查閱了很多Unity3D開發(fā)Android應(yīng)用調(diào)用串口的方法，很多資料介紹的都是用java調(diào)用serial_port庫，然后編寫jni供Unity3D調(diào)用。
Unity3D C#調(diào)用JNI庫

 void Update()
  {
    using (AndroidJavaClass cls_UnityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
    {
      using (AndroidJavaObject obj_Activity = cls_UnityPlayer.GetStatic("currentActivity"))
      {
        AndroidJavaClass cls_CompassActivity = new AndroidJavaClass("com.LB.UnityAndroid1.CompassActivity");
        cls_CompassActivity.CallStatic("openCom1", obj_Activity);
      }
    }
  }

對于很多C#程序員來說，配置java和android開發(fā)環(huán)境都很陌生，需要折騰很久。
然而，根本不用這么麻煩，android串口庫本來就是c語言寫的，而C#語言直接就可以調(diào)用C語言編寫的動態(tài)鏈接庫（android的動態(tài)庫擴展名是.so），所有jni是沒有必要的。
Unity3D C#引用C語言動態(tài)鏈接庫函數(shù)

#if  UNITY_ANDROID 
  [System.Runtime.InteropServices.DllImport("libserial_port.so")]
  protected static extern Int32 Serial_Open([MarshalAs(UnmanagedType.LPTStr)]String path, int baudrate, int flags);
  [System.Runtime.InteropServices.DllImport("libserial_port.so")]
  protected static extern void Serial_Close(Int32 port);
  [System.Runtime.InteropServices.DllImport("libserial_port.so")]
  protected static extern Int32 Serial_SendString(Int32 port, string str);
  [System.Runtime.InteropServices.DllImport("libserial_port.so")]
  protected static extern Int32 Serial_SendData(Int32 port, [MarshalAs(UnmanagedType.LPArray)]byte[] data, int size);
  [System.Runtime.InteropServices.DllImport("libserial_port.so")]
  protected static extern Int32 Serial_RecvData(Int32 port);
#endif

Int32 port = Serial_Open(portName, 9600, 0);
byte[] buff = { 0xFA, 0xFB, 0xFC, 0xFD, 0xFF };
int n = Serial_SendData(port, buff, buff.Length);
Serial_Close(port);

將libserial_port.so放入\Assets\Plugins\Android\libs目錄下，設(shè)置對應(yīng)CPU目錄

配置對應(yīng)的平臺和CPU