WaitDialog.swift

/*
This is a wait dialog to show "please wait" while the app is doing some
long running task.
To call it from a view controller:

  WaitDialog.show(self)
  // start long running task

  // Long running task is done.
  WaitDialog.hide()

*/
import UIKit


open class WaitDialog {
    static let sharedInstance = WaitDialog()

    open static func show(_ parent: UIViewController, message: String? = nil) {
        sharedInstance.showWaitDialog(parent.view)
    }

    open static func show(_ parent: UIView, message: String? = nil) {
        sharedInstance.showWaitDialog(parent)
    }
    
    open static func hide() {
        sharedInstance.hideWaitDialog()
    }
    
    
    var isWaiting: Bool = false
    let view: PleaseWaitView = {
        let width = 180
        let screen = UIScreen.main
        let x = Int(screen.bounds.width) / 2 - (width / 2)
        return PleaseWaitView(frame: CGRect(x: CGFloat(x), y: CGFloat(200), width: CGFloat(width), height: CGFloat(100)))
    }()
    
    open func showWaitDialog(_ parent: UIView, message: String? = nil) {
        isWaiting = true
        self.view.show(parent, customMessage: message)
    }
    
    open func hideWaitDialog() {
        isWaiting = false
        self.view.close()
    }
    
}

class PleaseWaitView: UIView {
    
    var messageLabel = UILabel()
    var spinner = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.gray)
    
    init() {
        super.init(frame: CGRect(x: 100, y: 200, width: 100, height: 100))
        self.initDefaults()
    }
    
    override init(frame:CGRect){
        super.init(frame: frame)
        self.initDefaults()
    }
    
    convenience init(frame: CGRect, message:String) {
        self.init(frame: frame)
        self.messageLabel.text = message
    }
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func initDefaults() {
        //        self.backgroundColor = UIColor(red:249.0/255.0, green:249.0/255.0, blue:249.0/255.0, alpha:1.0)
        self.backgroundColor = UIColor(red:25.0/255.0, green:25.0/255.0, blue:25.0/255.0, alpha:0.6)
        
        self.layer.cornerRadius = 5
        self.layer.borderWidth = 1
        self.layer.borderColor = UIColor(red:10.0/255.0, green:10.0/255.0, blue:10.0/255.0, alpha:0.8).cgColor
    }
    
    
    func show(_ superview: UIView, customMessage: String? = nil) {
        // Override the message if it was sent
        if let customMessage = customMessage {
            self.messageLabel.text = customMessage
        }
        else {
            self.messageLabel.text = "Please wait"
        }
        // Add ourself to the super view.
        superview.addSubview(self)
        // Figure out where things go.
        let width = self.frame.size.width
        let x = Int(self.frame.size.width/2) - (Int(width) / 2)
        let y = 8
        let height = CGFloat(24)
        self.messageLabel.frame = CGRect(x: CGFloat(x), y: CGFloat(y), width: width, height: height)
        self.messageLabel.textAlignment = NSTextAlignment.center
        self.messageLabel.textColor = UIColor.white
        self.addSubview(messageLabel)
        
        spinner.center = CGPoint(x: self.frame.width/2, y: 65.5)
        spinner.color = UIColor.white
        spinner.hidesWhenStopped = true
        spinner.startAnimating()
        self.addSubview(spinner)
    }
    
    func close() {
        spinner.stopAnimating()
        spinner.removeFromSuperview()
        self.removeFromSuperview()
    }

}