Firebase User Authentication Tutorial

In this post we will learn about Firebase User Authentication or Signin. If you have read the last tutorial about Firebase Authentication then you already know that in the last tutorial we covered the User Registration part using Firebase. In this Firebase User Authentication tutorial we will create a login option in our app using Email and Password.

First I will recommend you to go through the last tutorial from the below link, as I will be working on the same project.

Android Firebase Tutorial – User Registration with Authentication

Firebase User Authentication Video Tutorial

Modifying the User Registration Screen

If you don’t want to read the tutorial, just view this 20 minutes youtube video.

First open the last project we created.
Go inside activity_main.xml and change the layout as follows. We are adding a TextView where user can click to go to the login activity directly.

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="net.simplifiedcoding.firebaseauthdemo.MainActivity">

<LinearLayout

android:layout_centerVertical="true"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="User Registration"

android:id="@+id/textView"

android:layout_gravity="center_horizontal" />

<EditText

android:id="@+id/editTextEmail"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:hint="Enter email"

android:inputType="textEmailAddress" />

<EditText

android:id="@+id/editTextPassword"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:hint="Enter password"

android:inputType="textPassword" />

<Button

android:id="@+id/buttonSignup"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:text="Signup" />

<TextView

android:text="Already Registered? Signin Here"

android:id="@+id/textViewSignin"

android:textAlignment="center"

android:layout_margin="15dp"

android:layout_width="match_parent"

android:layout_height="wrap_content" />

</LinearLayout>

</RelativeLayout>

Now your Activity will look as follow in the preview.

Now come inside MainActivity.java and modify your code as follows.

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

package net.simplifiedcoding.firebaseauthdemo;

import android.app.ProgressDialog;

import android.content.Intent;

import android.support.annotation.NonNull;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.text.TextUtils;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;

import com.google.android.gms.tasks.Task;

import com.google.firebase.auth.AuthResult;

import com.google.firebase.auth.FirebaseAuth;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

//defining view objects

private EditText editTextEmail;

private EditText editTextPassword;

private Button buttonSignup;

private TextView textViewSignin;

private ProgressDialog progressDialog;

//defining firebaseauth object

private FirebaseAuth firebaseAuth;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//initializing firebase auth object

firebaseAuth = FirebaseAuth.getInstance();

//if getCurrentUser does not returns null

if(firebaseAuth.getCurrentUser() != null){

//that means user is already logged in

//so close this activity

finish();

//and open profile activity

startActivity(new Intent(getApplicationContext(), ProfileActivity.class));

}

//initializing views

editTextEmail = (EditText) findViewById(R.id.editTextEmail);

editTextPassword = (EditText) findViewById(R.id.editTextPassword);

textViewSignin = (TextView) findViewById(R.id.textViewSignin);

buttonSignup = (Button) findViewById(R.id.buttonSignup);

progressDialog = new ProgressDialog(this);

//attaching listener to button

buttonSignup.setOnClickListener(this);

textViewSignin.setOnClickListener(this);

}

private void registerUser(){

//getting email and password from edit texts

String email = editTextEmail.getText().toString().trim();

String password = editTextPassword.getText().toString().trim();

//checking if email and passwords are empty

if(TextUtils.isEmpty(email)){

Toast.makeText(this,"Please enter email",Toast.LENGTH_LONG).show();

return;

}

if(TextUtils.isEmpty(password)){

Toast.makeText(this,"Please enter password",Toast.LENGTH_LONG).show();

return;

}

//if the email and password are not empty

//displaying a progress dialog

progressDialog.setMessage("Registering Please Wait...");

progressDialog.show();

//creating a new user

firebaseAuth.createUserWithEmailAndPassword(email, password)

.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {

@Override

public void onComplete(@NonNull Task<AuthResult> task) {

//checking if success

if(task.isSuccessful()){

finish();

startActivity(new Intent(getApplicationContext(), ProfileActivity.class));

}else{

//display some message here

Toast.makeText(MainActivity.this,"Registration Error",Toast.LENGTH_LONG).show();

}

progressDialog.dismiss();

}

});

}

@Override

public void onClick(View view) {

if(view == buttonSignup){

registerUser();

}

if(view == textViewSignin){

//open login activity when user taps on the already registered textview

startActivity(new Intent(this, LoginActivity.class));

}

Now we will create the Profile Activity.

Adding Profile Activity to Project

Right click on package and create new activity named ProfileActivity.
Inside the layout file of this activity write the following xml code. (In my case it is activity_profile.xml)

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="net.simplifiedcoding.firebaseauthdemo.ProfileActivity">

<LinearLayout

android:orientation="vertical"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_centerVertical="true"

android:layout_centerHorizontal="true">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="Large Text"

android:id="@+id/textViewUserEmail"

android:layout_gravity="center_horizontal" />

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Logout"

android:id="@+id/buttonLogout"

android:layout_gravity="center_horizontal" />

</LinearLayout>

</RelativeLayout>

We haven’t done much on this activity as it contains a TextView and a Button only. In TextView we will show the logged in user email and the button will be used for logout.
The above XML code will show you the following layout.

