Adding advertising in the application?

I am using this code:

 <com.google.android.gms.ads.AdView android:id="@+id/adView"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   ads:adUnitId="MY_AD_UNIT_ID"
   ads:adSize="BANNER"/>

But is in error :

Description Resource Path Location Type error: No resource identifier
  found for attribute 'loadAdOnCreate' in package 'com.teste.teste1'
  activity_teste.xml /Teste/res/layout line 120 Android AAPT Problem