会偶现某一个item为空白的情况

[jaysonss]

Flutter doctor info:
[✓] Flutter (Channel unknown, v1.14.6, on Mac OS X 10.14.6 18G84, locale
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• Flutter version 1.14.6 at /Users/huangyumeng/flutter/sdk/flutter
• Framework revision fabeb2a16f (4 months ago), 2020-01-28 07:56:51 -0800
• Engine revision c4229bfbba
• Dart version 2.8.0 (build 2.8.0-dev.5.0 fc3af737c7)

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• Platform android-29, build-tools 29.0.0
• Java binary at: /Applications/Android
Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build
1.8.0_212-release-1586-b4-5784211)
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• Xcode at /Applications/Xcode.app/Contents/Developer
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• Flutter plugin version 45.1.1
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• Java version OpenJDK Runtime Environment (build
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[✓] Connected device (1 available)
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! Doctor found issues in 1 category.

问题描述：
产品瀑布流默认为两列，会偶现第二列某一个区域为空白的情况，滑动后第二列整个消失，第一列的布局会挤在一起。布局代码：

SliverPadding(
          padding: EdgeInsets.all(kMomentWaterfallCrossAxisSpacing),
          sliver: SliverWaterfallFlow(
            gridDelegate: SliverWaterfallFlowDelegate(
                crossAxisCount: kMomentWaterfallCrossAxisCount,
                mainAxisSpacing: kMomentWaterfallMainAxisSpacing,
                crossAxisSpacing: kMomentWaterfallCrossAxisSpacing,
                lastChildLayoutTypeBuilder: (idx) {
                  return idx == _model.momentList.length
                      ? LastChildLayoutType.foot
                      : LastChildLayoutType.none;
                },
                viewportBuilder: (firstIdx, lastIdx) {},
                collectGarbage: (List<int> collectIdxList) {
                  for (int idx in collectIdxList) {
                    dataList[idx].evictImageInfo();
                  }
                }),
            delegate: SliverChildBuilderDelegate((context, idx) {
              return ItemTile();
            }, childCount: dataList.length),
          ),
        )

Bugly报错：
NoSuchMethodError: The getter 'parentData' was called on null. Receiver: null Tried calling: parentData

#0 CrossAxisItems.insertLeading (package:waterfall_flow/src/rendering/sliver_waterfall_flow.dart:569)

2 #1 RenderSliverWaterfallFlow.performLayout (package:waterfall_flow/src/rendering/sliver_waterfall_flow.dart:199)
3 #2 RenderObject.layout (package:flutter/src/rendering/object.dart:1767)
4 #3 RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:134)
5 #4 RenderSliverPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:373)
6 #5 RenderObject.layout (package:flutter/src/rendering/object.dart:1767)
7 #6 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:452)
8 #7 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1444)
9 #8 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1353)
10 #9 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1628)
11 #10 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:888)
12 #11 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:401)
13 #12 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:797)
14 #13 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283)
15 #14 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1109)
16 #15 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1048)
17 #16 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:964)
18 #17 _rootRun (dart:async/zone.dart:1126)
19 #18 _CustomZone.run (dart:async/zone.dart:1023)
20 #19 _CustomZone.runGuarded (dart:async/zone.dart:925)
21 #20 _invoke (dart:ui/hooks.dart:260)
22 #21 _drawFrame (dart:ui/hooks.dart:218)

[zmtzawqlp]

最新版本？ 请提供一下可以重现的demo

[jaysonss]

版本是0.1.3

[zmtzawqlp]

#3 看起来跟这个问题一样，请使用最新版本

[jaysonss]

OK

[zmtzawqlp]

OK

测试之后，请反馈是否修复，谢谢

[jaysonss]

@zmtzawqlp 最近似乎没有再遇到这个问题了😃