本文介绍了使用DropdownButton小部件时，RenderFlex在右侧被无穷大像素溢出的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
当我创建一个下拉按钮小部件时，出现此错误，提示RenderFlex被右侧的Infinity像素溢出。
的源代码为：
import‘package：flutter / material.dart’;
类测试扩展了StatefulWidget {
@override
_testState createState（）=> _testState（）;
}
class _testState扩展State< test> {
//性别
List< DropdownMenuItem< int>> sexList = [];
void femaleLoad（）{
sexList.add（new DropdownMenuItem（child：new Text（ Male），value：1，））;
femaleList.add（new DropdownMenuItem（child：new Text（ Female），value：2，））;
}
//性别结束
@override
小部件build（BuildContext context）{
sexLoad（）;
return Scaffold（
body：new Container（
child：new Center（
child：new DropdownButton（items：sexList，onChanged：null），$ b $） b），
），
）；
}
}
构建程序后，我没有看到任何应用程序上的DropDownButton而不是控制台上的错误消息。
以下是错误消息：
执行热重启...
正在将文件同步到为x86构建的设备Android SDK ...
在5558毫秒内重新启动应用程序。
I / flutter（15333）：渲染库导致的异常╞═══ ══════════════════════════════════════════════════ ════
I / flutter（15333）：在performLayout（）期间引发了以下断言：
I / flutter（15333）：RenderIndexedStack对象在布局期间被赋予了无限大小。
I / flutter（15333）：这可能意味着它是一个试图尽可能大的渲染对象，但是它被放置在
I / flutter（15333）：另一个允许渲染的对象内它的孩子可以自己选择大小。
I / flutter（15333）：提供无限宽度约束的最接近祖先是：
I / flutter（15333）：RenderFlex＃9b57d relayoutBoundary = up7 NEEDS-LAYOUT NEEDS-PAINT
I / flutter（15333）：创建者：行←填充←容器←DefaultTextStyle←堆栈←侦听器←_GestureSemantics←
I / flutter（15333）：RawGestureDetector←GestureDetector←语义←DropdownButton< int> ←中心←⋯
I / flutter（15333）：parentData：offset = Offset（0.0，0.0）（可以使用大小）
I / flutter（15333）：约束：BoxConstraints（0.0< = w< ; = 411.4，0.0 I /颤振（15333）：大小：MISSING
I /颤振（15333）：方向：水平
I /颤振（15333） ）：mainAxisAlignment：spaceBetween
I / flutter（15333）：mainAxisSize：min
I / flutter（15333）：crossAxisAlignment：center
I / flutter（15333）：textDirection：ltr
I / flutter（15333）：verticalDirection：下降
I / flutter（15333）：应用于RenderIndexedStack的约束为：
I / flutter（15333）：BoxConstraints（0.0< = w< =无穷大，0.0 I /颤振（15333）：给出的确切大小为：
I / flutter（15333）：大小（Infinity，683.4）
I / flutter（15333）：有关更多信息，请参见https://flutter.io/layout/。
I / flutter（15333）：
I / flutter（15333）：引发异常时，堆栈为：
I / flutter（15333）：＃0 RenderBox.debugAssertDoesMeetConstraints。 <匿名闭包> （软件包：flutter / src / rendering / box.dart：1749：9）
I / flutter（15333）：＃1 RenderBox.debugAssertDoesMeetConstraints（软件包：flutter / src / rendering / box.dart：1823：6）
I / flutter（15333）：＃2 RenderBox.size =。<匿名闭包> （package：flutter / src / rendering / box.dart：1543：17）
I / flutter（15333）：＃3 RenderBox.size =（package：flutter / src / rendering / box.dart：1543：65 ）
I / flutter（15333）：＃4 RenderStack.performLayout（package：flutter / src / rendering / stack.dart：480：7）
I / flutter（15333）：＃5 RenderObject.layout （package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃6 RenderFlex.performLayout（package：flutter / src / rendering / flex.dart：738：15）
I / flutter（15333）：＃7 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃8 RenderPadding.performLayout（包：flutter / src / rendering / shifted_box.dart：199：11）
I / flutter（15333）：＃9 RenderObject.layout（包：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃10 RenderStack.performLayout（package：flutter / src / rendering / stack.dart：510：15）
I / flutter（15333）：＃11 RenderObject.layout（package ：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃12 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃13 RenderObject。布局（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃14 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box .dart：104：13）
I / flutter（15333）：＃15 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333） ：＃16 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃17 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃18 RenderPositionedBox.performLayout（package：flutter / src / rendering / shifted_box.dart：385：13）
I /颤振（153 33）：＃19 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃20 MultiChildLayoutDelegate.layoutChild（package：flutter / src / rendering / custom_layout.dart：142：11）
I / flutter（15333）：＃21 _ScaffoldLayout.performLayout（package：flutter / src / material / scaffold.dart：339：7）
I / flutter（15333 ）：＃22 MultiChildLayoutDelegate._callPerformLayout（package：flutter / src / rendering / custom_layout.dart：212：7）
I / flutter（15333）：＃23 RenderCustomMultiChildLayoutBox.performLayout（package：flutter / src / rendering / custom_layout .dart：356：14）
