小编Vin*_*ois的帖子

我是 Flutter 的新手，也是 Bloc 的新手。

编译代码时出现错误：

    The following assertion was thrown building Login(dirty, state: _LoginFormState#44e7f):
         BlocProvider.of() called with a context that does not contain a Bloc of type BtnBloc.
         No ancestor could be found starting from the context that was passed to
         BlocProvider.of<BtnBloc>().
       This can happen if the context you use comes from a widget above the BlocProvider.
         This can also happen if you used BlocProviderTree and didn't explicity provide 
         the BlocProvider types: BlocProvider(bloc: BtnBloc()) instead of BlocProvider<BtnBloc>(bloc:
         BtnBloc()).
         The …