Q:

Replace inputAccessoryView of keyboard in UIWebView in Swift

I've been looking for days for a simple answer but I cannot seem to find it.
I want to find and replace the inputAccessoryView of keyboard attached to my  UIWebView if the accessory view exists on the keyboard.  I want to replace it so I can have my own Prev and Next buttons.  Doing it in swift is a plus.
Sounds simple enough, but it's not obvious.

A:

import UIKit

extension UIViewController {

    func addNewAccessoryView(oldAccessoryView:UIView)
    {
        var frame = oldAccessoryView.frame;
        var newAccessoryView = UIView(frame:frame)
        newAccessoryView.backgroundColor = UIColor.lightGrayColor()

        let fn = ".HelveticaNeueInterface-Bold"
        var doneButton = UIButton(frame:CGRectMake(frame.size.width-80,6,100,30))
        doneButton.setTitle("Done", forState: UIControlState.Normal)
        doneButton.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)
        doneButton.titleLabel!.font = UIFont(name: fn, size: 15)
        doneButton.addTarget(self, action: "buttonAccessoryDoneAction:", forControlEvents: UIControlEvents.TouchUpInside)

        var prevButton = UIButton(frame:CGRectMake(2,6,50,30))
        prevButton.setTitle("<", forState: UIControlState.Normal)
        prevButton.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)
        prevButton.titleLabel!.font = UIFont(name: fn, size: 15)
        prevButton.addTarget(self, action: "buttonAccessoryPrevAction:", forControlEvents: UIControlEvents.TouchUpInside)

        var nextButton = UIButton(frame:CGRectMake(35,6,50,30))
        nextButton.setTitle(">", forState: UIControlState.Normal)
        nextButton.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)
        nextButton.titleLabel!.font = UIFont(name: fn, size: 15)
        nextButton.addTarget(self, action: "buttonAccessoryNextAction:", forControlEvents: UIControlEvents.TouchUpInside)

        newAccessoryView.addSubview(prevButton);
        newAccessoryView.addSubview(nextButton);
        newAccessoryView.addSubview(doneButton);

        oldAccessoryView.addSubview(newAccessoryView)

    }

    func traverseSubViews(vw:UIView) -> UIView
    {
        if (vw.description.hasPrefix("<UIWebFormAccessory")) {
            return vw
        }

        for(var i = 0 ; i < vw.subviews.count; i++) {
            var subview = vw.subviews[i] as UIView;
            if (subview.subviews.count > 0) {
                var subvw = self.traverseSubViews(subview)
                if (subvw.description.hasPrefix("<UIWebFormAccessory")) {
                    return subvw
                }
            }
        }
        return UIView()
    }

    func replaceKeyboardInputAccessoryView()
    {
        // locate accessory view
        let windowCount = UIApplication.sharedApplication().windows.count
        if (windowCount < 2) {
            return;
        }

        let tempWindow:UIWindow = UIApplication.sharedApplication().windows[1] as UIWindow
        var accessoryView:UIView = traverseSubViews(tempWindow)
        if (accessoryView.description.hasPrefix("<UIWebFormAccessory")) {
            // Found the inputAccessoryView UIView
            if (accessoryView.subviews.count > 0) {
                self.addNewAccessoryView(accessoryView)
            }
        }
    }

    // Override these in your UIViewController
    func buttonAccessoryNextAction(sender:UIButton!)
    {
        println("Next Clicked")
    }

    func buttonAccessoryPrevAction(sender:UIButton!)
    {
        println("Prev Clicked")
    }

    func buttonAccessoryDoneAction(sender:UIButton!)
    {
        println("Done Clicked")
    }        
}

Then from inside your UIViewController setup a Notification when the keyboard appears.  You can do this inside of viewDidAppear().
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardDidShow:"), name:UIKeyboardDidShowNotification, object: nil);

and from within your keyboardDidShow handler call the replaceKeyboardInputAccessoryView method of the UIViewController.
func keyboardDidShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        self.replaceKeyboardInputAccessoryView()
    }
}

