我正在开发一个最低目标版本为ICS的Android项目，因此我从Xamarin组件商店下载了Google Play Services ICS组件（版本18.0.0.1）。在添加对它包含的4个dll的引用之后，我无法构建项目，所以我必须在我的项目中调整目标android版本，如thread中所述。我目前的设置是：
使用Android版本进行编译：API级别17 最低Android目标：API级别14 目标Android版本：API等级17
但是，构建过程仍然失败，并出现以下错误：
2>JAVAC : warning : com\google\ads\mediation\MediationBannerListener.class(com\google\ads\mediation:MediationBannerListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\mediation\MediationBannerAdapter.class(com\google\ads\mediation:MediationBannerAdapter.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\AdRequest.class(com\google\ads:AdRequest.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\AdRequest$ErrorCode.class(com\google\ads:AdRequest$ErrorCode.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\mediation\MediationInterstitialListener.class(com\google\ads\mediation:MediationInterstitialListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\mediation\MediationInterstitialAdapter.class(com\google\ads\mediation:MediationInterstitialAdapter.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\ads\mediation\customevent\CustomEventListener.class(com\google\ads\mediation\customevent:CustomEventListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\doubleclick\AppEventListener.class(com\google\android\gms\ads\doubleclick:AppEventListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\mediation\MediationBannerListener.class(com\google\android\gms\ads\mediation:MediationBannerListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\mediation\MediationBannerAdapter.class(com\google\android\gms\ads\mediation:MediationBannerAdapter.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\mediation\MediationInterstitialListener.class(com\google\android\gms\ads\mediation:MediationInterstitialListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\mediation\MediationInterstitialAdapter.class(com\google\android\gms\ads\mediation:MediationInterstitialAdapter.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\mediation\customevent\CustomEventListener.class(com\google\android\gms\ads\mediation\customevent:CustomEventListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\purchase\InAppPurchaseListener.class(com\google\android\gms\ads\purchase:InAppPurchaseListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\purchase\InAppPurchase.class(com\google\android\gms\ads\purchase:InAppPurchase.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\purchase\PlayStorePurchaseListener.class(com\google\android\gms\ads\purchase:PlayStorePurchaseListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\ads\purchase\InAppPurchaseResult.class(com\google\android\gms\ads\purchase:InAppPurchaseResult.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\cast\RemoteMediaPlayer.class(com\google\android\gms\cast:RemoteMediaPlayer.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\cast\RemoteMediaPlayer$OnMetadataUpdatedListener.class(com\google\android\gms\cast:RemoteMediaPlayer$OnMetadataUpdatedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\cast\Cast.class(com\google\android\gms\cast:Cast.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\cast\Cast$MessageReceivedCallback.class(com\google\android\gms\cast:Cast$MessageReceivedCallback.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\cast\RemoteMediaPlayer$OnStatusUpdatedListener.class(com\google\android\gms\cast:RemoteMediaPlayer$OnStatusUpdatedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\GooglePlayServicesClient.class(com\google\android\gms\common:GooglePlayServicesClient.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\GooglePlayServicesClient$OnConnectionFailedListener.class(com\google\android\gms\common:GooglePlayServicesClient$OnConnectionFailedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\ConnectionResult.class(com\google\android\gms\common:ConnectionResult.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\images\ImageManager.class(com\google\android\gms\common\images:ImageManager.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\images\ImageManager$OnImageLoadedListener.class(com\google\android\gms\common\images:ImageManager$OnImageLoadedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\drive\DriveFile.class(com\google\android\gms\drive:DriveFile.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\drive\DriveFile$DownloadProgressListener.class(com\google\android\gms\drive:DriveFile$DownloadProgressListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\drive\DriveResource.class(com\google\android\gms\drive:DriveResource.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\drive\events\DriveEvent.class(com\google\android\gms\drive\events:DriveEvent.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\drive\events\DriveEvent$Listener.class(com\google\android\gms\drive\events:DriveEvent$Listener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\common\internal\safeparcel\SafeParcelable.class(com\google\android\gms\common\internal\safeparcel:SafeParcelable.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\OnInvitationReceivedListener.class(com\google\android\gms\games\multiplayer:OnInvitationReceivedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\Invitation.class(com\google\android\gms\games\multiplayer:Invitation.