UIViewController被关闭时重新加载TableView？

Question

The problem here is that I'm presenting EditCommentVC modally, over the current context of the CommentVC because I want to set the background of the UIView to semi-transparent. Now, on the EditCommentVC I have a UITextView that allows the user to edit their comment, along with 2 buttons - cancel (dismisses the EditCommentVC ) and update that updates the new comment and push it to the database.

In term of code, everything is working, except that once the new comment is being pushed and EditCommentVC is being dismissed, the UITableView on CommentsVC with all the comments is not being reloaded to show the updated comments. Tried calling it from viewWillAppear() but it doesn't work.

How can I reload the data in the UITableView in this case?

@IBAction func updateTapped(_ sender: UIButton) {
    guard let id = commentId else { return }
    Api.Comment.updateComment(forCommentId: id, updatedComment: editTextView.text!, onSuccess: {
        DispatchQueue.main.async {
            let commentVC = CommentVC()
            commentVC.tableView.reloadData()
            self.dismiss(animated: true, completion: nil)
        }
    }, onError: { error in
        SVProgressHUD.showError(withStatus: error)
    })

}

The code in the CommentVC where it transitions (and passes the id of the comment). CommentVC conforms to a CommentActionProtocol that passes the id of that comment:

extension CommentVC: CommentActionProtocol {

    func presentActionSheet(for commentId: String) {
        let actionSheet = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        let editAction = UIAlertAction(title: "Edit", style: .default) { _ in
            self.performSegue(withIdentifier: "CommentVCToEditComment", sender: commentId)
        }
        actionSheet.addAction(editAction)
        present(actionSheet, animated: true, completion: nil)

    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "CommentVCToEditComment" {
            let editCommentVC = segue.destination as! EditCommentVC
            let commentId = sender as! String
            editCommentVC.commentId = commentId
        }
    }

}

Answer 1

I see atleast 2 problems here:

1. You are creating a new CommentVC which you should not do if you want to update the tableView in the existing view controller.

2. Since you have mentioned that Api.Comment.updateComment is a an asynchronous call, you need to write the UI code to run on the main thread .

So first you need to have the instance of the commentVC in a variable inside this viewController. You can store the instance of the view controller from where you are presenting this view controller.

class EditCommentVC {

    var commentVCdelegate: CommentVC!   
    // Rest of your code

}

Now you need to pass the reference commentVC in this variable when you are presenting the edit view controller.

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "CommentVCToEditComment" {
        let editCommentVC = segue.destination as! EditCommentVC
        let commentId = sender as! String
        editCommentVC.commentId = commentId
        editCommentVC.commentVCdelegate = self
    }
}

Now you need to use this reference to reload your tableView.

Api.Comment.updateComment(forCommentId: id, updatedComment: editTextView.text!, onSuccess: {
    DispatchQueue.main.async {
        commentVCdelegate.tableView.reloadData() // - this commentVC must be an instance that you store of the your commentVC that you created the first time
        self.dismiss(animated: true, completion: nil)
    }
}, onError: { error in
    SVProgressHUD.showError(withStatus: error)
})

Answer 2

Well, i had this problem too, and the solution i found was to use Protocol . I would recommend you to search how to send data back to previous ViewController . That way, when you dismiss the EditCommentVC , you then send back a value(in my case i send true) to the previous ViewController(in your case, CommentVC), and then you'll have a function in CommentVC checking if the value is true and if it is, reload the TableView.

Here, let me show you an example of how i used (those are the names of my ViewControllers, functions and protocols, you can use whatever you want and send whatever data you want back):

In your CommentVC , you'll have something like this:

protocol esconderBlurProtocol {
    func isEsconder(value: Bool)
}

class PalestranteVC: UIViewController,esconderBlurProtocol {

func isEsconder(value: Bool) {
        if(value){
        //here is where you can call your api again if you want and reload the data
            tableView.reloadData()
        }
    }

}

Also, dont forget that you have to set the delegate of EditCommentVC, so do it when you're presenting EditCommentVC, like this:

let viewController = (self.storyboard?.instantiateViewController(withIdentifier: "DetalhePalestranteVC")) as! DetalhePalestranteVC
        viewController.modalPresentationStyle = .overFullScreen
        viewController.delegate = self
        self.present(viewController, animated: true, completion: nil)
//replace **DetalhePalestranteVC** with your **EditCommentVC**

And in your EditCommentVC you'll have something like this:

class DetalhePalestranteVC: UIViewController {

var delegate: esconderBlurProtocol?

override func viewWillDisappear(_ animated: Bool) {
        delegate?.isEsconder(value: true)
    }

}

That way, everything you dismiss EditCommentVC , you'll send back True and reload the tableView.