I'm trying to implement a login feature in my Swift app using Firebase Authentication. How can I check if a user is already logged in and redirect them to the home screen if they are?
I followed the Firebase Authentication documentation and was able to successfully set up my login flow with email and password. However, when a user opens the app and has already logged in previously, I want to check if they are already authenticated and automatically redirect them to the home screen. To do this, I tried using the addStateDidChangeListener method to listen for changes in the user's authentication state, but I'm not sure how to use this information to automatically redirect the user. I was expecting that if the user was already logged in, the listener would detect this and trigger a redirection to the home screen
you can use the Auth.auth().addStateDidChangeListener method to listen for changes in the user's authentication state inside your root view controller or main view controller.
When the listener is triggered, you can check whether the user is logged in by accessing the Auth.auth().currentUser property. If the user is logged in, you can use the performSegue method to programmatically transition to the home screen
Here's an example of how this might look in code:
import Firebase
class MainViewController: UIViewController {
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
Auth.auth().addStateDidChangeListener { [weak self] (auth, user) in
if let user = user {
// User is logged in, so redirect to home screen
self?.performSegue(withIdentifier: "HomeSegue", sender: self)
}
}
}
}
In your viewcontroller u can check like this.
if Auth.auth().currentUser != nil {
// User is already authenticated, redirect to home screen
// Redirect them to home screen
}else{
//user not logged in
//show login view
}
Related
I am in the process of adding the Create new user Method for Firebase. I have already completed the SignUp Auth process. However when users are creating a new account. How do I go about this if I have multiple ViewControllers?
For example,
The First SignUpViewController - User is asked to enter their email address.
When the user clicks next. This is then followed by another ViewController.
SecondViewControlle - User is asked to enter their name and create a password.
After this, The user is greeted with a Welcome page with their name they submitted. (Welcome to “App Name” Name). Which will then proceed to the home UI after next is clicked.
How do I implement The Auth.auth().CreateUserwith func when I have more than one ViewController? Is there a way to save the email and password using two different ViewControllers?
Update**
I have added the following code that was suggested below, however the App crashes every time I click next on the enter your " Email" View Controller. I am getting this warning. Does anyone know what I did wrong? The rest of the code seems to be working fine. Here is a screenshot.
You can save all information in a Dictionary and use it at the time of SignUp. In your AppDelegate class:
/// Instance of AppDelegate
static let shared: AppDelegate = UIApplication.shared.delegate as! AppDelegate
/// Dictionary for user information
var userInformation: Dictionary<String, Any> = [:]
On Email Screen - Next Button Click
/// #1. Validate the email address
/// #2. Save it in Dictionary
AppDelegate.shared.userInformation["email"] = "xyz#gmail.com" or tFEmail.text.lowercased()
Then On name and password screen
AppDelegate.shared.userInformation["name"] = "xyz" or tFName.text
AppDelegate.shared.userInformation["password"] = "xxxxxxx" or tFPassword.text
Now on last screen - Sign Up Button clicked you can use all this information
let email = AppDelegate.shared.userInformation["email"]
let name = AppDelegate.shared.userInformation["name"]
let password = AppDelegate.shared.userInformation["password"]
Implement the Firebase SignUp method and after successfully logged in show the welcome screen.
I'm fairly new to the whole Swift thing, but I'm trying to make a simple login screen where if the user is not logged in, it redirects them to a login page. I seem to have something not write in the code as when I click on the tab to take me to the login page as I'm not logged in nothing comes Up? When I type in the code, Xcode says everything is fine but I've named the root loginView and everything seems to be alright, but when I load it nothing happens it just come up with the page as If you were logged in.
Any ideas?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func viewDidAppear(_ animated: Bool)
{
self.performSegue(withIdentifier: "loginView", sender: self);
}
}
As you do not get any errors I believe you've correctly named your segue right? if that's the case. Please make sure you're doing as following:
Let's assume you have 2 View Controllers one is the main page that logged in users can go (we name it LandingVC) and the other one is the login view controller (we call it LoginVC).
First thing to check: make sure you're writing the code in LandingVC ?
Second: Have you assigned the class to VCs in StoryBoard? (see picture for reference)
I getting trying to get familiar with FB's newest IOS SDK (4.0.1). I've integrated it into an IOS8 Swift project and using the FBSDKLoginButton to log users in and out. I want the application to skip showing the Login view controller if the user has already logged in.
Should I just be checking the return result of FBSDKAccessToken currentAccessToken()? Does this return 'nil' if a user is not logged in? The docs have the following to say about this method:
You can load this with the SDK from a keychain cache or from an app
bookmark when your app cold launches. You should check its
availability in your view controller's viewDidLoad.
Something like:
// LoginViewController.swift
override func viewDidLoad() {
super.viewDidLoad()
if(FBSDKAccessToken.currentAccessToken()){
//They are logged in so show another view
}else{
//They need to log in
}
}
So this sounds like it might be what I'm looking for but I can't really tell from this description. How are the good people of SO handling this common use case? :)
-Nick
Yes, FBSDKAccessToken.currentAccessToken() is what you should be checking although the code you have won't work as this does not return a Boolean. You'll need something like:
if(FBSDKAccessToken.currentAccessToken() != nil) {
//They are logged in so show another view
} else {
//They need to log in
}
Also, this alone only works for when the app moves between foreground/background (user hits home button). If the app is killed and cold launched the token will be lost unless you implement the following in didFinishlaunchingWithOptions in the AppDelegate:
return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
You do not need to worry about the keychain as this is handled for you automatically provided you implement the necessary parts.
The following website has a good tutorial of getting a simple example working: http://www.brianjcoleman.com/tutorial-how-to-use-login-in-facebook-sdk-4-0-for-swift/
I have a login screen which is saying "SingnIn" when user is clicking on that he getting a pop of facebook login screen.
I want that if somebody successfully logged in, I want to change SignIn text with their name. But I am not getting place where I should write that part of code. Which view function load again after pop screen exit.
If you implemented facebook connect and if you meant facebook login then after login you can write code in facebook delegate method.
- (void)session:(FBSession*)session didLogin:(FBUID)uid {
//Write code here for changing label for user name
}
i have the default login button of fbconnect sdk . i tap it and i connect then i post to my facebook profile something. when the post is finished i see that the button has changed to logout . how can i detect when the user presses the logout button in order to dissapear another button i have on my uiview?
The obvious and easiest way is to know what is the status of the button. If the user is already loggined, the status of the button will say "Log out", and when user clicks on it, you just handling the event and call logout.
Now, how can you know that user is loggined? There is a method in FBConnect in FBSession classes.
[_session isConnected]; returns true if user is loggined and return false if user is not. And I think that you already have stored your session variable somewhere to call login