当 Stream 将触发新事件时无法读取节点更改。火力地堡数据库 v9

Question

适用于 firebase 数据库 v8，但不适用于 v9。从我从其他用户那里读到的-Firebase v9，他们从使用动态转向了对象？ . 我无法在我的代码中实施更改。你能看看吗？更多关于这个

     StreamSubscription<DatabaseEvent>? rideStreamSubscription;
      rideStreamSubscription = rideRequestRef!.onValue.listen((DatabaseEvent event) async {
       
        if (event.snapshot.value["car_details"] != null) {
          carDetailsDriver = (event.snapshot.value["car_details"].toString());
          Provider.of<AppData>(context, listen: false)
              .carDetailsDriverMainScreen(carDetailsDriver);

          if (event.snapshot.value!["driver_id"] != null) {
            rideReqAcceptDriver =
                (event.snapshot.value["driver_id"].toString());
            print("rideReqAcceptDriver $rideReqAcceptDriver");
          }
        }

错误在 event.snapshot.value["car_details"]

The method '[]' can't be unconditionally invoked because the receiver can be 'null'. Try making the call conditional (using '?.') or adding a null check to the target ('!')

以及 event.snapshot.value!["driver_id"]

The operator '[]' isn't defined for the type 'Object'. Try defining the operator '[]'

Answer 1

试试这个。

StreamSubscription<DatabaseEvent>? rideStreamSubscription;
  rideStreamSubscription = rideRequestRef!.onValue.listen((DatabaseEvent event) async {
    dynamic data = event.snapshot.value;
    if (data["car_details"] != null) {
      carDetailsDriver = (data["car_details"].toString());
      Provider.of<AppData>(context, listen: false)
          .carDetailsDriverMainScreen(carDetailsDriver);

      if (data["driver_id"] != null) {
        rideReqAcceptDriver =
            (data["driver_id"].toString());
        print("rideReqAcceptDriver $rideReqAcceptDriver");
      }
    }

当 Stream 将触发新事件时无法读取节点更改。火力地堡数据库 v9

Unable to read node changes when the Stream will fire a new event. firebase database v9

dart

firebase-realtime-database

flutter