display Loading using NVActivityIndicatorView

step - 1:

https://github.com/ninjaprox/NVActivityIndicatorView#animation-types
read the document 

Step -2

install using pod file

pod 'NVActivityIndicatorView'

Step-3

import NVActivityIndicatorView

step -4

class Classname: UIViewController, UIScrollViewDelegate,NVActivityIndicatorViewable

step-5 : 

• Start animating loading

        let activityData = ActivityData()

        NVActivityIndicatorPresenter.sharedInstance.startAnimating(activityData)

        NVActivityIndicatorPresenter.sharedInstance.setMessage("Loading")

•     stop animating loading

        NVActivityIndicatorPresenter.sharedInstance.stopAnimating()