Swift Change button position with AutoLayout - swift

Question

I have created the button programmatically in this way
func CreateButtonWithIndex(index:Int) {
let widthButton = 120
let heightButton = 80
let line = (index / 3)
let column = index % 3
let newButton = UIButton.buttonWithType(UIButtonType.System) as UIButton
newButton.frame = CGRect(x:line*widthButton+95, y:column*heightButton+15, width:widthButton, height:heightButton)
self.view.addSubview(newButton)
}
Now trying to place NSLayoutConstraint for this button in this way
func CreateButtonWithIndex(index:Int) {
let widthButton = 120
let heightButton = 80
let line = (index / 3)
let column = index % 3
let newButton = UIButton.buttonWithType(UIButtonType.System) as UIButton
newButton.setTranslatesAutoresizingMaskIntoConstraints(false)
self.view.addSubview(newButton)
let constraint1 = NSLayoutConstraint(item: newButton, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 1)
let constraint2 = NSLayoutConstraint(item: newButton, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 10)
view.addConstraints([constraint1,constraint2])
}
but obviously i get only that the various buttons are created in the same location.
i have tried e.g.
let constraint1 = NSLayoutConstraint(item: newButton, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: line)
But don't go !!!
how can I place the line and column with the NSLayoutConstraint ?

Answer 1

You are on the right track! The problem is that your calculation is not giving a big enough difference in the x positions. You are saying:
let constraint1 = NSLayoutConstraint(
item: newButton, attribute: .CenterX, relatedBy: .Equal,
toItem: view, attribute: .CenterX, multiplier: 1, constant: line)
But what is line?
let line = (index / 3)
Well, if index is 0, then 1, then 2, line is going to 0 every time. You need a much bigger difference if you want these buttons to be in different places!
(You should also declare or cast line to a CGFloat, obviously.)