flutter - 如何在 ListView 中快速显示广告？

Question

我一直试图在flutter应用中展示广告，而我使用的软件包是admob_flutter。我正在尝试在单独的列表 View 中展示广告，这是它的代码:-

class ListWithAds extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    List example = ['a', 'b', 'c', 'd', 'e'];
    return Container(
      child: ListView.separated(
          itemBuilder: (context, index) {
            return Card(child: Text(example[index]));
          },
          separatorBuilder: (context, index) {
            return Container(
              child: Card(
                  color: Colors.white,
                  child: AdmobBanner(
                      adUnitId: "ca-app-pub-3940256099942544/6300978111",
                      adSize: AdmobBannerSize.SMART_BANNER)),
            );
          },
          itemCount: example.length),
    );
  }
}

但是我得到了错误:

the getter 'length' was called on null

如何更正此错误并在列表 View 中获取广告？

Answer 1

只需将exmaple数组移出构建方法，例如:

List example = ['a', 'b', 'c', 'd', 'e'];

class ListWithAds extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
  
    return Container(
      child: ListView.separated(
          itemBuilder: (context, index) {
            return Card(child: Text(example[index]));
          },
          separatorBuilder: (context, index) {
            return Container(
              child: Card(
                  color: Colors.white,
                  child: AdmobBanner(
                      adUnitId: "ca-app-pub-3940256099942544/6300978111",
                      adSize: AdmobBannerSize.SMART_BANNER)),
            );
          },
          itemCount: example.length),
    );
  }
}