小编aeo*_*eon的帖子

我使用颤振框架，这部分代码使用操作“？”。但不明白

 if (state is WeatherLoaded) {
          final weather = state.weather;
          final themeBloc = BlocProvider.of<ThemeBloc>(context);
          themeBloc.dispatch(WeatherChanged(condition: weather.condition));

          _refreshCompleter?.complete();
          _refreshCompleter = Completer();

所有代码此链接