> 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/ios/standalone-modules/caffaceliveness/lifecycle.md).

# SDK Lifecycle

## CafFaceLivenessDelegate

The `CafFaceLivenessDelegate` protocol handles key events during the SDK's liveness detection process:

| Event                                                     | Description                                                                           |
| --------------------------------------------------------- | ------------------------------------------------------------------------------------- |
| `cancelled()`                                             | Triggered when the user cancels the process.                                          |
| `didFinishWithError(sdkFailure: CafSDKFailure)`           | Called on SDK failure, with error details provided in `sdkFailure`.                   |
| `loaded()`                                                | Triggered when the SDK is ready, if the loading screen is disabled.                   |
| `loading()`                                               | Indicates the SDK is initializing, called if no loading screen is shown.              |
| `didFinishWithSuccess(livenessResult: CafLivenessResult)` | Called upon successful detection, with the result in `livenessResult.signedResponse`. |

### Example

```swift
extension YourViewController: CafFaceLivenessDelegate {
    func didFinishWithSuccess(livenessResult: CafLivenessResult) {
        print("Success: \(livenessResult.signedResponse ?? "No response")")
    }

    func cancelled() {
        print("Liveness detection cancelled")
    }

    func didFinishWithError(sdkFailure: CafSDKFailure) {
        print("Error: \(sdkFailure.description ?? "Unknown error")")
    }

    func loading() {
        print("Liveness detection loading")
    }

    func loaded() {
        print("Liveness detection loaded")
    }
}
```


---

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