[Swift] How to implement the Twitter login function using Firebase UI ①

Introduction

Since I implemented the Twitter login function using Firebase UI when creating a personal application, We will share the command after the memorandum.

Also, I divided it into three articles because it was too long to write everything in one article. This article is the complete version and the code.

The article about the implementation procedure is below. ・ [Swift] How to implement Twitter login function using Firebase UI ② ・ [Swift] How to implement Twitter login function using Firebase UI ③

environment ・ Swift version 5.3 ・ XCode version 12.3 ・ CocoaPods version 1.10.1

As a premise

-CocoaPods must be installed -Registered in Twitter API -Registered in Firebase console

Completed form

After login Firebase Authentication

You can see that the user has been added.

code

AppDelegate.swift

import UIKit
import Firebase

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        FirebaseApp.configure()
        return true
    }

    // MARK: UISceneSession Lifecycle

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }

}

ViewController.swift

import UIKit
import Firebase
import FirebaseUI

class ViewController: UIViewController, FUIAuthDelegate {

    let authUI = FUIAuth.defaultAuthUI()
    let providers: [FUIAuthProvider] = [
        FUIOAuth.twitterAuthProvider()
    ]
        
    override func viewDidLoad() {
        super.viewDidLoad()
        
        authUI!.delegate = self
        authUI!.providers = providers
        
        checkLoggedIn()
    }
    
    //Login(Login failure)Method called later
    func authUI(_ authUI: FUIAuth, didSignInWith user: User?, error: Error?) {
        // handle user and error as necessary
    }

    func checkLoggedIn() {

        Auth.auth().addStateDidChangeListener{auth, user in
            if user != nil{
                print("success")
            } else {
                print("fail")
                self.login()
            }
        }
    }
    
    func login() {
        let authViewController = authUI!.authViewController()
        self.present(authViewController, animated: true, completion: nil)
    }
}