user2252374 user2252374 - 5 months ago 110
Swift Question

How to reload data in a TableView from a different ViewController in Swift

In a ViewController, I'm trying to reload data in a TableView in another ViewController like so:

(self.presentedViewController as! tableViewController).table.reloadData()


Where tableViewController is the class in the TableView's controller (It's not upper camel case, I know) and table is the TableView. Well, doing this yields "fatal error: unexpectedly found nil while unwrapping an Optional value" and I guess that makes sense since the "presentedViewController" hasn't been loaded yet.
I also tried this:

(self.navigationController!.viewControllers[self.navigationController!.viewControllers.count - 2] as! tableViewController).table.reloadData()


which yielded the same result (I made sure the tableViewController was under the current ViewController on the navigationController stack). I'm baffled about what I should do...I feel like it should be easier to refer to properties in different view controllers. I may be a little vague; if I am, tell me what you need to know!

Answer

You can post a notification

NSNotificationCenter.defaultCenter().postNotificationName("reload", object: nil)

And add an observer at the view controller that you want to reload the data:

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "reloadTableData:", name: "reload", object: nil)
}

func reloadTableData(notification: NSNotification) {
   tableView.reloadData()
}

Xcode 8 beta • Swift 3

You can post a notification

NotificationCenter.default().post(name: Notification.Name(rawValue: "reload"), object: nil)

And add an observer at the view controller that you want to reload the data:

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default().addObserver(self, selector: #selector(reloadTableData(_:)), name:"reload", object: nil)
}

func reloadTableData(_ notification: Notification) {
    tableView.reloadData()
}