Today I am going to show you how to use Firebase to integrate Google Sign-In into your app.. We will add this feature to the Android Application we created on the first post of the series
Firebase Configuration
- On the Firebase console, open the Authentication section, Click on Set up sign-in method .
- Update the module (app-level) Gradle file by adding the Firebase Authentication Android library. You also need to add the Google Play services library.
implementation 'com.google.firebase:firebase-auth'
implementation 'com.google.android.gms:play-services-auth:19.0.0'
- Make sure to run Gradle Sync
LoginActivity
- Add a new Empty Activity to the App and name it LoginActivity.
- Update the AndroidManifest.xml file to set the LoginActivity as a Launcher.
...
<activity android:name=".LoginActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
...
- Update activity_login.xml as below to add the SignIn button and a Progress bar
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".LoginActivity">
<com.google.android.gms.common.SignInButton
android:id="@+id/sign_in_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<FrameLayout
android:id="@+id/loginProgressLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@android:color/transparent"
android:gravity="center"
android:orientation="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sign_in_button">
<ProgressBar
android:id="@+id/log_in_progress"
style="@android:style/Widget.DeviceDefault.Light.ProgressBar.Large.Inverse"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="@android:color/transparent"
android:visibility="gone" />
</FrameLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
- Declare the following variables on LoginActivity.java
GoogleSignInClient googleSignInClient;
ProgressBar mLogInProgress;
SignInButton signInButton;
FirebaseAnalytics mFirebaseAnalytics;
- Update the onCreate method to set the setOnClickListener for signInButton and to call the configureGoogleClient() method
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
mLogInProgress = findViewById(R.id.log_in_progress);
signInButton = findViewById(R.id.sign_in_button);
signInButton.setSize(SignInButton.SIZE_WIDE);
signInButton.setColorScheme(SignInButton.COLOR_LIGHT);
signInButton.setOnClickListener(view -> {
mLogInProgress.setVisibility(View.VISIBLE);
signInToGoogle();
});
configureGoogleClient();
}
- The configureGoogleClient() is where you need to set Google Sign In Options and the FirebaseAuth. see below
private void configureGoogleClient() {
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
// for the requestIdToken, this is in the values.xml file that
// is generated from your google-services.json
.requestIdToken(getString(R.string.default_web_client_id))
.requestEmail()
.build();
// Build a GoogleSignInClient with the options specified by gso.
googleSignInClient = GoogleSignIn.getClient(this, gso);
// Set the dimensions of the sign-in button.
SignInButton signInButton = findViewById(R.id.sign_in_button);
signInButton.setSize(SignInButton.SIZE_WIDE);
// Initialize Firebase Auth
firebaseAuth = FirebaseAuth.getInstance();
}
- The signInToGoogle() is where we will start the signIn intent as below.
public void signInToGoogle() {
Intent signInIntent = googleSignInClient.getSignInIntent();
startActivityForResult(signInIntent, RC_SIGN_IN);
}
- We will capture the result of launching the signIn Intent in the onActivityResult as below.
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
if (requestCode == RC_SIGN_IN) {
Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
try {
// Google Sign In was successful, authenticate with Firebase
GoogleSignInAccount account = task.getResult(ApiException.class);
firebaseAuthWithGoogle(account);
} catch (ApiException e) {
// Google Sign In failed, update UI appropriately
mLogInProgress.setVisibility(View.GONE);
}
}
}
- We will use firebaseAuthWithGoogle to authenticate the user and launch the MainActivity.
private void firebaseAuthWithGoogle(GoogleSignInAccount account) {
AuthCredential credential = GoogleAuthProvider.getCredential(account.getIdToken(), null);
firebaseAuth.signInWithCredential(credential)
.addOnCompleteListener(this, task -> {
if (task.isSuccessful()) {
// Sign in success, update UI with the signed-in user's information
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
} else {
// failed
mLogInProgress.setVisibility(View.GONE);
}
});
}
- Update the onStart() method to check if the user is already signed in.
@Override
public void onStart() {
super.onStart();
// Check if user is signed in (non-null) and update UI accordingly.
FirebaseUser currentUser = firebaseAuth.getCurrentUser();
if (currentUser != null) {
mLogInProgress.setVisibility(View.VISIBLE);
signInButton.setVisibility(View.GONE);
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
}
MainActivity
- Let's use the button for signing out. Update the text of the Button on activity_main.xml as below.
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Sign Out"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.528"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.648" />
- Update the button onClick event to signOut the user and go back to the LoginActivity.
Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mFirebaseAnalytics.logEvent("button_clicked", null);
FirebaseAuth.getInstance().signOut();
startActivity(new Intent(MainActivity.this, LoginActivity.class));
}
});
Run the App
Check the code here
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Cover image Brett Jordan
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