Flutter firestore 保存 id 到列表

Question

how can I save all document Ids From firestore inside a list? Thats what I tried but I couldn't manage to only save the ID:

    List ticketIds = [];
    
    getTicketIds() async {
      SharedPreferences prefs = await SharedPreferences.getInstance();
      ticketIds = await FirebaseFirestore.instance
          .collection("users")
          .doc(prefs.getString("userId"))
          .collection("tickets")
          .get()
          .then((val) => val.docs);

Answer 1

Hello you need to loop trough the docs and you can retreive the docs id, here is the code:

 Future<List<String>> getTicketIds() async {
   SharedPreferences prefs = await SharedPreferences.getInstance();
   List<String> ticketIds = await FirebaseFirestore.instance
     .collection("users")
     .doc(prefs.getString("userId"))
     .collection("tickets")
     .get()
     .then((val) {
      List<String> idOfDocuments = [];
      val.docs.forEach((element) {
         idOfDocuments.add(element.id);
      });

      return idOfDocuments;
  });

  return ticketIds;
 }