如何在Flutter 的 initState 中初始化 Firestore 查询

我正在try 从FiRestore加载数据，在StreamBuilder的帮助下，我正在获取相应的数据并将其显示给用户.

我将这个值传递给一个名为‘Total’的变量，这个合计值被转换为0，当我试图显示这个合计值时，它首先应该是缺省的(0)值，它从FiRestore中获取值.

下面您可以看到代码

            StreamBuilder<DocumentSnapshot>(
                stream: FirebaseFirestore.instance.collection('UserData').doc(getUid()).snapshots(),
                builder: (context, AsyncSnapshot<DocumentSnapshot> snapshot) {
                  if (!snapshot.hasData) return const Text("Loading...");
                  final DocumentSnapshot? document = snapshot.data;
                  final Map<String, dynamic> documentData = document?.data() as Map<String, dynamic>;

                  accountList = (documentData['accounts'] as List).map((accountList) => accountList as Map<String, dynamic>).toList();
                  // getTotalFund(accountList);
                  List amountData=[];
                  double convertAmount;

                  for(int i=0; i<accountList.length;i++){
                    if(accountList[i]['accountType'] == 'Savings' || accountList[i]['accountType'] == 'Cash' ){
                      amountData.add(double.parse(accountList[i]['amountBalance'].replaceAll(',','')));
                    }
                  }
                  convertAmount = amountData.reduce((value, element) => value + element);
                  totalFund = amountFormat.format(convertAmount);

                  return Text(
                    documentData['name'],
                    style: const TextStyle(
                      fontSize: 16,
                      fontFamily: "Gilroy SemiBold",
                    ),
                  );
                }),

我在文本小部件中获得的值总金额.

Text('\u{20B9} ', style: TextStyle(color: Color(0xff9c9c9c), fontFamily: "Gilroy Medium", fontSize: 23)),
Text(totalFund.toString(),style: const TextStyle(color: Colors.black, fontFamily: "Gilroy Bold", fontSize: 35)),

如何在initState中加载totalFund，使其不会显示空值.