Unity OpenXR输入问题：TryGetFeatureValue始终返回0求助

调试数小时仍未解决：在其他类中调用RightHand.AButtonDown()时始终返回false，已打印所有日志排查但未发现错误，targetDevice输出为UnityEngine.XR.InputDevice且无报错或警告。

调用代码 #

Debug.Log(RightHand.AButtonDown());

函数实现代码 #

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR;

public static class RightHand
{
    private static InputDevice targetDevice;

    static RightHand()
    {
        
        TryInitialize();
    }

    private static void TryInitialize()
    {
        Debug.Log("ran inital");
        List<InputDevice> devices = new List<InputDevice>();

        InputDeviceCharacteristics rightControllerCharacteristics = InputDeviceCharacteristics.Right | InputDeviceCharacteristics.Controller;

        InputDevices.GetDevicesWithCharacteristics(rightControllerCharacteristics, devices);

        foreach (var item in devices)
        {
            Debug.Log("ran log");
            Debug.Log(item.name + item.characteristics);
        }
        
        Debug.Log("right controler characteristics" + rightControllerCharacteristics);

        if (devices.Count > 0)
        {
            targetDevice = devices[0];
        }

        Debug.Log(targetDevice);
    }

    public static bool AButtonDown()
    {
        targetDevice.TryGetFeatureValue(CommonUsages.primaryButton, out bool primaryButtonOut);
        if (primaryButtonOut)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}

排查与解决方向 #

• 修正初始化时机问题
  静态构造函数执行时XR设备可能还未完成初始化，导致targetDevice绑定无效。改成每次调用方法前检查设备有效性：

  private static void EnsureDeviceValid()
  {
      if (!targetDevice.isValid)
      {
          List<InputDevice> devices = new List<InputDevice>();
          InputDeviceCharacteristics rightControllerCharacteristics = InputDeviceCharacteristics.Right | InputDeviceCharacteristics.Controller;
          InputDevices.GetDevicesWithCharacteristics(rightControllerCharacteristics, devices);
          
          if (devices.Count > 0)
          {
              targetDevice = devices[0];
          }
      }
  }
  
  public static bool AButtonDown()
  {
      EnsureDeviceValid();
      targetDevice.TryGetFeatureValue(CommonUsages.primaryButton, out bool primaryButtonOut);
      return primaryButtonOut;
  }
  

• 添加设备有效性检查
  在方法里先判断设备是否有效，避免无效设备的调用返回错误结果：

  public static bool AButtonDown()
  {
      if (!targetDevice.isValid)
      {
          Debug.LogWarning("右手控制器设备未就绪");
          return false;
      }
      targetDevice.TryGetFeatureValue(CommonUsages.primaryButton, out bool primaryButtonOut);
      return primaryButtonOut;
  }
  

• 调整设备特性匹配条件
  部分控制器的特性可能包含TrackedDevice而非仅Controller，尝试放宽匹配条件：

  InputDeviceCharacteristics rightControllerCharacteristics = InputDeviceCharacteristics.Right | InputDeviceCharacteristics.TrackedDevice;
  

• 监听设备连接状态变更
  处理运行时设备断开重连的情况，动态更新targetDevice：

  static RightHand()
  {
      InputDevices.deviceConnected += OnDeviceConnected;
      InputDevices.deviceDisconnected += OnDeviceDisconnected;
      TryInitialize();
  }
  
  private static void OnDeviceConnected(InputDevice device)
  {
      if ((device.characteristics & (InputDeviceCharacteristics.Right | InputDeviceCharacteristics.Controller)) == (InputDeviceCharacteristics.Right | InputDeviceCharacteristics.Controller))
      {
          targetDevice = device;
      }
  }
  
  private static void OnDeviceDisconnected(InputDevice device)
  {
      if (targetDevice.name == device.name)
      {
          targetDevice = new InputDevice();
      }
  }
  

内容的提问来源于stack exchange，提问作者Titan1315