HB Blog 164: Google Sign-In Using Firebase.

Hello Guys, you can let your users authenticate with Firebase using their Google Accounts by integrating Google Sign-In into your app. Basically, it helps to avoid user to fill up the signup forms and provide them facility of single sign-on.

There are many other social media option available too such as Facebook, etc. In this tutorial, lets us start with Google Sign-In that will let your users authenticate their Google Accounts into your app.

Refer the below link for complete sample code:-

Download Sample Code

Have a look on few code snippets,

//activity_main.xml

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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_margin="16dp" android:gravity="center" android:orientation="vertical" android:layout_height="match_parent"> <com.google.android.gms.common.SignInButton android:id="@+id/btn_login_googleplus" android:layout_width="match_parent" android:layout_gravity="center" android:layout_height="wrap_content" /> <Button android:id="@+id/btn_signout" android:layout_width="match_parent" android:layout_gravity="center" android:text="Sign Out" android:layout_height="wrap_content" /> </LinearLayout>

//MainActivity.java

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package com.harshalbenake.firebasegooglesignin; import android.content.Intent; import android.support.annotation.NonNull; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import com.google.android.gms.auth.api.signin.GoogleSignIn; import com.google.android.gms.auth.api.signin.GoogleSignInAccount; import com.google.android.gms.auth.api.signin.GoogleSignInClient; import com.google.android.gms.auth.api.signin.GoogleSignInOptions; import com.google.android.gms.common.SignInButton; import com.google.android.gms.common.api.ApiException; import com.google.android.gms.tasks.OnCompleteListener; import com.google.android.gms.tasks.Task; import com.google.firebase.FirebaseApp; import com.google.firebase.auth.AuthCredential; import com.google.firebase.auth.AuthResult; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser; import com.google.firebase.auth.GoogleAuthProvider; public class MainActivity extends AppCompatActivity { private static final int RC_SIGN_IN = 1000; private FirebaseAuth mAuth; private GoogleSignInClient mGoogleSignInClient; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initGoogleSignIn(); } @Override public void onStart() { super.onStart(); // Check if user is signed in (non-null) and update UI accordingly. // FirebaseUser currentUser = mAuth.getCurrentUser(); // updateUI(currentUser); } private void initGoogleSignIn() { FirebaseApp.initializeApp(this); mAuth = FirebaseAuth.getInstance(); // Configure Google Sign In GoogleSignInOptions googleSignInOptions = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN) .requestIdToken("xxxrequestIdTokenxxx") .requestEmail() .build(); mGoogleSignInClient = GoogleSignIn.getClient(this, googleSignInOptions); SignInButton btn_login_googleplus=(SignInButton)findViewById(R.id.btn_login_googleplus); btn_login_googleplus.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { signIn(); } }); Button btn_signout=(Button)findViewById(R.id.btn_signout); btn_signout.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { signOut(); } }); } /** * signs In */ private void signIn() { Intent signInIntent = mGoogleSignInClient.getSignInIntent(); startActivityForResult(signInIntent, RC_SIGN_IN); } /** * sign Out */ private void signOut(){ FirebaseAuth.getInstance().signOut(); } /** * firebase Auths With Google * @param acct */ private void firebaseAuthWithGoogle(GoogleSignInAccount acct) { System.out.println("firebaseAuthWithGoogle:" + acct.getId()); AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null); mAuth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { // Sign in success, update UI with the signed-in user's information System.out.println("signInWithCredential:success"); FirebaseUser user = mAuth.getCurrentUser(); System.out.println(user.getEmail()+" data: "+user.getDisplayName()); // updateUI(user); } else { System.out.println("signInWithCredential:failure "+task.getException()); } } }); } @Override public void onActivityResult(int requestCode, int resultCode, 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) { System.out.println("Google sign in failed"); } } } }