我想添加Column个小部件到Row个小部件.
我有一个如下的数据 struct :
Scaffold
- Padding
- SingleChildScrollView
- Column
- Row
- CircleAvatar
- Column (The Column I am talking about below)
- Text
- Row
- Expanded
- MaterialButton
- Expanded
- Container
- Expanded
- MaterialButton
- ListTile
在将Column与Row相加时，我收到错误:
════════ Exception caught by rendering library ═════════════════════════════════
The following assertion was thrown during performLayout():
RenderFlex children have non-zero flex but incoming width constraints are unbounded.
When a row is in a parent that does not provide a finite width constraint, for example if it is in a horizontal scrollable, it will try to shrink-wrap its children along the horizontal axis. Setting a flex on a child (e.g. using Expanded) indicates that the child is to expand to fill the remaining space in the horizontal direction.
These two directives are mutually exclusive. If a parent is to shrink-wrap its child, the child cannot simultaneously expand to fit its parent.
Consider setting mainAxisSize to MainAxisSize.min and using FlexFit.loose fits for the flexible children (using Flexible rather than Expanded). This will allow the flexible children to size themselves to less than the infinite remaining space they would otherwise be forced to take, and then will cause the RenderFlex to shrink-wrap the children rather than expanding to fit the maximum constraints provided by the parent.
If this message did not help you determine the problem, consider using debugDumpRenderTree():
https://flutter.dev/debugging/#rendering-layer
http://api.flutter.dev/flutter/rendering/debugDumpRenderTree.html
The affected RenderFlex is: RenderFlex#acbae relayoutBoundary=up15 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
constraints: BoxConstraints(unconstrained)
size: MISSING
direction: horizontal
mainAxisAlignment: start
mainAxisSize: max
crossAxisAlignment: center
textDirection: ltr
verticalDirection: down
child 1: RenderConstrainedBox#404ec NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=3; fit=FlexFit.tight
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(w=180.0, h=50.0)
child: RenderSemanticsAnnotations#4f838 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
semantic boundary
size: MISSING
child: _RenderInputPadding#04251 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
size: MISSING
child: RenderConstrainedBox#3337d NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0)
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(88.0<=w<=Infinity, 36.0<=h<=Infinity)
child 2: RenderLimitedBox#593aa NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=1; fit=FlexFit.tight
constraints: MISSING
size: MISSING
maxWidth: 0.0
maxHeight: 0.0
child: RenderConstrainedBox#d1172 NEEDS-LAYOUT NEEDS-PAINT
parentData: <none>
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(biggest)
child 3: RenderConstrainedBox#42764 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=3; fit=FlexFit.tight
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(w=180.0, h=50.0)
child: RenderSemanticsAnnotations#7ec96 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
semantic boundary
size: MISSING
child: _RenderInputPadding#6aa1f NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
size: MISSING
child: RenderConstrainedBox#e1f60 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0)
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(88.0<=w<=Infinity, 36.0<=h<=Infinity)
The creator information is set to: Row ← Column ← Row ← Column ← _SingleChildViewport ← IgnorePointer-[GlobalKey#10aed] ← Semantics ← Listener ← _GestureSemantics ← RawGestureDetector-[LabeledGlobalKey<RawGestureDetectorState>#23575] ← Listener ← _ScrollableScope ← ⋯
The nearest ancestor providing an unbounded width constraint is: RenderFlex#ede32 relayoutBoundary=up13 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
See also: https://flutter.dev/layout/
If none of the above helps enough to fix this problem, please don't hesitate to file a bug:
https://github.com/flutter/flutter/issues/new?template=2_bug.md
The relevant error-causing widget was
Row
When the exception was thrown, this was the stack
#0 RenderFlex.performLayout.<anonymous closure>
#1 RenderFlex.performLayout
#2 RenderObject.layout
#3 RenderBox.layout
#4 ChildLayoutHelper.layoutChild
