---
title: setNeedsUserInterfaceAppearanceUpdate()
framework: uikit
role: symbol
role_heading: Instance Method
path: uikit/uiviewcontroller/setneedsuserinterfaceappearanceupdate()
---

# setNeedsUserInterfaceAppearanceUpdate()

Notifies the view controller that a change occurred that might affect the preferred interface style.

## Declaration

```swift
func setNeedsUserInterfaceAppearanceUpdate()
```

## Discussion

Discussion UIKit calls this method to let the view controller know when system-level interface style changes occur. You can also call it to let UIKit know when you change your view controller in a way that affects the preferred user interface style.

## See Also

### Adjusting the interface style

- [overrideUserInterfaceStyle](uikit/uiviewcontroller/overrideuserinterfacestyle.md)
- [preferredUserInterfaceStyle](uikit/uiviewcontroller/preferreduserinterfacestyle.md)
- [childViewControllerForUserInterfaceStyle](uikit/uiviewcontroller/childviewcontrollerforuserinterfacestyle.md)
- [UIUserInterfaceStyle](uikit/uiuserinterfacestyle.md)