablePlaceable.kt:145)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.replace(OuterMeasurablePlaceable.kt:170)
        at androidx.compose.ui.node.LayoutNode.replace$ui_release(LayoutNode.kt:838)
        at androidx.compose.ui.node.MeasureAndLayoutDelegate.remeasureAndRelayoutIfNeeded(MeasureAndLayoutDelegate.kt:262)
        at androidx.compose.ui.node.MeasureAndLayoutDelegate.access$remeasureAndRelayoutIfNeeded(MeasureAndLayoutDelegate.kt:36)
        at androidx.compose.ui.node.MeasureAndLayoutDelegate.measureAndLayout(MeasureAndLayoutDelegate.kt:201)
E/AndroidRuntime:     at androidx.compose.ui.platform.AndroidComposeView.onMeasure(AndroidComposeView.android.kt:773)
        at android.view.View.measure(View.java:25466)
        at androidx.compose.ui.platform.AbstractComposeView.internalOnMeasure$ui_release(ComposeView.android.kt:298)
        at androidx.compose.ui.platform.AbstractComposeView.onMeasure(ComposeView.android.kt:285)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:145)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:747)
        at android.view.View.measure(View.java:25466)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:3397)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:2228)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2486)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1952)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8171)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
        at android.view.Choreographer.doCallbacks(Choreographer.java:796)
        at android.view.Choreographer.doFrame(Choreographer.java:731)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

所以至少对我来说，当重组期间发生实际错误时，会抛出此错误。当然，如果它能向我显示实际错误而不是这个一般错误，那就太好了。

Answer 2

remember为了以后参考，我曾经在输入错误时遇到过这个问题rememberSavable。