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

I use two extension methods to add an UIActivityIndicatorView as the backgroundView of the tableview.

extension UITableView {
    func showActivityIndicator() {
        DispatchQueue.main.async {
            let activityView = UIActivityIndicatorView(style: .medium)
            self.backgroundView = activityView
            activityView.startAnimating()
        }
    }

    func hideActivityIndicator() {
        DispatchQueue.main.async {
            self.backgroundView = nil
        }
    }
}

You can show/hide it like this.

tableView.showActivityIndicator()
tableView.hideActivityIndicator()

Answer 2

Using "lazy var". It's better than function

fileprivate lazy var activityIndicatorView: UIActivityIndicatorView = {
    let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .gray)
    activityIndicatorView.hidesWhenStopped = true

    // Set Center
    var center = self.view.center
    if let navigationBarFrame = self.navigationController?.navigationBar.frame {
        center.y -= (navigationBarFrame.origin.y + navigationBarFrame.size.height)
    }
    activityIndicatorView.center = center

    self.view.addSubview(activityIndicatorView)
    return activityIndicatorView
}()

Just start the spinner anywhere

like this

func requestData() {
  // Request something
  activityIndicatorView.startAnimating()
}

Answer 3

Just try this:

var indicator = UIActivityIndicatorView()

func activityIndicator() {
    indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
    indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    indicator.center = self.view.center
    self.view.addSubview(indicator)    
}

And where you want to start animating

indicator.startAnimating()
indicator.backgroundColor = UIColor.whiteColor()

For stop:

indicator.stopAnimating()
indicator.hidesWhenStopped = true

Note: Avoid the calling of start and stop at the same time. Just give some conditions.

SWIFT : 4.2 Just try this:

var indicator = UIActivityIndicatorView()

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

And where you want to start animating

activityIndicator()
indicator.startAnimating()
indicator.backgroundColor = .white

For stop:

indicator.stopAnimating()
indicator.hidesWhenStopped = true

Answer 4

 func setupSpinner(){
    spinner = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height:40))
    spinner.color = UIColor(Colors.Accent)
    self.spinner.center = CGPoint(x:UIScreen.main.bounds.size.width / 2, y:UIScreen.main.bounds.size.height / 2)
    self.view.addSubview(spinner)
    spinner.hidesWhenStopped = true
}

Answer 5

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()
        })
    }

Answer 6

@brocolli's answer for swift 4.0. You have to use objc_ before getting or setting associated objects. According to the documentation, The APIs of getting and setting the associated object in Swift are:

func objc_getAssociatedObject(object: AnyObject!,
                                 key: UnsafePointer<Void>
                             )  -> AnyObject!

func objc_setAssociatedObject(object: AnyObject!,
                                 key: UnsafePointer<Void>,
                               value: AnyObject!,
                              policy: objc_AssociationPolicy)

Implementation:

import UIKit

fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"

extension UIView {
    var activityIndicatorView: UIActivityIndicatorView {
        get {
            if let activityIndicatorView = objc_getAssociatedObject(self, &ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
                return activityIndicatorView
            } else {
                let activityIndicatorView = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
                activityIndicatorView.activityIndicatorViewStyle = .gray
                activityIndicatorView.color = .gray
                activityIndicatorView.center = center
                activityIndicatorView.hidesWhenStopped = true
                addSubview(activityIndicatorView)

                objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, activityIndicatorView, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
                return activityIndicatorView
            }
        }

        set {
            addSubview(newValue)
            objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }

    }
}