ref路径不再可用时如何删除Firebase数据库侦听器 [英] How to remove firebase database listener when ref path is no longer available

问题描述

我在React Native应用中使用Firebase，并且我有一个类似于以下的监听器:

I'm using firebase in a react native app and I have a listener similar to this:

firebase.database().ref('users/'+uid+'/items').on('value', function(snapshot){
    ....
})

我要执行的操作是在用户注销时删除该侦听器.我知道我可以像这样使用off()来做到这一点:

What I'm trying to do is to remove that listener when the user logs out. I know that I can do it using off() like:

firebase.database().ref('users/'+uid+'/items').off('value', function(snapshot){
    ....
})

但是，一旦用户注销，我将无法再访问该用户ID.那么如何删除监听器?

But once the user logs out I no longer have access to the user id. So how do I remove the listener?

推荐答案

您需要保留连接侦听器的路径，以便可以在其上调用off().一种方法是:

You'll need to retain the path on which you've attached the listener so that you can call off() on it. One way to do this would be:

mUserRef = firebase.database().ref('users/'+uid+'/items');
mUserRef.on('value', function(snapshot){
    ....
})

再后来:

mUserRef.off('value');

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