Integrating Google Sign-In in Android App

In this tutorial, we will integrate the Google Sign-In functionality in our Android application using Google API. Combining Google API in Android app helps users to login using Google account.

To integrate the Google Sign-In API in our app, we need to configure our app to Google developer account and download the 'google-service.json' file for the Android application.

Steps to configure Android App on Google Developer Account

1. Create a Google developer account at https://developers.google.com/identity/sign-in/android/start-integrating and click on 'GET A CONFIGURATION FILE'.

2. Fill all the application detail and select your country/region and click 'Choose and configure services'.

3. After successful creation of the Google app support configuration, it will redirect to next windows for selecting Google services. We will select Google Sign-In service.

4. Now, we need to provide signing certification SHA-1 key of our application.

5. There are two different ways of generating certification SHA-1 key.

By using the command prompt.

Windows:

keytool -exportcert -list -v \
-alias androiddebugkey -keystore %USERPROFILE%\.android\debug.keystore

Mac/Linux

keytool -exportcert -list -v \
-alias androiddebugkey -keystore ~/.android/debug.keystore

By Android Studio itself.
1. Open Android project.
2. Open the Gradle tab from a right side panel.
3. Double click on 'signingReport'.
4. We will found our app SHA-1 key on 'Gradle Console'.

6. Paste the generated SHA-1 key to Google Sign-In service and click on 'ENABLE GOOGLE SIGN-IN' and 'Generate certification files'.

7. Now download the 'google-services.json' file to integrate it into the Android application.

Example of Integrate Google Sign-In in Android app

In this example, we will integrate the Google Sign-In in the Android app. Once the user successfully login through Google Sign-In, we will redirect to next activity (ProfileActivity) and retrieve user detail.

We need to paste the downloaded 'google-services.json' file in our Android project app directory.

Required Permission

Add the Internet permission in AndroidMenifest.xml file.

build.gradle (Project)

Add the following dependency in build.gradle file.

dependencies{
classpath 'com.google.gms:google-services:3.1.0'
}

build.gradle(Module)

dependencies {
    implementation 'com.google.android.gms:play-services-auth:11.6.0'
    implementation 'com.github.bumptech.glide:glide:3.7.0'
}
apply plugin: 'com.google.gms.google-services'

activity_main.xml

Add the TextView and Google SignInButton in activity_main.xml file.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="gloginexample.example.com.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:textSize="20dp"
        android:text="This is main activity, sign in to move next activity." />

    <com.google.android.gms.common.SignInButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/sign_in_button"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="20dp">

    </com.google.android.gms.common.SignInButton>

</RelativeLayout>

MainActivity.java

In the MainActivity.java class, we call the Auth.GoogleSignInApi.getSignInIntent() method to login through Google Sign-In API. The GoogleApiClient.OnConnectionFailedListener interface of Google API overrides its unimplemented method onConnectionFailed(ConnectionResult) which returns the connection failure result. The GoogleApiClient class is used to manage the connection between an Android application and Google Sign-In API.

package gloginexample.example.com;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;

public class MainActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener {
    SignInButton signInButton;
    private GoogleApiClient googleApiClient;
    TextView textView;
    private static final int RC_SIGN_IN = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        GoogleSignInOptions gso =  new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestEmail()
                .build();
        googleApiClient=new GoogleApiClient.Builder(this)
                .enableAutoManage(this,this)
                .addApi(Auth.GOOGLE_SIGN_IN_API,gso)
                .build();



        signInButton=(SignInButton)findViewById(R.id.sign_in_button);
        signInButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = Auth.GoogleSignInApi.getSignInIntent(googleApiClient);
                startActivityForResult(intent,RC_SIGN_IN);
            }
        });


    }


    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==RC_SIGN_IN){
            GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
            handleSignInResult(result);
        }
    }
    private void handleSignInResult(GoogleSignInResult result){
        if(result.isSuccess()){
            gotoProfile();
        }else{
            Toast.makeText(getApplicationContext(),"Sign in cancel",Toast.LENGTH_LONG).show();
        }
    }
    private void gotoProfile(){
        Intent intent=new Intent(MainActivity.this,ProfileActivity.class);
        startActivity(intent);
    }
}

activity_profile.xml

Add the following component in activity_profile.xml file.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="gloginexample.example.com.ProfileActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical">
        <ImageView
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/profileImage"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/name"
            android:text="name"
            android:textSize="20dp"
            android:layout_marginTop="20dp"/>
        <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/email"
        android:textSize="20dp"
        android:text="email"
        android:layout_marginTop="20dp"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/userId"
            android:textSize="20dp"
            android:text="id"
            android:layout_marginTop="20dp"/>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/logoutBtn"
            android:text="Logout"
            android:layout_marginTop="30dp"/>
    </LinearLayout>

</RelativeLayout>

Create a ProfileActivity.java class in which we will display the user detail after the successful login.

ProfileActivity.java

In this class, we will retrieve the user detail if the user successfully login. The GoogleSignInResult class implements the Result interface which represents the final result of invoking an API method of Google Play Services.

The GoogleSignInAccount class holds the basic information of user.

package gloginexample.example.com;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;
import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.OptionalPendingResult;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Status;

public class ProfileActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener {
    Button logoutBtn;
    TextView userName,userEmail,userId;
    ImageView profileImage;
    private GoogleApiClient googleApiClient;
    private GoogleSignInOptions gso;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_profile);

        logoutBtn=(Button)findViewById(R.id.logoutBtn);
        userName=(TextView)findViewById(R.id.name);
        userEmail=(TextView)findViewById(R.id.email);
        userId=(TextView)findViewById(R.id.userId);
        profileImage=(ImageView)findViewById(R.id.profileImage);

        gso =  new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestEmail()
                .build();

        googleApiClient=new GoogleApiClient.Builder(this)
                .enableAutoManage(this,this)
                .addApi(Auth.GOOGLE_SIGN_IN_API,gso)
                .build();


        logoutBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Auth.GoogleSignInApi.signOut(googleApiClient).setResultCallback(
                        new ResultCallback<Status>() {
                            @Override
                            public void onResult(Status status) {
                                if (status.isSuccess()){
                                    gotoMainActivity();
                                }else{
                                    Toast.makeText(getApplicationContext(),"Session not close",Toast.LENGTH_LONG).show();
                                }
                            }
                        });
            }
        });
    }

    @Override
    protected void onStart() {
        super.onStart();
        OptionalPendingResult<GoogleSignInResult> opr= Auth.GoogleSignInApi.silentSignIn(googleApiClient);
        if(opr.isDone()){
            GoogleSignInResult result=opr.get();
            handleSignInResult(result);
        }else{
            opr.setResultCallback(new ResultCallback<GoogleSignInResult>() {
                @Override
                public void onResult(@NonNull GoogleSignInResult googleSignInResult) {
                    handleSignInResult(googleSignInResult);
                }
            });
        }
    }
    private void handleSignInResult(GoogleSignInResult result){
        if(result.isSuccess()){
            GoogleSignInAccount account=result.getSignInAccount();
            userName.setText(account.getDisplayName());
            userEmail.setText(account.getEmail());
            userId.setText(account.getId());
            try{
                Glide.with(this).load(account.getPhotoUrl()).into(profileImage);
            }catch (NullPointerException e){
                  Toast.makeText(getApplicationContext(),"image not found",Toast.LENGTH_LONG).show();
            }

        }else{
            gotoMainActivity();
        }
    }
    private void gotoMainActivity(){
        Intent intent=new Intent(this,MainActivity.class);
        startActivity(intent);
    }
    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }
}

Output: