---
title: "custom(identifier:resolver:)"
framework: uikit
role: symbol
role_heading: Type Method
path: "uikit/uisheetpresentationcontroller/detent/custom(identifier:resolver:)"
---

# custom(identifier:resolver:)

Creates a custom detent for a sheet by computing its value according to the properties of the provided context.

## Declaration

```swift
@MainActor @preconcurrency static func custom(identifier: UISheetPresentationController.Detent.Identifier? = nil, resolver: @escaping (any UISheetPresentationControllerDetentResolutionContext) -> CGFloat?) -> UISheetPresentationController.Detent
```

## Parameters

- `identifier`: An identifier for the detent. Specify a unique identifier for each custom detent for a sheet. If you don’t specify an identifier, the system generates a random identifier.
- `resolver`: A closure for resolving the detent value with an input of type doc://com.apple.uikit/documentation/UIKit/UISheetPresentationControllerDetentResolutionContext. The value you return from this closure is a height within the safe area of the sheet. For example, return 200 for a detent with a height of 200 plus doc://com.apple.uikit/documentation/UIKit/UIView/safeAreaInsets.doc://com.apple.uikit/documentation/UIKit/UIEdgeInsets/bottom when the sheet is edge-attached, or 200 when the sheet is floating. Return nil to specify that the detent is inactive according to the provided context. If the closure depends on any external inputs, call doc://com.apple.uikit/documentation/UIKit/UISheetPresentationController/invalidateDetents() on the sheet when the external inputs change. Don’t set any properties on doc://com.apple.uikit/documentation/UIKit/UISheetPresentationController during the execution of this closure.

## See Also

### Creating a custom detent

- [resolvedValue(in:)](uikit/uisheetpresentationcontroller/detent/resolvedvalue(in:).md)
- [UISheetPresentationControllerDetentResolutionContext](uikit/uisheetpresentationcontrollerdetentresolutioncontext.md)