Flutter:发布结束，退出代码为 255

Question

我正在通过构建运行器、json 模型和 json 可序列化为我的 flutter 应用程序制作模型。但是我得到了这个错误

Unhandled exception:
RangeError (index): Invalid value: Valid value range is empty: 0
#0      _StringBase.[] (dart:core-patch/string_patch.dart:247:55)
#1      changeFirstChar (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:89:41)
#2      getType (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:116:20)
#3      walk.<anonymous closure>.<anonymous closure> (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:62:23)
#4      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
#5      walk.<anonymous closure> (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:50:37)
#6      List.forEach (dart:core-patch/growable_array.dart:282:8)
#7      walk (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:38:8)
#8      main (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/json_model-0.0.2/bin/json_model.dart:18:6)
#9      _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:299:32)
#10     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
pub finished with exit code 255

在我的 pubspec.yaml 文件中，我在开发依赖项中添加了这些 flutter 包:

dev_dependencies:
  flutter_test:
    sdk: flutter
  json_model: ^0.0.2
  json_serializable:
  build_runner:

我要为其制作模型的 Json 文件:

第一个 json 文件

{
  "id": 1,
  "country": "Australia",
  "currencySymbol": "$"
}

第二个 Json 文件

{
  "currencylist": "$[]currency"
}

你能帮我看看我哪里做错了吗，为什么我在终端运行命令时会出现这个错误flutter packages pub run json_model。

Answer 1

这为时已晚，但有人可能会使用它，这对我有用:

我认为当您更改模型中的某些内容并重新运行时可能会发生这种情况

flutter pub run build_runner build

更新:

运行它，它将为您完成工作:

flutter pub run build_runner build  --delete-conflicting-outputs 

old : 所以首先尝试删除所有以

结尾的生成文件

XXX.g.dart

然后运行

flutter clean 

然后

flutter pub get

最后

flutter pub run build_runner build