Firebase iOS Google sign in -- use of undeclared type GIDSignInDelegate

Question

I'm following the guide here to develop an iOS application using Firebase. This is literally my first day of iOS dev, so first I want to ask if anyone has any awesome iOS Swift development textbooks or tutorials?

After following the guide (in the link) I'm getting this error everywhere, use of undeclared type GIDSignInDelegate

For example, in the AppDelegate class declaration...

class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDelegate, GIDSignInDelegate {

I see other types in class declarations such as UIResponder and UIApplicationDelegate. Where are these types defined?

I'm guessing that I'm simply missing the type definitions.

I've created a header file Basketball-Vision-Bridging-Header.h and imported #import <GoogleSignIn/GoogleSignIn.h>

Do I have to somehow link that file?

I've added the following to my Podfile

pod 'Firebase'
pod 'Firebase/Auth'
pod 'GoogleSignIn'

UPDATE

I found out I was missing these dependencies:

import Google
import GoogleSignIn

But now when I imported these, I get the error type 'AppDelegate' does not conform to protocol 'GIDSignInDelegate'

Here is the full code for AppDelegate

import UIKit
import Firebase
import Google
import GoogleSignIn

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDelegate, GIDSignInDelegate {

    var window: UIWindow?

    func signIn(signIn: GIDSignIn!, didSignInForUser user: GIDGoogleUser!,
                withError error: NSError!) {
        if let error = error {
            print(error.localizedDescription)
            return
        }
        // ...
    }

    func signIn(signIn: GIDSignIn!, didDisconnectWithUser user:GIDGoogleUser!,
                withError error: NSError!) {
        // Perform any operations when the user disconnects from app here.
        // ...
    }

    func application(application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?)
        -> Bool {
            // Use Firebase library to configure APIs
            FIRApp.configure()

            GIDSignIn.sharedInstance().clientID = FIRApp.defaultApp()?.options.clientID
            GIDSignIn.sharedInstance().delegate = self
            return true
    }

    openURL url: NSURL, options: [String: AnyObject]) -> Bool {
    return GIDSignIn.sharedInstance().handleURL(url,
    sourceApplication: options[UIApplicationOpenURLOptionsSourceApplicationKey] as? String,
    annotation: options[UIApplicationOpenURLOptionsAnnotationKey])
    }

    openURL url: NSURL, sourceApplication: String?, annotation: AnyObject?) -> Bool {
    var options: [String: AnyObject] = [UIApplicationOpenURLOptionsSourceApplicationKey: sourceApplication,
    UIApplicationOpenURLOptionsAnnotationKey: annotation]
    return GIDSignIn.sharedInstance().handleURL(url,
    sourceApplication: sourceApplication,
    annotation: annotation)
    }

//    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
//        // Override point for customization after application launch.
//        let splitViewController = self.window!.rootViewController as! UISplitViewController
//        let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as! UINavigationController
//        navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem
//        splitViewController.delegate = self
//        return true
//    }

    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }

    // MARK: - Split view

    func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController:UIViewController, onto primaryViewController:UIViewController) -> Bool {
        guard let secondaryAsNavController = secondaryViewController as? UINavigationController else { return false }
        guard let topAsDetailController = secondaryAsNavController.topViewController as? DetailViewController else { return false }
        if topAsDetailController.detailItem == nil {
            // Return true to indicate that we have handled the collapse by doing nothing; the secondary controller will be discarded.
            return true
        }
        return false
    }

}

Answer 1

From your code, its vivid that you're currently running Swift 3.0 but some of your methods are still Swift 2. For Swift 3.0, the new delegate method is

func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error!)
{
    if error != nil
    {
        print("Google Sign In Error")        
    }
    else
    {
        // Do stuff
    }
}

openURL, didFinishLaunchingWithOptions and didDisconnectWithUser also have changed in Swift 3.0. I'd recommend you re-implement them.