Combining Facebook and Google auth for Firebase Android
Background
Hello, I'm new with Firebase for Android and I'm trying to implement the Facebook and Google auth/login for the first time. I followed these two tutorials for the corresponding authentication:
- http:// firebase.google.com/docs/auth/android/google-signin
- http:// firebase.google.com/docs/auth/android/facebook-login
Separately, the FacebookSignInActivity and GoogleSignInActivity are working as they should.
Problem
The problem is that I'm trying to use the Google and Facebook auth in the same activity, but it won't work. Like so:
What I did
I tried to keep the FacebookSignInActivity separate from the GoogleSignInActivity by letting them extend a MainActivity and set the layout in there.
But I think I'm supposed to merge the two into one. So I tried that but I'm getting a weird nullpointer exception:
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.firebase.auth.FirebaseAuth.addAuthStateListener(com.google.firebase.auth.FirebaseAuth$AuthStateListener)' on a null object reference
I don't know why the object is null in the onCreate because I've copied the same code from the other two activities which are working:
mAuth = FirebaseAuth.getInstance();
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
// User is signed in
Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
} else {
// User is signed out
Log.d(TAG, "onAuthStateChanged:signed_out");
}
// [START_EXCLUDE]
updateUI(user);
// [END_EXCLUDE]
}
};
I'm not even sure if I'm even supposed to merge the two into one activity. I've also checked these links:
- https://firebase.google.com/docs/auth/android/account-linking
- How to Link Multiple Auth Providers to an Firebase Account?
But it looks like that is something else from what I'm trying to do. If someone could help point me in the right direction, it would be gladly appreciated.
Answer
You can try this code:
public class LoginActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener,
View.OnClickListener {
private static final String TAG = "SignInActivity";
private static final int RC_SIGN_IN = 9001;
private GoogleApiClient mGoogleApiClient;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
private CallbackManager mCallbackManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
// Facebook Login
FacebookSdk.sdkInitialize(getApplicationContext());
mCallbackManager = CallbackManager.Factory.create();
LoginButton mFacebookSignInButton = (LoginButton) findViewById(R.id.facebook_button);
mFacebookSignInButton.setReadPermissions("email", "public_profile", "user_birthday", "user_friends");
mFacebookSignInButton.registerCallback(mCallbackManager, new FacebookCallback<LoginResult>() {
@Override
public void onSuccess(LoginResult loginResult) {
Log.d(TAG, "facebook:onSuccess:" + loginResult);
firebaseAuthWithFacebook(loginResult.getAccessToken());
}
@Override
public void onCancel() {
Log.d(TAG, "facebook:onCancel");
}
@Override
public void onError(FacebookException error) {
Log.d(TAG, "facebook:onError", error);
}
});
// Google Sign-In
// Assign fields
Button mGoogleSignInButton = (Button) findViewById(R.id.google_button);
// Set click listeners
mGoogleSignInButton.setOnClickListener(this);
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestIdToken(getString(R.string.default_web_client_id))
.requestEmail()
.build();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
.addApi(Auth.GOOGLE_SIGN_IN_API, gso)
.build();
// Initialize FirebaseAuth
mAuth = FirebaseAuth.getInstance();
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
// User is signed in
Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
} else {
// User is signed out
Log.d(TAG, "onAuthStateChanged:signed_out");
}
}
};
}
@Override
public void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
@Override
public void onStop() {
super.onStop();
if (mAuthListener != null) {
mAuth.removeAuthStateListener(mAuthListener);
}
}
private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
Log.d(TAG, "firebaseAuthWithGooogle:" + 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) {
Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());
// If sign in fails, display a message to the user. If sign in succeeds
// the auth state listener will be notified and logic to handle the
// signed in user can be handled in the listener.
if (!task.isSuccessful()) {
Log.w(TAG, "signInWithCredential", task.getException());
Toast.makeText(LoginActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
} else {
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
}
});
}
private void firebaseAuthWithFacebook(AccessToken token) {
Log.d(TAG, "handleFacebookAccessToken:" + token);
final AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
mAuth.signInWithCredential(credential)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());
// If sign in fails, display a message to the user. If sign in succeeds
// the auth state listener will be notified and logic to handle the
// signed in user can be handled in the listener.
if (!task.isSuccessful()) {
Log.w(TAG, "signInWithCredential", task.getException());
Toast.makeText(LoginActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
} else {
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
}
});
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.google_button:
signIn();
break;
default:
return;
}
}
private void signIn() {
Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
startActivityForResult(signInIntent, RC_SIGN_IN);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
mCallbackManager.onActivityResult(requestCode, resultCode, data);
// Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
if (requestCode == RC_SIGN_IN) {
GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
if (result.isSuccess()) {
// Google Sign In was successful, authenticate with Firebase
GoogleSignInAccount account = result.getSignInAccount();
firebaseAuthWithGoogle(account);
} else {
// Google Sign In failed
Log.e(TAG, "Google Sign In failed.");
}
}
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
// An unresolvable error has occurred and Google APIs (including Sign-In) will not
// be available.
Log.d(TAG, "onConnectionFailed:" + connectionResult);
Toast.makeText(this, "Google Play Services error.", Toast.LENGTH_SHORT).show();
}
}
Please let me know if you have any questions.