Swift3でインジケーター実装

ViewController.swift

import UIKit

class ViewController: UIViewController {

    //スピナー画面
    lazy var spinnerView: SpinnerView = {
        var spinnerView = SpinnerView()
        spinnerView.frame = UIScreen.main.bounds
        spinnerView.spinner.center = self.view.center
        return spinnerView
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(spinnerView)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

SpinnerView.swift

//ここはただのスピナー以外の機能はない？

import UIKit

class SpinnerView: UIView {

    //MARK: - Accessors

    lazy var spinner: UIActivityIndicatorView = {

        var spinner = UIActivityIndicatorView(activityIndicatorStyle: .white)

        spinner.startAnimating()

        return spinner
    }()

    //MARK - Init

    override init(frame: CGRect) {

        super.init(frame: frame)

        backgroundColor = UIColor.red

        addSubview(spinner)
    }

    required init?(coder aDecoder: NSCoder) {

        super.init(coder: aDecoder)
    }

}