---
title: "systemLayoutFittingSizeDidChange(forChildContentContainer:)"
framework: uikit
role: symbol
role_heading: Instance Method
path: "uikit/uicontentcontainer/systemlayoutfittingsizedidchange(forchildcontentcontainer:)"
---

# systemLayoutFittingSizeDidChange(forChildContentContainer:)

Notifies the container that a child view controller was resized using Auto Layout.

## Declaration

```swift
func systemLayoutFittingSizeDidChange(forChildContentContainer container: any UIContentContainer)
```

## Parameters

- `container`: The child view controller that received the resizing message.

## Discussion

Discussion This method is called when a view controller that doesn’t use Auto Layout has a child view controller that uses Auto Layout and the child view controller is resized. When the child view controller responds to the systemLayoutSizeFitting(_:) method, the systemLayoutFittingSizeDidChange(forChildContentContainer:) method is sent to the parent view controller.

## See Also

### Responding to changes in child view controllers

- [size(forChildContentContainer:withParentContainerSize:)](uikit/uicontentcontainer/size(forchildcontentcontainer:withparentcontainersize:).md)
- [preferredContentSizeDidChange(forChildContentContainer:)](uikit/uicontentcontainer/preferredcontentsizedidchange(forchildcontentcontainer:).md)
- [preferredContentSize](uikit/uicontentcontainer/preferredcontentsize.md)