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\realtime\RealTimeMessageReceivedListener.class(com\google\android\gms\games\multiplayer\realtime:RealTimeMessageReceivedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\realtime\RealTimeMessage.class(com\google\android\gms\games\multiplayer\realtime:RealTimeMessage.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\realtime\RoomStatusUpdateListener.class(com\google\android\gms\games\multiplayer\realtime:RoomStatusUpdateListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\realtime\Room.class(com\google\android\gms\games\multiplayer\realtime:Room.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\realtime\RoomUpdateListener.class(com\google\android\gms\games\multiplayer\realtime:RoomUpdateListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\turnbased\OnTurnBasedMatchUpdateReceivedListener.class(com\google\android\gms\games\multiplayer\turnbased:OnTurnBasedMatchUpdateReceivedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\multiplayer\turnbased\TurnBasedMatch.class(com\google\android\gms\games\multiplayer\turnbased:TurnBasedMatch.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\quest\QuestUpdateListener.class(com\google\android\gms\games\quest:QuestUpdateListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\quest\Quest.class(com\google\android\gms\games\quest:Quest.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\request\OnRequestReceivedListener.class(com\google\android\gms\games\request:OnRequestReceivedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\games\request\GameRequest.class(com\google\android\gms\games\request:GameRequest.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\location\LocationClient.class(com\google\android\gms\location:LocationClient.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\location\LocationClient$OnAddGeofencesResultListener.class(com\google\android\gms\location:LocationClient$OnAddGeofencesResultListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\location\LocationClient$OnRemoveGeofencesResultListener.class(com\google\android\gms\location:LocationClient$OnRemoveGeofencesResultListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\location\LocationListener.class(com\google\android\gms\location:LocationListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap.class(com\google\android\gms\maps:GoogleMap.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnCameraChangeListener.class(com\google\android\gms\maps:GoogleMap$OnCameraChangeListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\model\CameraPosition.class(com\google\android\gms\maps\model:CameraPosition.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnIndoorStateChangeListener.class(com\google\android\gms\maps:GoogleMap$OnIndoorStateChangeListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\model\IndoorBuilding.class(com\google\android\gms\maps\model:IndoorBuilding.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnInfoWindowClickListener.class(com\google\android\gms\maps:GoogleMap$OnInfoWindowClickListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\model\Marker.class(com\google\android\gms\maps\model:Marker.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMapClickListener.class(com\google\android\gms\maps:GoogleMap$OnMapClickListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\model\LatLng.class(com\google\android\gms\maps\model:LatLng.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMapLongClickListener.class(com\google\android\gms\maps:GoogleMap$OnMapLongClickListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMarkerClickListener.class(com\google\android\gms\maps:GoogleMap$OnMarkerClickListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMarkerDragListener.class(com\google\android\gms\maps:GoogleMap$OnMarkerDragListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMyLocationButtonClickListener.class(com\google\android\gms\maps:GoogleMap$OnMyLocationButtonClickListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\GoogleMap$OnMyLocationChangeListener.class(com\google\android\gms\maps:GoogleMap$OnMyLocationChangeListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\LocationSource.class(com\google\android\gms\maps:LocationSource.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\LocationSource$OnLocationChangedListener.class(com\google\android\gms\maps:LocationSource$OnLocationChangedListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\StreetViewPanorama.class(com\google\android\gms\maps:StreetViewPanorama.class): major version 51 is newer than 50, the highest major version supported by this compiler.
2>JAVAC : warning : com\google\android\gms\maps\StreetViewPanorama$OnStreetViewPanoramaCameraChangeListener.class(com\google\android\gms\maps:StreetViewPanorama$OnStreetViewPanoramaCameraChangeListener.class): major version 51 is newer than 50, the highest major version supported by this compiler.
这是否与我PC上的JDK版本有关？有什么想法吗？
提前致谢。
答案 0 :(得分：6)
我遇到了类似的问题。从android相关的stackoverflow参考我发现＆＃39; ＆＃34;主要版本＆＃34;表示Java版本。 Java 7 = 51，Java 6 = 50.＆＃39; （Android Studio: what compiler settings when including Google Maps）。它说它正在使用的编译器（在你的情况下是JDK 6）不够高。
首先，您要确保安装了Java版本7的Java Development Kit。在我的情况下，它已经安装，但版本6仍在使用。
在Xamarin Studio中，您可以转到选项/首选项 - ＆gt;项目 - ＆gt; SDK位置指向版本7的JDK位置。
在使用Xamarin插件的Visual Studios中，我无法弄清楚如何指定使用JDK 7进行编译。因此，我从计算机中删除了第6版，现在代码已编译完成。
答案 1 :(得分：0)
我遇到了同样的问题，改用JDK 7部分解决了这个问题。我已经在谷歌游戏商店发布了我的应用程序，但发现有些智能手机无法处理JDK 7的签名。在这些手机上下载应用程序时出现错误“包文件未正确签名”。
xamarin.android App signing does not work
如果更改为JDK 7会导致此问题，可能还有另一种方法可以解决此问题。