Firebase: Sign-In Authentication Using Phone Number

Sign-In Authentication Using Phone Number

We can use Firebase authentication to the sign-in user by sending a text message to the user's phone. The user will sign-in using a one-time code that they have received in their message box.

Starting steps are the same, such as creating a Firebase project, creating an Android Studio project, adding firebase to our Android app, adding firebase-auth and firebase-core dependencies, adding SHA-1 and SHA-256 keys, add JSON file, and apply plugins. for reference first read Firebase: Google Sign-In Authentication or Firebase: Facebook Sign-In Authentication.

The next steps are to enable phone number authentication in Firebase console. After these preliminary steps, we have to perform the following steps:

Step1:

Now, we will add permission to use the Internet in our Manifest file.

Step2:

Now, we will modify our 'activity_main.xml' file for phone number authentication. The layout design will be as followed:

Step3:

Now, add code for the phone number authentication. and modify your 'MainActivity.java' file. Below is the code for the phone number authentication.

//Implementing onClickListener
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "PhoneAuthActivity";
//Adding a member variable for the key verification in progress
private static final String KEY_VERIFY_IN_PROGRESS = "key_verify_in_progress";
//Creating FirebaseAuth member variable
private FirebaseAuth mAuth;
//Adding a bunch of member variables for view groups, edit text, and buttons.
private ViewGroup mPhoneNumberViews;
private ViewGroup mSignedInViews;
private EditText mPhoneNumberField;
private EditText mVerificationField;
private Button mStartButton;
private Button mVerifyButton;
private Button mResendButton;
private Button mSignOutButton;
//Setting Boolean to say whether or not we are in progress.
private boolean mVerificationInProgress = false;
//Adding verification id as a member variable.
private String mVerificationId;
//Adding a member variable for PhoneAuthProvider.ForceResendingToken callback.
private PhoneAuthProvider.ForceResendingToken mResendToken;
//Adding a member variable for a callback which is our PhoneAuthProvider.OnVerificationStateChangeCallbacks.
private PhoneAuthProvider.OnVerificationStateChangedCallbacks mCallbacks;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Restoring the instance state
if (savedInstanceState != null) {
onRestoreInstanceState(savedInstanceState);
}
// Assigning all the views
mPhoneNumberViews = findViewById(R.id.phoneAuthFields);
mSignedInViews = findViewById(R.id.signedInButtons);
mPhoneNumberField = findViewById(R.id.fieldPhoneNumber);
mVerificationField = findViewById(R.id.fieldVerificationCode);
mStartButton = findViewById(R.id.buttonStartVerification);
mVerifyButton = findViewById(R.id.buttonVerifyPhone);
mResendButton = findViewById(R.id.buttonResend);
mSignOutButton = findViewById(R.id.signOutButton);
// Setting all the click listeners
mStartButton.setOnClickListener(this);
mVerifyButton.setOnClickListener(this);
mResendButton.setOnClickListener(this);
mSignOutButton.setOnClickListener(this);
// Initialize Firebase Auth
mAuth = FirebaseAuth.getInstance();
// Initializing phone auth callbacks (For verification, Not entering code yet, To get text send to device)
mCallbacks = new PhoneAuthProvider.OnVerificationStateChangedCallbacks() {
@Override
public void onVerificationCompleted(PhoneAuthCredential credential) {
// It will be invoked in two situations, i.e., instant verification and auto-retrieval:
// 1 - In few of the cases, the phone number can be instantly verified without needing to enter or send a verification code.
// 2 - On some devices, Google Play services can automatically detect the incoming verification SMS and perform verification without
// user action.
Log.d(TAG, "onVerificationCompleted:" + credential);
mVerificationInProgress = false;
//Calling signInWithPhoneAuthCredential.
signInWithPhoneAuthCredential(credential);
}
//Creating onVerificationFailed() method.
@Override
public void onVerificationFailed(FirebaseException e) {
// It is invoked when an invalid request is made for verification.
//For instance, if the phone number format is not valid.
Log.w(TAG, "onVerificationFailed", e);
mVerificationInProgress = false;
if (e instanceof FirebaseAuthInvalidCredentialsException) {
// Invalid request
// Setting error to text field
mPhoneNumberField.setError("Invalid phone number.");
} else if (e instanceof FirebaseTooManyRequestsException) {
// The SMS quota has been exceeded for the project
Toast.makeText(getApplicationContext(), "Quota exceeded", Toast.LENGTH_SHORT).show();
}
}
// Creating onCodeSent() method called after the verification code has been sent by SMS to the provided phone number.
@Override
public void onCodeSent(String verificationId,
PhoneAuthProvider.ForceResendingToken token) {
// The SMS verification code will be sent to the provided phone number
