code: private boolean canUseThisAd(NativeAd adNative) {
          if (adNative != null) {
              NativeAd.Image logoImage = null;
              CharSequence header = null, body = null;
              if (adNative instanceof NativeContentAd) {
                  NativeContentAd ad = (NativeContentAd) adNative;
                  logoImage = ad.getLogo();
                  header = ad.getHeadline();
                  body = ad.getBody();
              } else if (adNative instanceof NativeAppInstallAd) {
                  NativeAppInstallAd ad = (NativeAppInstallAd) adNative;
                  logoImage = ad.getIcon();
                  header = ad.getHeadline();
                  body = ad.getBody();
              }
  
              if (!TextUtils.isEmpty(header)
                      && !TextUtils.isEmpty(body)) {
                  return true;
              }
          }
          return false;
      }
docs: Determines if the native ad can be used.
  
  @param adNative the native ad object
  @return <code>true</code> if the ad object can be used, false otherwise