ParentDatawidget的使用不正确。 parentdatawidget扩展（flex：1）希望将flexparentdata类型的parentdata应用于renderObject，
我在列内使用柔韧性中的标签栏视图。结果，我得到了ParentDatawidget的不正确使用。
这是我身体的代码：
Widget _buildBody() {
TabController _topTabController = TabController(length: 2, vsync: this, animationDuration: Duration.zero);
var loc = Utils.getLocalizations(context)!;
double deviceWidth = Utils.deviceWidth(context);
_topTabController.animateTo(tabIndex);
_topTabController.addListener(() {
if (!_topTabController.indexIsChanging) {
tabIndex = _topTabController.index;
}
});
//this gesture detector ensures that the search bar loses focus when an empty space on the screen is tapped
return GestureDetector(
onTap: () => FocusScope.of(context).unfocus(),
child: Material(
color: Colors.white,
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
HomePageBanner(title: loc.messagesTitle,),
Padding(
padding: const EdgeInsets.only(top: 20),
child: DecoratedBox(
decoration: BoxDecoration(
//This is for bottom border that is needed
border: Border(bottom: BorderSide(color: Colors.grey.shade300, width: 0.8)),
),
child: TabBar(
labelColor: Colors.black,
labelStyle: const TextStyle(fontWeight: FontWeight.bold),
unselectedLabelColor: Colors.black,
unselectedLabelStyle: const TextStyle(fontWeight: FontWeight.normal),
controller: _topTabController,
indicator: const UnderlineTabIndicator(
borderSide: BorderSide(color: Colors.black, width: 3.0),
),
tabs: [
Tab( text: loc.messagesJustMetTabName,),
Tab(text: loc.messagesFriendsTabName,)
],
),
),
),
Flexible(
child: Padding(
padding: EdgeInsets.only(left: deviceWidth*0.012, right: deviceWidth*0.012, top: 5),
child: TabBarView(
controller: _topTabController,
children: [
StatefulBuilder(
builder: (BuildContext context, void Function(void Function()) setMetState) {
return _justMetTab(context, setMetState);
},
),
StatefulBuilder(
builder: (BuildContext context, void Function(void Function()) setFriendState) {
return _friendsTab(context, setFriendState);
},
),
],
),
),
),
],
),
),
);
}
我尝试将列包装在尺寸的盒子中并给出固定高度，但这只是使屏幕上的每个小部件都消失了。我还尝试将尺寸的栏本身包裹在大小的盒子中，但所有小部件也消失了。
这是页面外观的一个示例，以更好地理解：
现在看起来都不错，但是当我在测试飞行中运行应用程序时，我会得到一个灰色屏幕ParentDatawidgetError。
编辑： 我在此处添加了Body（）方法，以获取_buildbody（）位于窗口基上的上下文：
@override
Widget build(BuildContext context) {
return FutureBuilder<dynamic>(
future: getAllChatRequests(), // async work
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.waiting: return const Center(child: CircularProgressIndicator());
default:
if (snapshot.hasError) {
return Center(child: Text('Error: ${snapshot.error}'));
} else {
return _buildBody();
}
}
},
);
}
edit：
还在此处添加错误日志以获取更多上下文：
======== Exception caught by widgets library =======================================================
The following assertion was thrown while applying parent data.:
Incorrect use of ParentDataWidget.
The ParentDataWidget Expanded(flex: 1) wants to apply ParentData of type FlexParentData to a RenderObject, which has been set up to accept ParentData of incompatible type ParentData.
Usually, this means that the Expanded widget has the wrong ancestor RenderObjectWidget. Typically, Expanded widgets are placed directly inside Flex widgets.
The offending Expanded is currently placed inside a RepaintBoundary widget.
