我正在开发一个flutter应用程序。我想添加两种不同的风格，以分离出一些特定于风格的功能。我已经遵循了this文档。这里是我的pubspec.yaml文件。

name: flutter_app
version: 1.0.20+20

environment:
  sdk: ">=2.3.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  provider: ^4.0.1
  cupertino_icons: ^0.1.2
  intl: ^0.16.0
  shared_preferences:
  http: ^0.12.0+4
  sqflite: ^1.2.0
  path_provider:
  permission_handler: ^4.1.0
  package_info: ^0.4.0+18
  flutter_localizations:
    sdk: flutter
  #flutter_local_notifications: ^0.7.1+1
  #firebase_messaging: ^5.0.1+1
  #fluttertoast: ^3.1.0

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_flavorizr: ^1.0.7

flavorizr:
  app:
    android:
      flavorDimensions: "flavor-type"
    ios:

  flavors:
    mainapp:
      app:
        name: "Main App"

      android:
        applicationId: "com.example.app1"

      ios:
        bundleId: "com.example.app1"

    banana:
      master:
        name: "App Master"

      android:
        applicationId: "com.example.app2"
      ios:
        bundleId: "com.example.app2"

flutter:
  uses-material-design: true
  assets:
    - assets/
    - assets/fonts/
    - assets/drawables/
    - assets/icon/
    - assets/lang/en.json
    - assets/lang/de.json
    - assets/lang/de-DE.json
    - assets/lang/de-CH.json
    - assets/lang/de-AT.json
    - assets/lang/en-IN.json

  fonts:
    - family: Poppins-Bold
      fonts:
        - asset: assets/fonts/Poppins-Bold.ttf
    - family: Poppins-Medium
      fonts:
        - asset: assets/fonts/Poppins-Medium.ttf

字符串
在运行flutter pub run flutter_flavorizr后，我得到以下错误。

The following fields were missing: [app]. Read the docs for further details
Unhandled exception:
NoSuchMethodError: The getter 'flavorizr' was called on null.
Receiver: null
Tried calling: flavorizr
       Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
       Processor._initAvailableProcessors (package:flutter_flavorizr/processors/processor.dart:110:18)
       new Processor (package:flutter_flavorizr/processors/processor.dart:88:5)
       execute (package:flutter_flavorizr/flutter_flavorizr.dart:52:25)
       main (file:///D:/Users/Dhaval/Flutter/.pub-cache/hosted/pub.dartlang.org/flutter_flavorizr-1.0.7/bin/flutter_flavorizr.dart:4:3)
       _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:299:32)
       _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
pub finished with exit code 255

型
我错过了什么吗？我如何解决这个问题？任何帮助都表示感谢。谢谢。