Flutter升级后遇TextTheme及MediaQuery相关依赖错误求助

问题现象 #

升级Flutter到最新版本后出现以下编译错误：

• TextTheme类未定义subtitle1/subtitle2 getter
• Scrollbar无isAlwaysShown参数
• MediaQuery.boldTextOverride成员未找到

具体错误日志：

/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/dropdown_search-2.0.1/lib/dropdown_search.dart:491:46: Error: The getter 'subtitle2' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart'
 ('/C:/src/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 'subtitle2'.
          style: Theme.of(context).textTheme.subtitle2,
                                             ^^^^^^^^^
/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/dropdown_search-2.0.1/lib/dropdown_search.dart:515:46: Error: The getter 'subtitle1' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart'
 ('/C:/src/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 'subtitle1'.
          style: Theme.of(context).textTheme.subtitle1);
                                             ^^^^^^^^^
/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/dropdown_search-2.0.1/lib/src/popupMenu.dart:193:25: Error: The
getter 'subtitle1' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart'
 ('/C:/src/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 'subtitle1'.
        theme.textTheme.subtitle1;
                        ^^^^^^^^^
/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/dropdown_search-2.0.1/lib/src/selection_widget.dart:221:31:
Error: No named parameter with the name 'isAlwaysShown'.
                              isAlwaysShown:
                              ^^^^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/material/scrollbar.dart:87:9: Context: Found this candidate, but the arguments
don't match.
  const Scrollbar({
        ^^^^^^^^^
/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/dropdown_search-2.0.1/lib/src/selection_widget.dart:723:48:
Error: The getter 'subtitle1' isn't defined for the class 'TextTheme'.
 - 'TextTheme' is from 'package:flutter/src/material/text_theme.dart'
 ('/C:/src/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 'subtitle1'.
            style: Theme.of(context).textTheme.subtitle1,
                                               ^^^^^^^^^
/C:/Users/AppData/Local/Pub/Cache/hosted/pub.dev/fl_chart-0.55.2/lib/src/utils/utils.dart:257:20: Error: Member
not found: 'MediaQuery.boldTextOverride'.
    if (MediaQuery.boldTextOverride(context)) {
                   ^^^^^^^^^^^^^^^^

根本原因 #

错误全部来自第三方依赖包版本过低，dropdown_search:2.0.1和fl_chart:0.55.2的内部代码使用了Flutter已废弃/移除的API，与最新版Flutter不兼容。你之前尝试的删除Android文件夹重建、更新Material Theme等操作仅针对项目自身代码，无法解决第三方包的内部问题。

解决方案 #

方案1：升级第三方依赖包（推荐） #

1. 打开项目根目录的pubspec.yaml文件，找到对应依赖的版本声明。
2. 将版本号更新为当前最新的稳定版：

   dependencies:
     dropdown_search: ^5.0.6
     fl_chart: ^0.65.0
   

3. 执行以下命令更新依赖：

   flutter pub upgrade
   

4. 若更新后仍有缓存问题，可清理缓存后重新获取：

   flutter pub cache clean
   flutter pub get
   

方案2：临时兼容修复（不推荐长期使用） #

如果因特殊原因无法升级包，可通过修改第三方包代码临时兼容：

• 将TextTheme.subtitle1替换为TextTheme.bodyLarge，TextTheme.subtitle2替换为TextTheme.bodyMedium（Flutter 3.0+后文本样式API变更）
• 将Scrollbar(isAlwaysShown: true)替换为Scrollbar(thumbVisibility: true)（参数名变更）
• 将MediaQuery.boldTextOverride(context)替换为MediaQuery.of(context).boldText（静态方法移除）

内容的提问来源于stack exchange，提问作者sonalika