> For the complete documentation index, see [llms.txt](https://docs.caf.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.caf.io/caf-sdk/flutter/standalone-modules/documentdetector/lifecycle.md).

# SDK Lifecycle

## DocumentDetectorEvent (Flutter)

The `DocumentDetectorEvent` in Flutter represents the different outcomes of the document detection process. Below are the events you can handle during the SDK's document detection lifecycle:

| **Event**                        | **Description**                                                                                                                  |
| -------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
| **DocumentDetectorEventClosed**  | Triggered when the user cancels the document capture process, such as pressing the close button.                                 |
| **DocumentDetectorEventSuccess** | Called when the document is successfully captured, providing details like `captures`, `documentType`, and `trackingId`.          |
| **DocumentDetectorEventFailure** | Triggered when the document capture process fails, with error details like `errorType`, `errorMessage`, and `securityErrorCode`. |

### Example Implementation

Below is an example of how to handle `DocumentDetectorEvent` events in Flutter:

```dart
void _setupDocumentDetectorListener(Stream<DocumentDetectorEvent> stream) {
  stream.listen((event) {
    if (event is DocumentDetectorEventClosed) {
      print('Document capture process was closed by the user.');
    } else if (event is DocumentDetectorEventSuccess) {
      print('Success! Captures: ${event.captures}, '
          'Document type: ${event.documentType}, '
          'Tracking ID: ${event.trackingId}');
    } else if (event is DocumentDetectorEventFailure) {
      print(
        'Failure! Error type: ${event.errorType}, '
        'Error message: ${event.errorMessage}, '
        'Security error code: ${event.securityErrorCode}',
      );
    }
  });
}
```


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