文档中官方代码上的 Unity3D 无效令牌错误

Question

我试图在我的游戏中统一设置简单的广告系统，但统一文档中的奖励广告脚本给了我无效令牌错误，我不知道为什么

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Advertisements;

public class RewardedAdsButton : MonoBehaviour, IUnityAdsLoadListener, IUnityAdsShowListener
{
    [SerializeField] Button _showAdButton;
    [SerializeField] string _androidAdUnitId = "Rewarded_Android";
    [SerializeField] string _iOSAdUnitId = "Rewarded_iOS";
    public string _adUnitId = null;
#if UNITY_IOS
        _adUnitId = _iOSAdUnitId;
#elif UNITY_ANDROID
        _adUnitId = _androidAdUnitId;
#endif

Assets\Scripts\RewardedAdsButton.cs(14,13)：错误 CS1519：类、结构或接口成员声明中的标记“=”无效

Assets\Scripts\RewardedAdsButton.cs(14,31)：错误 CS1519：无效令牌“;”在类、结构或接口成员声明中

Answer 1

在这种情况下，文档极具误导性！

您不能只在班级级别重新分配字段。特别是不使用其他非常量字段！您不能在任何方法之外使用它。

---

这可能应该以类似的方法发生，例如在Awake

public class RewardedAdsButton : MonoBehaviour, IUnityAdsLoadListener, IUnityAdsShowListener
{
    [SerializeField] Button _showAdButton;
    [SerializeField] string _androidAdUnitId = "Rewarded_Android";
    [SerializeField] string _iOSAdUnitId = "Rewarded_iOS";

    [NonSerialized] public string _adUnitId = null;

    private void Awake ()
    {
#if UNITY_IOS
        _adUnitId = _iOSAdUnitId;
#elif UNITY_ANDROID
        _adUnitId = _androidAdUnitId;
#endif
    }

    ...
}

---

或者，我实际上宁愿简单地使用property，例如

public class RewardedAdsButton : MonoBehaviour, IUnityAdsLoadListener, IUnityAdsShowListener
{
    [SerializeField] Button _showAdButton;
    [SerializeField] string _androidAdUnitId = "Rewarded_Android";
    [SerializeField] string _iOSAdUnitId = "Rewarded_iOS";

    public string _adUnitId
    {
        get
        {
#if UNITY_IOS
            return _iOSAdUnitId;
#elif UNITY_ANDROID
            return _androidAdUnitId;
#else
            return null;
#endif
        }
    }