根据 Firebase 文档，如果用户使用凭据进行身份验证，则如果该凭据尚未与其他凭据关联，他应严格使用相同的凭据登录。
换句话说，如果我使用 Google 登录创建帐户，然后（注销后）尝试使用与 Google 凭据相同的电子邮件登录 Facebook 凭据，则应在 logcat 中看到此异常：
"An account already exists with the same email address but different sign-in credentials. Sign in using a provider associated with this email address."
毫不奇怪，我收到了这个异常。但是，如果我使用 Facebook 创建帐户，然后尝试使用 Google 凭据登录，那么此帐户的提供程序（Facebook）将转换为 Google。这次身份验证不会失败，但这不是预期的结果。我想以某种方式将每个用户与特定的凭据关联起来。我该如何解决？您可以查看下面的代码:
换句话说，如果我使用 Google 登录创建帐户，然后（注销后）尝试使用与 Google 凭据相同的电子邮件登录 Facebook 凭据，则应在 logcat 中看到此异常：
"An account already exists with the same email address but different sign-in credentials. Sign in using a provider associated with this email address."
毫不奇怪，我收到了这个异常。但是，如果我使用 Facebook 创建帐户，然后尝试使用 Google 凭据登录，那么此帐户的提供程序（Facebook）将转换为 Google。这次身份验证不会失败，但这不是预期的结果。我想以某种方式将每个用户与特定的凭据关联起来。我该如何解决？您可以查看下面的代码:
public class SignInActivity 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 mFirebaseAuth;
private FirebaseAuth.AuthStateListener mFirebaseAuthListener;
private CallbackManager mCallbackManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_in);
// Facebook Login
FacebookSdk.sdkInitialize(getApplicationContext());
mCallbackManager = CallbackManager.Factory.create();
LoginButton mFacebookSignInButton = (LoginButton) findViewById(R.id.facebook_login_button);
mFacebookSignInButton.setReadPermissions("email", "public_profile");
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
SignInButton mGoogleSignInButton = (SignInButton) findViewById(R.id.google_sign_in_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
mFirebaseAuth = FirebaseAuth.getInstance();
mFirebaseAuthListener = 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();
mFirebaseAuth.addAuthStateListener(mFirebaseAuthListener);
}
@Override
public void onStop() {
super.onStop();
if (mFirebaseAuthListener != null) {
mFirebaseAuth.removeAuthStateListener(mFirebaseAuthListener);
}
}
private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
Log.d(TAG, "firebaseAuthWithGooogle:" + acct.getId());
AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
mFirebaseAuth.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(SignInActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
} else {
startActivity(new Intent(SignInActivity.this, MainActivity.class));
finish();
}
}
});
}
private void firebaseAuthWithFacebook(AccessToken token) {
Log.d(TAG, "handleFacebookAccessToken:" + token);
final AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
mFirebaseAuth.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(SignInActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
}
else {
startActivity(new Intent(SignInActivity.this, MainActivity.class));
finish();
}
}
});
}
/*
private void handleFirebaseAuthResult(AuthResult authResult) {
if (authResult != null) {
// Welcome the user
FirebaseUser user = authResult.getUser();
Toast.makeText(this, "Welcome " + user.getEmail(), Toast.LENGTH_SHORT).show();
// Go back to the main activity
startActivity(new Intent(this, MainActivity.class));
}
}
*/
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.google_sign_in_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();
}
}
