Injecting a new stylesheet into a website via uiwebview using iOS8 Swift XCode 6

Question

I\'ve seen a few options on here using just Objective-C, but I\'m having trouble doing this with Swift iOS8 in XCode 6. I\'m using the uiwebview to load a website. For sake

Answer 1

Using the now preferred WKWebView you can put the external css file, say tweaks.css in the root of your project or in a sub-folder, then you can inject it into your page like this:

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    guard let path = Bundle.main.path(forResource: "tweaks", ofType: "css") else { return }
    let css = try! String(contentsOfFile: path).replacingOccurrences(of: "\\n", with: "", options: .regularExpression)
    let js = "var style = document.createElement('style'); style.innerHTML = '\(css)'; document.head.appendChild(style);"
    webView.evaluateJavaScript(js)
}

To make the file available:

1. Click your project
2. Click your target
3. Select Build Phases
4. Expand Copy Bundle Resources
5. Click '+' and select your file.

Also make sure that your controller implements WKNavigationDelegate:

class ViewController: UIViewController, WKNavigationDelegate