无法从 pubspec.yaml 导入“包”

Question

运行“flutter pud upgrade”后，我所有的导入都抛出错误。 '错误 • URI 目标不存在：'package:provider/provider.dart' • lib/main.dart:2:8 • uri_does_not_exist 我认为这是我的应用程序错误，但我能够使用计数器应用程序。 截屏：

这是 flutter run --verbose 的输出

descobar@davids-mbp flutter_app_123 % flutter run --verbose
[  +19 ms] executing: [/Users/descobar/Downloads/flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[  +33 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[        ] 27321ebbad34b0a3fafe99fac037102196d655ff
[        ] executing: [/Users/descobar/Downloads/flutter/] git describe --match v*.*.* --first-parent --long --tags
[  +14 ms] Exit code 0 from: git describe --match v*.*.* --first-parent --long --tags
[        ] v1.12.13+hotfix.5-0-g27321ebba
[   +7 ms] executing: [/Users/descobar/Downloads/flutter/] git rev-parse --abbrev-ref --symbolic @{u}
[  +12 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
[        ] origin/stable
[        ] executing: [/Users/descobar/Downloads/flutter/] git ls-remote --get-url origin
[  +11 ms] Exit code 0 from: git ls-remote --get-url origin
[        ] https://github.com/flutter/flutter.git
[  +65 ms] executing: [/Users/descobar/Downloads/flutter/] git rev-parse --abbrev-ref HEAD
[  +15 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[        ] stable
[   +6 ms] executing: sw_vers -productName
[  +16 ms] Exit code 0 from: sw_vers -productName
[        ] Mac OS X
[        ] executing: sw_vers -productVersion
[  +17 ms] Exit code 0 from: sw_vers -productVersion
[        ] 10.15.2
[        ] executing: sw_vers -buildVersion
[  +19 ms] Exit code 0 from: sw_vers -buildVersion
[        ] 19C57
[  +37 ms] executing: /usr/bin/xcode-select --print-path
[   +8 ms] Exit code 0 from: /usr/bin/xcode-select --print-path
[        ] /Applications/Xcode.app/Contents/Developer
[   +1 ms] executing: /usr/bin/xcodebuild -version
[ +106 ms] Exit code 0 from: /usr/bin/xcodebuild -version
[   +2 ms] Xcode 11.3
           Build version 11C29
[  +56 ms] executing: /Users/descobar/Library/Android/sdk/platform-tools/adb devices -l
[   +6 ms] Exit code 0 from: /Users/descobar/Library/Android/sdk/platform-tools/adb devices -l
[        ] List of devices attached
[  +18 ms] executing: /Users/descobar/Downloads/flutter/bin/cache/artifacts/libimobiledevice/idevice_id -h
[  +54 ms] /usr/bin/xcrun simctl list --json devices
[  +94 ms] No supported devices connected.
[   +9 ms] "flutter run" took 473ms.

#0      throwToolExit (package:flutter_tools/src/base/common.dart:28:3)
#1      RunCommand.validateCommand (package:flutter_tools/src/commands/run.dart:289:7)
<asynchronous suspension>
#2      FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:590:11)
#3      FlutterCommand.run.<anonymous closure> (package:flutter_tools/src/runner/flutter_command.dart:515:33)
<asynchronous suspension>
#4      AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:146:29)
#5      _rootRun (dart:async/zone.dart:1126:13)
#6      _CustomZone.run (dart:async/zone.dart:1023:19)
#7      _runZoned (dart:async/zone.dart:1518:10)
#8      runZoned (dart:async/zone.dart:1465:12)
#9      AppContext.run (package:flutter_tools/src/base/context.dart:145:18)
#10     FlutterCommand.run (package:flutter_tools/src/runner/flutter_command.dart:505:20)
#11     CommandRunner.runCommand (package:args/command_runner.dart:197:27)
#12     FlutterCommandRunner.runCommand.<anonymous closure> (package:flutter_tools/src/runner/flutter_command_runner.dart:413:21)
<asynchronous suspension>
#13     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:146:29)
#14     _rootRun (dart:async/zone.dart:1126:13)
#15     _CustomZone.run (dart:async/zone.dart:1023:19)
#16     _runZoned (dart:async/zone.dart:1518:10)
#17     runZoned (dart:async/zone.dart:1465:12)
#18     AppContext.run (package:flutter_tools/src/base/context.dart:145:18)
#19     FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:364:19)
#20     CommandRunner.run.<anonymous closure> (package:args/command_runner.dart:112:25)
#21     new Future.sync (dart:async/future.dart:224:31)
#22     CommandRunner.run (package:args/command_runner.dart:112:14)
#23     FlutterCommandRunner.run (package:flutter_tools/src/runner/flutter_command_runner.dart:250:18)
#24     run.<anonymous closure>.<anonymous closure> (package:flutter_tools/runner.dart:63:22)
#25     _rootRun (dart:async/zone.dart:1126:13)
#26     _CustomZone.run (dart:async/zone.dart:1023:19)
#27     _runZoned (dart:async/zone.dart:1518:10)
#28     runZoned (dart:async/zone.dart:1502:12)
#29     run.<anonymous closure> (package:flutter_tools/runner.dart:61:18)
<asynchronous suspension>
#30     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:146:29)
#31     _rootRun (dart:async/zone.dart:1126:13)
#32     _CustomZone.run (dart:async/zone.dart:1023:19)
#33     _runZoned (dart:async/zone.dart:1518:10)
#34     runZoned (dart:async/zone.dart:1465:12)
#35     AppContext.run (package:flutter_tools/src/base/context.dart:145:18)
#36     runInContext (package:flutter_tools/src/context_runner.dart:64:24)
#37     run (package:flutter_tools/runner.dart:50:10)
#38     main (package:flutter_tools/executable.dart:65:9)
#39     main (file:///Users/descobar/Downloads/flutter/packages/flutter_tools/bin/flutter_tools.dart:8:3)
#40     _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:305:32)
#41     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:174:12)

我尝试过的步骤。

1. 已删除 pubspec.lock 文件，运行 pub get
2. 重启 android studio 和笔记本电脑
3. 打开了一个新项目，问题在新项目中

Answer 1

问题已解决。以下是需要完成的步骤。

1. 卸载 Android Studio
2. 重新安装 Android Studio
3. 打开项目