IOS Swift how can I reload a tableView from a different controller - ios

Question

I have 2 controllers A and Controller B . Controller A has a TableView and Controller B is a subview that when clicked opens a form and on Submit it enters data into the database. My problem is that I attempt to reload my TableView from Controller B from the user hits submit and I get the following error
fatal error: unexpectedly found nil while unwrapping an Optional value from this line
self.TableSource.reloadData()
Now the data from Controller B is successfully inserted so after I restart my app the data I submit is there . This is my code (TableSource is the TableView outlet)
Controller A
func reloadTable(latmin: Float,latmax: Float,lonmin: Float, lonmax: Float) {
let url:URL = URL(string:ConnectionString+"MY-URL")!
let session = URLSession.shared
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.cachePolicy = NSURLRequest.CachePolicy.reloadIgnoringCacheData
let parameter = "parameters"
request.httpBody = parameter.data(using: String.Encoding.utf8)
session.dataTask(with:request, completionHandler: {(data, response, error) in
if error != nil {
} else {
do {
let parsed = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! [String:Any]
if let S = parsedData["myData"] as? [AnyObject] {
for A in Data {
// gets Json Data
}
DispatchQueue.main.async {
// This is what I named my TableView
self.TableSource.reloadData()
}
}
} catch let error as NSError {
print(error)
}
}
}).resume()
}
That is my HTTP-Request that gets data from the database, now in that same Controller A I have a button that when clicked opens the SubView to Controller B and this is the code
#IBAction func Post_Action(_ sender: Any) {
let Popup = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ControllerB") as! Controller B
self.addChildViewController(Popup)
Popup.view.frame = self.view.frame
self.view.addSubview(Popup.view)
Popup.didMove(toParentViewController: self)
}
This is the code in Controller B and this is how I try to reload the TableView in Controller A
#IBAction func Submit_Form(_ sender: Any) {
// Code that submits the form no issues here
latmin = 32.18
latmax = 32.50
lonmin = -81.12
lonmax = -81.90
let Homepage = ControllerA()
Homepage.reloadTable(latmin: latmin!,latmax: latmax!,lonmin: lonmin!,lonmax: lonmax!)
}
So as stated before Controller A loads the data from the Database, Controller B has a form and when submitted it enters new data into the database . That whole process works I just now want to update the TableView in Controller A from the form is submitted in Controller B

Answer 1

I would suggest using protocol:
protocol SomeActionDelegate {
func didSomeAction()
}
In ViewController B
var delegate: SomeActionDelegate?
In ViewController A when segue
viewControllerB.delegate = self
You should add this
extension ViewControllerA: SomeActionDelegate {
func didSomeAction() {
self.tableView.reloadData()
}
}
And in ViewController B
func didChangeSomething() {
self.delegate?.didSomeAction()
}
It works like when ViewController B didChangeSomething() it sends message to ViewController A that it should didSomeAction()

Answer 2

You can do it with NSNotification
in swift 3.0
Think you have two viwe controllers called viewcontrollerA and viewControllerB
viewcontrollerA has the tableview.
you need to reload it from viewcontrolerB
implementaion of viewcontrollerA
create a function to relod your tableview in viewcontrollerA and call it in viewDidLoad
override func viewDidLoad() {
let notificationNme = NSNotification.Name("NotificationIdf")
NotificationCenter.default.addObserver(self, selector: #selector(YourControllername.reloadTableview), name: notificationNme, object: nil)
}
func relodaTableview() {
self.TableSource.reloadData()
}
implementation in viewcontrollerB (where you want to reload tableview)
post the notification in button click or anywhere you want like below
let notificationNme = NSNotification.Name("NotificationIdf")
NotificationCenter.default.post(name: notificationNme, object: nil)
hope this will help to you.