How can view controller present it's self? - ios

Question

I have the following class below. The idea is it will use a custom Progress Window View Controller to handle progress of various different events. The problem is since this is in a class and not a view controller it's self, I'm not sure how to make the progressWindow actually show up after I instantiate it from the storyboard?
How do I do this? Currently I get an error that the application tried to present model view controller on itself.
import Foundation
import UIKit
class StatusProgress{
static var cancelCode = {}
static var runCode = {}
static var theProgressWindowController = ProgressWindowViewController()
static var returningViewControllerIdentifier = ""
static let storyboard = UIStoryboard(name: "Main", bundle: nil)
static func run(){
// This will run in parralel but on main queue. Has to be on this Queue because it might involve UI
dispatch_async(dispatch_get_main_queue(), {
// Update the UI on the main thread.
StatusProgress.runCode()
});
}
static func cancel(){
dispatch_async(dispatch_get_main_queue(), {
StatusProgress.cancelCode()
dispatch_sync(dispatch_get_main_queue(),{
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier(returningViewControllerIdentifier)
vc.presentViewController(vc, animated: true, completion: nil)
})
});
}
static func show(){
dispatch_async(dispatch_get_main_queue(),{
theProgressWindowController = self.storyboard.instantiateViewControllerWithIdentifier("progressWindow") as! ProgressWindowViewController
theProgressWindowController.presentViewController(theProgressWindowController, animated: true, completion: nil) //use own instance to show it's self? (throws error! application tried to present modal view controller on itself. Presenting controller is <Inventory_Counter.ProgressWindowViewController: 0x1466ea390>.')
})
}
}
My problem is essentially I need a replacement for this line of code.
theProgressWindowController.presentViewController(theProgressWindowController, animated: true, completion: nil)
I forgot to mention here is the code that runs it inside another view controller.
SyncViewController.swift
import UIKit
class SyncViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func yesSyncButtonAction(sender: UIButton) {
StatusProgress.returningViewControllerIdentifier = "syncWindow"
StatusProgress.runCode = {
print("run code test")
}
StatusProgress.cancelCode = {
print("cancel code test")
}
StatusProgress.show()
}
#IBAction func noSyncActionButton(sender: UIButton) {
tabBarController?.selectedIndex = 1 //assume back to inventory section
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}

Answer 1

The biggest problem is that your StatusProgress class is instantiating and showing a view controller. View controllers should instantiate and show other view controllers, model objects should not. So you need to move the logic for presenting the new view controller into you SyncViewController. Then use delegation to communicate to the SyncViewController that the syncing is done.
protocol StatusProgressDelegate {
func statusProgress(status: StatusProgress, shouldShow: Bool)
func statusProgress(status: StatusProgress, shouldCancel: Bool)
}
Your StatusProgress object would have a delegate that conforms to that protocol and call that delegate inside of its show and cancel methods. This means that you need to make the static functions instance methods, and write an initializer for the class so you can instantiate it.

Answer 2

If the view life cycle events are not much important for you, you may just add the view of your progress controller to view of your current controller. or it's even better if you supply the UIView parameter in your show() function.
static func show(attachToView: UIView ){
dispatch_async(dispatch_get_main_queue(),{
theProgressWindowController = self.storyboard.instantiateViewControllerWithIdentifier("progressWindow") as! ProgressWindowViewController
attachToView.addSubview(theProgressWindowController.view)
})
}
After all you'd better to remove your progress view from superview
static func cancel(){
dispatch_async(dispatch_get_main_queue(),{
theProgressWindowController = self.storyboard.instantiateViewControllerWithIdentifier("progressWindow") as! ProgressWindowViewController
theProgressWindowController.view.removeFromSuperview()
})
}