Add view over tableview (UITableViewController)

Question

Situation: I\'ve got a UITableViewController loading some data asynchronously from a service. During this time I would like to place a full screen (except n

Answer 1

Swift / Storyboard Solution

Note: The code below assumes one has a custom view (ratingView in my case) that is to be presented over a UITableView.

I've read many answers to this and similar questions on SO. The other answers from these sources worked to varying degrees for me (e.g.,view loaded but not shown or not accessible,...). I am using Swift 2.0+ and I am sharing the complete solution for doing this using a UITableViewController.

Create an outlet to the Navigation Bar and the view, which you want to bring over the tableview.

//MARK:Outlets
@IBOutlet weak var navBar:UINavigationBar!
@IBOutlet var ratingView: MNGStarRating!

In my case I also wanted to animate the view over the tableview so I used a class variable to hold a reference to the inflection point and a point above the scene (off-screen).

var centerYInflection:NSLayoutConstraint!
var aPointAboveScene = -(max(UIScreen.mainScreen().bounds.width,UIScreen.mainScreen().bounds.height) * 2.0)

Then in viewDidLoad I called a function (configureRatingViewAutoLayout) which configures and adds the constraints for the new view to be animated over the tableview.

func configureRatingViewAutoLayout() {
    //REQUIRED    
    self.navBar.superview?.addSubview(self.ratingView)

    var newConstraints:[NSLayoutConstraint] = []
    newConstraints.append(self.ratingView.leadingAnchor.constraintEqualToAnchor(self.view.leadingAnchor,constant: 10)) 
    newConstraints.append(self.ratingView.trailingAnchor.constraintEqualToAnchor(self.view.trailingAnchor,constant: 10))
    newConstraints.append(self.ratingView.centerXAnchor.constraintEqualToAnchor(self.view.centerXAnchor))

    //hides the rating view above the scene
    self.centerYInflection = self.ratingView.centerYAnchor.constraintEqualToAnchor(self.view.centerYAnchor, constant: self.aPointAboveScene)

    //the priority must be set below 1000 if you intend to change it after it has been added to a view
    self.centerYInflection.priority = 750
    newConstraints.append(self.centerYInflection)

    //constraints must be added to the container view of the two items
    self.ratingView.superview?.addConstraints(newConstraints)

}

Nota Bene - On a UITableViewController; the self.view is the self.tableView. They point to the same thing so I guess one could also use the self.tableView reference above.

Sometime later... In response to a UIControl event I call this method.

@IBAction func toggleRatingView (sender:AnyObject?){

    //REQUIRED
    self.ratingView.superview?.layoutIfNeeded()

    UIView.animateWithDuration(1.0, delay: 0.0, usingSpringWithDamping: 0.37, initialSpringVelocity: 0.99, options: [.CurveEaseOut], animations: { () -> Void in

        if CGRectContainsRect(self.view.frame, self.ratingView.frame) {

            //in frame ~ animate away
            //I play a sound to alert the user something is happening 

            self.centerYInflection.constant = self.aPointAboveScene
            self.centerYInflection.priority = UILayoutPriority(950)
            //I disable portions of the UI
            self.disableUIElements(nil)



        } else {

            //out of frame ~ animate in
            //I play a different sound here                

            self.centerYInflection.constant = 0
            self.centerYInflection.priority = UILayoutPriority(950)

            //I enable the UI fully
            self.enableUIElements(nil)


        }
        //REQUIRED
        self.ratingView.superview?.setNeedsLayout()
        self.ratingView.superview?.layoutIfNeeded()


        }) { (success) -> Void in

            //do something else

    }

}

These helper methods can be configured to control access to elements in your scene during the presentation of the view.

func disableUIElements(sender:AnyObject?) {
    //UI

}
func enableUIElements(sender:AnyObject?) {

    //UI

}

Caveats

My view is a custom view in the Storyboard (sitting outside of the tableview but connected to the TableView Controller). The view has a required user runtime attribute defined layer.zPosition with a Number value set to 2 (this ensures that it presents in front of the UITableView).

One could also try playing around with bringSubviewToFront: and sendSubviewToBack: methods if you don't want to set the zPosition (I think zPosition is simpler to use)