FirebaseAuthApp

Simple Xamarin.Forms cross-platform (Android & iOS) application presenting Firebase Authentication.

Remember to add Android & iOS applications to your Firebase project and download google services confing files. Put the files to the correct directories and change Build Action in the properties:

• FirebaseAuthApp\FirebaseAuthApp.Android\google-services.json (Build Action -> GoogleServicesJson),
• FirebaseAuthApp\FirebaseAuthApp.iOS\GoogleService-Info.plist (Build Action -> BundleResource).

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#0. Wanna cofigure your own cross-platform Fireabase Authentication project?

There are a few things you need to do in order to make Firebase Authentication working on both (Android & iOS) operating systems.

#1. Start by creating new blank project for Android & iOS in the Visual Studio.

#2. Configure shared project.

• create IFirebaseAuthentication in shared project:

using System.Threading.Tasks;

namespace FirebaseAuthApp
{
    public interface IFirebaseAuthentication
    {
        Task<string> LoginWithEmailPassword(string email, string password);
        Task<string> RegisterWithEmailPassword(string email, string password);
    }
}

#3. Configure Android project.

• add Xamarin.Firebase.Auth dependency using NuGet package manager,
• create FirebaseAuthentication implementing IFirebaseAuthentication interface:

using Firebase.Auth;
using FirebaseAuthApp.Droid;
using System.Threading.Tasks;
using Xamarin.Forms;

[assembly: Dependency(typeof(FirebaseAuthentication))]
namespace FirebaseAuthApp.Droid
{
	public class FirebaseAuthentication : IFirebaseAuthentication
	{
		public async Task<string> LoginWithEmailPassword(string email, string password)
		{
			var user = await FirebaseAuth.Instance.SignInWithEmailAndPasswordAsync(email, password);
			var token = await user.User.GetIdTokenAsync(false);
			return token.Token;
		}

		public async Task<string> RegisterWithEmailPassword(string email, string password)
		{
			var user = await FirebaseAuth.Instance.CreateUserWithEmailAndPasswordAsync(email, password);
			var token = await user.User.GetIdTokenAsync(false);
			return token.Token;
		}
	}
}

• in YourAppName.Android.csproj (FirebaseAuthApp.Android.csproj in my case) file add:

<ItemGroup>
  <GoogleServicesJson Include="google-services.json" />
</ItemGroup>

• add Android appliaction to your Firebase project & download google-services.json config file,
• add google-services.json to your Android project and change Build Action to GoogleServicesJson in its properties.

#4. Configure iOS project.

• add Xamarin.Firebase.iOS.Auth dependency using NuGet package manager,
• create FirebaseAuthentication implementing IFirebaseAuthentication interface:

using Firebase.Auth;
using FirebaseAuthApp.iOS;
using System.Threading.Tasks;
using Xamarin.Forms;

[assembly: Dependency(typeof(FirebaseAuthentication))]
namespace FirebaseAuthApp.iOS
{
	public class FirebaseAuthentication : IFirebaseAuthentication
	{
		public async Task<string> LoginWithEmailPassword(string email, string password)
		{
			var user = await Auth.DefaultInstance.SignInWithPasswordAsync(email, password);
			return await user.User.GetIdTokenAsync();
		}

		public async Task<string> RegisterWithEmailPassword(string email, string password)
		{
			var user = await Auth.DefaultInstance.CreateUserAsync(email, password);
			return await user.User.GetIdTokenAsync();
		}
	}
}

• initialize Firebase in AppDelegate.cs by adding Firebase.Core.App.Configure();:

using Foundation;
using UIKit;

namespace FirebaseAuthenticationApp.iOS
{
	[Register("AppDelegate")]
    public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
    {
        public override bool FinishedLaunching(UIApplication app, NSDictionary options)
        {
            global::Xamarin.Forms.Forms.Init();
            LoadApplication(new App());

            Firebase.Core.App.Configure();

            return base.FinishedLaunching(app, options);
        }
    }
}

• add iOS appliaction to your Firebase project & download GoogleService-Info.plist config file,
• add GoogleService-Info.plist to your iOS project and change Build Action to BundleResource in its properties.

4. Check if app is working using the code below.

IFirebaseAuthentication auth = DependencyService.Get<IFirebaseAuthentication>();

// Register.
string token = await auth.RegisterWithEmailPassword(Email, Password);

// Login.
string token = await auth.LoginWithEmailPassword(Email, Password);