DioError [DioErrorType.DEFAULT]: type 'int' is not a subtype of type 'String' of 'value'

[joker-fu]

dio: 2.0.10

class RequestInterceptor extends Interceptor{

@OverRide
onRequest(RequestOptions options) {

var headers = {"x-access-from": Constants.X_ACCESS_FROM};
if (Constants.X_ACCESS_ROLE != null) {
  headers["x-access-role"] = Constants.X_ACCESS_ROLE;
}
if (Constants.X_ACCESS_TOKEN != null) {
  headers["x-access-token"] = Constants.X_ACCESS_TOKEN;
}

options.headers = headers;

return options;

}
}
写了个拦截器添加统一header报错了，请求头添加成功了。

I/flutter (13951): DioError [DioErrorType.DEFAULT]: type 'int' is not a subtype of type 'String' of 'value'#0 __InternalLinkedHashMap&_HashVMBase&MapMixin&_LinkedHashMapMixin.[]= (dart:collection/runtime/libcompact_hash.dart)
I/flutter (13951): #1 Dio._transformData (package:dio/src/dio.dart:782:22)
I/flutter (13951):
I/flutter (13951): #2 Dio._makeRequest (package:dio/src/dio.dart:692:26)
I/flutter (13951):
I/flutter (13951): #3 Dio._request.. (package:dio/src/dio.dart:672:22)
I/flutter (13951): #4 _RootZone.runUnary (dart:async/zone.dart:1379:54)
I/flutter (13951): #5 _FutureListener.handleValue (dart:async/future_impl.dart:129:18)
I/flutter (13951): #6 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:642:45)
I/flutter (13951): #7 Future._propagateToListeners (dart:async/future_impl.dart:671:32)
I/flutter (13951): #8 Future._complete (dart:async/future_impl.dart:476:7)
I/flutter (13951): #9 _SyncCompleter.complete (dart:async/future_impl.dart:51:12)
I/flutter (13951): #10 _AsyncAwaitCompleter.complete (dart:async/runtime/libasync_patch.dart:28:18)
I/flutter (13951): #11 _completeOnAsyncReturn
I/flutter (13951): null

[wendux]

1. 首先不建议在拦截器中直接覆盖options.headers，应该直接添加和修改，如：

options.headers["x-access-role"]=Constants.X_ACCESS_TOKEN;

2. 你这个问题应该是Map类型不对, 你可以在定义Map时显式指定类型：

 var headers = Map<String, dynamic> {"x-access-from": Constants.X_ACCESS_FROM};

如果是这个原因的话，自己好好调一下，下个断点，就应该能找到原因。。。

[joker-fu]

是的 覆盖是错误的 昨天就改了忘了回复了，但是能不能兼容呢

[wendux]

你这个主要是类型问题，如果保证前后key对应的value类型一致就没问题的。不建议覆盖是因为header中可能会有一些其他的字段，如dio全局header，覆盖了这些就没了。