CarPlay停车应用程序在从Xcode 12 CarPlay模拟器启动时崩溃

Question

我们正在为Xamarin.iOS扩展我们的CarPlay应用程序(由Xamarin.Forms提供)。打开CarPlay模拟器时，应用程序会显示在CarPlay的屏幕上，但在从CarPlay模拟器启动时却会崩溃。

下面是Info.plist场景配置：

    <key>UIApplicationSceneManifest</key>
    <dict>
        <key>UISceneConfigurations</key>
        <dict>
            <key>CPTemplateApplicationSceneSessionRoleApplication</key>
            <array>
                <dict>
                    <key>UISceneClassName</key>
                    <string>CPTemplateApplicationScene</string>
                    <key>UISceneConfigurationName</key>
                    <string>ParkingPlus-Car</string>
                    <key>UISceneDelegateClassName</key>
                    <string>ParkingPlus.AppSceneDelegateImp</string>
                </dict>
            </array>
        </dict>
    </dict>

"ParkingPlus“是应用程序包的名称！

类AppSceneDelegateImp (位于iOS项目的根文件夹下)

    public class AppSceneDelegateImp : UIResponder, ICPTemplateApplicationSceneDelegate
    {
        private CPInterfaceController _interfaceController;

        public async void DidConnect(CPTemplateApplicationScene templateApplicationScene, CPInterfaceController interfaceController)
        {
            _interfaceController = interfaceController;
           .....
        }

        public void DidDisconnect(CPTemplateApplicationScene templateApplicationScene, CPInterfaceController interfaceController)
        {
            _interfaceController.Dispose();
            _interfaceController = null;
        }
   }

当我覆盖AppDelegate.GetConfiguration时，如下所示

public override UISceneConfiguration GetConfiguration(UIApplication application, UISceneSession connectingSceneSession, UISceneConnectionOptions options)
{
...
}

当点击CarPlay上的应用图标时，将调用该方法。但是当我检查connectingSceneSession时，我发现变量成员中有一些异常。"CPTemplateApplicationSceneSessionRoleApplication在这个平台上没有关联的枚举值“。

用于connectingSceneSession检查的截图

如果继续，则应用程序将抛出一个异常，该异常似乎提示SceneDelegate未正确加载：异常

：Visual for MacVersion8.7.8 Xamarin.iOS 14.0.0 Xcode 12.0

Xamarin.ios 14在绑定iOS库时似乎遗漏了一些东西。任何人都有类似的问题。我是否做错了什么，或者是否有其他方法可以在Xamarin.Forms/Xamarin.iOS上实现移动应用程序的CarPlay部件特性？

感谢您的评论或帮助。

Answer 1

在Xamarin.ios团队的帮助下，下面是这个问题的完整解决方案：https://github.com/xamarin/xamarin-macios/issues/9749

1. 为两种情况创建场景配置的AppDelegate (CarPlay和phone)

        [DllImport("/usr/lib/libobjc.dylib", EntryPoint = "objc_msgSend")]
        public extern static IntPtr IntPtr_objc_msgSend_IntPtr_IntPtr(IntPtr receiver, IntPtr selector, IntPtr arg1, IntPtr arg2);

        public static UISceneConfiguration Create(string? name, NSString sessionRole)
        {
            global::UIKit.UIApplication.EnsureUIThread();
            var nsname = NSString.CreateNative(name);

            UISceneConfiguration sceneConfig;
            sceneConfig = Runtime.GetNSObject<UISceneConfiguration>(IntPtr_objc_msgSend_IntPtr_IntPtr(Class.GetHandle("UISceneConfiguration"), Selector.GetHandle("configurationWithName:sessionRole:"), nsname, sessionRole.Handle));
            NSString.ReleaseNative(nsname);
            //Because only the CarPlay scene will be here to create a scene configuration
            //We need manually assign the CarPlay scene delegate here!
            sceneConfig.DelegateType = typeof(AppCarSceneDelegateImp);
            return sceneConfig!;
        }

        [Export("application:configurationForConnectingSceneSession:options:")]
        public UISceneConfiguration GetConfiguration(UIApplication application, UISceneSession connectingSceneSession, UISceneConnectionOptions options)
        {
            UIWindowSceneSessionRole sessionRole;
            bool isCarPlaySceneSession = false;
            try
            {
                //When the connecting scene is a CarPlay scene, an expected exception will be thrown
                //Under this moment from Xamarin.iOS.
                sessionRole = connectingSceneSession.Role;
            }
            catch (NotSupportedException ex)
            {
                if (!string.IsNullOrEmpty(ex.Message) &&
                    ex.Message.Contains("CPTemplateApplicationSceneSessionRoleApplication"))
                {
                    isCarPlaySceneSession = true;
                }
            }

            if (isCarPlaySceneSession && UIDevice.CurrentDevice.CheckSystemVersion(14,0))
            {
                return Create("Car", CarPlay.CPTemplateApplicationScene.SessionRoleApplication);
            }
            else
            {
                //If it is phone scene, we need the regular UIWindow scene
                UISceneConfiguration phoneScene = new UISceneConfiguration("Phone", UIWindowSceneSessionRole.Application);
                //And assign the scene delegate here.
                phoneScene.DelegateType = typeof(AppWindowSceneDelegateImp);
                return phoneScene;
            }
        }

1. 创建一个UIWindowScene委托来处理常规的移动场景窗口

    public class AppWindowSceneDelegateImp : UISceneDelegate
    {
        public override void WillConnect(UIScene scene, UISceneSession session, UISceneConnectionOptions connectionOptions)
        {
            var windowScene = scene as UIWindowScene;
            if (windowScene != null)
            {
                //Assign the Xamarin.iOS app window to this scene 
                UIApplication.SharedApplication.KeyWindow.WindowScene = windowScene;
                UIApplication.SharedApplication.KeyWindow.MakeKeyAndVisible();
            }
        }
    }