小编Mar*_*uti的帖子

我有这两种方法来编写构造函数。className()和className._()

它们之间有什么区别，我什么时候应该使用哪个？

 class GlobalState{

      final Map<dynamic,dynamic> _data=<dynamic,dynamic>{};
      static GlobalState instance = new GlobalState._();

      GlobalState._();
    }
    //In Main Class 
       GlobalState _store=GlobalState.instance;

    and 

    class GlobalState{

      final Map<dynamic,dynamic> _data=<dynamic,dynamic>{};
      static GlobalState instance = new GlobalState();
    }
    //In Main Class 
       GlobalState _store=GlobalState();