I / flutter（15333）：＃24 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333） ：＃25 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃26 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（ 15333）：＃27 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃28 _RenderCustomClip.performLayout（package： flutter / src / rendering / proxy_box.dart：1188：11）
I / flutter（15333）：＃29 RenderObject.layout（包：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃30 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃31 RenderObject .layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃32 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃33 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333 ）：＃34 _ RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃35 RenderObject.layout（package：flutter / src / renderinging /object.dart:1634:7）
I / flutter（15333）：＃36 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃37 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃38 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃39 RenderObject.layout（package：flutter / src / rendering / object.dart：1634） ：7）
I / flutter（15333）：＃40 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_b ox.dart：104：13）
I / flutter（15333）：＃41 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333 ）：＃42 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃43 RenderObject.layout（package：flutter /src/rendering/object.dart:1634:7）
I / flutter（15333）：＃44 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104： 13）
I / flutter（15333）：＃45 RenderOffstage.performLayout（package：flutter / src / rendering / proxy_box.dart：2881：13）
I / flutter（15333）：＃46 RenderObject。布局（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃47 RenderStack.performLayout（package：flutter / src / rendering / stack.dart：510：15 ）
I / flutter（15333）：＃48 RenderObject.layout（package：flutter / src / renderin g / object.dart：1634：7）
I / flutter（15333）：＃49 __RenderTheatre& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃50 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃51 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& ; RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃52 RenderObject.layout（package：flutter / src / rendering / object.dart： 1634：7）
I / flutter（15333）：＃53 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter （15333）：＃54 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃55 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMix in.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃56 RenderObject.layout（package：flutter / src / rendering / object.dart：1634 ：7）
I / flutter（15333）：＃57 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package：flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（ 15333）：＃58 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃59 _RenderProxyBox& RenderBox& RenderObjectWithChildMixin& RenderProxyBoxMixin.performLayout（package： flutter / src / rendering / proxy_box.dart：104：13）
I / flutter（15333）：＃60 RenderObject.layout（package：flutter / src / rendering / object.dart：1634：7）
I / flutter（15333）：＃61 RenderView.performLayout（package：flutter / src / rendering / view.dart：147：13）
I / flutter（15333）：＃62 RenderObject._layoutWithoutResize（package：flutter /src/rendering/object.dart:1509:7）
I / flutter（15333）：＃63 PipelineOwner.flushLayout（package：flutter / src / rendering / object.dart：768：18）
I / flutter（15333）：＃64 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& SchedulerBinding& PaintingBinding& SemanticsBinding& Renderer。 （包：flutter / src / rendering / binding.dart：281：19）
I / flutter（15333）：＃65 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& SchedulerBinding& PaintingBinding& SemanticsBinding& RendererBinding& WidgetsBinding。包：flutter / src / widgets / binding.dart：677：13）
I / flutter（15333）：＃66 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& SchedulerBinding& PaintingBinding& SemanticsBinding& RendererBindingFrame._handlePersistent /src/rendering/binding.dart:219:5）
I / flutter（15333）：＃67 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& Sched ulerBinding._invokeFrameCallback（包：flutter / src / scheduler / binding.dart：990：15）
