颤振/飞镖get_It单件定位器方法失败

Question

我有一个简单的飞镖课如下：

import 'package:flutter/material.dart';

class UiUtils {
  // TEMPORARY FOR UNIT TEST PURPOSES ONLY
  int addition(int x, int y) {
    return x + y;
  }
}

（注意：上面是一个示例，实际类确实有不止那个temp函数。）

我的pubspec.yml文件包含以下内容：

dependencies:
  flutter:
    sdk: flutter
  flutter_localizations:
    sdk: flutter
  intl: ^0.17.0

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  get_it: ^7.1.3
  provider: ^6.0.1
  mockito: ^5.0.16

我有一个＜code＞依赖项定位器

import 'package:get_it/get_it.dart';
import 'package:quiz_test/utils/UiUtils.dart';

GetIt dependencyLocator = GetIt.instance;

void setupDependencyLocator() {
  //dependencyLocator.registerSingleton(() => UiUtils());
  dependencyLocator.registerFactory(() => UiUtils());
}

最后，在< code>main.dart中，我有以下内容:

void main() {
  setupDependencyLocator();
  runApp(MyApp());
}

（当然还有更多的代码）。

正如它所显示的，代码工作正常，但是如果我将dependancy _ locator文件从当前的工厂方法改为singleton(即注释掉一个以启用另一个)，我会得到以下错误:

[VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception: type '_ServiceFactory<() => UiUtils, void, void>' is not a subtype of type '_ServiceFactory<Object, dynamic, dynamic>' of 'value'
#0      _LinkedHashMapMixin.[]= (dart:collection-patch/compact_hash.dart)
#1      _GetItImplementation._register (package:get_it/get_it_impl.dart:844:35)
#2      _GetItImplementation.registerSingleton (package:get_it/get_it_impl.dart:587:5)
#3      setupDependencyLocator (package:quiz_test/utils/dependency_locator.dart:7:21)
#4      main (package:quiz_test/main.dart:13:3)
#5      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:145:25)
#6      _rootRun (dart:async/zone.dart:1428:13)
#7      _CustomZone.run (dart:async/zone.dart:1328:19)
#8      _runZoned (dart:async/zone.dart:1863:10)
#9      runZonedGuarded (dart:async/zone.dart:1851:12)
#10     _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:141:5)
#11     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.<…>

任何人都可以帮助我理解为什么我不能使用单例调用而不是工厂调用？我的思考过程是，我不需要这个类的唯一实例，我相信工厂会给我，我只需要一个它需要它的类的实例。

任何帮助都非常感谢。

Answer 1

我通过以下方式解决了这个问题：

dependencyLocator.registerSingleton<UiUtils>(UiUtils());

因此，我的dependencyLocator类现在看起来像这样:

import 'package:get_it/get_it.dart';
import 'package:quiz_test/utils/UiUtils.dart';

GetIt dependencyLocator = GetIt.instance;

void setupDependencyLocator() {
  dependencyLocator.registerSingleton<UiUtils>(UiUtils());
}

我希望这能帮助其他人免于陷入困境！