The ownership chain for the RenderObject that received the incompatible parent data was:
Padding ← Expanded ← StatefulBuilder ← KeyedSubtree-[<0>] ← RepaintBoundary ← IndexedSemantics ← NotificationListener<KeepAliveNotification> ← KeepAlive ← AutomaticKeepAlive ← KeyedSubtree-[Key <[<0>]>] ← ⋯
When the exception was thrown, this was the stack:
#0 RenderObjectElement._updateParentData.<anonymous closure> (package:flutter/src/widgets/framework.dart:5960:11)
#1 RenderObjectElement._updateParentData (package:flutter/src/widgets/framework.dart:5977:6)
#2 RenderObjectElement.attachRenderObject (package:flutter/src/widgets/framework.dart:5999:7)
#3 RenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5673:5)
#4 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6214:11)
... Normal element mounting (53 frames)
#57 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3817:16)
#58 Element.updateChild (package:flutter/src/widgets/framework.dart:3551:18)
#59 SliverMultiBoxAdaptorElement.updateChild (package:flutter/src/widgets/sliver.dart:1265:37)
#60 SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1250:20)
#61 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2597:19)
#62 SliverMultiBoxAdaptorElement.createChild (package:flutter/src/widgets/sliver.dart:1242:12)
#63 RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:349:23)
#64 RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:2025:59)
#65 PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:918:15)
#66 RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:2025:14)
#67 RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:338:5)
#68 RenderSliverMultiBoxAdaptor.addInitialChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:422:5)
#69 RenderSliverFixedExtentBoxAdaptor.performLayout (package:flutter/src/rendering/sliver_fixed_extent_list.dart:205:12)
#70 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#71 RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:137:12)
#72 _RenderSliverFractionalPadding.performLayout (package:flutter/src/widgets/sliver_fill.dart:167:11)
#73 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#74 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:510:13)
#75 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1580:12)
#76 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1489:20)
#77 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#78 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#79 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#80 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#81 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#82 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#83 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#84 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#85 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#86 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#87 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#88 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#89 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#90 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:233:12)
#91 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#92 ChildLayoutHelper.layoutChild (package:flutter/src/rendering/layout_helper.dart:56:11)
#93 RenderFlex._computeSizes (package:flutter/src/rendering/flex.dart:896:45)
#94 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:931:32)
#95 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#96 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#97 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#98 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#99 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1376:11)
#100 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#101 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#102 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#103 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#104 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#105 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#106 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1757:7)
#107 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:887:18)
#108 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:504:19)
#109 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:892:13)
#110 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:370:5)
#111 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1146:15)
#112 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1083:9)
#113 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:997:5)
#117 _invoke (dart:ui/hooks.dart:151:10)
#118 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:308:5)
#119 _drawFrame (dart:ui/hooks.dart:115:31)
(elided 3 frames from dart:async)
====================================================================================================
I am using a tab bar view in a flexible, which is inside a column. As a result, I am getting the incorrect use of ParentDataWidget.
Here's the code to my body:
Widget _buildBody() {
TabController _topTabController = TabController(length: 2, vsync: this, animationDuration: Duration.zero);
var loc = Utils.getLocalizations(context)!;
double deviceWidth = Utils.deviceWidth(context);
_topTabController.animateTo(tabIndex);
_topTabController.addListener(() {
if (!_topTabController.indexIsChanging) {
tabIndex = _topTabController.index;
}
});
//this gesture detector ensures that the search bar loses focus when an empty space on the screen is tapped
return GestureDetector(
onTap: () => FocusScope.of(context).unfocus(),
child: Material(
color: Colors.white,
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
HomePageBanner(title: loc.messagesTitle,),
Padding(
padding: const EdgeInsets.only(top: 20),
child: DecoratedBox(
decoration: BoxDecoration(
//This is for bottom border that is needed
border: Border(bottom: BorderSide(color: Colors.grey.shade300, width: 0.8)),
),
child: TabBar(
labelColor: Colors.black,
labelStyle: const TextStyle(fontWeight: FontWeight.bold),
unselectedLabelColor: Colors.black,
unselectedLabelStyle: const TextStyle(fontWeight: FontWeight.normal),
controller: _topTabController,
indicator: const UnderlineTabIndicator(
borderSide: BorderSide(color: Colors.black, width: 3.0),
),
tabs: [
Tab( text: loc.messagesJustMetTabName,),
Tab(text: loc.messagesFriendsTabName,)
],
),
),
),
Flexible(
child: Padding(
padding: EdgeInsets.only(left: deviceWidth*0.012, right: deviceWidth*0.012, top: 5),
child: TabBarView(
controller: _topTabController,
children: [
StatefulBuilder(
builder: (BuildContext context, void Function(void Function()) setMetState) {
return _justMetTab(context, setMetState);
},
),
StatefulBuilder(
builder: (BuildContext context, void Function(void Function()) setFriendState) {
return _friendsTab(context, setFriendState);
},
),
],
),
),
),
],
),
),
);
}
I have tried wrapping the column in a sized box and giving it a fixed height, but this just makes every widget on the screen disappear. I have also tried wrapping the sized bar itself in a sized box, but all the widgets disappear as well.
