Study Swift: Google Sign-In for iOS - Create a GIDSignInButton programmatically in Swift

Update:

May 27, 2016 - Update Step 4 for CocoaPods 1.0.

This tutorial explains how to create a Google Sign-In button without storyboard using Google Sign-In for iOS. The code below was developed in Swift 2 with Xcode 7.2.1.

More information: Google Sign-In iOS SDK Release Notes

Procedure

1. Install CocoaPods. (More information about CocoaPods is written at the bottom of this post.)

Type this command in the terminal:

sudo gem install cocoapods

2. Create an Xcode project and close it.

3. Go to the project directory in the terminal and type:

pod init

4. In the Podfile just created, edit it as below:

pod 'Google/SignIn'

(You may open the Podfile with this command: open -a Xcode Podfile)

Update May 27, 2016:

The above code may not work with the new CocoaPods 1.0. If you see error like this:

The dependency `GoogleMaps` is not used in any concrete target.

Try modify your Podfile as below:

target "Project_name" do

pod 'Google/SignIn'

end

5. Run the terminal and type the command below in the project directory:

pod install

You may see something like this in the terminal:

5. Open the projectName.xcworkspace file just automatically created. (Don't open the original .xcodeproj file)

You may see the project navigator like this with a new Pods folder:

6. We are going to download a configuration file. Just follow the instructions in the Google Sign-In for iOS page.

Click the GET A CONFIGURATION FILE Button.

Enter the App name and iOS Bundle ID. Click CONTINUE TO Choose and configure services.

Click ENABLE GOOGLE SIGN-IN.

Click CONTINUE TO Generate configuration files.

Download the GoogleService-Info.plist file and drag it to the Xcode project.

Click Continue Adding Sign-In. The browser will be redirected to Integrating Google Sign-In into your iOS app.

Select Swift.
Don't select ~~Download the dependencies and configure your Xcode project~~.

7. Open the GoogleService-Info.plist file in the Xcode project. Copy the value of REVERSED_CLIENT_ID.

Select the projectName as Targets. Select Info -> URL Types -> + sign.

Paste the value you just copied into URL Schemes. Give the Identifier any name you like, such as REVERSED_CLIENT_ID.

Select the + sign again and paste the bundle identifier in URL Schemes.

8. Add a temporary Objective-C file to your project. You may give it any name you like.

Select Create Bridging Header to configure an Objective-C bridging header.

Delete the temporary Objective-C file you just created.

8. In the projectName-Bridging-Header.h file just created, add this line:

#import <Google/SignIn.h>

9. Replace the AppDelegate.swift file with this file from GitHub. Put comment characters with these lines to remove warnings:

//let userId = user.userID // For client-side use only!

//let idToken = user.authentication.idToken // Safe to send to the server

let name = user.profile.name

//let email = user.profile.email

10. Edit ViewController.swift as below:

import UIKit

class ViewController: UIViewController, GIDSignInUIDelegate {

var btnSignIn : GIDSignInButton!

var btnSignOut : UIButton!

var btnDisconnect : UIButton!

var label : UILabel!

override func viewDidLoad() {

super.viewDidLoad()

GIDSignIn.sharedInstance().uiDelegate = self

btnSignIn = GIDSignInButton(frame: CGRectMake(0,0,230,48))

btnSignIn.center = view.center

btnSignIn.style = GIDSignInButtonStyle.Standard

view.addSubview(btnSignIn)

btnSignOut = UIButton(frame: CGRectMake(0,0,100,30))

btnSignOut.center = CGPointMake(view.center.x, 100)

btnSignOut.setTitle("Sign Out", forState: UIControlState.Normal)

btnSignOut.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

btnSignOut.setTitleColor(UIColor.cyanColor(), forState: UIControlState.Highlighted)

btnSignOut.addTarget(self, action: "btnSignOutPressed:", forControlEvents: UIControlEvents.TouchUpInside)

view.addSubview(btnSignOut)

btnDisconnect = UIButton(frame: CGRectMake(0,0,100,30))

btnDisconnect.center = CGPointMake(view.center.x, 200)

btnDisconnect.setTitle("Disconnect", forState: UIControlState.Normal)

btnDisconnect.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

btnDisconnect.setTitleColor(UIColor.cyanColor(), forState: UIControlState.Highlighted)

btnDisconnect.addTarget(self, action: "btnDisconnectPressed:", forControlEvents: UIControlEvents.TouchUpInside)

view.addSubview(btnDisconnect)

label = UILabel(frame: CGRectMake(0,0,200,100))

label.center = CGPointMake(view.center.x, 400)

label.numberOfLines = 0 //Multi-lines

label.text = "Please Sign in."

label.textAlignment = NSTextAlignment.Center

view.addSubview(label)

NSNotificationCenter.defaultCenter().addObserver(self,

selector: "receiveToggleAuthUINotification:",

name: "ToggleAuthUINotification",

object: nil)

toggleAuthUI()

}

func btnSignOutPressed(sender: UIButton) {

GIDSignIn.sharedInstance().disconnect()

label.text = "Disconnecting."

}

func btnDisconnectPressed(sender: UIButton) {

label.text = "Signed out."

toggleAuthUI()

}

func toggleAuthUI() {

if (GIDSignIn.sharedInstance().hasAuthInKeychain()){

// Signed in

btnSignIn.hidden = true

btnSignOut.hidden = false

btnDisconnect.hidden = false

} else {

btnSignIn.hidden = false

btnSignOut.hidden = true

btnDisconnect.hidden = true

}

deinit {

NSNotificationCenter.defaultCenter().removeObserver(self,

name: "ToggleAuthUINotification",

object: nil)

}

@objc func receiveToggleAuthUINotification(notification: NSNotification) {

if (notification.name == "ToggleAuthUINotification") {

self.toggleAuthUI()

if notification.userInfo != nil {

let userInfo:Dictionary<String,String!> =

notification.userInfo as! Dictionary<String,String!>

self.label.text = userInfo["statusText"]

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

}

The above code is derived from Google's ViewController.swift example.

Various Sign-In Button Sizes (See GIDSignInButton Class):

GIDSignInButtonStyle.Standard => 230x48
GIDSignInButtonStyle.Wide => 312x48
GIDSignInButtonStyle.IconOnly => 48x48

11. If you build the code now, you'll see this error:

clang: error: linker command failed with exit code 1 (use -v to see invocation)

Try to disable the bitcode:

Targets -> Build Settings -> Build Options -> Enable Bitcode (Search: bitcode) -> No

12. Build and run the code. It should work.

Result

Press the Sign in button.

Enter the ID (Gmail address) and password.

Press Allow.

The username is displayed.

=============

Additional Information

Some CocoaPods commands for reference:

1. Check the CocoaPods version installed:
pod --version

2. Check if CocoaPods framework of a project is outdated:

Go to the directory including the Podfile. Type:

pod outdated

The pod outdated command also checks if new CocoaPods version is available.

3. Update CocoaPods using the install command:

sudo gem install cocoapods

4. Update CocoaPods to a pre-release version:

sudo gem install cocoapods --pre

5. Update local repositories:

pod update