Flutter 升级 v3.13 后运行当前项目出错答案

【问题标题】：Error run current project after flutter upgrade v3.13Flutter 升级 v3.13 后运行当前项目出错
【发布时间】：2020-11-26 13:36:23
【问题描述】：

flutter 升级 v3.13 后，我的 vscode 调试控制台中出现以下错误运行项目：

Invalid depfile: C:\Users\DIMAS\FlutterCode\skip\.dart_tool\flutter_build\35269fa8986c9ee7a9c97697217003ec\kernel_snapshot.d
Invalid depfile: C:\Users\DIMAS\FlutterCode\skip\.dart_tool\flutter_build\35269fa8986c9ee7a9c97697217003ec\kernel_snapshot.d
Error: Could not resolve the package 'characters' in 'package:characters/characters.dart'.
/C:/src/flutter/packages/flutter/lib/src/material/text_field.dart:9:8: Error: Not found: 'package:characters/characters.dart'
import 'package:characters/characters.dart';
       ^
/C:/src/flutter/packages/flutter/lib/widgets.dart:18:1: Error: Not found: 'package:characters/characters.dart'
export 'package:characters/characters.dart';
^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:10:8: Error: Not found: 'package:characters/characters.dart'
import 'package:characters/characters.dart';
       ^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:9:8: Error: Not found: 'package:characters/characters.dart'
import 'package:characters/characters.dart';
       ^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:88:26: Error: Type 'DiagnosticableMixin' not found.
class PictureStream with DiagnosticableMixin {
                         ^^^^^^^^^^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:192:44: Error: Type 'DiagnosticableMixin' not found.
abstract class PictureStreamCompleter with DiagnosticableMixin {
                                           ^^^^^^^^^^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:88:7: Error: The type 'DiagnosticableMixin' can't be mixed in.
class PictureStream with DiagnosticableMixin {
      ^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:192:16: Error: The type 'DiagnosticableMixin' can't be mixed in.
abstract class PictureStreamCompleter with DiagnosticableMixin {
               ^
/C:/src/flutter/packages/flutter/lib/src/material/text_field.dart:822:61: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
  int get _currentLength => _effectiveController.value.text.characters.length;
                                                            ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/material/text_field.dart:824:118: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
  bool get _hasIntrinsicError => widget.maxLength != null && widget.maxLength > 0 && _effectiveController.value.text.characters.length > widget.maxLength;
                                                                                                                     ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:244:64: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
       assert(obscuringCharacter != null && obscuringCharacter.characters.length == 1),
                                                               ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:361:35: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
    assert(value != null && value.characters.length == 1);
                                  ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:567:11: Error: 'Characters' isn't a type.
    final Characters remaining = string.characters.skipWhile((String currentString) {
          ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:567:41: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
    final Characters remaining = string.characters.skipWhile((String currentString) {
                                        ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:600:47: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
    for (final String currentString in string.characters) {
                                              ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/rendering/editable.dart:602:40: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
          !_isWhitespace(currentString.characters.first.toString().codeUnitAt(0))) {
                                       ^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:167:11: Error: Superclass has no method named 'debugFillProperties'.
    super.debugFillProperties(properties);
          ^^^^^^^^^^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:171:30: Error: The method 'toStringShort' isn't defined for the class 'PictureStreamCompleter'.
 - 'PictureStreamCompleter' is from 'package:flutter_svg/src/picture_stream.dart' ('/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart').
Try correcting the name to the name of an existing method, or defining a method named 'toStringShort'.
      ifPresent: _completer?.toStringShort(),
                             ^^^^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_svg-0.17.4/lib/src/picture_stream.dart:266:11: Error: Superclass has no method named 'debugFillProperties'.
    super.debugFillProperties(description);
          ^^^^^^^^^^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:355:11: Error: 'CharacterRange' isn't a type.
    final CharacterRange iterator = CharacterRange(value.text);
          ^^^^^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:355:37: Error: Method not found: 'CharacterRange'.
    final CharacterRange iterator = CharacterRange(value.text);
                                    ^^^^^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:356:20: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
    if (value.text.characters.length > maxLength) {
                   ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:375:61: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
    if (maxLength != null && maxLength > 0 && newValue.text.characters.length > maxLength) {
                                                            ^^^^^^^^^^
/C:/src/flutter/packages/flutter/lib/src/services/text_formatter.dart:378:25: Error: The getter 'characters' isn't defined for the class 'String'.
Try correcting the name to the name of an existing getter, or defining a getter or field named 'characters'.
      if (oldValue.text.characters.length == maxLength) {
                        ^^^^^^^^^^

