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Simple Swift Auto Layout Extensions
//
// Layout.swift
//
// Created by Justin Driscoll on 2/22/15.
//
import UIKit
struct Inset {
let value: CGFloat
let attr: NSLayoutAttribute
init(_ value: CGFloat, from attr: NSLayoutAttribute) {
self.attr = attr;
switch (attr) {
case .Right, .Bottom: self.value = -value
default: self.value = value
}
}
}
extension UIView {
func addSubviews(views: UIView...) {
for view in views {
self.addSubview(view)
}
}
func layoutRelativeTo(otherView: AnyObject, insets: Inset...) -> [NSLayoutConstraint] {
var constraints: [NSLayoutConstraint] = []
for inset in insets {
constraints.append(NSLayoutConstraint(item: self, attribute: inset.attr, relatedBy: NSLayoutRelation.Equal, toItem: otherView, attribute: inset.attr, multiplier: 1.0, constant: inset.value))
}
return constraints
}
func layoutInside(otherView: AnyObject) -> [NSLayoutConstraint] {
return layoutRelativeTo(otherView, insets: Inset(0, from: .Top), Inset(0, from: .Right), Inset(0, from: .Bottom), Inset(0, from: .Left))
}
func constrainDimension(dimension: NSLayoutAttribute, relation: NSLayoutRelation, constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: dimension, relatedBy: relation, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: constant)]
}
func constrainDimension(dimension: NSLayoutAttribute, relation: NSLayoutRelation, toView otherView: AnyObject, constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: dimension, relatedBy: relation, toItem: otherView, attribute: dimension, multiplier: 1, constant: constant)]
}
func constrainWidth(relation: NSLayoutRelation, toWidth constant: CGFloat) -> [NSLayoutConstraint] {
return constrainDimension(.Width, relation: relation, constant: constant)
}
func constrainWidth(relation: NSLayoutRelation, toView otherView: AnyObject, plus constant: CGFloat) -> [NSLayoutConstraint] {
return constrainDimension(.Width, relation: relation, toView: otherView, constant: constant)
}
func constrainHeight(relation: NSLayoutRelation, toHeight constant: CGFloat) -> [NSLayoutConstraint] {
return constrainDimension(.Height, relation: relation, constant: constant)
}
func constrainHeight(relation: NSLayoutRelation, toView otherView: AnyObject, plus constant: CGFloat) -> [NSLayoutConstraint] {
return constrainDimension(.Height, relation: relation, toView: otherView, constant: constant)
}
func layoutAbove(otherView: AnyObject, distance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Bottom, relatedBy: .Equal, toItem: otherView, attribute: .Top, multiplier: 1, constant: -constant)]
}
func layoutAbove(otherView: AnyObject, minimumDistance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Bottom, relatedBy: .GreaterThanOrEqual, toItem: otherView, attribute: .Top, multiplier: 1, constant: -constant)]
}
func layoutBelow(otherView: AnyObject, distance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Top, relatedBy: .Equal, toItem: otherView, attribute: .Bottom, multiplier: 1, constant: constant)]
}
func layoutBelow(otherView: AnyObject, minimumDistance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Top, relatedBy: .GreaterThanOrEqual, toItem: otherView, attribute: .Bottom, multiplier: 1, constant: constant)]
}
func layoutBefore(otherView: AnyObject, distance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Right, relatedBy: .Equal, toItem: otherView, attribute: .Left, multiplier: 1, constant: -constant)]
}
func layoutBefore(otherView: AnyObject, minimumDistance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Right, relatedBy: .GreaterThanOrEqual, toItem: otherView, attribute: .Left, multiplier: 1, constant: -constant)]
}
func layoutAfter(otherView: AnyObject, distance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Left, relatedBy: .Equal, toItem: otherView, attribute: .Right, multiplier: 1, constant: constant)]
}
func layoutAfter(otherView: AnyObject, minimumDistance constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Left, relatedBy: .GreaterThanOrEqual, toItem: otherView, attribute: .Right, multiplier: 1, constant: constant)]
}
func alignWith(otherView: AnyObject, attr: NSLayoutAttribute, offsetBy constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: attr, relatedBy: .Equal, toItem: otherView, attribute: attr, multiplier: 1, constant: constant)]
}
func alignBaselineWith(otherView: AnyObject, offsetBy constant: CGFloat) -> [NSLayoutConstraint] {
return [NSLayoutConstraint(item: self, attribute: .Baseline, relatedBy: .Equal, toItem: otherView, attribute: .Baseline, multiplier: 1, constant: constant)]
}
}
extension Array {
func withPriority(priority: UILayoutPriority) -> [NSLayoutConstraint] {
var members: [NSLayoutConstraint] = []
for member in self {
switch member {
case let constraint as NSLayoutConstraint:
constraint.priority = priority
members.append(constraint)
default: break
}
}
return members
}
}
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