Flutter 参数类型“对象？” 无法分配给参数类型“Map <String，dynamic>”

Question

参数类型“对象？” 无法分配给参数类型“Map<String,dynamic>”。我不明白如何解决这个问题。

 @override
Future<List<Users>?> getAllUsers() async {
QuerySnapshot querySnapshot = await firestore.collection("users").get();
List<Users> allUsers = [];

allUsers = querySnapshot.docs.map((e) => Users.fromMap(e.data())).toList();
return allUsers;
}

Answer 1

QuerySnapshot<Map<String, dynamic>> querySnapshot = await firestore.collection("users").get();