How to redraw my view in SWIFT?

Question

On my iPad app, I have a UIViewController with a button that open a modalView.

@IBAction func showPostCommentViewController(sender: AnyObject){

    let modalView = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("PostCommentViewController") as! PostCommentViewController
    modalView.modalTransitionStyle = UIModalTransitionStyle.CoverVertical
    modalView.modalPresentationStyle = UIModalPresentationStyle.FormSheet
    modalView.delegate=self
    self.presentViewController(modalView, animated: true, completion: nil)
}

When I close the modalView with dismissViewControllerAnimated, I would like "refresh" my view controller (because I added new content). But as the modal view is a "formsheet" style, viewDidAppear or viewWillAppear aren't called.

I tried to use setNeedsDisplay, but it doesn't work.

I don't know how to do.

What do you want to happen? setNeedsDisplay may update the layout and stuff like that, but the content of labels etc. will not change, you have to change them explicitly. What exactly are you trying to do? — luk2302
You can create a delegate at "PostCommentViewController" which will be created when the view itself disappears. Then at the callee, you can define whatever action you want to perform with the specific delegate — Audrey Li

BenJammin BenJammin · Accepted Answer · 2015-07-05T19:23:07

This would be a perfect use case for the delegate pattern.

1) define a protocol within PostCommentViewController.

protocol PostCommentVCInformationDelegate {
    func hasDismissedPostCommentViewController(controller:PostCommentViewController)
}

2) Set a delegate variable within PostCommentViewController

var delegate: PostCommentVCInformationDelegate?

3) When you dismiss PostCommentViewController, you will call delegate?.hasDismissedPostCommentViewController(self)

This will send information back to the presenting VC.

4) Now we have our presenting View Controller conform to this protocol.

class ViewController: UIViewController, PostCommentVCInformationDelegate

5) When presenting the modal View:

modalView.delegate = self

6) Finally, we implement:

func hasDismissedPostCommentViewController(controller: PostCommentViewController) {
    //Update
}

How to redraw my view in SWIFT?

1 Answers