dart - Flutter 相机插件无法导入/可用

Question

开始实现 camera plugin 时出现以下错误在我的 flutter 应用程序上:

  [VERBOSE-2:dart_error.cc(16)] Unhandled exception:
  MissingPluginException(No implementation found for method init on channel plugins.flutter.io/camera)
  #0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:153:7)
  <asynchronous suspension>
  #1      _channel (package:camera/camera.dart:7:5)
  #2      _channel (package:camera/camera.dart:6:21)
  #3      availableCameras (package:camera/camera.dart:42:41)
  <asynchronous suspension>
  #4      main (file:///Users/waynerumble/Desktop/scott_and_viki/lib/main.dart:10:19)
  <asynchronous suspension>
  #5      _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:279:19)
  #6      _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
  [VERBOSE-2:dart_error.cc(16)] Unhandled exception:
  MissingPluginException(No implementation found for method list on channel plugins.flutter.io/camera)
  #0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:153:7)
  <asynchronous suspension>
  #1      availableCameras (package:camera/camera.dart:42:50)
  <asynchronous suspension>
  #2      main (file:///Users/waynerumble/Desktop/scott_and_viki/lib/main.dart:10:19)
  <asynchronous suspension>
  #3      _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:279:19)
  #4      _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)

直到我开始使用插件本身时才会发生错误，即如果我替换 Future<null> main() etc与 void main() => runApp(new App());该应用程序运行良好。我已经按照提供的链接中的安装说明进行操作，并尝试粘贴所有示例代码来代替我的代码，但仍然出现错误

我的 main.dart:

  import 'package:flutter/material.dart';
  import 'Localisations.dart';
  import 'package:flutter_localizations/flutter_localizations.dart';
  import 'dart:async';
  import 'package:camera/camera.dart';

  List<CameraDescription> cameras;

  Future<Null> main() async {
    cameras = await availableCameras();
    runApp(new App());
  }

  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      var statusBarHeight = MediaQuery.of(context).padding.top;
      var titleText = new Text(Localize.of(context).appTitle,
          textAlign: TextAlign.center,
          style: new TextStyle(fontFamily: 'CallingAngelsPersonalUse',
          fontSize: 50.0,
          color: Colors.black)
      );
      var backgroundImage = new BoxDecoration(
          image: new DecorationImage(
           image: new AssetImage('assets/background.png'),
          fit: BoxFit.cover,
        ),
      );

      var mainContainer = new Container(
        padding: EdgeInsets.only(top: statusBarHeight),
        height: double.infinity,
        width: double.infinity,
        decoration: backgroundImage,
        child: new Column(
          children: <Widget>[
                new Container(
                  margin: EdgeInsets.only(top: 10.0),
                  child: titleText
            )
          ],
        ),

      );

      return new Scaffold(
        body: mainContainer,
      );
    }
  }

  class App extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return new MaterialApp(
        onGenerateTitle: (BuildContext context) => Localize.of(context).appTitle,
        localizationsDelegates: [
          const LocalizeDelegate(),
          GlobalMaterialLocalizations.delegate,
          GlobalWidgetsLocalizations.delegate,
        ],
        supportedLocales: [
          const Locale('en', '')
        ],
        home: new MyApp(),
      );
    }
  }

我的 pubspec.yml:

dependencies:
  flutter:
    sdk: flutter
  camera: ^0.1.2
  path_provider: ^0.4.0
  flutter_localizations:
      sdk: flutter

这是我的第一个真正的 Flutter 应用程序，因此我们将不胜感激。

谢谢

Answer 1

首先检查您的 app.build minSdkVersion。确保 minSdkVersion 为 21。

       minSdkVersion 21

这里的代码示例。

List<CameraDescription> cameras = [];
main() async{
  WidgetsFlutterBinding.ensureInitialized();
  try {
    cameras = await availableCameras();

  } on CameraException catch (e) {
   logError(e.code, e.description);
  }
  runApp(MyApp());
}