我想显示文本(或其他类型的内容)和卡片列表。我只能显示卡片列表，但如果我添加另一个类，它会抛出异常。
仅用于卡片列表的代码(有效):
class CardPageState extends State<CardPage> {
//DeckCard is a class which contains title, description, etc
final decks = <DeckCard>[];
CardPageState(data){
decks.addAll(data);
}
@override
Widget build(BuildContext context) {
return Container(
child: buildCardPage(),
);
}
Widget buildCardPage() {
return new Container(
child: new ListView.builder(
itemCount: decks.length,
itemBuilder: /*1*/ (context, i) {
return _buildRow(decks[i]);
})
);
}
Widget _buildRow(DeckCard deckCard) {
return new Card(
child: Text(deckCard.getTitle(), style: TextStyle(fontWeight: FontWeight.bold,fontSize: 20, color:Colors.black),)
);
}
}
CardPage 从带有正文的主页调用:
body: new Container(
child: new FutureBuilder<DeckCardResponse>(
future: fetchDecksFromFirebase(),
builder: (context, snapshot) {
if (snapshot.hasData) {
return new CardPage(snapshot.data.getDecks());
}
else if (snapshot.hasError) {
return new MessageError(499);
}
return new CircularProgressIndicator(strokeWidth: 5.0);
}),
)
当我尝试添加其他内容时抛出异常:
Widget buildCardPage() {
return new Container(
child:
new Column(
children:[
new Text("hello", style: TextStyle(fontWeight: FontWeight.bold,fontSize: 20, color:Colors.black),),
new Container(
child: new ListView.builder(
itemCount: decks.length,
itemBuilder: /*1*/ (context, i) {
return _buildRow(decks[i]);
})
),
]
),
);
有什么想法吗？我尝试只使用一个没有前一个容器的 Column，但是，我有同样的异常。
I/flutter (18134): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (18134): The following assertion was thrown during performResize():
I/flutter (18134): Vertical viewport was given unbounded height.
I/flutter (18134): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
I/flutter (18134): viewport was given an unlimited amount of vertical space in which to expand. This situation
I/flutter (18134): typically happens when a scrollable widget is nested inside another scrollable widget.
I/flutter (18134): If this widget is always nested in a scrollable widget there is no need to use a viewport because
I/flutter (18134): there will always be enough vertical space for the children. In this case, consider using a Column
I/flutter (18134): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
I/flutter (18134): the height of the viewport to the sum of the heights of its children.
I/flutter (18134):
I/flutter (18134): When the exception was thrown, this was the stack:
I/flutter (18134): #0 RenderViewport.performResize.<anonymous closure> (package:flutter/src/rendering/viewport.dart:1135:15)
I/flutter (18134): #1 RenderViewport.performResize (package:flutter/src/rendering/viewport.dart:1188:6)
I/flutter (18134): #2 RenderObject.layout (package:flutter/src/rendering/object.dart:1617:9)
I/flutter (18134): #3 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #4 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #5 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #6 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #7 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #8 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #9 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #10 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #11 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #12 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #13 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #14 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #15 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #16 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #17 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #18 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #19 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:738:15)
I/flutter (18134): #20 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #21 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11)
I/flutter (18134): #22 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:350:7)
I/flutter (18134): #23 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7)
I/flutter (18134): #24 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14)
I/flutter (18134): #25 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #26 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #27 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #28 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #29 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1206:11)
I/flutter (18134): #30 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #31 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #32 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #33 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #34 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #35 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #36 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #37 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #38 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #39 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #40 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #41 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #42 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #43 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #44 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #45 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #46 RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:3032:13)
