Webview, different behavior in simulator compared to device

Question

Good day,

I have found an interesting behaviour that I can not understand.

I have an app that has a WKWebView. I use locally saved html files to present in the webview. To present each view I have a button for each html file. In the simulator I can go between the views as I tap each button. But in the actual device, I can see both views once and then it is stuck on the second view and will not change back to the first view.

I have moved this issue into a new project where I can play with it with out messing with the rest of the app. I am getting the same issue in the test project.

@IBOutlet weak var wec: WKWebView!

override func viewDidLoad() {
    super.viewDidLoad()
    wec.uiDelegate = self
    // Do any additional setup after loading the view.
}

@IBAction func one() {
    show_web(str: "one")
}

@IBAction func two() {
    show_web(str: "two")
}

func show_web(str: String) {
    var dir_name: String!
    switch str {
    case "one":
        dir_name = "one"
    case "two":
        dir_name = "two"
    default:
        return
    }
    
    let documentDirectory = create_directory_if_needed(directory: dir_name)
    let index_html_url = documentDirectory!.appendingPathComponent("index.html")
         
    print("--------------- LOADING WEB VIEW ------------------/n",
          index_html_url.path,
          "--------------- LOADING WEB VIEW END ------------------/n")
    let request = URLRequest(url: index_html_url)
    print("???????", request)
    self.wec.load(request)
}

func create_directory_if_needed(directory: String) -> URL? {
    let fm = FileManager.default
    let documentDirectory = fm.urls(for: .documentDirectory, in: .userDomainMask)[0]
    let new_folder = documentDirectory.appendingPathComponent(directory)
    if !fm.fileExists(atPath: new_folder.path) {
        do {
            try fm.createDirectory(at: new_folder, withIntermediateDirectories: true, attributes: nil)
        }catch {
            print("*********** ERROR create directory ***************")
            print(error)
            print("*********** ERROR End ***************")
            return nil
        }
    }
    
    return new_folder
}

When I print the request it always shows the correct path that I want to be presented but it does not load the correct path.

--------------- LOADING WEB VIEW ------------------/n /Users/jonasrafnsson/Library/Developer/CoreSimulator/Devices/189C901B-CD20-4636-B176-0DCE7AED456D/data/Containers/Data/Application/CB8A2C28-3406-4162-9A6E-6C0B924F6874/Documents/two/index.html --------------- LOADING WEB VIEW END ------------------/n

??????? file:///Users/jonasrafnsson/Library/Developer/CoreSimulator/Devices/189C901B-CD20-4636-B176-0DCE7AED456D/data/Containers/Data/Application/CB8A2C28-3406-4162-9A6E-6C0B924F6874/Documents/two/index.html

--------------- LOADING WEB VIEW ------------------/n /Users/jonasrafnsson/Library/Developer/CoreSimulator/Devices/189C901B-CD20-4636-B176-0DCE7AED456D/data/Containers/Data/Application/CB8A2C28-3406-4162-9A6E-6C0B924F6874/Documents/one/index.html --------------- LOADING WEB VIEW END ------------------/n

??????? file:///Users/jonasrafnsson/Library/Developer/CoreSimulator/Devices/189C901B-CD20-4636-B176-0DCE7AED456D/data/Containers/Data/Application/CB8A2C28-3406-4162-9A6E-6C0B924F6874/Documents/one/index.html

Anyone seen this behaviour before?

Regards, Jonas

When do you copy something in the directory and especially index.html ? — Ptit Xav, Jan 01 '22 at 16:14
Both on start up and possible to get them on request with a button. The files are downloaded from a server and placed in the correct directory. I know that they are there because they both appear once when I press the button to show them. In the simulator they come on every time when I tap the button. — Jónas Rafnsson, Jan 01 '22 at 16:34
What I see in your code is only where you create the directory if it does not exist. In this case there is no index.html download . Try to check for the existence of index.html file before opening web view. You must also assume that downloading a file may take undetermined amount if time . — Ptit Xav, Jan 01 '22 at 21:37

score 0 · Answer 1 · answered Jan 02 '22 at 10:14

The solution I came down to was to add the web view programmatically and create a new web view every time I changed the view.

import UIKit
import WebKit

class ViewController: UIViewController, WKUIDelegate {

  @IBOutlet weak var web_view: UIView!
  var web: WKWebView!

  override func viewDidLoad() {
      super.viewDidLoad()
    
      // Do any additional setup after loading the view.
  }

  override func viewDidAppear(_ animated: Bool) {
      super.viewDidAppear(animated)
      setup_web()
  }

  @IBAction func copyD() {
      let fm = FileManager.default
      let urls = [create_directory_if_needed(directory: "one"), create_directory_if_needed(directory: "two")]
    
      let files = [Bundle.main.url(forResource: "index_1", withExtension: "html"), Bundle.main.url(forResource: "index_2", withExtension: "html")]
    
      for f in 0..<files.count {
          do {
              try fm.copyItem(atPath: files[f]!.path,
                            toPath: urls[f]!.appendingPathComponent("index.html").path)
          }catch {
              print("*********** ERROR Copying Single file **************")
              print(error)
              print("*********** ERROR End **************")
          }
      }
  }

  @IBAction func one() {
      reset_webview()
      show_web(str: "one")
  }

  @IBAction func two() {
      reset_webview()
      show_web(str: "two")
  }

  func setup_web() {
      web = WKWebView(frame: CGRect(x: 0, y: 0, width: web_view.frame.width, height: web_view.frame.height))
      web.uiDelegate = self
      web_view.addSubview(web)
  }

  func reset_webview() {
      web.removeFromSuperview()
      web = nil
      setup_web()
  }

  func show_web(str: String) {
      var dir_name: String!
      switch str {
      case "one":
          dir_name = "one"
      case "two":
          dir_name = "two"
      default:
          return
      }
    
      let documentDirectory = create_directory_if_needed(directory: dir_name)

      let index_html_url = documentDirectory!.appendingPathComponent("index.html")
         
      print("--------------- LOADING WEB VIEW ------------------/n",
            index_html_url.path,
            "--------------- LOADING WEB VIEW END ------------------/n")
      let request = URLRequest(url: index_html_url)
      print("???????", request)
      self.web.load(request)
  }

  func create_directory_if_needed(directory: String) -> URL? {
      let fm = FileManager.default
      let documentDirectory = fm.urls(for: .documentDirectory, in: .userDomainMask)[0]
      let new_folder = documentDirectory.appendingPathComponent(directory)
      if !fm.fileExists(atPath: new_folder.path) {
          do {
              try fm.createDirectory(at: new_folder, withIntermediateDirectories: true, attributes: nil)
          }catch {
              print("*********** ERROR create directory ***************")
              print(error)
              print("*********** ERROR End ***************")
              return nil
          }
      }
    
      return new_folder
  }

  func check_if_file_exists(url: URL) -> URL? {
      let fm = FileManager.default
      // Check if the file exists, in case it doesnt we stop here.
      let path = url.path
      guard fm.fileExists(atPath: path) else {
          return nil
      }
      return url
  }
}

These works as intended. Maybe not the easiest way but the only one I managed.

Jonas

Webview, different behavior in simulator compared to device

1 Answers1