Distance between screen border and bar button item - ios

Question

Is there a way to get the the distance between the outer screen border and the bar button item. I was thinking of something similar like how to get the status bar height?
(I am asking this, because it is different depending on the device.)
This is some trial code:
let navigationBar = UINavigationBar(frame: CGRectMake(0, 0, view.frame.size.width, 64))
let navigationBar.backgroundColor = UIColor.redColor()
let barButtonItem = UIBarButtonItem(barButtonSystemItem: .Camera, target: self, action: nil)
navigationItem.leftBarButtonItem = barButtonItem
navigationBar.items = [navigationItem]
let buttonItemView = barButtonItem.valueForKey("view") as! UIView
let frame = buttonItemView.superview!.convertRect(buttonItemView.frame, toView: UIApplication.sharedApplication().keyWindow?.rootViewController?.view)
let xCoordinateMin = CGRectGetMinX(frame)
let yCoordinateMax = CGRectGetMaxY(frame)
let yCoordinateMin = CGRectGetMinY(frame)
let label = UILabel(frame: CGRectMake(CGFloat(xCoordinateMin), CGFloat(yCoordinateMin), 100, yCoordinateMax - yCoordinateMin))
label.backgroundColor = UIColor.greenColor()
But it still gives me 0 as xMin, although it seems to work with the y-coordinate..

Answer 1

By outer screen, I assume you are talking about the main window.
You can try converting the bar button's frame into window's coordinate in order to find the distance to each direction:
let buttonItemView = barButtonItem.valueForKey("view") as! UIView
let frame = buttonItemView.superview!.convertRect(buttonItemView.frame, toView: nil)
print("Distance to left: ", CGRectGetMinX(frame))
print("Distance to top: ", CGRectGetMinY(frame))
However, main window receives rotation events and passes them onto controllers which means it doesn't change its frame size so the above solution will not work properly for landscape mode.
You can try converting button's rect to the root view controller's coordinate system, but now you have to take the status bar height into consideration:
let frame = buttonItemView.superview!.convertRect(buttonItemView.frame, toView: UIApplication.sharedApplication().keyWindow?.rootViewController?.view)

Answer 2

Solved with this code:
let navigationBar = UINavigationBar(frame: CGRectMake(0, 0, view.frame.size.width, 124))
navigationBar.backgroundColor = UIColor.redColor()
let barButtonItem = UIBarButtonItem(barButtonSystemItem: .Camera, target: self, action: nil)
navigationItem.leftBarButtonItem = barButtonItem
navigationBar.items = [navigationItem]
let buttonItemView = barButtonItem.valueForKey("view") as! UIView
let frame = buttonItemView.superview!.convertRect(buttonItemView.frame, toView: nil)
let xCoordinateMin: CGFloat = CGRectGetMinX(frame)
let xCoordinateMax: CGFloat = CGRectGetMaxX(frame)
let yCoordinateMax: CGFloat = CGRectGetMaxY(frame)
let yCoordinateMin = CGRectGetMinY(frame)
let label = UILabel(frame: CGRectMake(abs(xCoordinateMin), yCoordinateMin, xCoordinateMax - xCoordinateMin, yCoordinateMax - yCoordinateMin))
label.backgroundColor = UIColor.greenColor()
The trick was to declare the let xCoordinateMin as CGFloat because then it was considered as negative value. Then when creating the label just use abs() to get the absolute value. You now have a label that is absolutely the same size as your bar button item!

Answer 3

UIApplication.sharedApplication().statusBarFrame.height