package testiklan.com.test;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.InterstitialAd;

public class MainActivity extends AppCompatActivity {
    private String TAG = MainActivity.class.getSimpleName();
    InterstitialAd mInterstitialAd;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mInterstitialAd = new InterstitialAd(this);

        // set the ad unit ID
        mInterstitialAd.setAdUnitId(Iklan.Interstitial);

        AdRequest adRequest = new AdRequest.Builder()
                .build();

        // Load ads into Interstitial Ads
        mInterstitialAd.loadAd(adRequest);

        mInterstitialAd.setAdListener(new AdListener() {
            public void onAdLoaded() {
                showInterstitial();
            }
        });
    }

    private void showInterstitial() {
        if (mInterstitialAd.isLoaded()) {
            mInterstitialAd.show();
        }
    }

}


===========

package testiklan.com.test;

public class Iklan {
    public static String Interstitial = "ca-app-pub-3940256099942544/1033173712";
    public static String DEVELOPER_NAME = "";
}