---
title: QLPreviewItem
framework: quicklookui
role: symbol
role_heading: Protocol
path: quicklookui/qlpreviewitem
---

# QLPreviewItem

A protocol that defines a set of properties you implement to make a preview of your application’s content.

## Declaration

```swift
protocol QLPreviewItem : NSObjectProtocol
```

## Overview

Overview Implement the properties in this protocol to make your application’s content visible in a Quick Look preview. Use  QLPreviewController to display a Quick Look preview on iOS, QLPreviewPanel and QLPreviewView on macOS. The properties in the QLPreviewItem protocol are also declared as a category on the NSURL class. As a result, you can use NSURL objects directly as preview items — provided that you want to use the default titles of those items. The default title for an NSURL object is the last path component of an item’s URL. To supply custom titles for preview objects, implement a class conforming to this protocol, supplying the title with the previewItemTitle property.

## Topics

### Instance Properties

- [previewItemDisplayState](quicklookui/qlpreviewitem/previewitemdisplaystate.md)
- [previewItemTitle](quicklookui/qlpreviewitem/previewitemtitle.md)
- [previewItemURL](quicklookui/qlpreviewitem/previewitemurl.md)

## Relationships

### Inherits From

- [NSObjectProtocol](objectivec/nsobjectprotocol.md)

## See Also

### Previews

- [QLPreviewPanel](quicklookui/qlpreviewpanel.md)
- [QLPreviewView](quicklookui/qlpreviewview.md)
- [QLPreviewPanelDataSource](quicklookui/qlpreviewpaneldatasource.md)
- [QLPreviewPanelDelegate](quicklookui/qlpreviewpaneldelegate.md)
- [QLPreviewItemLoadingBlock](quicklookui/qlpreviewitemloadingblock.md)