异步加载广告

Question

我想将广告加载到我的屏幕上，并且我得到了预期的广告，但是问题是由于要加载的项目很多，这会使我的应用变慢。

• 我要异步加载广告，就像其他项目应该先加载广告一样。我在下面粘贴了代码，将广告放入了容器

  static  Widget cinemaView(AsyncSnapshot<List<CinemaModel>> snapshot) {
  return Column(
     children: <Widget>[
     Expanded(
      child: Container(
      child: ListView.builder(
          shrinkWrap: true,
          itemCount: snapshot.data.length,
          itemBuilder: (BuildContext context, int index) {
            return GestureDetector(
              onTap: () {
                Navigator.push(
                    context,
                    new MaterialPageRoute(
                        builder: (context) =>
                            CinemaNewsDetails(id: snapshot.data[index].id)));
              },
              child: Card(
                elevation: 2.0,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: <Widget>[
                    Stack(
                      children: <Widget>[
                        Row(
                          children: <Widget>[
                            new Column(
                              children: <Widget>[
                                Padding(
                                  padding:
                                      EdgeInsets.only(top: 4.0, bottom: 4.0),
                                  child: Padding(
                                    padding: const EdgeInsets.all(4.0),
                                    child: snapshot.data[index].image.isNotEmpty
                                        ? Image.network(
                                            snapshot.data[index].image,
                                            fit: BoxFit.cover,
                                            height: MediaQuery.of(context)
                                                    .size
                                                    .height /
                                                8,
                                            width: MediaQuery.of(context)
                                                    .size
                                                    .width /
                                                4,
                                          )
                                        : Image.network(
                                            'https://lh3.googleusercontent.com/zUofRpElgAioazdFZyPTybX3JKFmuBGS0Z0gPR6xuVm3V9f3xGmpUsdTWzNujJWWc5yq',
                                            fit: BoxFit.cover,
                                          ),
                                  ),
                                )
                              ],
                            ),
                            Expanded(
                                child: Column(
                              children: <Widget>[
                                Align(
                                  alignment: Alignment.topLeft,
                                  child: Padding(
                                    padding: const EdgeInsets.only(left: 8.0),
                                    child: Text(snapshot.data[index].title,
                                        overflow: TextOverflow.ellipsis,
                                        maxLines: 3,
                                        style: TextStyle(
                                            fontWeight: FontWeight.w600)),
                                  ),
                                ),
                                Align(
                                  alignment: Alignment.centerLeft,
                                  child: Padding(
                                    padding: const EdgeInsets.only(
                                        top: 5.0, left: 8.0),
  
                                    child: Text(dateEngine(
                                        snapshot.data[index].publishdate)),
                                  ),
                                ),
                              ],
                            ))
                          ],
                        ),
                      ],
                    ),
                  ],
                ),
              ),
            );
          }),
    ),
  ),
  StreamBuilder<Object>(
    stream: null,
    builder: (context, snapshot) {
      return
  
  
       Container(
        child:  AdmobBanner(
          adSize: AdmobBannerSize.FULL_BANNER,
          adUnitId: unitId,
        ),
      );
    }
  ),
  ],
  );
  }
  

任何帮助将不胜感激