---
title: NSSplitViewItem
framework: appkit
role: symbol
role_heading: Class
path: appkit/nssplitviewitem
---

# NSSplitViewItem

An item in a split view controller.

## Declaration

```swift
class NSSplitViewItem
```

## Overview

Overview A split view item represents a single pane in a split view controller (NSSplitViewController). Each split view item contains information about a child view controller in the split view controller, like its preferred thickness, holding priority, and collapsed state. To add one or more accessory views to the top or bottom of a split view item, such as a search field above a list, use the topAlignedAccessoryViewControllers and bottomAlignedAccessoryViewControllers properties to specify  NSSplitViewItemAccessoryViewController types.

## Topics

### Creating a split view item

- [init(sidebarWithViewController:)](appkit/nssplitviewitem/init(sidebarwithviewcontroller:).md)
- [init(contentListWithViewController:)](appkit/nssplitviewitem/init(contentlistwithviewcontroller:).md)
- [init(viewController:)](appkit/nssplitviewitem/init(viewcontroller:).md)
- [init(inspectorWithViewController:)](appkit/nssplitviewitem/init(inspectorwithviewcontroller:).md)

### Managing the item thickness

- [automaticMaximumThickness](appkit/nssplitviewitem/automaticmaximumthickness.md)
- [preferredThicknessFraction](appkit/nssplitviewitem/preferredthicknessfraction.md)
- [minimumThickness](appkit/nssplitviewitem/minimumthickness.md)
- [maximumThickness](appkit/nssplitviewitem/maximumthickness.md)
- [unspecifiedDimension](appkit/nssplitviewitem/unspecifieddimension.md)

### Getting Auto Layout behaviors

- [holdingPriority](appkit/nssplitviewitem/holdingpriority.md)
- [automaticallyAdjustsSafeAreaInsets](appkit/nssplitviewitem/automaticallyadjustssafeareainsets.md)

### Getting the item behavior

- [behavior](appkit/nssplitviewitem/behavior-swift.property.md)
- [NSSplitViewItem.Behavior](appkit/nssplitviewitem/behavior-swift.enum.md)

### Collapsing and expanding the item

- [isCollapsed](appkit/nssplitviewitem/iscollapsed.md)
- [canCollapse](appkit/nssplitviewitem/cancollapse.md)
- [collapseBehavior](appkit/nssplitviewitem/collapsebehavior-swift.property.md)
- [NSSplitViewItem.CollapseBehavior](appkit/nssplitviewitem/collapsebehavior-swift.enum.md)
- [isSpringLoaded](appkit/nssplitviewitem/isspringloaded.md)
- [canCollapseFromWindowResize](appkit/nssplitviewitem/cancollapsefromwindowresize.md)

### Customizing appearance

- [allowsFullHeightLayout](appkit/nssplitviewitem/allowsfullheightlayout.md)
- [titlebarSeparatorStyle](appkit/nssplitviewitem/titlebarseparatorstyle.md)
- [NSTitlebarSeparatorStyle](appkit/nstitlebarseparatorstyle.md)

### Configuring accessory views

- [topAlignedAccessoryViewControllers](appkit/nssplitviewitem/topalignedaccessoryviewcontrollers.md)
- [bottomAlignedAccessoryViewControllers](appkit/nssplitviewitem/bottomalignedaccessoryviewcontrollers.md)
- [addTopAlignedAccessoryViewController(_:)](appkit/nssplitviewitem/addtopalignedaccessoryviewcontroller(_:).md)
- [insertTopAlignedAccessoryViewController(_:at:)](appkit/nssplitviewitem/inserttopalignedaccessoryviewcontroller(_:at:).md)
- [removeTopAlignedAccessoryViewController(at:)](appkit/nssplitviewitem/removetopalignedaccessoryviewcontroller(at:).md)
- [addBottomAlignedAccessoryViewController(_:)](appkit/nssplitviewitem/addbottomalignedaccessoryviewcontroller(_:).md)
- [insertBottomAlignedAccessoryViewController(_:at:)](appkit/nssplitviewitem/insertbottomalignedaccessoryviewcontroller(_:at:).md)
- [removeBottomAlignedAccessoryViewController(at:)](appkit/nssplitviewitem/removebottomalignedaccessoryviewcontroller(at:).md)
- [NSSplitViewItemAccessoryViewController](appkit/nssplitviewitemaccessoryviewcontroller.md)

### Getting the View Controller

- [viewController](appkit/nssplitviewitem/viewcontroller.md)

### Initializers

- [init(coder:)](appkit/nssplitviewitem/init(coder:).md)

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSAnimatablePropertyContainer](appkit/nsanimatablepropertycontainer.md)
- [NSCoding](foundation/nscoding.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)

## See Also

### Split View Interface

- [NSSplitViewController](appkit/nssplitviewcontroller.md)
- [NSSplitView](appkit/nssplitview.md)