Admob Reklamı Görünmüyor

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

MobileAds.initialize(getApplicationContext(), "XXXXXXXXXXXXXXXXXXXXX"); 
          AdView mAdView = (AdView) findViewById(R.id.adView); 
          AdRequest adRequest2 = new AdRequest.Builder().addTestDevice(AdRequest.DEVICE_ID_EMULATOR).build(); 
          mAdView.loadAd(adRequest2);