QLPreviewController remove or add UIBarButtonItems

Question

I have seen this kind of question a lot on the internet but it seems no one really knows the answer?

I am using QLPreviewController for displaying PDF documents. I f

Answer 1

I took the response from Lukas Gross and applied it in Swift on iOS 8 and came up with this solution that worked for me:

NOTE: I have the QLPreviewController embedded in a UINavigationController!

Code:

var QLNavigationBar: UINavigationBar?
var overlayNavigationBar: UINavigationBar?

func getQLNavigationBar(fromView view: UIView) -> UINavigationBar? {
    for v in view.subviews {
        if v is UINavigationBar {
            return v as? UINavigationBar
        } else {
            if let navigationBar = self.getQLNavigationBar(fromView: (v as! UIView)) {
                return navigationBar
            }
        }
    }

    return nil
}

func handleNavigationBar() {
    self.QLNavigationBar = self.getQLNavigationBar(fromView: self.navigationController!.view)

    self.overlayNavigationBar = UINavigationBar(frame: CGRectMake(0, 0, self.view.bounds.size.width, 64.0))
    self.overlayNavigationBar?.autoresizingMask = UIViewAutoresizing.FlexibleWidth

    if let qln = self.QLNavigationBar {
        qln.addObserver(self, forKeyPath: "hidden", options: (NSKeyValueObservingOptions.New | NSKeyValueObservingOptions.Old), context: nil)
        qln.superview?.addSubview(self.overlayNavigationBar!)
    }

    var item = UINavigationItem(title: self.navigationItem.title!)
    var doneBtn = UIBarButtonItem(barButtonSystemItem: .Done, target: self, action: "doneBtnPressed")
    item.leftBarButtonItem = doneBtn
    item.hidesBackButton = true

    self.overlayNavigationBar?.pushNavigationItem(item, animated: false)
    self.overlayNavigationBar?.tintColor = .whiteColor()
    self.overlayNavigationBar?.barTintColor = .blackColor()
    self.overlayNavigationBar?.titleTextAttributes = [
        NSForegroundColorAttributeName : UIColor.whiteColor() ]
}

And applying this code like this:

override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer) {
    if self.QLNavigationBar!.hidden {
        self.overlayNavigationBar?.hidden = self.QLNavigationBar!.hidden
    }

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(0.5 * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), {
        self.QLNavigationBar?.superview?.sendSubviewToBack(self.QLNavigationBar!)

        if !self.QLNavigationBar!.hidden {
            self.overlayNavigationBar?.hidden = self.QLNavigationBar!.hidden
        }
    })
}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    self.handleNavigationBar()
}

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    self.overlayNavigationBar?.frame = CGRectMake(0, 0, self.view.bounds.size.width, 64.0)
}