---
title: longestActivity
framework: deviceactivity
role: symbol
role_heading: Instance Property
path: deviceactivity/deviceactivitydata/activitysegment/longestactivity
---

# longestActivity

Access the date interval of the longest activity session during the activity segment.

## Declaration

```swift
var longestActivity: DateInterval?
```

## Discussion

Discussion This value may be nil if the person didn’t use this device during dateInterval.

## See Also

### Measuring activity

- [totalActivityDuration](deviceactivity/deviceactivitydata/activitysegment/totalactivityduration.md)