LoadingView

LoadingView.swift

import Foundation
import UIKit
import Cartography

class LoadingView: UIView {
    
    let activityView = UIActivityIndicatorView(frame: .zero)
    let overlayView = UIView(frame: .zero)
    
    override init(frame: CGRect) {
        super.init(frame: .zero)
        setup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    static func show(inView view: UIView ) {
        if let _ = findLoading(inView: view) {
            return
        }
        
        let loading = LoadingView(frame: .zero)
        view.addSubview(loading)
        loading.frame = view.bounds
        
    }
    
    static func hide(fromView view: UIView) {
        guard let loading = findLoading(inView: view) else {
            return
        }
        
        loading.removeFromSuperview()
    }
    
    static func show(inVC vc: UIViewController ) {
        if let navVC = vc.navigationController {
            LoadingView.show(inVC: navVC)
            return
        }
        show(inView: vc.view)
    }
    
    static func hide(fromVC vc: UIViewController) {
        if let navVC = vc.navigationController {
            LoadingView.hide(fromVC: navVC)
            return
        }
        hide(fromView: vc.view)
    }
    
    static func findLoading(inView view: UIView) -> UIView? {
        var found: UIView?
        view.subviews.forEach { (view) in
            if view is LoadingView {
                found = view
            }
        }
        return found
    }
    
    fileprivate func setup() {
        addSubview(overlayView)
        
        addSubview(activityView)
        
        overlayView.backgroundColor = UIColor.black
        overlayView.alpha = 0.5
        
        backgroundColor = UIColor.clear
        
        constrain(overlayView,activityView) {  overlayView,activityView in
            overlayView.edges == overlayView.superview!.edges
            activityView.height == 60
            activityView.width == 60
            activityView.center == activityView.superview!.center
        }
        activityView.startAnimating()
    }
    
}