NSLayoutConstraint Issue on different devices
<p>I'm using NSLayoutconstraint but it seems to mess up the position of the views when passing from iphone 6 plus to iphone 6.</p>

<p>It should work since I'm creating constraint related to the attribute of the view that should change in case of using differente devices.</p>

<p>Here some example of constraint:</p>

<pre><code>v=getBitmapView("V -.-")
    self.view.addSubview(v)
    var myConstraint =
        NSLayoutConstraint(item: v,
            attribute: NSLayoutAttribute.CenterX,
            relatedBy: NSLayoutRelation.Equal,
            toItem: self.view,
            attribute: NSLayoutAttribute.CenterX,
            multiplier: 1.0,
            constant: 0)



    self.view.addConstraint(myConstraint)
     myConstraint =
    NSLayoutConstraint(item: v,
        attribute: NSLayoutAttribute.BottomMargin,
        relatedBy: NSLayoutRelation.Equal,
        toItem: self.view,
        attribute: NSLayoutAttribute.BottomMargin,
        multiplier: 1.0,
        constant: -30)



    self.view.addConstraint(myConstraint)
    myConstraint =
        NSLayoutConstraint(item: v,
            attribute: NSLayoutAttribute.Width,
            relatedBy: NSLayoutRelation.Equal,
            toItem: self.view,
            attribute: NSLayoutAttribute.Width,
            multiplier: 1.0,
            constant: -200)



    self.view.addConstraint(myConstraint)
    myConstraint =
        NSLayoutConstraint(item: v,
            attribute: NSLayoutAttribute.Height,
            relatedBy: NSLayoutRelation.Equal,
            toItem: self.view,
            attribute: NSLayoutAttribute.Height,
            multiplier: 1.0,
            constant: -650)



    self.view.addConstraint(myConstraint)
</code></pre>

<p>If i ran iphone 6 plus the view is positioned 30 point above the bottom margin but if I use the iphone 6 the view disappears.</p>