1# ArkUI_ContextCallback 2 3 4## Overview 5 6Event type. 7 8**Since**: 12 9 10**Related module**: [ArkUI_NativeModule](_ark_u_i___native_module.md) 11 12 13## Summary 14 15 16### Member Variables 17 18| Name| Description| 19| -------- | -------- | 20| void \* [userData](#userdata) | Custom type. | 21| void(\* [callback](#callback) )(void \*[userData](#userdata)) | Event callback. | 22 23 24## Member Variable Description 25 26 27### callback 28 29``` 30void(* ArkUI_ContextCallback::callback) (void *userData) 31``` 32**Description** 33 34Event callback. 35 36 37### userData 38 39``` 40void* ArkUI_ContextCallback::userData 41``` 42**Description** 43 44Custom type. 45