Setup Google One Tap with Coroutines and Activity Result Contract API

GoogleOneTapAuth.kt

// InvalidFragmentVersionForActivityResult: https://issuetracker.google.com/issues/182388985
@SuppressLint("InvalidFragmentVersionForActivityResult")
@ExperimentalCoroutinesApi
private fun setupGoogleContinueButton() {
    activity?.let { fragmentActivity ->
        oneTapClient = Identity.getSignInClient(fragmentActivity)
        signInRequest = createBeginSignInRequest(fragmentActivity)

        val intentSender: ActivityResultLauncher<IntentSenderRequest> =
            getGoogleActivityResultLauncher()

        binding?.buttonContinueGoogle?.setOnClickListener {
            activity?.lifecycleScope?.launchWhenStarted {
                val result = beginSignInGoogleOneTap(fragmentActivity, intentSender)
                oneTapLauncher.launch(
                    IntentSenderRequest.Builder(result.pendingIntent.intentSender)
                        .build()
                )
            }
        }
    }
}

private fun createBeginSignInRequest(fragmentActivity: FragmentActivity): BeginSignInRequest =
    BeginSignInRequest.builder()
        .setGoogleIdTokenRequestOptions(
            BeginSignInRequest.GoogleIdTokenRequestOptions.builder()
                .setSupported(true)
                .setServerClientId(fragmentActivity.getString(R.string.server_client_id))
                .setFilterByAuthorizedAccounts(false)
                .build()
        )
        .build()

private fun getGoogleActivityResultLauncher(): ActivityResultLauncher<IntentSenderRequest> =
    registerForActivityResult(StartIntentSenderForResult()) { activityResult ->
        val credential: SignInCredential =
            oneTapClient.getSignInCredentialFromIntent(activityResult.data)
        Log.d("Credential", credential.googleIdToken.toString())
        activity?.lifecycleScope?.launchWhenStarted {
            loginViewModel.loginToOurServerWithGoogle(credential.googleIdToken.toString())
        }
    }

@ExperimentalCoroutinesApi
suspend fun beginSignInGoogleOneTap(
    fragmentActivity: FragmentActivity,
    oneTapClient: SignInClient,
    signInRequest: BeginSignInRequest,
    onCancel: () -> Unit
    ): BeginSignInResult =
    suspendCancellableCoroutine { continuation ->
        oneTapClient.beginSignIn(signInRequest)
            .addOnSuccessListener(fragmentActivity) { result ->
                continuation.resume(result) { throwable ->
                    Log.e("SignUp UI", "beginSignInGoogleOneTap: ", throwable)
                }
            }
            .addOnFailureListener(fragmentActivity) { e ->
                // No Google Accounts found. Just continue presenting the signed-out UI.
                continuation.resumeWithException(e)
            }
            .addOnCanceledListener {
                Log.d("SignUp UI", "beginSignInGoogleOneTap: cancelled")
                onCancel()
            }
    }