LogCat中的Google Ads_Error

Question

        <meta-data android:name="com.google.android.gms.version"
         android:value="17"/>

<activity android:name="com.google.android.gms.ads.AdActivity"
          android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"
          android:theme="@android:style/Theme.Translucent" />

 AdView mAdView = (AdView) findViewById(R.id.adView);
    AdRequest adRequest = new AdRequest.Builder().build();
    mAdView.loadAd(adRequest);

import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;

和

  <com.google.android.gms.ads.AdView
            android:id="@+id/adView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_alignParentBottom="true"
            ads:adSize="BANNER"
            ads:adUnitId="@string/banner_ad_unit_id">
    </com.google.android.gms.ads.AdView>

这是链接（github）中的日志错误。