我在尝试从firebase获取数据并更新值时遇到了麻烦。
我有一个餐馆名称和它被选中的次数（用户选择去那个餐馆吃饭）。我试图检索numPicked，如果用户决定再次去那里，我就通过添加一个来更新它。
在这里，我试图获取一个特定的文档，并试图存储docID和变量，我需要更新。

Future<bool> searchQuery(
      {required String restaurantName,
      required var userID,
      required db}) async {
    int addOne = 1; //addes one if it has been picked

//this is not working
    try {
      Query query2 =
          db.where('userId', isEqualTo: FirebaseAuth.instance.currentUser!.uid);
      Query query = query2.where('restaurantName', isEqualTo: restaurantName);
      await query.get().then((querySnapshot) {
        // ignore: avoid_function_literals_in_foreach_calls
        querySnapshot.docs.forEach((doc) {
          docID = doc.id;
          numPicked = doc['numPicked'];
          restaurantExist = true;
        
        });
      }).catchError((error) {
        // print('error querying: #error');
      });
    } catch (ex) {
      // ignore: avoid_print
      print(ex);
    }

//this is not working

    int totalPicked = numPicked + addOne;
//if the restaurant exist then update the numpicked for that specific restaurant
    if (restaurantExist) {
      try {
        var query = db
            //.collection('NumRestaurantPicked')
            .doc(docID);
        await query.update({'numPicked': totalPicked.toString()});
      } catch (ex) {}
    }
    return restaurantExist;
  }