错误：没有为“TextTheme”类定义 getter“title”

Question

我去年开始学习flutter，创建了一个运行良好的小项目，直到现在才停止学习......

所以今天，将 flutter 更新到最新版本（2.5.0）并再次开始运行该项目后，在尝试再次运行它时遇到了此错误：

Launching lib\order_route.dart on ASUS X01BDA in debug mode...
Running Gradle task 'assembleDebug'...
/D:/progie/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_widgets-0.1.12/lib/src/tagged_text/tagged_text.dart:295:36: Error: No named parameter with the name 'nullOk'.
            MediaQuery.of(context, nullOk: true)?.textScaleFactor ??
                                   ^^^^^^
/D:/progie/flutter/packages/flutter/lib/src/widgets/media_query.dart:841:25: Context: Found this candidate, but the arguments don't match.
  static MediaQueryData of(BuildContext context) {
                        ^^
/D:/progie/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_widgets-0.1.12/lib/src/feature_discovery/src/overlay_widgets.dart:239:20: Error: The getter 'title' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart' ('/D:/progie/flutter/packages/flutter/lib/src/material/text_theme.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'title'.
      style: theme.title.copyWith(color: Colors.white),
                   ^^^^^
/D:/progie/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_widgets-0.1.12/lib/src/feature_discovery/src/overlay_widgets.dart:248:20: Error: The getter 'subhead' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart' ('/D:/progie/flutter/packages/flutter/lib/src/material/text_theme.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'subhead'.
      style: theme.subhead.copyWith(color: Colors.white70),
                   ^^^^^^^


FAILURE: Build failed with an exception.

* Where:
Script 'D:\progie\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1005

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command 'D:\progie\flutter\bin\flutter.bat'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 14s
Exception: Gradle task assembleDebug failed with exit code 1

我已经做了什么：

• 运行flutter doctor，一切正常
• 使缓存无效/重新启动
• pubspec.yaml 中的 Pub 升级

但根本没有帮助

我使用的是android studio 4.1版本

从错误来看，代码有 700 行左右，但我不知道哪个部分生成了上述错误，而且我什至没有在代码中使用 TextTheme 或 MediaQuery。

运行酒吧已过时：

Showing outdated packages.
[*] indicates versions that are not the latest available.

Package Name  Current    Upgradable  Resolvable  Latest   

direct dependencies: all up-to-date.

transitive dependencies:
async         *2.8.1     *2.8.1      *2.8.1      2.8.2    
characters    *1.1.0     *1.1.0      *1.1.0      1.2.0    
csslib        *0.16.2    *0.16.2     *0.16.2     0.17.0   
html          *0.14.0+4  *0.14.0+4   *0.14.0+4   0.15.0   
matcher       *0.12.10   *0.12.10    *0.12.10    0.12.11  
quiver        *2.1.5     *2.1.5      *2.1.5      3.0.1    

transitive dev_dependencies:
test_api      *0.4.2     *0.4.2      *0.4.2      0.4.3    
all dependencies are up-to-date.
Process finished with exit code 0

问题与上面的依赖关系有关吗？

任何帮助将非常感激，提前谢谢您！

Answer 1

在过去的一年里，flutter 发生了很多事情。升级到 2.5 意味着您的 flutter 项目将具有 null 安全性，并且您可能需要将任何依赖项更新到可能支持 null 安全性的最新版本。所以错误来自 flutter widgets 包。如果您检查https://pub.dev/packages/flutter_widgets，它会显示该软件包不再更新，因此它已过时，建议您使用可用的替代方案之一。