AdMob interstial adapter for Appnext

I needed intergration Appnext into AdMob mediation bt there was not AdMob adapter, so I wrote one. Please note this adapter uses Appnext's Activities & not in-activity popups.

package com.appnext.appnextsdk;

import android.content.Context;
import android.os.Bundle;

import com.google.android.gms.ads.mediation.MediationAdRequest;
import com.google.android.gms.ads.mediation.customevent.CustomEventInterstitial;
import com.google.android.gms.ads.mediation.customevent.CustomEventInterstitialListener;

public class AppnextAdMobAdapter implements CustomEventInterstitial {
 private CustomEventInterstitialListener mCustomEventInterstitialListener;
 private String mPlacementId;
 private Context mContext;
 
 @Override
 public void onDestroy() {
 }

 @Override
 public void onPause() {
 }

 @Override
 public void onResume() {
 }

 @Override
 public void requestInterstitialAd(Context context,
            CustomEventInterstitialListener listener,
            String serverParameter,
            MediationAdRequest mediationAdRequest,
            Bundle customEventExtras) {
  mContext = context;
  mPlacementId = serverParameter;
  mCustomEventInterstitialListener = listener;

  if (mCustomEventInterstitialListener != null)
   mCustomEventInterstitialListener.onAdLoaded();
 }

 @Override
 public void showInterstitial() {
  PopupActivity.setAdLoadInterface(new OnAdLoadInterface() {   
   @Override
   public void adLoaded() {
    if (mCustomEventInterstitialListener != null)
     mCustomEventInterstitialListener.onAdLoaded();
   }
  });
  PopupActivity.setNoAdsInterface(new NoAdsInterface() {   
   @Override
   public void noAds() {
    if (mCustomEventInterstitialListener != null)
     mCustomEventInterstitialListener.onAdFailedToLoad(0);
   }
  });
  PopupActivity.setPopupOpenedInterface(new PopupOpenedInterface() {   
   @Override
   public void popupOpened() {
    if (mCustomEventInterstitialListener != null)
     mCustomEventInterstitialListener.onAdOpened();
   }
  });
  PopupActivity.setPopupClickedCallback(new PopupClickedInterface() {
   @Override
   public void popupClicked() {
    if (mCustomEventInterstitialListener != null)
     mCustomEventInterstitialListener.onAdClicked();
   }
  });
  PopupActivity.setPopupClosedCallback(new PopupClosedInterface() {   
   @Override
   public void popupClosed() {
    if (mCustomEventInterstitialListener != null)
     mCustomEventInterstitialListener.onAdClosed();
   }
  });

  Appnext.showPopupInActivity(mContext, mPlacementId, false);
 }
}