---
title: FxCustomParameterViewHost_v2
framework: Professional Video Applications
role: symbol
role_heading: Protocol
platforms: [fxplug 4.0+]
path: professional_video_applications/fxcustomparameterviewhost_v2
---

# FxCustomParameterViewHost_v2

Defines the methods a plug-in needs to implement to associate a custom NSView with one of its parameters.

## Declaration

```swift
protocol FxCustomParameterViewHost_v2
```

## Mentioned in

Adding parameters to plug-ins

## Overview

Overview An FxPlug that wants to present custom UI for one or more of its parameters must conform to the FxCustomParmeterViewHost protocol. This protocol allows the plug-in to provide a subclass of NSView. It is up to the plug-in to handle NSEvents in its custom view(s). When an event in a custom view necessitates a change to the value of the associated parameter, the plug-in then uses methods in the host API FxCustomParameterActionAPI to tell the host application to change the parameter value.

## Topics

### Instance Methods

- [createView(forParameterID:)](professional_video_applications/fxcustomparameterviewhost_v2/createview(forparameterid:).md)

## See Also

### Custom Parameter APIs

- [FxCustomParameterActionAPI_v4](professional_video_applications/fxcustomparameteractionapi_v4.md)
- [FxCustomParameterInterpolation_v2](professional_video_applications/fxcustomparameterinterpolation_v2.md)