Flutter packages get failed

错误出处：

Flutter Docs--Write your first app

具体错误信息：

Running "flutter packages get" in startup_namer...
The setter 'readEventsEnabled=' was called on null.
Receiver: null
Tried calling: readEventsEnabled=false
package:pub/src/source/hosted.dart 344                                                   BoundHostedSource._throwFriendlyError
package:pub/src/source/hosted.dart 144                                                   BoundHostedSource.doGetVersions
===== asynchronous gap ===========================
package:pub/src/source.dart 168                                                          BoundSource.getVersions
package:pub/src/solver/package_lister.dart 76                                            PackageLister._versions.<fn>.<fn>
dart:async                                                                               runZoned
package:pub/src/http.dart 275                                                            withDependencyType
package:pub/src/solver/package_lister.dart 75                                            PackageLister._versions.<fn>
===== asynchronous gap ===========================
dart:async                                                                               new Future.sync
package:async/src/async_memoizer.dart 43                                                 AsyncMemoizer.runOnce
package:pub/src/solver/package_lister.dart 74                                            PackageLister._versions
package:pub/src/solver/package_lister.dart 111                                           PackageLister.countVersions
===== asynchronous gap ===========================
package:pub/src/solver/version_solver.dart 355                                           VersionSolver._choosePackageVersion.<fn>
===== asynchronous gap ===========================
package:pub/src/utils.dart 309                                                           minByAsync
===== asynchronous gap ===========================
package:pub/src/solver/version_solver.dart 351                                           VersionSolver._choosePackageVersion
===== asynchronous gap ===========================
package:pub/src/solver/version_solver.dart 98                                            VersionSolver.solve
===== asynchronous gap ===========================
package:pub/src/solver.dart 35                                                           resolveVersions.<fn>
package:pub/src/log.dart 378                                                             progress
package:pub/src/solver.dart 32                                                           resolveVersions
package:pub/src/entrypoint.dart 193                                                      Entrypoint.acquireDependencies
===== asynchronous gap ===========================
package:pub/src/command/get.dart 38                                                      GetCommand.run
package:args/command_runner.dart 194                                                     CommandRunner.runCommand
===== asynchronous gap ===========================
package:pub/src/command_runner.dart 168                                                  PubCommandRunner.runCommand.<fn>
dart:async                                                                               new Future.sync
package:pub/src/utils.dart 115                                                           captureErrors.<fn>
dart:async                                                                               runZoned
package:pub/src/utils.dart 134                                                           captureErrors
package:pub/src/command_runner.dart 168                                                  PubCommandRunner.runCommand
===== asynchronous gap ===========================
package:pub/src/command_runner.dart 117                                                  PubCommandRunner.run
===== asynchronous gap ===========================
/b/build/slave/Mac_Engine/build/src/third_party/dart/third_party/pkg/pub/bin/pub.dart 8  main
This is an unexpected error. Please run

    pub --trace --verbosity=warning get --no-precompile

and include the logs in an issue on https://github.com/dart-lang/pub/issues/new
pub get failed (1)

解决思路

1. 使用国内镜像

• 标准的国内镜像

export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn

• 上海交通大学镜像

export PUB_HOSTED_URL=https://dart-pub.mirrors.sjtug.sjtu.edu.cn
export FLUTTER_STORAGE_BASE_URL=https://mirrors.sjtug.sjtu.edu.cn 

2.使用终端代理

export http_proxy=http://127.0.0.1:54660
export https_proxy=http://127.0.0.1:54660

3. 偏方(用polipo建立一个http代理到socks5代理的中间转换)

docker run -d -p 8080:8123 clue/polipo proxyAddress=0.0.0.0
export http_proxy=http://127.0.0.1:8080
export https_proxy=http://127.0.0.1:8080

最后向帮助我的朋友表示感谢，也希望能帮到更多的人。

文章参考

https://github.com/flutter/flutter/wiki/Using-Flutter-in-China
https://www.jianshu.com/p/cdca06fcb828