I/flutter (18134): #47 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #48 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter (18134): #49 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #50 __RenderTheatre&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #51 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #52 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #53 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #54 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #55 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #56 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #57 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #58 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #59 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #60 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter (18134): #61 RenderObject.layout (package:flutter/src/rendering/object.dart:1632:7)
I/flutter (18134): #62 RenderView.performLayout (package:flutter/src/rendering/view.dart:151:13)
I/flutter (18134): #63 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1507:7)
I/flutter (18134): #64 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:766:18)
I/flutter (18134): #65 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:329:19)
I/flutter (18134): #66 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:701:13)
I/flutter (18134): #67 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:268:5)
I/flutter (18134): #68 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:988:15)
I/flutter (18134): #69 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:928:9)
I/flutter (18134): #70 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:749:7)
I/flutter (18134): #72 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:382:19)
I/flutter (18134): #73 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
I/flutter (18134): #74 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
I/flutter (18134): (elided one frame from package dart:async)
I/flutter (18134):
I/flutter (18134): The following RenderObject was being processed when the exception was fired:
I/flutter (18134): RenderViewport#85bc5 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (18134): creator: Viewport ← IgnorePointer-[GlobalKey#ddac3] ← Semantics ← Listener ← _GestureSemantics ←
I/flutter (18134): RawGestureDetector-[LabeledGlobalKey<RawGestureDetectorState>#142b9] ← _ScrollableScope ←
I/flutter (18134): _ScrollSemantics-[GlobalKey#1902d] ← RepaintBoundary ← CustomPaint ← RepaintBoundary ←
I/flutter (18134): NotificationListener<ScrollNotification> ← ⋯
I/flutter (18134): parentData: <none> (can use size)
I/flutter (18134): constraints: BoxConstraints(0.0<=w<=411.4, 0.0<=h<=Infinity)
I/flutter (18134): size: MISSING
I/flutter (18134): axisDirection: down
I/flutter (18134): crossAxisDirection: right
I/flutter (18134): offset: ScrollPositionWithSingleContext#06797(offset: 0.0, range: null..null, viewport: null,
I/flutter (18134): ScrollableState, AlwaysScrollableScrollPhysics -> ClampingScrollPhysics, IdleScrollActivity#c3663,
I/flutter (18134): ScrollDirection.idle)
I/flutter (18134): anchor: 0.0
I/flutter (18134): This RenderObject had the following descendants (showing up to depth 5):
I/flutter (18134): RenderSliverPadding#e7182 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (18134): RenderSliverList#6b5c0 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (18134): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderViewport#85bc5 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderViewport#85bc5 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderIgnorePointer#c5ace relayoutBoundary=up9 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderSemanticsAnnotations#f4095 relayoutBoundary=up8 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderPointerListener#1d571 relayoutBoundary=up7 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderSemanticsGestureHandler#5cee1 relayoutBoundary=up6 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: _RenderScrollSemantics#1f2eb relayoutBoundary=up5 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderRepaintBoundary#70e3d relayoutBoundary=up4 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderCustomPaint#b103f relayoutBoundary=up3 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderRepaintBoundary#4b75f relayoutBoundary=up2 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: RenderBox was not laid out: RenderFlex#aaf3d relayoutBoundary=up1 NEEDS-PAINT
I/flutter (18134): Another exception was thrown: NoSuchMethodError: The method '<=' was called on null.
Reloaded 2 of 573 libraries in 1,622ms.
最佳答案
当 listview 和 Column 小部件扩展以匹配高度时，您必须给父级 Container 高度他们的 parent ，在你的情况下是 Container。如果你没有任何特定的尺寸，请尝试使用 MediaQuery 给它屏幕高度:
body: new Container(
height: MediaQuery.of(context).size.height, // This will make the size of it the same as the device screen
child: new FutureBuilder<DeckCardResponse>(
future: fetchDecksFromFirebase(),
builder: (context, snapshot) {
if (snapshot.hasData) {
return new CardPage(snapshot.data.getDecks());
}
else if (snapshot.hasError) {
return new MessageError(499);
}
return new CircularProgressIndicator(strokeWidth: 5.0);
}),
)
关于dart - Flutter - 在同一页面上添加卡片和文本列表后出现异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55327833/
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