我尝试从 Flutter 官方的in-app-purchase plugin 示例中运行示例脚本，该示例位于此处。我将这些示例添加到我的应用程序屏幕之一。
但是，从我的应用程序屏幕到应用内购买的示例屏幕，我收到以下错误：
E/flutter（2557）：[错误：flutter/lib/ui/ui_dart_state.cc（148）]未处理的异常：MissingPluginException（在通道plugins.flutter.io/in_app_purchase上找不到方法BillingClient#startConnection（BillingClientStateListener）的实现） E/flutter (2557): #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:314:7) E/flutter (2557): E/flutter (2557): #1 BillingClient.startConnection (package :in_app_purchase/src/billing_client_wrappers/billing_client_wrapper.dart:89:62) E/flutter (2557): E/flutter (2557): #2 GooglePlayConnection._connect (package:in_app_purchase/src/in_app_purchase/google_play_connection.dart:166:21 ) E/flutter (2557): #3 新的 GooglePlayConnection._ (package:in_app_purchase/src/in_app_purchase/google_play_connection.dart:27:20) E/flutter (2557): #4 GooglePlayConnection._getOrCreateInstance (package:in_app_purchase/src/ in_app_purchase/google_play_connection.dart:161:38) E/flutter (2557): #5 GooglePlayConnection.instance (package:in_app_purchase/src/in_app_purchase/google_play_connection.dart:32:47) E/flutter (2557): #6 InAppPurchaseConnection._getOrCreateInstance (package:in_app_purchase/src/in_app_purchase/in_app_purchase_connection.dart:225:40) E/flutter (2557): #7 InAppPurchaseConnection.instance (package:in_app_purchase/src/in_app_purchase/in_app_purchase_connection.dart:216:50) E/flutter (2557): #8 new _PermanentDonorScreenState (package:zipediaapps/src/ui/sadaqah/permanent_donor_screen.dart:79: 71) E/flutter (2557): #9 PermanentDonorScreen.createState (package:zipediaapps/src/ui/sadaqah/permanent_donor_screen.dart:52:47) E/flutter (2557): #10 new StatefulElement (package:flutter/src /widgets/framework.dart:3989:25) E/flutter (2557): #11 StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:802:38) E/flutter (2557): #12 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3082:40) E/flutter (2557): #13 Element.updateChild (package:flutter/src/ widgets/framework.dart:2887:12) E/flutter (2557): #14 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14) E/flutter (2557): #15 元素。 inflateWidget (package:flutter/src/widgets/framework.dart:3084:14) E/flutter (2557): #16 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12) E/flutter (2557):#17 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16) E/flutter (2557):#18 Element.rebuild (package:flutter/src/widgets/framework.dart :3721:5) E/flutter (2557):#19 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5) E/flutter (2557): #20 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5) E/flutter (2557): #21 Element.inflateWidget (package:flutter/src/ widgets/framework.dart:3084:14) E/flutter (2557): #22 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12) E/flutter (2557): #23 SingleChildRenderObjectElement。 mount (package:flutter/src/widgets/framework.dart:5092:14) E/flutter (2557): #24 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14) E/flutter (2557):#25 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12) E/flutter (2557):#26 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart :5092:14) E/flutter (2557): #27 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14) E/flutter (2557): #28 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12) E/flutter (2557): #29 SingleChildRenderObjectElement.mount (package:flutter/src/ widgets/framework.dart:5092:14) E/flutter (2557): #30 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14) E/flutter (2557): #31 Element. updateChild (package:flutter/src/widgets/framework.dart:2887:12) E/flutter (2557): #32 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14) E/flutter (2557):#33 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14) E/flutter (2557):#34 Element.updateChild (package:flutter/src/widgets/framework.dart :2887:12) E/flutter (2557):#35 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16) E/flutter (2557): #36 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5) E/flutter (2557): #37 ComponentElement._firstBuild (package: flutter/src/widgets/framework.dart:3907:5) E/flutter (2557): #38 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11) E/flutter (2557): #39 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5) E/flutter (2557): #40 E I/flutter (2557): 0#39 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5) E/flutter (2557): #40 E I/flutter (2557): 0#39 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5) E/flutter (2557): #40 E I/flutter (2557): 0
关于颤振医生，这里是状态：
[✓] Flutter (Channel stable, v1.7.8+hotfix.3, on Mac OS X 10.14.1 18B75, locale en-ID)
• Flutter version 1.7.8+hotfix.3 at /Users/anunixercoder/development/flutter
• Framework revision b712a172f9 (3 weeks ago), 2019-07-09 13:14:38 -0700
• Engine revision 54ad777fd2
• Dart version 2.4.0
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
• Android SDK at /Users/anunixercode/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-28, build-tools 28.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 10.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 10.1, Build version 10B61
• CocoaPods version 1.7.2
[✓] iOS tools - develop for iOS devices
• ios-deploy 1.9.4
[✓] Android Studio (version 3.2)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 31.2.1
• Dart plugin version 181.5656
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
[!] Connected device
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! Doctor found issues in 1 category.
有什么想法可以解决吗？
提前致谢...