身份验证状态更改侦听器被激发两次？ [英] Auth state change listener being fired twice?

问题描述

当我的页面加载时，我需要知道用户是否登录，并根据这个执行不同的任务。我做的第一件事就是检查他们是否已经登录，但是由于某些原因， if 语句检查被验证两次。这里是我的代码：

pre $ override func viewDidAppear（_ animated：Bool）{
FIRAuth.auth（）?. addStateDidChangeListener {auth，user
if user = user {
print（User is logged in）
}


当页面加载而不是一次时，用户已登录会被打印两次到控制台。我正在做一些不正确的事情吗？

解决方案

我面临同样的问题。而不是用于登录。它可以面对流动选项
https://firebase.google.com/docs/reference/android/com/google/firebase/auth/FirebaseAuth.AuthStateListener

• 
  
• 当用户登录时


• 当前用户注销时


• 当前用户更改


• 当当前用户令牌发生变化时

所以只是一个标志，然后检查一个。或检查回应 nil 或不是

试试这个方法：

  override func viewDidAppear（_ animated：Bool）{
 FIRAuth.auth（）?. addStateDidChangeListener {auth，user in $ b $ if let user = user {
 if user！= nil {
 print（User is logged in）
} 
} 
  

注意：尝试使用标记并检查 user =！零

When my page loads I need to know whether the user is logged in and perform different tasks based on that. The first thing I do is check if the they are logged in, but for some reason the if statement to check that is being validated twice. Here is my code:

override func viewDidAppear(_ animated: Bool) {
    FIRAuth.auth()?.addStateDidChangeListener { auth, user in
        if let user = user {
           print("User is logged in")
        }

"User is logged in" gets printed out twice to the console when the page loads instead of just once. Am I doing something incorrectly?

解决方案

i faced same problem. and it is not for logged in . it can be faced flowing option https://firebase.google.com/docs/reference/android/com/google/firebase/auth/FirebaseAuth.AuthStateListener

• Right after the listener has been registered
• When a user is signed in
• When the current user is signed out
• When the current user changes
• When there is a change in the current user's token

so just crate a flag then check that one . or check response nil or not

Try this way :

override func viewDidAppear(_ animated: Bool) {
    FIRAuth.auth()?.addStateDidChangeListener { auth, user in
        if let user = user {
            if user != nil {
               print("User is logged in")
           }
        }

Note : try to use both flag and check user =! nil

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