How can I get UIWebView to open Facebook login page in response to the OAuth request on iOS 5 and iOS 6?

Question

We have:
(1) Facebook API-based web application with Facebook OAuth functionality (“the FB web app”)
(2) UIWebView-based browser on iPad (“the Browser”

Answer 1

How to facebook login in UIWebView.

Objective-c

Use taylorstine's answer. He saved my day. Thank you taylorstine

But I'm using Swift 3. so I just converted code below from taylorstine's answer.

Swift 3.

func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool {

    if let _ = request.url?.absoluteString.range(of: "m.facebook.com" ) {
        if let _ = request.url?.absoluteString.range(of: "back"){
            self.popUp?.removeFromSuperview()
            self.popUp = nil
            return false
        }

        if let _ = self.popUp {
            return true
        }

        let wv = popUpWebView()
        wv.loadRequest(request)

        return false
    }

    return true
}

func popUpWebView() -> UIWebView {

    let webView = UIWebView(frame: self.view.frame)

    webView.delegate = self
    self.popUp = webView
    self.view.addSubview(webView)

    return webView
}

func webViewDidFinishLoad(_ webView: UIWebView) {
    if let _ = self.popUp {

        let jsFromFile = "window.close=function(){window.location.assign('back://' + window.location);};"

        let _ = webView.stringByEvaluatingJavaScript(from: jsFromFile)

        let openerContext = self.webView.value(forKeyPath: "documentView.webView.mainFrame.javaScriptContext") as! JSContext

        let popupContext = webView.value(forKeyPath: "documentView.webView.mainFrame.javaScriptContext") as! JSContext

        popupContext.setObject("opener", forKeyedSubscript: "window" as (NSCopying & NSObjectProtocol)!)
        popupContext.setObject(openerContext.objectForKeyedSubscript("window"), forKeyedSubscript: "opener"  as (NSCopying & NSObjectProtocol)!)

    }

    if webView == self.popUp
        && (webView.request?.url?.absoluteString.range(of:"m.facebook.com") != nil)
        && webView.stringByEvaluatingJavaScript(from: "document.body.innerHTML") == "" {

        webView.stringByEvaluatingJavaScript(from: "eval(document.getElementsByTagName('script')[0].text)")

    }

}