Load local web files & resources in WKWebView

问题:

Unlike with UIWebView and previous versions of WKWebView (iOS 10 & macOS 10.12), the default load operation for local files has moved from Bundle.main.path to Bundle.main.url. Similarly, loadFileURL has also become the default function to load local resources in WKWebView.

I know that .path and .url are entirely different and have both worked in the past – .path historically being the default-chosen method; however, it seems that the latest versions of Swift have broken most, if not all, .path solutions. The .path solutions seem to now flatten the directory hierarchy, putting all of the CSS, JS, and any other sub-directory contents, into one big directory. This causes loading errors when WKWebView attempts to load index.html, for example, with a linked, sub-folder stylesheet (ie. /css/style.css).

After seeing numerous questions and countless uncertain/broken answers to match, is there a quick and painless solution for implementing a WKWebView that can load local resources (including linked CSS/JS files), without any workarounds?

回答1:

Updated for Swift 4, Xcode 9.3

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This methods allows WKWebView to properly read your hierarchy of directories and sub-directories for linked CSS, JS and most other files. You do NOT need to change your HTML, CSS or JS code.

Solution (Quick)

1. Add the web folder to your project (File > Add Files to Project)
   • Copy items if needed
   • Create folder references *
   • Add to targets (that are applicable)

2. Add the following code to the viewDidLoad and personalize it to your needs:

   let url = Bundle.main.url(forResource: "index", withExtension: "html", subdirectory: "website")!
   webView.loadFileURL(url, allowingReadAccessTo: url)
   let request = URLRequest(url: url)
   webView.load(request)
   

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Solution (In-Depth)

Step 1

Import the folder of local web files anywhere into your project. Make sure that you:

☑️ Copy items if needed

☑️ Create folder references (not "Create groups")

☑️ Add to targets

Step 2

Go to the View Controller with the WKWebView and add the following code to the viewDidLoad method:

let url = Bundle.main.url(forResource: "index", withExtension: "html", subdirectory: "website")!
webView.loadFileURL(url, allowingReadAccessTo: url)
let request = URLRequest(url: url)
webView.load(request)

• index – the name of the file to load (without the .html extension)
• website – the name of your web folder (index.html should be at the root of this directory)

Conclusion

The overall code should look something like this:

import UIKit
import WebKit

class ViewController: UIViewController, WKUIDelegate, WKNavigationDelegate {

    @IBOutlet weak var webView: WKWebView!

    override func viewDidLoad() {
        super.viewDidLoad()

        webView.uiDelegate = self
        webView.navigationDelegate = self

        let url = Bundle.main.url(forResource: "index", withExtension: "html", subdirectory: "Website")!
        webView.loadFileURL(url, allowingReadAccessTo: url)
        let request = URLRequest(url: url)
        webView.load(request)
    }

}

If any of you have further questions about this method or the code, I'll do my best to answer!

回答2:

This work For Me:

        WKWebView *wkwebView = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, 1024, 768)];
        wkwebView.navigationDelegate = self;
        wkwebView.UIDelegate = self;
        [wkwebView.configuration.preferences setValue:@"TRUE" forKey:@"allowFileAccessFromFileURLs"];
        NSURL *url = [NSURL fileURLWithPath:YOURFILEPATH];
        [wkwebView loadFileURL:url allowingReadAccessToURL:url.URLByDeletingLastPathComponent];
        [self.view addSubview:wkwebView];

回答3:

I was facing the same issue my condition was, I am downloading some HTML content from the server and save it to the Document directory and show it inside the application. The same controller uses the LIVE URL also I have to put the condition with url scheme. Tested on iOS 13 Xcode 11

  if Url.scheme == "file" as String {
         wkWebView.loadFileURL(Url, allowingReadAccessTo: Url)
    }
    else {
         let request = URLRequest.init(url: Url, cachePolicy:.reloadIgnoringLocalCacheData, timeoutInterval:60)
         wkWebView.load(request)
    }

it worked perfect for me