---
title: "pageViewController(_:willTransitionTo:)"
framework: uikit
role: symbol
role_heading: Instance Method
path: "uikit/uipageviewcontrollerdelegate/pageviewcontroller(_:willtransitionto:)"
---

# pageViewController(_:willTransitionTo:)

Called before a gesture-driven transition begins.

## Declaration

```swift
optional func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController])
```

## Parameters

- `pageViewController`: The page view controller.
- `pendingViewControllers`: The view controllers that are being transitioned to.

## Discussion

Discussion If the user aborts the navigation gesture, the transition doesn’t complete and the view controllers stay the same.

## See Also

### Responding to Page View Controller Events

- [pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:)](uikit/uipageviewcontrollerdelegate/pageviewcontroller(_:didfinishanimating:previousviewcontrollers:transitioncompleted:).md)
- [pageViewController(_:spineLocationFor:)](uikit/uipageviewcontrollerdelegate/pageviewcontroller(_:spinelocationfor:).md)