Swift: Set UIBarButtonItem as source for popover WITHOUT tap? - swift

Question

I want to show a popover on iPad as soon as my view loads having as source a button on the top right corner.
The popover displays properly on button tap, but I'm having trouble finding a way to display it without the button tap, when the page first loads. Is this possible?
This is what I have:
func displayOptions(sourceButton: UIBarButtonItem)
let actionSheet = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
if let popoverController = actionSheet.popoverPresentationController {
var rect = CGRect(x: 0, y: 0, width: 0, height: 0)
popoverController.barButtonItem = sourceButton
popoverController.sourceRect = rect
popoverController.permittedArrowDirections = .up
}
viewController.present(actionSheet, animated: true, completion: nil)
}
This code works properly on button tap, but the app crashes if I try to call this function from viewDidLoad or viewDidAppear:
You must provide location information for this popover through the alert controller's popoverPresentationController. You must provide either a sourceView and sourceRect or a barButtonItem.

Answer 1

Try using UIPopoverPresentationControllerDelegate
Code example:
viewDidLoad
let buttonCustom = UIBarButtonItem(title: "Custom", style: .done, target: self, action: #selector(ViewController.customBarButtonAction))
self.navigationItem.rightBarButtonItem = buttonCustom
displayOptions()
displayOptions
func displayOptions() {
let actionSheet = UIAlertController(title: "Title", message: "Message", preferredStyle: .actionSheet)
if let popoverController = actionSheet.popoverPresentationController {
let rect = CGRect(x: 0, y: 0, width: 0, height: 0)
popoverController.sourceRect = rect
popoverController.sourceView = self.view
popoverController.permittedArrowDirections = .up
popoverController.delegate = self
}
self.present(actionSheet, animated: true, completion: nil)
}
using UIPopoverPresentationControllerDelegate
func prepareForPopoverPresentation(_ popoverPresentationController: UIPopoverPresentationController) {
popoverPresentationController.barButtonItem = self.navigationItem.rightBarButtonItem
}

Answer 2

You need to provide the sourceView.
UIAlertController must have a title, a message or an action to display.
// Create a bar button item in ViewDidLoad.
let button1 = UIBarButtonItem(image: UIImage(named: "imagename"), style: .plain, target: self, action: Selector("action"))
self.navigationItem.rightBarButtonItem = button1
// Call in ViewDidLoad
displayOptions(sourceButton: button1)
func displayOptions(sourceButton: UIBarButtonItem) {
let actionSheet = UIAlertController(title: "title", message: "message", preferredStyle: .actionSheet)
if let popoverController = actionSheet.popoverPresentationController {
let rect = CGRect(x: 0, y: 0, width: 0, height: 0)
popoverController.barButtonItem = sourceButton
popoverController.sourceRect = rect
popoverController.sourceView = self.view
popoverController.permittedArrowDirections = .up
}
self.present(actionSheet, animated: true, completion: nil)
}