Unhandled exception:
FileSystemException(uri=org-dartlang-untransla
table-uri:package%3Acharacters%2Fcharacters.dart; message=StandardFileSystem only supports file:* and data:* URIs)
[38;5;248m#0      StandardFileSystem.entityForUri  (package:front_end/src/api_prototype/standard_file_system.dart:33:7)[39;49m

[38;5;248m#1      asFileUri  (package:vm/kernel_front_end.dart:659:37)[39;49m
[38;5;248m#2      writeDepfile  (package:vm/kernel_front_end.dart:853:21)[39;49m
<asynchronous suspen
sion>
[38;5;248m#3      FrontendCompiler.compile  (package:frontend_server/frontend_server.dart:574:15)[39;49m
[38;5;244m<asynchronous suspension>[39;49m
#4      _FlutterFrontendCompiler.compile (packa
ge:flutter_frontend_server/server.dart:43:22)
[38;5;248m#5      starter  (package:flutter_frontend_server/server.dart:182:27)[39;49m

#6      main (file:///C:/b/s/w/ir/cache/builder/src/flut
ter/flutter_frontend_server/bin/starter.dart:9:30)
[38;5;244m#7      _startIsolate.<anonymous closure>  (dart:isolate-patch/isolate_patch.dart:299:32)[39;49m
#8      _RawReceivePortImpl
._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)

FAILURE：构建失败并出现异常。

在哪里：脚本 'C:\src\flutter\packages\flutter_tools\gradle\flutter.gradle' 行：896
出了什么问题：任务 ':app:compileFlutterBuildDebug' 执行失败。

Process 'command 'C:\src\flutter\bin\flutter.bat'' 以非零退出值 1 结束

尝试：使用 --stacktrace 选项运行以获取堆栈跟踪。使用 --info 或 --debug 选项运行以获得更多日志输出。运行 --scan 以获得完整的见解。
通过https://help.gradle.org获得更多帮助

在 57 秒内构建失败异常：Gradle 任务 assembleDebug 失败，退出代码为 1

它似乎缺少 character.dart 和一些 gradle 的东西，但我现在在谷歌上找不到确切的问题和答案，

但是，如果我创建并运行一个新项目，它没有任何错误，我的 pubspec.yaml （我已经比较了旧项目和新项目 pubspec.yaml 没有显着不同的附加包除外）：

【问题讨论】：

标签： flutter dart

【解决方案1】：

您的 pubspec.yaml 中似乎缺少字符包。

确保它存在并且您的 pubspec 格式正确。然后再次运行flutter pub get。

如果失败，您应该运行flutter pub cache repair

【讨论】：

【解决方案2】：

有同样的问题。

在 pubspec.yaml 中只需执行 flutter pub get 和 flutter pub upgrade。

然后在根目录下终端执行flutter clean就可以正常运行了。

【讨论】：

【解决方案3】：

在更新 Flutter SDK 后，我的 Flutter 应用程序也遇到了类似的问题。

解决我的问题的方法是执行以下操作。

打开一个终端 (CMD) 导航到您的颤振项目，即 pubspec.yaml 所在的位置。运行以下命令：

解决方案

flutter pub get

flutter pub upgrade

之后，如果您仍然有问题，您可以运行 flutter pub cache repair，但是

flutter clean

帮我解决了这个问题。

可以肯定的是，我重新启动了 Visual Studio 和 AVD 虚拟设备重新开始。

我使用什么工具和软件：

Visual Studio 代码 1.47.3

Android Studio 4.0.1（Android 虚拟设备）

Flutter 1.20.1（发布日期 6.8.2020）

飞镖 2.9.0

【讨论】：

【解决方案4】：

刷新flutter pub get 后，我遇到了错误的SVG 问题，我将flutter_svg: ^0.17.4 更新为flutter_svg: ^0.18.0 它解决了SVG 问题，

【讨论】：

【解决方案5】：

在新的 Flutter 版本上运行 flutter upgrade 后，我曾多次遇到此问题。就我而言，解决方案与错误无关。只是过时的依赖项。

我首先做了flutter clean（来自工具>Flutter>Flutter clean 的 IntelliJ/Android Studio。）

将我的 pubspec.yaml 依赖项更新到最新版本并运行 flutter pub upgrade

完成！现在你应该可以构建和运行了

【讨论】：

【解决方案6】：

在终端尝试

$     flutter clean

之后

$     flutter doctor

应该可以解决你的问题

【讨论】：

【解决方案7】：

我遇到了同样的问题，删除.dart_tool目录/文件夹并再次运行应用程序后，问题解决了

【讨论】：