如何在Flutter中重置Firebase侦听器 [英] How to reset Firebase listeners in Flutter

问题描述

我正在创建一个Flutter应用程序，该应用程序允许用户拥有多个帐户。当用户通过应用程序注销时，它将带他们进入登录屏幕，他们可以登录另一个帐户。我看到的问题是Firebase正在提取新的帐户数据并将其与以前的帐户数据合并。我假设听众没有断开连接，这会导致问题。如何重置Firebase监听器，类似于用户打开应用程序？以下是我的听众的一个例子。谢谢您的帮助或建议。

I am creating a Flutter app that allows a user to have multiple accounts. When the user logout via the app it will bring them to a login screen which they can login to another account. The issue i am seeing is the firebase is pulling in the new account data and merging it with the previous account data. I am assuming that the listeners were not disconnected which cause the issue. How do I reset the Firebase listeners similar to the user opening the app? Below is an example of my listener I have. Thanks for any help or suggestions.

FirebaseDatabase.instance
        .reference()
        .child("accounts")
          ..onChildAdded
              .listen((event) => OnAddedAction(event)))
          ..onChildChanged
              .listen((event) => OnChangedAction(event)))
          ..onChildRemoved
              .listen((event) => OnRemovedAction(event))))); 

推荐答案

您需要存储订阅并致电 cancel（）：

You need to store the subscriptions and call cancel() on them:

var ref = FirebaseDatabase
            .instance
            .reference()
            .child("accounts");

var sub1 = ref.onChildAdded
              .listen((event) => OnAddedAction(event));
var sub2 = ref..onChildChanged
              .listen((event) => OnChangedAction(event))
var sub3 = ref.onChildRemoved
              .listen((event) => OnRemovedAction(event)); 

...

@override
dispose() {
  sub1?.cancel();
  sub2?.cancel();
  sub3?.cancel();
  super.dispose();
}

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