Elite Technority: February 2019

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

<?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

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");
            }
        }
    }

}

Pages

Thursday 14 February 2019

HB Blog 164: Google Sign-In Using Firebase.