Angular Dart教程第4部分-“未解决的未来”

Question

Total newbie to Dart and Angular. Long-time SW developer with a lot of experience with multiple languages and platforms.

I'm working through the 'Tour of Heroes' tutorial, but am stumped in section 4. , under the heading 'The Hero Service returns a Future'.

Thus far, I've gotten things to work pretty well, but now when I try to mod the code to return a future (per the tutorial), I get an error.

In hero_service.dart, this:

Future<List<Hero>> getHeroes() async => mockHeroes;

and in app_component.dart, this:

  Future<Null> getHeroes() async {
     heroes = await _heroService.getHeroes();
     }

But, I'm getting this error:

EXCEPTION: 'package:Tour_Of_Heroes/app_component.dart': malformed type: line 
            86 pos 3: cannot resolve class 'Future' from 'AppComponent'
            Future<Null> getHeroes() async {
            ^

I've backed it out and re-entered everything to make sure I've entered everything correctly and still getting the error.

I'm wondering if something in the core was refactored and I need to import something else or clean the build (not sure how to do that...) to get it fresh or what.

(BTW: Doing everything from the CL and VIM. Webstorm was a disaster...)

Answer 1

Remember to add import 'dart:async'; ? (The library that Future is in.)