Android studio 在将包导入Flatter时面临一个大问题（Andriod Studio）。我已经尝试了其他解决方案中的所有方法

我正在尝试导入URL launcher包，但颤振似乎无法识别该包

我在pubspec.yaml文件中提到了这个包。 我还使用了命令flatterpackagesget。我可以看到在外部库中导入的包，但无法导入它。这似乎是个问题 导入“package:url_launcher/url_launcher.dart”

为了供您参考，我还粘贴了我的错误消息、我的代码和pubspec.yaml文件

我收到了以下错误

Error: Could not resolve the package 'url_launcher' in 'package:url_launcher/url_launcher.dart'.
lib/main.dart:2:8: Error: Not found: 'package:url_launcher/url_launcher.dart'
import 'package:url_launcher/url_launcher.dart';
       ^
lib/main.dart:8:5: Error: The method 'launch' isn't defined for the class 'XylophoneApp'.
 - 'XylophoneApp' is from 'package:xylophone/main.dart' ('lib/main.dart').
Try correcting the name to the name of an existing method, or defining a method named 'launch'.
    launch('https://flutter.dev');
    ^^^^^^

下面是我的代码

import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';

void main() => runApp(XylophoneApp());

class XylophoneApp extends StatelessWidget {
  launchURL() {
    launch('https://flutter.dev');
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Xylophone'),
        ),
        body: Center(
          child: RaisedButton(
            onPressed: launchURL,
            child: Text('Show Flutter homepage'),
          ),
        ),
      ),
    );
  }
}

这是我的pubspec.yaml文件

name: xylophone
description: A new Flutter application.

version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^0.1.2
  url_launcher: ^5.4.0


dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:

  uses-material-design: true

  assets:
    - assets/

---

始终在导入任何包后重新启动程序。 使用“运行”按钮而不是“热重新加载”或“热重新启动”按钮