Now come inside ProfileActivity.java and write the following code.

package net.simplifiedcoding.firebaseauthdemo;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import com.google.firebase.auth.FirebaseAuth;

import com.google.firebase.auth.FirebaseUser;

public class ProfileActivity extends AppCompatActivity implements View.OnClickListener {

//firebase auth object

private FirebaseAuth firebaseAuth;

//view objects

private TextView textViewUserEmail;

private Button buttonLogout;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_profile);

//initializing firebase authentication object

firebaseAuth = FirebaseAuth.getInstance();

//if the user is not logged in

//that means current user will return null

if(firebaseAuth.getCurrentUser() == null){

//closing this activity

finish();

//starting login activity

startActivity(new Intent(this, LoginActivity.class));

}

//getting current user

FirebaseUser user = firebaseAuth.getCurrentUser();

//initializing views

textViewUserEmail = (TextView) findViewById(R.id.textViewUserEmail);

buttonLogout = (Button) findViewById(R.id.buttonLogout);

//displaying logged in user name

textViewUserEmail.setText("Welcome "+user.getEmail());

//adding listener to button

buttonLogout.setOnClickListener(this);

}

@Override

public void onClick(View view) {

//if logout is pressed

if(view == buttonLogout){

//logging out the user

firebaseAuth.signOut();

//closing activity

finish();

//starting login activity

startActivity(new Intent(this, LoginActivity.class));

}

Now we will add Login Activity to our project.

Adding Login Activity to Project

Again right click on package and new -> activity -> empty activity, and create a new Activity. Name it LoginActivity.
Inside the layout file of this activity activity_login.xml write the following xml code.

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="net.simplifiedcoding.firebaseauthdemo.LoginActivity">

<LinearLayout

android:layout_centerVertical="true"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="User Login"

android:id="@+id/textView"

android:layout_gravity="center_horizontal" />

<EditText

android:id="@+id/editTextEmail"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:hint="Enter email"

android:inputType="textEmailAddress" />

<EditText

android:id="@+id/editTextPassword"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:hint="Enter password"

android:inputType="textPassword" />

<Button

android:id="@+id/buttonSignin"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_margin="15dp"

android:text="Signup" />

<TextView

android:text="Not have an account? Signup Here"

android:id="@+id/textViewSignUp"

android:textAlignment="center"

android:layout_margin="15dp"

android:layout_width="match_parent"

android:layout_height="wrap_content" />

</LinearLayout>

</RelativeLayout>

You will see the following layout in preview.

Now lets code this activity, so come inside LoginActivity.java and write the following code.

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

package net.simplifiedcoding.firebaseauthdemo;

import android.app.ProgressDialog;

import android.content.Intent;

import android.support.annotation.NonNull;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.text.TextUtils;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;

import com.google.android.gms.tasks.Task;

import com.google.firebase.auth.AuthResult;

import com.google.firebase.auth.FirebaseAuth;

public class LoginActivity extends AppCompatActivity implements View.OnClickListener {

//defining views

private Button buttonSignIn;

private EditText editTextEmail;

private EditText editTextPassword;

private TextView textViewSignup;

//firebase auth object

private FirebaseAuth firebaseAuth;

//progress dialog

private ProgressDialog progressDialog;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_login);

//getting firebase auth object

firebaseAuth = FirebaseAuth.getInstance();

//if the objects getcurrentuser method is not null

//means user is already logged in

if(firebaseAuth.getCurrentUser() != null){

//close this activity

finish();

//opening profile activity

startActivity(new Intent(getApplicationContext(), ProfileActivity.class));

}

//initializing views

editTextEmail = (EditText) findViewById(R.id.editTextEmail);

editTextPassword = (EditText) findViewById(R.id.editTextPassword);

buttonSignIn = (Button) findViewById(R.id.buttonSignin);

textViewSignup = (TextView) findViewById(R.id.textViewSignUp);

progressDialog = new ProgressDialog(this);

//attaching click listener

buttonSignIn.setOnClickListener(this);

textViewSignup.setOnClickListener(this);

}

//method for user login

private void userLogin(){

String email = editTextEmail.getText().toString().trim();

String password = editTextPassword.getText().toString().trim();

//checking if email and passwords are empty

if(TextUtils.isEmpty(email)){

Toast.makeText(this,"Please enter email",Toast.LENGTH_LONG).show();

return;

}

if(TextUtils.isEmpty(password)){

Toast.makeText(this,"Please enter password",Toast.LENGTH_LONG).show();

return;

}

//if the email and password are not empty

//displaying a progress dialog

progressDialog.setMessage("Registering Please Wait...");

progressDialog.show();

//logging in the user

firebaseAuth.signInWithEmailAndPassword(email, password)

.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {

@Override

public void onComplete(@NonNull Task<AuthResult> task) {

progressDialog.dismiss();

//if the task is successfull

if(task.isSuccessful()){

//start the profile activity

finish();

startActivity(new Intent(getApplicationContext(), ProfileActivity.class));

}

});

}

@Override

public void onClick(View view) {

if(view == buttonSignIn){

userLogin();

}

if(view == textViewSignup){

finish();

startActivity(new Intent(this, MainActivity.class));

}

Thats it now just run your app go to login and try logging in.

Bingo! it is working absolutely fine. You can also get the source code from the link given below.

[sociallocker id=1372] Firebase User Authentication Example [/sociallocker]

So thats all for this Firebase User Authentication Example friends. In the next Firebase User Authentication Tutorial we will do some more operations like password reset, email change, account deletion etc. And don’t forget to share this Firebase user Authentication Tutorial among your friends. Thank You 🙂