#5 RenderFlex._computeSizes
#6 RenderFlex.performLayout
#7 RenderObject.layout
#8 RenderBox.layout
#9 ChildLayoutHelper.layoutChild
#10 RenderFlex._computeSizes
#11 RenderFlex.performLayout
#12 RenderObject.layout
#13 RenderBox.layout
#14 ChildLayoutHelper.layoutChild
#15 RenderFlex._computeSizes
#16 RenderFlex.performLayout
#17 RenderObject.layout
#18 RenderBox.layout
#19 _RenderSingleChildViewport.performLayout
#20 RenderObject.layout
#21 RenderBox.layout
#22 RenderProxyBoxMixin.performLayout
#23 RenderObject.layout
#24 RenderBox.layout
#25 RenderProxyBoxMixin.performLayout
#26 RenderObject.layout
#27 RenderBox.layout
#28 RenderProxyBoxMixin.performLayout
#29 RenderObject.layout
#30 RenderBox.layout
#31 RenderProxyBoxMixin.performLayout
#32 RenderObject.layout
#33 RenderBox.layout
#34 RenderProxyBoxMixin.performLayout
#35 RenderObject.layout
#36 RenderBox.layout
#37 RenderProxyBoxMixin.performLayout
#38 RenderObject.layout
#39 RenderBox.layout
#40 RenderProxyBoxMixin.performLayout
#41 RenderObject.layout
#42 RenderBox.layout
#43 RenderProxyBoxMixin.performLayout
#44 RenderCustomPaint.performLayout
#45 RenderObject.layout
#46 RenderBox.layout
#47 RenderProxyBoxMixin.performLayout
#48 RenderObject.layout
#49 RenderBox.layout
#50 RenderPadding.performLayout
#51 RenderObject.layout
#52 RenderBox.layout
#53 MultiChildLayoutDelegate.layoutChild
#54 _ScaffoldLayout.performLayout
#55 MultiChildLayoutDelegate._callPerformLayout
#56 RenderCustomMultiChildLayoutBox.performLayout
#57 RenderObject._layoutWithoutResize
#58 PipelineOwner.flushLayout
#59 RendererBinding.drawFrame
#60 WidgetsBinding.drawFrame
#61 RendererBinding._handlePersistentFrameCallback
#62 SchedulerBinding._invokeFrameCallback
#63 SchedulerBinding.handleDrawFrame
#64 SchedulerBinding._handleDrawFrame
#68 _invoke (dart:ui/hooks.dart:150:10)
#69 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:318:5)
#70 _drawFrame (dart:ui/hooks.dart:115:31)
(elided 3 frames from dart:async)
The following RenderObject was being processed when the exception was fired: RenderFlex#acbae relayoutBoundary=up15 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
RenderObject: RenderFlex#acbae relayoutBoundary=up15 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
constraints: BoxConstraints(unconstrained)
size: MISSING
direction: horizontal
mainAxisAlignment: start
mainAxisSize: max
crossAxisAlignment: center
textDirection: ltr
verticalDirection: down
child 1: RenderConstrainedBox#404ec NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=3; fit=FlexFit.tight
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(w=180.0, h=50.0)
child: RenderSemanticsAnnotations#4f838 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
semantic boundary
size: MISSING
child: _RenderInputPadding#04251 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
size: MISSING
child: RenderConstrainedBox#3337d NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0)
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(88.0<=w<=Infinity, 36.0<=h<=Infinity)
child 2: RenderLimitedBox#593aa NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=1; fit=FlexFit.tight
constraints: MISSING
size: MISSING
maxWidth: 0.0
maxHeight: 0.0
child: RenderConstrainedBox#d1172 NEEDS-LAYOUT NEEDS-PAINT
parentData: <none>
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(biggest)
child 3: RenderConstrainedBox#42764 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=3; fit=FlexFit.tight
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(w=180.0, h=50.0)
child: RenderSemanticsAnnotations#7ec96 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
semantic boundary
size: MISSING
child: _RenderInputPadding#6aa1f NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: <none>
constraints: MISSING
size: MISSING
child: RenderConstrainedBox#e1f60 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0)
constraints: MISSING
size: MISSING
additionalConstraints: BoxConstraints(88.0<=w<=Infinity, 36.0<=h<=Infinity)
════════════════════════════════════════════════════════════════════════════════
…
我的代码是:
Row(
children: [
CircleAvatar(
backgroundImage: NetworkImage(userAvatarUrl),
),
Column(
children: [
Text(userName),
Row(
children: …,
),
],
),
],
),
如果您需要更多信息，请随时留言.
如何将Column个小部件添加到Row个小部件中？如果有任何帮助，我将不胜感激.提前谢谢您！