When load WKWebview, its nil - ios

Question

I use Xcode 11.0 and Swift 5.1.
and I use WKWebview for load website, and There's no problem when I first loaded it.
but the second time to load a problem.
filename: TabBarController.swift
import UIKit
class TabBarController: UITabBarController, UITabBarControllerDelegate {
var isSelected = true
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
let tabBarIndex = tabBar.items?.firstIndex(of: item)
if isSelected == true && tabBarIndex == 0{
let vc = ViewController()
print("Go to amazon page")
vc.handleReload()
}
else{
if tabBarIndex == 0{
isSelected = true
print("home!")
}
else{
isSelected = false
print("setting!")
}
}
}
}
filename: ViewController.swift
import UIKit
import WebKit
class ViewController: UIViewController {
var webView: WKWebView!
override func loadView() {
let webConfiguration = WKWebViewConfiguration()
webView = WKWebView(frame: .zero, configuration: webConfiguration)
webView.uiDelegate = self
view = webView
}
override func viewDidLoad() {
super.viewDidLoad()
let url: URL = URL(string: "https://google.com")!
self.webView.load(URLRequest(url: url))
}
}
//MARK: - function
extension ViewController: WKUIDelegate, WKNavigationDelegate{
func handleReload() {
let url: URL = URL(string: "https://www.amazon.com")!
self.webView.load(URLRequest(url: url))
}
func cacheReset() {
let DataTypes = NSSet(array: [WKWebsiteDataTypeDiskCache, WKWebsiteDataTypeMemoryCache])
let date = NSDate(timeIntervalSince1970: 0)
WKWebsiteDataStore.default().removeData(ofTypes: DataTypes as! Set<String>, modifiedSince: date as Date){
print("Cache Reset End")
}
}
}
The error occurs at self.webView.load(URLRequest(url: url)) in func handleReload() and Here's the error log:
Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
I don't understand why WKWebview become nil :( Did I do something wrong?

Answer 1

You don't need to create ViewController again as you have already added as a child to TabBarController. You can grab that instance as below and call the require method on that same instance instead of creating a new.
if isSelected == true && tabBarIndex == 0 {
if let viewController = self.children.first(where: { $0 is ViewController }) as? ViewController {
viewController.handleReload()
}
}