exemplo_googleads_layout.dart

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text(
          Constants.APP_NAME,
        ),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Expanded(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const Text(
                  Constants.APP_NAME,
                ),
                const SizedBox(
                  height: 10,
                ),
                ElevatedButton(
                    onPressed: () => _showInterstitialAd(),
                    child: const Text("Abrir Intertiscial"))
              ],
            ),
          ),
          _bannerAd != null
              ? Container(
                  height: 50,
                  color: Colors.white10,
                  child: SizedBox(
                    height: _bannerAd!.size.height.toDouble(),
                    width: _bannerAd!.size.width.toDouble(),
                    child: AdWidget(ad: _bannerAd!),
                  ),
                )
              : Container()
        ],
      ),
    );
  }