MissingPluginException：找不到方法的实现

Question

我的 Flutter 应用程序在运行时抛出了这个异常。

MissingPluginException（在通道 plugins.flutter.io/path_provider 上找不到方法 getTemporaryDirectory 的实现）

main.dart

Directory tp = await getTemporaryDirectory();

File tempFile = File('${tp.path}/flutter.pdf');

ByteData bd = await rootBundle.load('assets/flutter.pdf');

tempFile=await tempFile.writeAsBytes(bd.buffer.asUint8List(), flush: true);

pupspec.yaml

 name: flutterapp
    description: A new Flutter project.

    # The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# 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: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  path_provider: ^1.6.9

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.3

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:
    - assets/flutter.pdf
  #   - 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

已经这样做了： 1.flutter clean和flutter run 2.import这个包 1.package:path_provider/path_provider.dart 2.飞镖：io 3.dart:异步

提前致谢

Answer 1

我的类似问题 (MissingPluginException) 仅在发布版本中出现。 这行解决了：

proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'),'proguard-rules.pro'

根据 https://developer.android.com/studio/build/shrink-code#enable

Answer 2

你检查过这个帖子吗：https://github.com/flutter/flutter/issues/10912