1.Dart_LoadScriptFromKernel: The binary program does not contain ‘main’
解決方案：保存一下（Ctrl+S），然後在code run，就OK了。
Error: No pubspec.yaml file found.
This command should be run from the root of your Flutter project.
Do not run this command from the root of your git clone of Flutter.
打開項目總文件夾運行，不要打開上一級目錄運行
D:\Projects\flutter\Demo\flutter_app> flutter run（ 項目名）這裏打開
D:\Projects\flutter\Demo> flutter run 不要在這裏打開