private void requestAdapterRewardedAd() {
  RewardedAdLoadCallback adLoadCallback = new RewardedAdLoadCallback() {
    @Override
    public void onRewardedAdLoaded() {
      adapterRewardedButton.setEnabled(true);
    }

    @Override
    public void onRewardedAdFailedToLoad(int errorCode) {
      Toast.makeText(MainActivity.this,
          String.format("Rewarded ad failed to load with code %d", errorCode),
          Toast.LENGTH_LONG).show();
      adapterRewardedButton.setEnabled(true);
    }
  };
  rewardedAd = new RewardedAd(this, getString(R.string.adapter_rewarded_ad_unit_id));
  rewardedAd.loadAd(new AdRequest.Builder().build(), adLoadCallback);
}
 

private void requestCustomEventRewardedAd() {
  RewardedAdLoadCallback adLoadCallback = new RewardedAdLoadCallback() {
    @Override
    public void onRewardedAdLoaded() {
      customEventRewardedButton.setEnabled(true);
    }

    @Override
    public void onRewardedAdFailedToLoad(int errorCode) {
      Toast.makeText(MainActivity.this,
          String.format("Rewarded ad failed to load with code %d", errorCode),
          Toast.LENGTH_LONG).show();
      customEventRewardedButton.setEnabled(true);
    }
  };
  customEventRewardedAd = new RewardedAd(this,
      getString(R.string.customevent_rewarded_ad_unit_id));
  customEventRewardedAd.loadAd(new AdRequest.Builder().build(), adLoadCallback);
}