I / flutter（15333）：＃68 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& SchedulerBinding.handleDrawFrame（包：flutter / src /scheduler/binding.dart:930:9）
I / flutter（15333）：＃69 _WidgetsFlutterBinding& BindingBase& GestureBinding& ServicesBinding& SchedulerBinding.scheduleWarmUpFrame。<匿名闭包> （包：flutter / src / scheduler / binding.dart：751：7）
I / flutter（15333）：＃71 _Timer._runTimers（dart：isolate / runtime / libtimer_impl.dart：382：19）
I / flutter（15333）：＃72 _Timer._handleMessage（dart：isolate / runtime / libtimer_impl.dart：416：5）
I / flutter（15333）：＃73 _RawReceivePortImpl._handleMessage（dart：isolate / runtime / libisolate_patch.dart：171：12）
I / flutter（15333）：（从dart：async包中删除了一帧）
I / flutter（15333）：
I / flutter（ 15333）：触发异常时正在处理以下RenderObject：
I / flutter（15333）：RenderIndexedStack＃d77d9 relayoutBoundary = up8 NEEDS-LAYOUT NEEDS-PAINT
I / flutter（15333）：创建者：IndexedStack←行←填充←容器←DefaultTextStyle←堆栈←侦听器←
I / flutter（15333）：_GestureSemantics←RawGestureDetector←GestureDetector←语义←DropdownButton< int> ←⋯
I / flutter（15333）：parentData：offset = Offset（0.0，0.0）; flex = null; fit = null（可以使用大小）
I / flutter（15333）：约束条件：BoxConstraints（0.0 I / flutter（15333） ）：size：Size（Infinity，683.4）
I / flutter（15333）：对齐方式：AlignmentDirectional.centerStart
I / flutter（15333）：textDirection：ltr
I / flutter（15333） ：适合：松散
I / flutter（15333）：溢出：剪辑
I / flutter（15333）：索引：null
I / flutter（15333）：此RenderObject没有子孙。
I / flutter（15333）：═══════════════════════════════════════ ══════════════════════════════════════════════════ ═══════════
I / flutter（15333）：引发了另一个异常：RenderFlex被右侧的Infinity像素溢出。
解决方案
设置
有一个打开的
When I created a drop-down button widget I got this error saying RenderFlex overflowed by Infinity pixels on the right.The source code is:
import 'package:flutter/material.dart';
class test extends StatefulWidget {
@override
_testState createState() => _testState();
}
class _testState extends State<test> {
//gender
List<DropdownMenuItem<int>> genderList = [];
void genderLoad(){
genderList.add(new DropdownMenuItem(child: new Text("Male"),value: 1,));
genderList.add(new DropdownMenuItem(child: new Text("Female"),value: 2,));
}
//end of gender
@override
Widget build(BuildContext context) {
genderLoad();
return Scaffold(
body: new Container(
child: new Center(
child: new DropdownButton(items: genderList, onChanged: null),
),
),
);
}
}
After I build the program I didn't see any DropDownButton on the app rather I got error message on the console.Below is the Error message:
Performing hot restart...Syncing files to device Android SDK built for x86...Restarted application in 5,558ms.
I/flutter (15333): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (15333): The following assertion was thrown during performLayout():
I/flutter (15333): RenderIndexedStack object was given an infinite size during layout.
I/flutter (15333): This probably means that it is a render object that tries to be as big as possible, but it was put
I/flutter (15333): inside another render object that allows its children to pick their own size.
I/flutter (15333): The nearest ancestor providing an unbounded width constraint is:
I/flutter (15333): RenderFlex#9b57d relayoutBoundary=up7 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (15333): creator: Row ← Padding ← Container ← DefaultTextStyle ← Stack ← Listener ← _GestureSemantics ←
I/flutter (15333): RawGestureDetector ← GestureDetector ← Semantics ← DropdownButton<int> ← Center ← ⋯
I/flutter (15333): parentData: offset=Offset(0.0, 0.0) (can use size)
I/flutter (15333): constraints: BoxConstraints(0.0<=w<=411.4, 0.0<=h<=683.4)
I/flutter (15333): size: MISSING
I/flutter (15333): direction: horizontal
I/flutter (15333): mainAxisAlignment: spaceBetween
I/flutter (15333): mainAxisSize: min
I/flutter (15333): crossAxisAlignment: center
I/flutter (15333): textDirection: ltr
I/flutter (15333): verticalDirection: down
I/flutter (15333): The constraints that applied to the RenderIndexedStack were:
I/flutter (15333): BoxConstraints(0.0<=w<=Infinity, 0.0<=h<=683.4)
I/flutter (15333): The exact size it was given was:
I/flutter (15333): Size(Infinity, 683.4)
I/flutter (15333): See https://flutter.io/layout/ for more information.