// Now need to ask the user for entering the code and then construct a credential
// through integrating the code with a verification ID.
Log.d(TAG, "onCodeSent:" + verificationId);
// Save the verification ID and resend token to use them later
mVerificationId = verificationId;
mResendToken = token;
}
};
}
// Creating onStart method.
@Override
public void onStart() {
super.onStart();
// Checking if the user is signed in or not. If signed in, then update UI accordingly.
FirebaseUser currentUser = mAuth.getCurrentUser();
if (currentUser != null) {
Log.d(TAG, "Currently Signed in: " + currentUser.getEmail());
Toast.makeText(MainActivity.this, "Currently Logged in: " + currentUser.getEmail(), Toast.LENGTH_LONG).show();
mPhoneNumberViews.setVisibility(View.GONE);
mSignedInViews.setVisibility(View.VISIBLE);
}
else {
mPhoneNumberViews.setVisibility(View.VISIBLE);
mSignedInViews.setVisibility(View.GONE);
}
//check if a verification is in progress. If it is then we have to re verify.
if (mVerificationInProgress && validatePhoneNumber()) {
startPhoneNumberVerification(mPhoneNumberField.getText().toString());
}
}
//Implementing SaveInstanceState to save the flag.
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean(KEY_VERIFY_IN_PROGRESS, mVerificationInProgress);
}
//Implementing RestoreInstanceState to restore the flag.
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
mVerificationInProgress = savedInstanceState.getBoolean(KEY_VERIFY_IN_PROGRESS);
}
// Creating startPhoneNumberVerification() method
//Getting text code sent. So we can use it to sign-in.
private void startPhoneNumberVerification(String phoneNumber) {
PhoneAuthProvider.getInstance().verifyPhoneNumber(
phoneNumber, // Phone number to verify
60, // Timeout duration
TimeUnit.SECONDS, // Unit of timeout
this, // Activity (for callback binding)
mCallbacks); // OnVerificationStateChangedCallbacks
//Setting flag to say that the verification is in process.
mVerificationInProgress = true;
}
//Creating a helper method for verification of phone number with code.
// Entering code and manually signing in with that code
private void verifyPhoneNumberWithCode(String verificationId, String code) {
PhoneAuthCredential credential = PhoneAuthProvider.getCredential(verificationId, code);
signInWithPhoneAuthCredential(credential);
}
// Creating helper method signInWithPhoneAuthCredential().
//Use text to sign-in.
private void signInWithPhoneAuthCredential(PhoneAuthCredential credential) {
//Adding onCompleteListener to signInWithCredential.
mAuth.signInWithCredential(credential)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
//Sign-In is successful, update the UI with the signed-in user's information
Log.d(TAG, "signInWithCredential:success");
FirebaseUser user = task.getResult().getUser();
mPhoneNumberViews.setVisibility(View.GONE);
mSignedInViews.setVisibility(View.VISIBLE);
} else {
// If the SignIn fails, it will display a message and also update the UI
Log.w(TAG, "signInWithCredential:failure", task.getException());
if (task.getException() instanceof FirebaseAuthInvalidCredentialsException) {
// The verification code entered was invalid
mVerificationField.setError("Invalid code.");
}
}
}
});
}
// Creating helper method for validating phone number.
private boolean validatePhoneNumber() {
String phoneNumber = mPhoneNumberField.getText().toString();
if (TextUtils.isEmpty(phoneNumber)) {
mPhoneNumberField.setError("Invalid phone number.");
return false;
}
return true;
}
//Creating helper method for resending verification code.
private void resendVerificationCode(String phoneNumber,
PhoneAuthProvider.ForceResendingToken token) {
PhoneAuthProvider.getInstance().verifyPhoneNumber(
phoneNumber, // Phone number to verify
60, // Timeout duration
TimeUnit.SECONDS, // Unit of timeout
this, // Activity (for callback binding)
mCallbacks, // OnVerificationStateChangedCallbacks
token); // ForceResendingToken from callbacks
}
//Adding onClick method which handles the button clicks.
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.buttonStartVerification:
if (!validatePhoneNumber()) {
return;
}
//Calling startPhoneNumberVerification helper method for verifying phone number.
startPhoneNumberVerification(mPhoneNumberField.getText().toString());
break;
case R.id.buttonVerifyPhone:
String code = mVerificationField.getText().toString();
if (TextUtils.isEmpty(code)) {
mVerificationField.setError("Cannot be empty.");
return;
}
//Call the verifyPhoneNumberWithCode () method.
verifyPhoneNumberWithCode(mVerificationId, code);
break;
case R.id.buttonResend:
//Call the resendVerificationCode () method.
resendVerificationCode(mPhoneNumberField.getText().toString(), mResendToken);
break;
case R.id.signOutButton:
//Call the signOut() method.
signOut();
break;
}
}
//Create the signOut() method.
private void signOut() {
mAuth.signOut();
mPhoneNumberViews.setVisibility(View.VISIBLE);
mSignedInViews.setVisibility(View.GONE);
}
}