---
title: "materializedItemsDidChange(completionHandler:)"
framework: fileprovider
role: symbol
role_heading: Instance Method
path: "fileprovider/nsfileproviderreplicatedextension/materializeditemsdidchange(completionhandler:)"
---

# materializedItemsDidChange(completionHandler:)

Tells the file provider that the set of materialized items changed.

## Declaration

```swift
optional func materializedItemsDidChange(completionHandler: @escaping @Sendable () -> Void)
```

```swift
optional func materializedItemsDidChange() async
```

## Parameters

- `completionHandler`: A block that you call after you finish processing the changes.

## Mentioned in

Synchronizing the File Provider Extension

## Discussion

Discussion important: You can call this method from synchronous code using a completion handler, as shown on this page, or you can call it as an asynchronous method that has the following declaration: optional func materializedItemsDidChange() async For information about concurrency and asynchronous code in Swift, see Calling Objective-C APIs Asynchronously. The system calls this method when the set of materialized items changes, such as when the system downloads the content of a dataless item, or deletes the contents of a materialized item. note: The system doesn’t call this method when the item’s content changes. Keep track of the items in the working set—the set of items that the system has downloaded and is managing on disk—to optimize updates. Your file provider must let the system know about any changes to the working set. If you don’t track the working set, then you need to let the system know about any changes to any items in the remote storage. For more information, see Synchronizing the File Provider Extension.