我试图在Flutter项目中运行我的.dart文件，以了解Flutter应用程序中的SQlite数据库是如何工作的。当我执行我的.dart文件时，就出现了这个错误。
C:\Users\ChangNoi\Desktop\GitHub\project_fight_2\lib\backend>dart database.dart
database.dart: Warning: Interpreting this as package URI,'package:projectfight2/backend/database.dart'.
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/binary_messenger.dart:7:8: Error: Notfound: 'dart:ui'
import 'dart:ui' as ui;
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/binding.dart:7:8: Error: Not found: 'dart:ui'
import 'dart:ui' as ui;
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/font_loader.dart:7:8: Error: Not found: 'dart:ui'
import 'dart:ui';
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/platform_messages.dart:7:8: Error: Not found: 'dart:ui'
import 'dart:ui' as ui;
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/platform_views.dart:7:8: Error: Not found: 'dart:ui'
import 'dart:ui';
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/raw_keyboard.dart:7:8: Error: Not found: 'dart:ui'
import 'dart:ui';
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/system_channels.dart:5:8: Error: Not found: 'dart:ui'
import 'dart:ui';
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/system_chrome.dart:6:8: Error: Not found: 'dart:ui'
import 'dart:ui';
^
/C:/Program%20Files/Flutter/packages/flutter/lib/src/services/system_chrome.dart:12:1: Error: Not found: 'dart:ui'
export 'dart:ui' show Brightness;
我不确定为什么在多次重启IDE和运行flutter pub get之后，这个错误仍然持续出现。
以下是我的flutter doctor的完整结果：
[√] Flutter (Channel master, 1.19.0-2.0.pre.143, on Microsoft Windows [Version 10.0.18362.836], locale en-US)
• Flutter version 1.19.0-2.0.pre.143 at C:\Program Files\Flutter
• Framework revision 9d58a87066 (5 hours ago), 2020-05-22 22:37:01 -0700
• Engine revision 9ce1e5c5c7
• Dart version 2.9.0 (build 2.9.0-10.0.dev 7706afbcf5)
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
• Android SDK at C:\Users\ChangNoi\AppData\Local\Android\sdk
• Platform android-29, build-tools 29.0.3
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
• All Android licenses accepted.
[√] Android Studio (version 3.6)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 45.1.1
• Dart plugin version 192.8052
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
[√] VS Code, 64-bit edition (version 1.45.1)
• VS Code at C:\Program Files\Microsoft VS Code
• Flutter extension version 3.10.2
[√] Connected device (1 available)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 7.1.1 (API 25) (emulator)
lib文件夹并运行flutter run命令。 - JideGuru