从另一个 dart.file (Flutter) 导入和调用 Class 的代码有什么区别

Question

1) As you can see I'm practicing flutter bloc pattern. There are lots of imports here. What is difference between them? ( package:bloc/bloc.dart)(bloc.dart)(package:test1/bloc.dart) test1 is my project name.

2) And I try to call Bloc Class which is in the bloc.dart file. But it says Bloc() isn't a function. What should I do?

also my bloc.dart file:

Answer 1

There is no pratical difference between packages imports and relative imports, but packages imports are prefered for code legibility and organization. Also, relative imports tend to be a pain when you change a file from place and have to rename all the imports.

You "can" use both kinds of imports for the same file cause Dart treats them as 2 different namespaces but that will probably lead to bugs, probably that is what is causing your error.

Regarding the BLoC pattern, it seems that you are using a the pure core of BLoC, I recommend you to study the implementation of flutter_bloc (which is made by the BLoC team). It's the way that BLoC is used more often. There is also a great documentation by the BLoC team in here .