I/flutter (15333):
I/flutter (15333): When the exception was thrown, this was the stack:
I/flutter (15333): #0 RenderBox.debugAssertDoesMeetConstraints.<anonymous closure> (package:flutter/src/rendering/box.dart:1749:9)
I/flutter (15333): #1 RenderBox.debugAssertDoesMeetConstraints (package:flutter/src/rendering/box.dart:1823:6)
I/flutter (15333): #2 RenderBox.size=.<anonymous closure> (package:flutter/src/rendering/box.dart:1543:17)
I/flutter (15333): #3 RenderBox.size= (package:flutter/src/rendering/box.dart:1543:65)
I/flutter (15333): #4 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:480:7)
I/flutter (15333): #5 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #6 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:738:15)
I/flutter (15333): #7 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #8 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:199:11)
I/flutter (15333): #9 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #10 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter (15333): #11 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #12 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #13 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #14 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #15 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #16 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #17 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #18 RenderPositionedBox.performLayout (package:flutter/src/rendering/shifted_box.dart:385:13)
I/flutter (15333): #19 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #20 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11)
I/flutter (15333): #21 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:339:7)
I/flutter (15333): #22 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7)
I/flutter (15333): #23 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14)
I/flutter (15333): #24 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #25 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #26 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #27 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #28 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1188:11)
I/flutter (15333): #29 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #30 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #31 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #32 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #33 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #34 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #35 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #36 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #37 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #38 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #39 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #40 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #41 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #42 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #43 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #44 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #45 RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:2881:13)
I/flutter (15333): #46 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #47 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter (15333): #48 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #49 __RenderTheatre&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #50 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #51 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #52 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #53 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #54 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #55 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #56 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #57 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #58 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #59 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter (15333): #60 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter (15333): #61 RenderView.performLayout (package:flutter/src/rendering/view.dart:147:13)
I/flutter (15333): #62 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1509:7)
I/flutter (15333): #63 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:768:18)
I/flutter (15333): #64 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:281:19)
I/flutter (15333): #65 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:677:13)
I/flutter (15333): #66 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:219:5)
I/flutter (15333): #67 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:990:15)
I/flutter (15333): #68 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:930:9)
I/flutter (15333): #69 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:751:7)
I/flutter (15333): #71 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:382:19)
I/flutter (15333): #72 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
I/flutter (15333): #73 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
I/flutter (15333): (elided one frame from package dart:async)
I/flutter (15333):
I/flutter (15333): The following RenderObject was being processed when the exception was fired:
I/flutter (15333): RenderIndexedStack#d77d9 relayoutBoundary=up8 NEEDS-LAYOUT NEEDS-PAINT
I/flutter (15333): creator: IndexedStack ← Row ← Padding ← Container ← DefaultTextStyle ← Stack ← Listener ←
I/flutter (15333): _GestureSemantics ← RawGestureDetector ← GestureDetector ← Semantics ← DropdownButton<int> ← ⋯
I/flutter (15333): parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
I/flutter (15333): constraints: BoxConstraints(0.0<=w<=Infinity, 0.0<=h<=683.4)
I/flutter (15333): size: Size(Infinity, 683.4)
I/flutter (15333): alignment: AlignmentDirectional.centerStart
I/flutter (15333): textDirection: ltr
I/flutter (15333): fit: loose
I/flutter (15333): overflow: clip
I/flutter (15333): index: null
I/flutter (15333): This RenderObject has no descendants.
I/flutter (15333): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (15333): Another exception was thrown: A RenderFlex overflowed by Infinity pixels on the right.
解决方案
set isExpanded: true. And give its Container a proper height (e.g. 48), or set isDense: true or do not pass a null onChanged event or a null list of items, but if you want to disable the widget for any reason (user have not to click on it) I guess that setting the former conditions allow to do all you want.
class _testState extends State<test> {
//gender
List<DropdownMenuItem<int>> genderList = [];
void genderLoad() {
genderList.clear();
genderList.add(new DropdownMenuItem(
child: new Text("Male"),
value: 1,
));
genderList.add(new DropdownMenuItem(
child: new Text("Female"),
value: 2,
));
}
//end of gender
@override
Widget build(BuildContext context) {
genderLoad();
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text('hello'),
),
body: Container(
height: 48,
color: Colors.lightGreenAccent,
child: DropdownButton(
isDense: false,
isExpanded: true,
items: genderList,
onChanged: (selected){
print(selected);
})));
}
}
There is this open issue that makes DropDownButton widget not rendering when you pass empty values on required fields.
So that all these:
DropdownButton(items: [], onChanged: (int) {})DropdownButton(items: genderList, onChanged: null)DropdownButton(items: [], onChanged: null)
Have problems. A workaround is the one shown in this post.
return Scaffold(
body: new Container(
width: 48,
child: new Center(
child: new DropdownButton (
isExpanded: true,
items: [],
onChanged: null
),
),
),
);
这篇关于使用DropdownButton小部件时，RenderFlex在右侧被无穷大像素溢出的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！