sign_in.kt

private fun signin() {
    lifecycleScope.launch(errorHandler { signup() }) {
        val result = oneTapClient.suspendBeginSignInRequest(buildSignInRequest())
        loginResult.launch(
            IntentSenderRequest.Builder(result.pendingIntent)
                .build()
        )
    }
}

private fun buildSignInRequest() = 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.one_tap_client_id))   .setFilterByAuthorizedAccounts(true)
            .build()
    )
    .build()