通过遵循此documentation，可以集成Graphql graphql_flutter。在Android和iOS的开发模式下，一切正常，但是当我尝试在发布模式下部署Android时，我能够生成APK。在手机上运行后，我在Logcat上看到此错误
2020-03-03 12:15:09.822 7384-7408/? E/flutter: [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The getter 'host' was called on null.
Receiver: null
Tried calling: host
#0 translateNetworkFailure (package:graphql/src/exceptions/io_network_exception.dart:14)
#1 translateFailure (package:graphql/src/exceptions/exceptions.dart:13)
#2 new HttpLink.<anonymous closure>.onListen (package:graphql/src/link/http/link_http.dart:104)
<asynchronous suspension>
#3 _runGuarded (dart:async/stream_controller.dart:807)
#4 _StreamController._subscribe.<anonymous closure> (dart:async/stream_controller.dart:686)
#5 _BufferingStreamSubscription._guardCallback (dart:async/stream_impl.dart:416)
#6 _StreamController._subscribe (dart:async/stream_controller.dart:685)
#7 _ControllerStream._createSubscription (dart:async/stream_controller.dart:820)
#8 _StreamImpl.listen (dart:async/stream_impl.dart:474)
#9 Stream.first (dart:async/stream.dart:1251)
#10 QueryManager._resolveQueryOnNetwork (package:graphql/src/core/query_manager.dart:119)
#11 QueryManager.fetchQueryAsMultiSourceResult (package:graphql/src/core/query_manager.dart:97)
#12 ObservableQuery.fetchResults (package:graphql/src/core/observable_query.dart:123)
#13 new ObservableQuery (package:graphql/src/core/observable_query.dart:32)
#14 QueryManager.watchQuery (package:graphql/src/core/query_manager.dart:35)
#15 GraphQLClient.watchQuery (package:graphql/src/graphql_client.dart:99)
#16 QueryState._initQuery (package:graphql_flutter/src/widgets/query.dart:60)
#17 QueryState.didChangeDependencies (package:graphql_flutter/src/widgets/query.dart:66)
#18 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4376)
#19 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201)
#20 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194)
#21 Element.updateChild (package:flutter/src/widgets/framework.dart:2988)
#22 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243)
#23 Element.rebuild (package:flutter/src/widgets/framework.dart:3947)
#24 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206)
#25 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201)
#26 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194)
#27 Element.updateChild (package:flutter/src/widgets/framework.dart:2988)
#28 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243)
#29 Element.rebuild (package:flutter/src/widgets/framework.dart:3947)
#30 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206)
#31 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201)
#32 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194)
#33 Element.updateChild (package:flutter/src/widgets/framework.dart:2988)
#34 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243)
#35 Element.rebuild (package:flutter/src/widgets/framework.dart:3947)
#36 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206)
#37 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201)
#38 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194)
#39 Element.updateChild (package:flutter/src/widgets/framework.dart:2988)
#40 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243)
#41 Element.rebuild (package:flutter/src/widgets/framework.dart:3947)
#42 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206)
#43 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201)
#44 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194)
#45 Element.updateChild (package:flutter/src/widgets/framework.dart:2988)
#46 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243)
#47 Ele
答案 0 :(得分：0)
弄清楚了。这是因为权限问题。默认情况下，当Android应用程序在开发中运行时，它将具有INTERNET权限。
发布后，INTERNET权限将不再可用。您可以检查官方的documentation here
解决方案： 打开android清单
./android/app/src/main/AndroidManifest.xml
为清单添加Internet权限
<manifest xlmns:android...>
...
<uses-permission android:name="android.permission.INTERNET" />
<application ...
</manifest>