ورود کاربران به سیستم با اعتبارنامه‌های ذخیره‌شده

public class YourActivity extends AppCompatActivity {
    // ...

    private SignInClient oneTapClient;
    private BeginSignInRequest signInRequest;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState,
                         @Nullable PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);

        oneTapClient = Identity.getSignInClient(this);
        signInRequest = BeginSignInRequest.builder()
                .setPasswordRequestOptions(PasswordRequestOptions.builder()
                        .setSupported(true)
                        .build())
                .setGoogleIdTokenRequestOptions(GoogleIdTokenRequestOptions.builder()
                        .setSupported(true)
                        // Your server's client ID, not your Android client ID.
                        .setServerClientId(getString(R.string.default_web_client_id))
                        // Only show accounts previously used to sign in.
                        .setFilterByAuthorizedAccounts(true)
                        .build())
                // Automatically sign in when exactly one credential is retrieved.
                .setAutoSelectEnabled(true)
                .build();
        // ...
    }
    // ...
}

class YourActivity : AppCompatActivity() {
      // ...

      private lateinit var oneTapClient: SignInClient
      private lateinit var signInRequest: BeginSignInRequest

      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
          setContentView(R.layout.activity_main)

          oneTapClient = Identity.getSignInClient(this)
          signInRequest = BeginSignInRequest.builder()
              .setPasswordRequestOptions(BeginSignInRequest.PasswordRequestOptions.builder()
                  .setSupported(true)
                  .build())
              .setGoogleIdTokenRequestOptions(
                  BeginSignInRequest.GoogleIdTokenRequestOptions.builder()
                      .setSupported(true)
                      // Your server's client ID, not your Android client ID.
                      .setServerClientId(getString(R.string.your_web_client_id))
                      // Only show accounts previously used to sign in.
                      .setFilterByAuthorizedAccounts(true)
                      .build())
              // Automatically sign in when exactly one credential is retrieved.
              .setAutoSelectEnabled(true)
              .build()
          // ...
      }
      // ...
  }

oneTapClient.beginSignIn(signUpRequest)
        .addOnSuccessListener(this, new OnSuccessListener<BeginSignInResult>() {
            @Override
            public void onSuccess(BeginSignInResult result) {
                try {
                    startIntentSenderForResult(
                            result.getPendingIntent().getIntentSender(), REQ_ONE_TAP,
                            null, 0, 0, 0);
                } catch (IntentSender.SendIntentException e) {
                    Log.e(TAG, "Couldn't start One Tap UI: " + e.getLocalizedMessage());
                }
            }
        })
        .addOnFailureListener(this, new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                // No saved credentials found. Launch the One Tap sign-up flow, or
                // do nothing and continue presenting the signed-out UI.
                Log.d(TAG, e.getLocalizedMessage());
            }
        });

oneTapClient.beginSignIn(signInRequest)
    .addOnSuccessListener(this) { result ->
        try {
            startIntentSenderForResult(
                result.pendingIntent.intentSender, REQ_ONE_TAP,
                null, 0, 0, 0, null)
        } catch (e: IntentSender.SendIntentException) {
            Log.e(TAG, "Couldn't start One Tap UI: ${e.localizedMessage}")
        }
    }
    .addOnFailureListener(this) { e ->
        // No saved credentials found. Launch the One Tap sign-up flow, or
        // do nothing and continue presenting the signed-out UI.
        Log.d(TAG, e.localizedMessage)
    }

public class YourActivity extends AppCompatActivity {

    // ...
    private static final int REQ_ONE_TAP = 2;  // Can be any integer unique to the Activity.
    private boolean showOneTapUI = true;
    // ...

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
            case REQ_ONE_TAP:
                try 
                    SignInCredential credential = oneTapClient.getSignInCredentialFromIntent(data);
                    String idToken = credential.getGoogleIdToken();
                    String username = credential.getId();
                    String password = credential.getPassword();
                    if (idToken !=  null) {
                        // Got an ID token from Google. Use it to authenticate
                        // with your backend.
                        Log.d(TAG, "Got ID token.");
                    } else if (password != null) {
                        // Got a saved username and password. Use them to authenticate
                        // with your backend.
                        Log.d(TAG, "Got password.");
                    }
                } catch (ApiException e) {
                    // ...
                }
                break;
        }
    }
}

class YourActivity : AppCompatActivity() {

      // ...
      private val REQ_ONE_TAP = 2  // Can be any integer unique to the Activity
      private var showOneTapUI = true
      // ...

      override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
          super.onActivityResult(requestCode, resultCode, data)

          when (requestCode) {
               REQ_ONE_TAP -> {
                  try 
                      val credential = oneTapClient.getSignInCredentialFromIntent(data)
                      val idToken = credential.googleIdToken
                      val username = credential.id
                      val password = credential.password
                      when {
                          idToken != null -> {
                              // Got an ID token from Google. Use it to authenticate
                              // with your backend.
                              Log.d(TAG, "Got ID token.")
                          }
                          password != null -> {
                              // Got a saved username and password. Use them to authenticate
                              // with your backend.
                              Log.d(TAG, "Got password.")
                          }
                          else -> {
                              // Shouldn't happen.
                              Log.d(TAG, "No ID token or password!")
                          }
                      }
                  } catch (e: ApiException) {
                      // ...
                  }
              }
          }
      }
      // ...
  }

public class YourActivity extends AppCompatActivity {

    // ...
    private static final int REQ_ONE_TAP = 2;  // Can be any integer unique to the Activity.
    private boolean showOneTapUI = true;
    // ...

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
            case REQ_ONE_TAP:
                try {
                    // ...
                } catch (ApiException e) {
                    switch (e.getStatusCode()) {
                        case CommonStatusCodes.CANCELED:
                            Log.d(TAG, "One-tap dialog was closed.");
                            // Don't re-prompt the user.
                            showOneTapUI = false;
                            break;
                        case CommonStatusCodes.NETWORK_ERROR:
                            Log.d(TAG, "One-tap encountered a network error.");
                            // Try again or just ignore.
                            break;
                        default:
                            Log.d(TAG, "Couldn't get credential from result."
                                    + e.getLocalizedMessage());
                            break;
                    }
                }
                break;
        }
    }
}

class YourActivity : AppCompatActivity() {

      // ...
      private val REQ_ONE_TAP = 2  // Can be any integer unique to the Activity
      private var showOneTapUI = true
      // ...

      override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
          super.onActivityResult(requestCode, resultCode, data)

          when (requestCode) {
              REQ_ONE_TAP -> {
                  try {
                      // ...
                  } catch (e: ApiException) {
                      when (e.statusCode) {
                          CommonStatusCodes.CANCELED -> {
                              Log.d(TAG, "One-tap dialog was closed.")
                              // Don't re-prompt the user.
                              showOneTapUI = false
                          }
                          CommonStatusCodes.NETWORK_ERROR -> {
                              Log.d(TAG, "One-tap encountered a network error.")
                              // Try again or just ignore.
                          }
                          else -> {
                              Log.d(TAG, "Couldn't get credential from result." +
                                  " (${e.localizedMessage})")
                          }
                      }
                  }
              }
          }
      }
      // ...
  }