ios - How do I move the button from one position to another? -

i have button @ x position when view loaded, , when button clicked want button go right under text field. don't want use static points (1,2) instead want use position of text field , shift button or down relative text field. appreciated.

  @iboutlet weak var name: uitextfield!   @iboutlet weak var log: uibutton!   name.addtarget(self, action: "name:", forcontrolevents: uicontrolevents.editingdidbegin) 

when text field clicked, want button move below name text field. nothing happens when click text field.

  func name(sender: uitextfield){   var y: int = int(name.frame.origin.y)   var x: int = int(name.frame.origin.x)   log.frame = cgrect(x: x, y: y - 50, width: 157, height: 40) } 

i create @iboutlet nslayoutconstraint links center of button center of text field. in interface builder, can set initial distance between 2 objects please. in action (or delegate method) change constant of constraint.

distanceconstraint.constant = 0 uiview.animatewithduration(0.3) { self.view.layoutifneeded() } 

similarly, set constant original distance when want show button again.