Using convertPoint to get the relative position inside a parent UIView

Question

I\'ve looked at a dozen SO questions on this topic, and none of the answers have worked for me. Maybe this will help get me back on the right path.

Imagine this set

Answer 1

in swift 2.2 worked for me:

var OrignTxtNomeCliente:CGPoint!

if let orign = TXT_NomeCliente.superview, let win = UIApplication.sharedApplication().keyWindow {
        OrignTxtNomeCliente = orign.convertPoint(TXT_NomeCliente.frame.origin, toView: win)
    }

Answer 2

Here is Swift 3 update of @Pablo's answer, which off course worked great in my case.

if let window = UIApplication.shared.keyWindow {
    parent.convert(child.frame.origin, to: window)
}

Answer 3

button.center is the center specified within the coordinate system of its superview, so I assume that the following works:

CGPoint p = [button.superview convertPoint:button.center toView:self.view]

Or you compute the button's center in its own coordinate system and use that:

CGPoint buttonCenter = CGPointMake(button.bounds.origin.x + button.bounds.size.width/2,
                                   button.bounds.origin.y + button.bounds.size.height/2);
CGPoint p = [button convertPoint:buttonCenter toView:self.view];

Swift 4

var p = button.convert(button.center, to: self.view)

Answer 4

Swift 5.2

You need to call convert from the button, not the superview. In my case I needed width data so I converted the bounds instead of just center point. The code below works for me:

let buttonAbsoluteFrame = button.convert(button.bounds, to: self.view)

Answer 5

Martin answer is correct. For developers using Swift, you can get the position of an object (button, view,...) relative to the screen by using:

var p = obj.convertPoint(obj.center, toView: self.view)

println(p.x)  // this prints the x coordinate of 'obj' relative to the screen
println(p.y)  // this prints the y coordinate of 'obj' relative to the screen