Flutter中如何将登录获取的邮箱传递给CustomerInfo类调用getCustomerData

• 你在LoginScreen中创建的CustomerInfo(email: email)是局部临时实例，没有传递给CustomerScreen，跳转完成后就被系统回收
• CustomerScreen中CustomerInfo customerInfo = CustomerInfo();是新创建的空实例，没有传入邮箱参数，所以调用getCustomerData()时email属性为null，自然查不到数据

步骤1：给CustomerScreen添加接收邮箱的构造参数 #

修改CustomerScreen的Widget定义：

class CustomerScreen extends StatefulWidget {
  // 新增邮箱接收参数
  final String? email;
  const CustomerScreen({Key? key, this.email}) : super(key: key);

  @override
  _CustomerScreenState createState() => _CustomerScreenState();
}

步骤2：修改LoginScreen跳转逻辑，传递邮箱 #

删掉无用的临时CustomerInfo实例，跳转时把邮箱传给CustomerScreen：

if (user != null) {
  Navigator.push(
      context,
      MaterialPageRoute(
          builder: (context) => CustomerScreen(email: email)));
}

步骤3：修改CustomerScreen的getData方法，传邮箱给CustomerInfo #

获取数据后记得调用setState更新页面UI：

void getData() async {
  // 把页面拿到的邮箱传给CustomerInfo
  CustomerInfo customerInfo = CustomerInfo(email: widget.email);
  await customerInfo.getCustomerData();

  setState(() {
    name = customerInfo.name;
    surname = customerInfo.surname;
    balance = customerInfo.balance;
    image = customerInfo.avatarLink;
  });
  print("Name: $name");
}

登录成功后FirebaseAuth会全局保存当前用户的信息，不需要手动跨页传递邮箱，更稳妥：
直接修改CustomerScreen的getData方法即可：

void getData() async {
  // 直接从FirebaseAuth获取当前登录用户的邮箱
  String? loginEmail = FirebaseAuth.instance.currentUser?.email;
  CustomerInfo customerInfo = CustomerInfo(email: loginEmail);
  await customerInfo.getCustomerData();

  setState(() {
    name = customerInfo.name;
    surname = customerInfo.surname;
    balance = customerInfo.balance;
    image = customerInfo.avatarLink;
  });
}

内容的提问来源于stack exchange，提问作者themmfa