android - 为什么 Flutter 导入提供程序包不起作用?
问题描述
因此,请按照本教程在 Flutter 中创建一个简单的登录 UI
https://medium.com/better-programming/simple-firebase-login-flow-in-flutter-6f44c2b5c58a
显然,flutter 中的这个包没有被正确导入。不工作的特定行是这 3 行代码
import 'package:provider/provider.dart';
ChangeNotifierProvider<AuthService>( //TODO: authservices and provider pages
future: Provider.of<AuthService>(context).getUser(),
我一直在搜索一堆并尝试阅读文档并且无法得到任何简单的答案,但无论如何感谢任何给我答案的人
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'home_page.dart';
import 'auth.dart';
import 'login_page.dart';
void main() => runApp(
ChangeNotifierProvider<AuthService>( //TODO: authservices and provider pages
child: MyApp(),
builder: (BuildContext context) {
return AuthService();
},
),
);
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(primarySwatch: Colors.blue),
home: FutureBuilder(
future: Provider.of<AuthService>(context).getUser(),
builder: (context, AsyncSnapshot snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
return snapshot.hasData ? HomePage() : LoginPage();
} else {
return Container(color: Colors.white);
}
},
),
);
}
}
pubspec.yaml 文件供任何人查看
name: login_flutter_app
description: A new Flutter application.
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1
environment:
sdk: ">=2.1.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^0.1.2
dev_dependencies:
flutter_test:
sdk: flutter
# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
# assets:
# - images/a_dot_burr.jpeg
# - images/a_dot_ham.jpeg
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.dev/assets-and-images/#resolution-aware.
# For details regarding adding assets from package dependencies, see
# https://flutter.dev/assets-and-images/#from-packages
# To add custom fonts to your application, add a fonts section here,
# in this "flutter" section. Each entry in this list should have a
# "family" key with the font family name, and a "fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.dev/custom-fonts/#from-packages
解决方案
不得不将这些放入项目中
Cupertino_icons:^0.1.2 flutter_blue:^0.6.3+1 提供者:^4.0.4
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