在下面的代码中,textAlign属性无法工作。如果删除上面几个级别的DefaultTextStyle包装器,textAlign就会开始工作。
为什么和如何确保它总是有效的?
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildCon
Flutter当我使用ListTile ThreeLines时,我不知道如何使用ThreeLine
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp
我想要隐藏一个文本小部件可见性在一个按钮点击使用可见性小部件。我如何在Flutter中实现这一点?我已经创建了一个接受bool变量的函数,该变量定义了文本小部件的可见性。单击按钮时,我将调用该函数。第一次,文本显示给用户。但在单击按钮时,文本并不是不可见的。
//created a method to show and hide the text using visibility widget
hideTextVisibility(bool visibilityStatus){
return visibilityStatus? Visibility(
visible: visibilitySt
我目前正在尝试学习Flutter。我想创建一个像这样的Layout with side navigation bar and upper navigation bar in a row布局 我已经创建了一个类HomeScreen,它将包含行的侧边栏和上边栏。如下所示: @override
Widget build(BuildContext context) {
return Container(
child: Row(
children: <Widget>[
SideNav(),
RightCon
这是错误:
I/flutter ( 736): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 736): The following assertion was thrown during performResize():
I/flutter ( 736): Horizontal viewport was given unbounded height.
I/flutter ( 736): Viewports
为什么我的小部件会出现这个错误?
======== Exception caught by widgets library =======================================================
The following assertion was thrown building StreamBuilder<UserData>(dirty, state: _StreamBuilderBaseState<UserData, AsyncSnapshot<UserData>>#1e46f):
A build functio
我一直试图将中的一些代码移植到中,并且遇到了一些我似乎无法修复的像素溢出问题。
这是在VSCode调试控制台中引发的错误;
flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
flutter: The following assertion was thrown during performLayout():
flutter: 'package:flutter/src/rendering/object.dart'
我想将可用的设备写在如下所示的图像下: ? 如果我删除图像部分,我只得到可用的设备,但我需要在BLE设备上添加图像。 但是如果我运行我的代码,我会得到一个错误: Performing hot reload...
Syncing files to device Redmi Note 8 Pro...
════════ Exception caught by rendering library ═════════════════════════════════════════════════════
The following assertion was thrown during per
在我的flutter项目中,我初始化了一个Row。在其中,我在一个列中创建了一些文本,在那之后,我想添加一行,但它没有显示任何内容。出于这个原因,我使用了扩展,并遵循给定的解决方案- Horizontal divider with text in the middle in Flutter? 但它们也都不起作用。 这是我的代码输出的图像- ? 这是我的代码- Container(
color:Colors.white,
child: (
Row(
children: <Widget>[
P
我创建了一个自定义的ListTile,它应该在中间有两个分数,在这个()的左边和右边有信息。
左边的信息可以有任意的长度,当它太长时应该使用TextOverflow.ellipsis。我不能让它工作,因为文本似乎不知道它应该具有的宽度和溢出。我已经尝试过将文本小部件包装成SizedBox、扩展等,但都不起作用。
flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
flutter: The following me
我试图创建一个ListView,但是当我导入list_form.dart类时,我会得到这个错误。也许我在布局上犯了一些错误,因为如果我试图在主文件中运行它,我就不会得到这个错误。
这是一个错误:
I/flutter (12956): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (12956): The following assertion was thrown during performResize():
我的应用程序有一个页面,其中只包含一个包含Column的Card,其末尾是一个MaterialList。即使我的列表只有一两个项目,卡片也会将其垂直空间延伸到屏幕底部,而不是停在列表项目的末尾。建议这是正常的列行为(“将每个子元素设置为空或零弹性因子(例如,那些未展开的元素),并具有无界的垂直约束”)。我认为将列表包装在Flexible中可能会达到预期的效果,但当我尝试时,我得到了以下错误:
RenderFlex children have non-zero flex but incoming height constraints are unbounded.
I/flutter (11469
我希望将我的ListView.seperated添加到列中,以便在加载更多项时,可以在此ListvView下面添加CircularProgressIndicator。我使用了来自的建议,使结构列->扩展了-> ListVie,但是我得到了错误,无法加载列表:
======== Exception caught by rendering library =====================================================
RenderBox was not laid out: RenderRepaintBoundary#e8fad NEEDS-L
我想在左边显示一个GridView,在右边显示一个ExpansionPanelList。我把它们放在一个Row Widget中,但是它没有工作,错误是:
Assertion failed:
D:\…\rendering\box.dart:1929
hasSize
"RenderBox was not laid out: RenderRepaintBoundary#bb5e9 NEEDS-LAYOUT NEEDS-PAINT"
The relevant error-causing widget was
Row
lib\main.dart:69
这是我在main.dart中的所有