<!--
{
  "availability" : [
    "macOS: 15.2.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AppKit",
  "identifier" : "/documentation/AppKit/NSWritingToolsCoordinator/AnimationParameters/progressHandler",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "AppKit"
    ],
    "preciseIdentifier" : "c:objc(cs)NSWritingToolsCoordinatorAnimationParameters(py)progressHandler"
  },
  "title" : "progressHandler"
}
-->

# progressHandler

A custom block that runs at the same time as the system animations.

```
var progressHandler: ((Float) -> Void)? { get set }
```

## Discussion

If you have animations you want to run at the same time as the system
animations, assign a block to this property and use it to run your
animations. The block you provide must have no return value and take
a floating-point value as a parameter. The parameter indicates the
current progress of the animations as a percentage value between
`0.0` to `1.0`. The system executes your block multiple times during
the course of the animations, providing an updated completion value each time.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)