Popover notification view, independent of current view controller in swift - ios

Question

I want to notify users that an action has been completed in the background. Currently, the AppDelegate receives notification of this:
func didRecieveAPIResults(originalRequest: String, apiResponse: APIResponse) {
if(originalRequest == "actionName") {
// do something
}
}
I'd really like to display a pop over notification (e.g. "Awarded points to 10 students") over the currently active view.
I know how to do this with NSNotification, but that means I have to add a listener to each of the views. An alternative to that would be great!
The next part of question is how do I actually get the view to fade in and then fade out again in front of whatever view I have - be that a table view, collection view or whatever else. I've tried the following code (in the viewDidLoad for the sake of testing):
override func viewDidLoad() {
// set up views
let frame = CGRectMake(0, 200, 320, 200)
let notificationView = UIView(frame: frame)
notificationView.backgroundColor = UIColor.blackColor()
let label = UILabel()
label.text = "Hello World"
label.tintColor = UIColor.whiteColor()
// add the label to the notification
notificationView.addSubview(label)
// add the notification to the main view
self.view.addSubview(notificationView)
print("Notification should be showing")
// animate out again
UIView.animateWithDuration(5) { () -> Void in
notificationView.hidden = true
print("Notification should be hidden")
}
}
The view does appear without the hiding animation, but with that code in it hides straight away. I'm also not sure how to stick this to the bottom of the view, although perhaps that's better saved for another question. I assume I'm doing a few things wrong here, so any advice pointing me in the right direction would be great! Thanks!

Answer 1

For your notification issue, maybe UIAlertController suits your needs?
This would also solve your issues with fading in/out a UIView
func didRecieveAPIResults(originalRequest: String, apiResponse: APIResponse) {
if(originalRequest == "actionName") {
// Creates an UIAlertController ready for presentation
let alert = UIAlertController(title: "Score!", message: "Awarded points to 10 students", preferredStyle: UIAlertControllerStyle.Alert)
// Adds the ability to close the alert using the dismissViewControllerAnimated
alert.addAction(UIAlertAction(title: "Close", style: UIAlertActionStyle.Cancel, handler: { action in alert.dismissViewControllerAnimated(true, completion: nil)}))
// Presents the alert on top of the current rootViewController
UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(alert, animated: true, completion: nil)
}
}
UIAlertController
When adding a subview you want to be on top of everything else, do this:
self.view.addSubview(notificationView)
self.view.bringSubviewToFront(notificationView)
Fading a UIView by changing the alpha directly:
For testing, you should be calling this in your viewDidAppear so that the fading animation starts after the view actually is shown.
// Hides the view
UIView.animateWithDuration(5) { () -> Void in
notificationView.alpha = 0
}
// Displays the view
UIView.animateWithDuration(5) { () -> Void in
notificationView.alpha = 0
}
This solution takes up unnecessary space in your code, I would recommend extensions for this purpose.
Extensions:
Create a Extensions.swift file and place the following code in it.
Usage: myView.fadeIn(), myView.fadeOut()
import UIKit
extension UIView {
// Sets the alpha to 0 over a time period of 0.15 seconds
func fadeOut(){
UIView.animateWithDuration(0.15, animations: {
self.alpha = 0
})
}
// Sets the alpha to 1 over a time period of 0.15 seconds
func fadeIn(){
UIView.animateWithDuration(0.15, animations: {
self.alpha = 1
})
}
}
Swift 2.1 Extensions
Hope this helps! :)