untiy 串口权限怎么打开

Unity 串口权限需要在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.usb.host" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

同时，需要在Unity中使用AndroidJavaObject调用Android的Context对象，然后调用checkSelfPermission方法检查是否有相应权限，如果没有则需要调用requestPermissions方法来请求权限。

示例代码：

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.IO.Ports;

public class SerialController : MonoBehaviour {

    private SerialPort serialPort;
    private string portName = "COM3";
    private int baudRate = 9600;

    void Start () {
        serialPort = new SerialPort(portName, baudRate);
        serialPort.ReadTimeout = 1000;
        serialPort.Open();

        if (Application.platform == RuntimePlatform.Android) {
            AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
            AndroidJavaObject activity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
            int permissionCheck = activity.Call<int>("checkSelfPermission", "android.permission.WRITE_EXTERNAL_STORAGE");

            if (permissionCheck != AndroidJavaObject.GetStatic<int>("PackageManager.PERMISSION_GRANTED")) {
                string[] permissions = { "android.permission.WRITE_EXTERNAL_STORAGE" };
                activity.Call("requestPermissions", permissions, 0);
            }
        }
    }

    void Update () {
        try {
            string message = serialPort.ReadLine();
            Debug.Log(message);
        } catch (System.Exception) {

        }
    }

    void OnDestroy() {
        serialPort.Close();
    }
}

上述代码中，在Start方法中打开了串口，并且在Android平台下调用了Android的Context对象来检查并请求WRITE_EXTERNAL_STORAGE权限。在Update方法中，读取串口数据并输出到控制台。在OnDestroy方法中，关闭串口连接。