小贝子编程

Stack内部的ListView.builder不起作用



我正试图在flutter中使用Stack小部件和Stack小程序中的三个ListView构建一个Jackpot游戏，但它不起作用。当我将ListView放入堆栈中时，会出现错误。我试过先把它包装在Expanded、Container和Flexible小部件中，但它不起作用。

这是构建脚手架主体的代码：

Widget _buildBody(GameArguments args) {
return Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
_buildJackpot(),
_buildPuller(),
],
));
}

以下是构建头奖的代码：

List<Image> left = [
Image.asset(
'src/images/hites_logo_trans2.png',
height: 100,
width: 200,
)
];
Widget build(BuildContext context) {
return Container(
child: Stack(
children: [
Container(),
Image.asset('src/images/jackpot_fome.png'),
Container(
child: ListView.builder(
itemBuilder: (BuildContext context, int index) {
return left[index];
},
),
)
],
),
);
}

这是完整的错误日志，我真的不知道发生了什么：(

[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
[38;5;244mThe following assertion was thrown during performResize():[39;49m
Vertical viewport was given unbounded width.
[38;5;244mViewports expand in the cross axis to fill their container and constrain their children to match their extent in the cross axis. In this case, a vertical viewport was given an unlimited amount of horizontal space in which to expand.[39;49m
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;244mWhen the exception was thrown, this was the stack[39;49m
[38;5;244m#0      RenderViewport.performResize.<anonymous closure>[39;49m
package:flutter/…/rendering/viewport.dart
[38;5;244m#1      RenderViewport.performResize[39;49m
package:flutter/…/rendering/viewport.dart
[38;5;244m#2      RenderObject.layout[39;49m
package:flutter/…/rendering/object.dart
[38;5;244m#3      RenderProxyBoxMixin.performLayout[39;49m
package:flutter/…/rendering/proxy_box.dart
[38;5;244m#4      RenderObject.layout[39;49m
package:flutter/…/rendering/object.dart
[38;5;244m...[39;49m
[38;5;244mThe following RenderObject was being processed when the exception was fired: RenderViewport#d36b3 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE[39;49m
[38;5;244mRenderObject: RenderViewport#d36b3 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE[39;49m
[38;5;244mneeds compositing[39;49m
[38;5;244mparentData: <none> (can use size)[39;49m
[38;5;244mconstraints: BoxConstraints(0.0<=w<=Infinity, 0.0<=h<=552.9)[39;49m
[38;5;244msize: MISSING[39;49m
[38;5;244maxisDirection: down[39;49m
[38;5;244mcrossAxisDirection: right[39;49m
[38;5;244moffset: ScrollPositionWithSingleContext#86e2d(offset: 0.0, range: null..null, viewport: null, ScrollableState, AlwaysScrollableScrollPhysics -> ClampingScrollPhysics -> RangeMaintainingScrollPhysics, IdleScrollActivity#0f03e, ScrollDirection.idle)[39;49m
[38;5;244manchor: 0.0[39;49m
[38;5;244mcenter child: RenderSliverPadding#b94be NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE[39;49m
[38;5;244mparentData: paintOffset=Offset(0.0, 0.0)[39;49m
[38;5;244mconstraints: MISSING[39;49m
[38;5;244mgeometry: null[39;49m
[38;5;244mpadding: EdgeInsets(0.0, 24.0, 0.0, 0.0)[39;49m
[38;5;244mtextDirection: ltr[39;49m
[38;5;244mchild: RenderSliverList#00bb5 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE[39;49m
[38;5;244mparentData: paintOffset=Offset(0.0, 0.0)[39;49m
[38;5;244mconstraints: MISSING[39;49m
[38;5;244mgeometry: null[39;49m
[38;5;244mno children current live[39;49m
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderViewport#d36b3 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderViewport#d36b3 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderIgnorePointer#313f0 relayoutBoundary=up11 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderSemanticsAnnotations#a67f0 relayoutBoundary=up10 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderPointerListener#ec676 relayoutBoundary=up9 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderSemanticsGestureHandler#1df12 relayoutBoundary=up8 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderPointerListener#f871d relayoutBoundary=up7 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: _RenderScrollSemantics#5c527 relayoutBoundary=up6 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderRepaintBoundary#50cc7 relayoutBoundary=up5 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderCustomPaint#7a42d relayoutBoundary=up4 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mListView[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderRepaintBoundary#a7239 relayoutBoundary=up3 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mStack[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m
Reloaded 3 of 581 libraries in 571ms.
[38;5;248m════════ Exception caught by rendering library ═════════════════════════════════[39;49m
RenderBox was not laid out: RenderRepaintBoundary#a7239 relayoutBoundary=up3 NEEDS-PAINT
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1785 pos 12: 'hasSize'
[38;5;244mThe relevant error-causing widget was[39;49m
[38;5;248mStack[39;49m
lib/pages/GamePage.dart
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m

这段代码有很多问题。首先，您必须在Listview.builder中给出itemcount。其次，您需要调整包装它所描述的ListView的Container的大小。

有两个主要问题
  1. ListView没有项目计数
  2. 你必须用Containerror大小的盒子或卡片包裹你的lsitview才能给它一些高度

尝试此代码：我想你可能会得到你的答案

Container(
height: 500,width: MediaQuery.of(context).size.width,
child:
ListView.builder(
itemCount: 13,
itemBuilder: (context, i) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: ListTile(title: Text("Try it"),),
);
},
),
),

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