Simple Firebase Sign-in UI Demo App

Simple Jetpack Compose example to demonstrate how to sign in with a Firebase Authentication pre-build UI using FirebaseUI

This is part of the Firebase tutorial series:

• Part 1 - Simple Firebase Sign-in UI Demo App

• Part 2 - Integrate Firebase Realtime Database and User Authentication into your Android App

In this demo app, we will guide you through the steps to enable FirebaseUI for authentication and demonstrate how to integrate it into your Jetpack Compose application.

We're going to add these 2 sign-in methods:

• Email/Password

• Google

Connect Your App to Firebase

1. Go to the Firebase console, and log in with your Google account.

2. Add project and follow on-screen instructions

3. Turn off Enable Google Analytics for this project, and click Create project.

4. Register the app with Android package name (applicationId in your build.gradle file)

* Add **app nickname** (it can be any name)

* Add **Debug signing certificate SHA-1** if you want to use Google sign-in method. In the Android Studio terminal, run this command **./gradlew signingReport.** Copy the SHA-1 and paste it here.

1. Download google-services.json to your project app folder.

2. Go to Authentication -> Sign-in method. Add and enable Email/Password, and Google sign-in providers.

The google-services.json and debug singing certificate fingerprints can also be accessed from the Project Overview -> Project settings at the top left corner.

Add Firebase Authentication SDK to your app

1. Add Google services Gradle plugin in your project-level build.gradle.kts.
   

   buildscript {
       dependencies {
           classpath("com.google.gms:google-services:4.3.15")
       }
   }
   

2. Add Google service Gradle plugin in your app-level build.gradle.kts/
   

   plugins {
       /*...*/
       id ("com.google.gms.google-services")
   }
   

3. Add FirebaseUI and Play Services Auth libraries
   

   dependencies {
       /*...*/
       implementation ("com.firebaseui:firebase-ui-auth:7.2.0")
       implementation ("com.google.android.gms:play-services-auth:20.5.0") 
   }
   

   The Play Services Auth library is required for the Email/Password sign-in method.

In Android Studio, all the above steps can be automated with the Firebase Assistant (Tools -> Firebase) except that you need to manually add the Debug signing certificate SHA-1 and also manually modify the library dependencies.

Integrate pre-build Firebase Sign-in UI

Quick steps on what you need to do to launch the pre-build Sign-in UI:

1. Create ActivityResultLauncher

2. Choose authentication providers

3. Create and launch sign-in intent. Here is an example of SignInScreen() composable functions:
   

   @Composable
   fun SignInScreen(
       onSignInResult: (FirebaseAuthUIAuthenticationResult) -> Unit
   ) {
       // (1) Create ActivityResultLauncher
       val launcher = rememberLauncherForActivityResult(
           contract = FirebaseAuthUIActivityResultContract(),
           onResult = onSignInResult
       )
   
       // (2) Choose authentication providers
       val providers = arrayListOf(
           AuthUI.IdpConfig.GoogleBuilder().build(),
           AuthUI.IdpConfig.EmailBuilder().build(),
       )
   
       // (3) Create and launch sign-in intent
       val intent = AuthUI.getInstance()
           .createSignInIntentBuilder()
           .setAvailableProviders(providers)
           .build()
   
       LaunchedEffect(true){
           launcher.launch(intent)
       }
   }
   

4. Handle the sign-in result callback
   

   SignInScreen { result ->
       // (4) Handle the sign-in result callback
       if (result.resultCode == ComponentActivity.RESULT_OK) {
           signInStatus = "Signed In"
           val user = FirebaseAuth.getInstance().currentUser
           userId = user!!.uid
   
       } else {
           val response = result.idpResponse
           signInStatus = if (response == null) {
               "Not Signed In"
           } else {
               val errorCode = response.getError()?.getErrorCode()
               "Failed - Error Code: $errorCode"
           }
       }    
       /*...*/
   }
   

When the response is null, the user cancels the sign-in operation (e.g. press the back button)

Some Thoughts

The Firebase Assistant in Android Studio is quick and helpful, but if you're new, I recommend you go through the Firebase console project setup steps above to fully understand the actual steps that need to be done.

Next Step

Well, this is just a quick demo app to demonstrate the Firebase sign-in APIs. I probably should move the sign-in state to a ViewModel when I port this change to my actual app.

[Updated - Aug 08, 2023]: Yeah, I have moved the sign-in state to the VIewModel if you look at the source code.

I also want to learn how to store the user data in the remote server using Firebase real-time database instead of using Preferences and Proto DataStore on the local phone.

Source Code

GitHub Repository: Demo_FirebaseSignInRealtimeDB

Originally published at https://vtsen.hashnode.dev.