How to show activity indicator while tableView loads?

Question

When I switch between my tabs it loads some seconds and I want to know that my data is loading. For that I decided to add an activity indicator.

I wrote a little functio

Answer 1

Update Swift 4.2:

1.call the activityIndicator function on viewDidLoad
eg:

var indicator = UIActivityIndicatorView()
override func viewDidLoad() {
    //Initializing the Activity Indicator
    activityIndicator()
    //Starting the Activity Indicator
    indicator.startAnimating()
    //Call Your WebService or API
    callAPI()
}

Here is the Code For Adding ActivityIndicator as Subview

func activityIndicator() {
            indicator = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
            indicator.style = UIActivityIndicatorView.Style.whiteLarge
            indicator.color = .red
            indicator.center = self.view.center
            self.view.addSubview(indicator)
    }

2. Do UI related Operations or API Call and stop activity indicator

    func callAPI() {     
        YourModelClass.fetchResult(someParams, 
        completionHandler: { (response) in 
        //Do necessary UIUpdates
        //And stop Activity Indicator
        self.indicator.stopAnimating()
        })
    }