init admob
package ... import ... import com.google.android.gms.ads.MobileAds; import com.google.android.gms.ads.initialization.InitializationStatus; import com.google.android.gms.ads.initialization.OnInitializationCompleteListener; public class MainActivity extends AppCompatActivity { protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); MobileAds.initialize(this, new OnInitializationCompleteListener() { @Override public void onInitializationComplete(InitializationStatus initializationStatus) { } }); } }