求助，请帮我看看show_InterstitialAd函数哪里错了

Cocos2d-x
#1

public class AppActivity extends Cocos2dxActivity {
private static final String TAG = “AppActivity”;
private static Object appActivity;//静态函数
private RewardedAd rewardedAd;
private static InterstitialAd mInterstitialAd;//插入式广告

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.setEnableVirtualButton(false);
    super.onCreate(savedInstanceState);
    if (!isTaskRoot()) {
        return;
    }
    // DO OTHER INITIALIZATION BELOW
    //MobileAds.initialize(this, "ca-app-pub-3940256099942544~3347511713");//初始化广告sdk,后面就可以选择广告类型了"ca-app-pub-7333122515883217~9069023857"
    //MobileAds.initialize(this, new OnInitializationCompleteListener()); //com.google.android.gms.ads.initialization.OnInitializationCompleteListener o
    MobileAds.initialize(this, new OnInitializationCompleteListener() {
        @Override
        public void onInitializationComplete(InitializationStatus initializationStatus) {
        }
    });

    //要放在oncreate里面
    mInterstitialAd = new InterstitialAd(this);//在 Cocos2dxActivity 的整个生命周期内，只需使用一个 
    InterstitialAd 对象，即可请求并展示多个插页式广告，因此该对象只需构建一次。
    mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");
    mInterstitialAd.loadAd(new AdRequest.Builder().build());//加载广告

}

public static void show_InterstitialAd()
{//显示插页式广告
    Log.d("TAG", "isLoaded_before");

    if (mInterstitialAd.isLoaded()) {
        mInterstitialAd.show();
        Log.d("TAG", "show_InterstitialAd");
    } else {
        Log.d("TAG", "The interstitial wasn't loaded yet.");
    }
}

}

上面的函数，每次运行JniHelper::callStaticVoidMethod(classPath, “show_InterstitialAd”);，不会报错，也会出现log “isLoaded_before”，但是后面的mInterstitialAd.isLoaded()， mInterstitialAd.show();这些都没有反应，显示错误
2020-12-17 22:27:44.095 2335-2385/gklutz.Game_AVGs.panda619 E/JniHelper: Classloader failed to find class of org.cocos2dx.lib.Cocos2dxHelper
2020-12-17 22:27:44.096 2335-2385/gklutz.Game_AVGs.panda619 E/JniHelper: Failed to find class org.cocos2dx.lib.Cocos2dxHelper
2020-12-17 22:27:44.096 2335-2385/gklutz.Game_AVGs.panda619 E/JniHelper: Failed to find static java method. Class name: org.cocos2dx.lib.Cocos2dxHelper, method name: getCocos2dxWritablePath, signature: ()Ljava/lang/String;

但是不会死机，只是广告的部分完全没有用，请问问什么找不到JniHelper，或者是别的原因吗？卡了我好几天:cry: