webview turns nil after calling function from another controller - ios

Question

Hello if anybody can help me thanks!
I got two viewcontrollers HomeController and TableController
In HomeController i got a webview and when i go to the TableController and call a function to load an another request for the webview. The webview returns nil.
The HomeController is the main screen of the application which is a webview. The TableController is a table from a hamburger menu left of the application. When i open it and click on an item, I want to get the url of that item and use that url to send a request with the same HomeController. But at the moment when i reach connectUrl() i get an fatal error and it is because the webView is nil.
edit: answer below
Code below:
TableController
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
var HomeViewController: HomeController {
return self.storyboard?.instantiateViewControllerWithIdentifier("homeController") as! HomeController
}
let url = self.item[indexPath.item].url
HomeViewController.connectUrl(url!)
}
HomeController
class HomeController: UIViewController{
static let sharedInstance = HomeController()
var webView: WKWebView!
override func viewDidLoad() {
super.viewDidLoad()
let preferences = WKPreferences()
preferences.javaScriptEnabled = true
let configuration = WKWebViewConfiguration()
configuration.preferences = preferences
webView = WKWebView(frame: view.bounds, configuration: configuration)
self.view.addSubview(self.webView)
}
func connectUrl(url: String){
let url2 = NSURL(string: url)
let req = NSURLRequest(URL: url2!)
print(req)
self.webView!.loadRequest(req)
}}

Answer 1

Is there any domain erron in console?/
if yes
add it to plist.
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>

Answer 2

I found the solution after trial and error with many development options like delegates, segue, instantiateViewController etc.
In the end NSNotificationCenter was the solution for me.
I created this function in my TableController to send a notification to the HomeController to call ConnectUrl.
func sendData(url: String){
self.dismissViewControllerAnimated(true, completion: nil)
let itemDictionary = ["itemUrl": url]
NSNotificationCenter.defaultCenter().postNotificationName("connectUrl", object: nil, userInfo: itemDictionary)
}
}
}
In the HomeController I added an Observer to receive the noticatification and unpack the dictionary is received to get the url.
override func viewDidLoad() {
super.viewDidLoad()
webView = WKWebView(frame: view.bounds, configuration: configuration)
self.view.addSubview(self.webView!)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "connectUrl:", name: "connectUrl", object: nil)
}
func connectWithSpecifiedItem(notification: NSNotification){
let itemUrl = notification.userInfo!["itemUrl"] as! String
let url2 = NSURL(string: itemUrl)
let req = NSURLRequest(URL: url2!)
self.webView!.loadRequest(req)
}

Answer 3

This is not a WKWebView related issue. The actual problem here is that you don't know how to return data from a view controller.
The most basic solution for this is a delegate. First, create a TableControllerDelegate.
protocol TableControllerDelegate {
func tableController(tableController: TableController, didSelectItemWithURL: NSURL)
}
Then you implement this in your HomeController:
class HomeController: UIViewController, TableControllerDelegate {
func tableController(tableController: TableController, didSelectItemWithURL url: NSURL) {
webView.loadRequest(NSURLRequest(URL: url))
}
}
In your TableController, things get a little simpler and less connected. You let it have a TableControllerDelegate field and simply call that to pass the selected item URL back to whatever view opened it.
Note that there is no direct relationship between TableController and HomeController anymore. This is a good practice.
class TableController: UITableViewController {
weak delegate: TableControllerDelegate?
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let url = self.item[indexPath.item].url
delegate?.tableController(self, didSelectItemWithURL: url)
}
}
Now when you present your TableController from your HomeController you simply configure its delegate:
func displayTableController() {
let tableController = storyboard?.instantiateViewControllerWithIdentifier("tableController") as! TableControllerController
tableController.delegate = self
}
More code, but this is a very common pattern in iOS.