---
title: "numberOfPreviewItems(in:)"
framework: quicklook
role: symbol
role_heading: Instance Method
path: "quicklook/qlpreviewcontrollerdatasource/numberofpreviewitems(in:)"
---

# numberOfPreviewItems(in:)

Returns the number of preview items to include in the preview navigation list.

## Declaration

```swift
func numberOfPreviewItems(in controller: QLPreviewController) -> Int
```

## Parameters

- `controller`: The Quick Look preview controller that’s requesting the number of preview items.

## Return Value

Return Value The number of items that the Quick Look preview controller should include in its preview navigation list.

## Discussion

Discussion The system invokes this method to inform the preview controller of the number of preview items available. If you push a Quick Look preview controller into view using a UINavigationController object that has a toolbar, the system automatically displays arrows in the toolbar to navigate among the items in the navigation list. If you’re not displaying a toolbar and want to provide your own method of switching among items, use the currentPreviewItemIndex property to indicate the item you want to display. If you display a preview controller modally (full screen), the controller includes navigation arrows if there’s more than one item in the navigation list.

## See Also

### Providing data to a preview controller

- [previewController(_:previewItemAt:)](quicklook/qlpreviewcontrollerdatasource/previewcontroller(_:previewitemat:).md)