Connection API

如需确定您的应用是在 Android Auto 上还是在 Android Automotive OS 上运行，请使用 CarConnection API 在运行时检索连接信息。例如：

1. 在您的汽车应用的 Session 中，初始化 CarConnection 并订阅 LiveData 更新：

   Kotlin

   CarConnection(carContext).type.observe(this, ::onConnectionStateUpdated)
   

   Java

   new CarConnection(getCarContext()).getType().observe(this, this::onConnectionStateUpdated);
   

2. 在观察器中，对连接状态的变化做出响应：

   Kotlin

   fun onConnectionStateUpdated(connectionState: Int) {
     val message = when(connectionState) {
       CarConnection.CONNECTION_TYPE_NOT_CONNECTED -> "Not connected to a head unit"
       CarConnection.CONNECTION_TYPE_NATIVE -> "Connected to Android Automotive OS"
       CarConnection.CONNECTION_TYPE_PROJECTION -> "Connected to Android Auto"
       else -> "Unknown car connection type"
     }
     CarToast.makeText(carContext, message, CarToast.LENGTH_SHORT).show()
   }
   

   Java

   private void onConnectionStateUpdated(int connectionState) {
     String message;
     switch(connectionState) {
       case CarConnection.CONNECTION_TYPE_NOT_CONNECTED:
         message = "Not connected to a head unit";
         break;
       case CarConnection.CONNECTION_TYPE_NATIVE:
         message = "Connected to Android Automotive OS";
         break;
       case CarConnection.CONNECTION_TYPE_PROJECTION:
         message = "Connected to Android Auto";
         break;
       default:
         message = "Unknown car connection type";
         break;
     }
     CarToast.makeText(getCarContext(), message, CarToast.LENGTH_SHORT).show();
   }