在flutter中使用流生成器时，我不断收到轻微的null错误 [英] I keep getting a slight null error when using stream builder in flutter

问题描述

在显示我的商品之前，我总是收到一个轻微的null错误.请问我能否获得使用streambuilder的最佳方式的帮助，而不会遇到任何错误?

I keep getting a slight null error before displaying my items. Please can I get help on the best way to use streambuilder without encountering any error?

推荐答案

使用 ConnectionState :

          StreamBuilder(
            stream:  Firestore.instance.collection('stores').document(currentUserUID).snapshots(),
            builder: (context, AsyncSnapshot<DocumentSnapshot> snapshot) {
              if (snapshot.connectionState == ConnectionState.done) {
                return ListView.builder(
                    shrinkWrap: true,
                    itemCount: 1,
                    itemBuilder: (BuildContext context, int index) {
                      return ListTile(
                          contentPadding: EdgeInsets.all(8.0),
                          title: Text(snapshot.data.data["about"]),
                          leading: Text(
                            snapshot.data.data["location"],
                          ));
                    });
              } else if (snapshot.connectionState == ConnectionState.none) {
                return Text("No data");
              }
              return CircularProgressIndicator();
            },
          ),

https://api.flutter.dev/flutter/widgets/ConnectionState-class.html

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