---
title: Callback / Listener interfaces
canonical: https://developer.unico.io/dual-api/developers/sdks-and-tools/flutter/api-reference/callback-listener-interfaces
locale: en
generated_by: markdown-export
---

## UnicoListener (lifecycle)

| Method | Trigger |
|---|---|
| `onErrorUnico(UnicoError error)` | Implementation error during SDK operation |
| `onUserClosedCameraManually()` | User closed the camera manually |
| `onSystemClosedCameraTimeoutSession()` | Session expired due to timeout (default: 40 s) |
| `onSystemChangedTypeCameraTimeoutFaceInference()` | No face detected for 13 s — capture switches to manual |

## UnicoSelfie (selfie callbacks)

| Method | Trigger |
|---|---|
| `onSuccessSelfie(ResultCamera result)` | Selfie capture succeeded |
| `onSuccess(SuccessResult result)` | Journey flow completed — returns a `processId` (User Journeys only) |
| `onErrorSelfie(UnicoError error)` | Selfie capture failed |

## UnicoDocument (document callbacks)

| Method | Trigger |
|---|---|
| `onSuccessDocument(ResultCamera result)` | Document capture succeeded |
| `onErrorDocument(UnicoError error)` | Document capture failed |