Here's an example of the what the page looks like for better understanding:
It all looks good now, but when I run the app in test flight, I get a grey screen because of the ParentDataWidgetError.
EDIT:
I have added the body() method here for context on where _buildBody() is located in the widget tree:
@override
Widget build(BuildContext context) {
return FutureBuilder<dynamic>(
future: getAllChatRequests(), // async work
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.waiting: return const Center(child: CircularProgressIndicator());
default:
if (snapshot.hasError) {
return Center(child: Text('Error: ${snapshot.error}'));
} else {
return _buildBody();
}
}
},
);
}
EDIT:
Also adding the error log here for more context:
======== Exception caught by widgets library =======================================================
The following assertion was thrown while applying parent data.:
Incorrect use of ParentDataWidget.
The ParentDataWidget Expanded(flex: 1) wants to apply ParentData of type FlexParentData to a RenderObject, which has been set up to accept ParentData of incompatible type ParentData.
Usually, this means that the Expanded widget has the wrong ancestor RenderObjectWidget. Typically, Expanded widgets are placed directly inside Flex widgets.
The offending Expanded is currently placed inside a RepaintBoundary widget.
The ownership chain for the RenderObject that received the incompatible parent data was:
Padding ← Expanded ← StatefulBuilder ← KeyedSubtree-[<0>] ← RepaintBoundary ← IndexedSemantics ← NotificationListener<KeepAliveNotification> ← KeepAlive ← AutomaticKeepAlive ← KeyedSubtree-[Key <[<0>]>] ← ⋯
When the exception was thrown, this was the stack:
#0 RenderObjectElement._updateParentData.<anonymous closure> (package:flutter/src/widgets/framework.dart:5960:11)
#1 RenderObjectElement._updateParentData (package:flutter/src/widgets/framework.dart:5977:6)
#2 RenderObjectElement.attachRenderObject (package:flutter/src/widgets/framework.dart:5999:7)
#3 RenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5673:5)
#4 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6214:11)
... Normal element mounting (53 frames)
#57 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3817:16)
#58 Element.updateChild (package:flutter/src/widgets/framework.dart:3551:18)
#59 SliverMultiBoxAdaptorElement.updateChild (package:flutter/src/widgets/sliver.dart:1265:37)
#60 SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1250:20)
#61 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2597:19)
#62 SliverMultiBoxAdaptorElement.createChild (package:flutter/src/widgets/sliver.dart:1242:12)
#63 RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:349:23)
#64 RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:2025:59)
#65 PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:918:15)
#66 RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:2025:14)
#67 RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:338:5)
#68 RenderSliverMultiBoxAdaptor.addInitialChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:422:5)
#69 RenderSliverFixedExtentBoxAdaptor.performLayout (package:flutter/src/rendering/sliver_fixed_extent_list.dart:205:12)
#70 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#71 RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:137:12)
#72 _RenderSliverFractionalPadding.performLayout (package:flutter/src/widgets/sliver_fill.dart:167:11)
#73 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#74 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:510:13)
#75 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1580:12)
#76 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1489:20)
#77 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#78 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#79 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#80 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#81 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#82 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#83 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#84 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#85 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#86 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#87 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#88 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#89 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#90 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:233:12)
#91 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#92 ChildLayoutHelper.layoutChild (package:flutter/src/rendering/layout_helper.dart:56:11)
#93 RenderFlex._computeSizes (package:flutter/src/rendering/flex.dart:896:45)
#94 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:931:32)
#95 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#96 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#97 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#98 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#99 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1376:11)
#100 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#101 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#102 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#103 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#104 RenderObject.layout (package:flutter/src/rendering/object.dart:1915:7)
#105 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:116:14)
#106 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1757:7)
#107 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:887:18)
#108 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:504:19)
#109 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:892:13)
#110 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:370:5)
#111 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1146:15)
#112 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1083:9)
#113 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:997:5)
#117 _invoke (dart:ui/hooks.dart:151:10)
#118 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:308:5)
#119 _drawFrame (dart:ui/hooks.dart:115:31)
(elided 3 frames from dart:async)
====================================================================================================
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评论（1）
您在这里不需要灵活的小部件。.请删除灵活性。或者，如果您希望将其保留，则用与设备相同的尺寸盒子包裹列，并使用弹性扩展。
You dont need the flexible widget here.. please remove the flexible. Or if you wish to keep it wrap the column with a sized box of size same as device and use expanded in place of flexible.