iOS Swift - Function from other class doesn't run - ios

Question

I want to create a class with a blurred view that should appear on the existing view if any problems occurred. Here is the code:
import Foundation
import UIKit
class checkProblems{
let effectView:UIVisualEffectView = UIVisualEffectView (effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
var view: UIView
let label = UILabel()
let retry = UIButton()
init(view: UIView){
self.view = view
self.check()
}
func check(){
effectView.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.height)
label.frame = CGRectMake(0, (self.view.frame.height/2)-20, self.view.frame.width, 40)
label.text = "Server connection problems."
label.textAlignment = NSTextAlignment.Center
label.textColor = UIColor.darkGrayColor()
label.font = UIFont (name: "HelveticaNeue-Light", size: 20)
retry.frame = CGRectMake(0, (self.view.frame.height/2)+10, self.view.frame.width, 40)
retry.setTitle("Tap here to retry.", forState: UIControlState.Normal)
retry.addTarget(self, action: "pressed:", forControlEvents: .TouchUpInside)
self.view.addSubview(effectView)
effectView.addSubview(label)
effectView.addSubview(retry)
}
func pressed(sender: UIButton!){
println("here")
}
}
And this is how I call it on the view controller:
let checkObject = checkProblems(view: view)
Everything works fine until I press the button "Tap here to retry".
Then, my app crashes.

Answer 1

I think you break the MVC-Pattern with your approach. Followed by problems with the corresponding references for the addAction method.
Please add all view-creating or -alternating code to the viewController. This will make your app a lot easier to understand.
I changed your code to correctly implement the MVC-Pattern (and making it runnable altogether)
import UIKit
class ViewController: UIViewController {
let effectView:UIVisualEffectView = UIVisualEffectView (effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
let label = UILabel()
let retry = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
check()
}
func check(){
effectView.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.height)
label.frame = CGRectMake(0, (self.view.frame.height/2)-20, self.view.frame.width, 40)
label.text = "Server connection problems."
label.textAlignment = NSTextAlignment.Center
label.textColor = UIColor.darkGrayColor()
label.font = UIFont (name: "HelveticaNeue-Light", size: 20)
retry.frame = CGRectMake(0, (self.view.frame.height/2)+10, self.view.frame.width, 40)
retry.backgroundColor = .blueColor()
retry.setTitle("Tap here to retry.", forState: UIControlState.Normal)
retry.addTarget(self, action: "pressed:", forControlEvents: UIControlEvents.TouchUpInside)
effectView.addSubview(label)
effectView.addSubview(retry)
view.addSubview(effectView)
}
func pressed(sender: UIButton){
println("here")
}
}
In addition to your comment, I show you an example of a MVC-conserving approach, which will subclass UIViewController. You can then load your checkProblems class with presentViewController:
Code from the calling VC:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
let checkProblemsVC = CheckProblemsViewController()
presentViewController(checkProblemsVC, animated: true, completion: nil)
}
}
And the new subclassed CheckProblemsViewController:
import UIKit
class CheckProblemsViewController: UIViewController {
let effectView:UIVisualEffectView = UIVisualEffectView (effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
let label = UILabel()
let retry = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
check()
}
func check(){
effectView.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.height)
label.frame = CGRectMake(0, (self.view.frame.height/2)-20, self.view.frame.width, 40)
label.text = "Server connection problems."
label.textAlignment = NSTextAlignment.Center
label.textColor = UIColor.darkGrayColor()
label.font = UIFont (name: "HelveticaNeue-Light", size: 20)
retry.frame = CGRectMake(0, (self.view.frame.height/2)+10, self.view.frame.width, 40)
retry.backgroundColor = .blueColor()
retry.setTitle("Tap here to retry.", forState: UIControlState.Normal)
retry.addTarget(self, action: "pressed:", forControlEvents: UIControlEvents.TouchUpInside)
effectView.addSubview(label)
effectView.addSubview(retry)
view.addSubview(effectView)
}
func pressed(sender: UIButton){
println("here")
}
}