Android admob native express广告不显示

我尝试了stackoverflow中的所有内容，但没有显示广告。横幅和其他工作，但本地不工作，请帮助我

inal NativeExpressAdView mAdView2 = (NativeExpressAdView) findViewById(R.id.adView2);
    // Set its video options.
    mAdView2.setVideoOptions(new VideoOptions.Builder()
            .setStartMuted(true)
            .build());

    // The VideoController can be used to get lifecycle events and info about an ad's video
    // asset. One will always be returned by getVideoController, even if the ad has no video
    // asset.
    mVideoController = mAdView2.getVideoController();
    mVideoController.setVideoLifecycleCallbacks(new VideoController.VideoLifecycleCallbacks() {
        @Override
        public void onVideoEnd() {
            Log.d(LOG_TAG, "Video playback is finished.");
            super.onVideoEnd();
        }
    });

    // Set an AdListener for the AdView, so the Activity can take action when an ad has finished
    // loading.
    mAdView2.setAdListener(new AdListener() {
        @Override
        public void onAdLoaded() {
            mAdView2.setVisibility(View.VISIBLE);
            if (mVideoController.hasVideoContent()) {
                Log.d(LOG_TAG, "Received an ad that contains a video asset.");
            } else {
                Log.d(LOG_TAG, "Received an ad that does not contain a video asset.");
            }
        }
    });

    mAdView2.loadAd(adRequest);

<com.google.android.gms.ads.NativeExpressAdView
    android:id="@+id/adView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    ads:adUnitId="ca-app-pub-000000"
    ads:adSize="300x150"
    android:visibility="gone"
    >
</com.google.android.gms.ads.NativeExpressAdView>

此活动代码

这是xml代码。请帮帮我

inal NativeExpressAdView mAdView2 = (NativeExpressAdView) findViewById(R.id.adView2);
    // Set its video options.
    mAdView2.setVideoOptions(new VideoOptions.Builder()
            .setStartMuted(true)
            .build());

    // The VideoController can be used to get lifecycle events and info about an ad's video
    // asset. One will always be returned by getVideoController, even if the ad has no video
    // asset.
    mVideoController = mAdView2.getVideoController();
    mVideoController.setVideoLifecycleCallbacks(new VideoController.VideoLifecycleCallbacks() {
        @Override
        public void onVideoEnd() {
            Log.d(LOG_TAG, "Video playback is finished.");
            super.onVideoEnd();
        }
    });

    // Set an AdListener for the AdView, so the Activity can take action when an ad has finished
    // loading.
    mAdView2.setAdListener(new AdListener() {
        @Override
        public void onAdLoaded() {
            mAdView2.setVisibility(View.VISIBLE);
            if (mVideoController.hasVideoContent()) {
                Log.d(LOG_TAG, "Received an ad that contains a video asset.");
            } else {
                Log.d(LOG_TAG, "Received an ad that does not contain a video asset.");
            }
        }
    });

    mAdView2.loadAd(adRequest);

<com.google.android.gms.ads.NativeExpressAdView
    android:id="@+id/adView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    ads:adUnitId="ca-app-pub-000000"
    ads:adSize="300x150"
    android:visibility="gone"
    >
</com.google.android.gms.ads.NativeExpressAdView>

Logcat报告

---

你只需要等一会儿。您的广告id是新创建的，因此从google服务器获取广告需要一些时间

我也遇到了错误“无法加载广告0”，但没有问题，只要等待一个小时、2个小时甚至5个小时，你就会收到广告