constaints_helper.swift

gistfile1.txt

import Foundation
import UIKit

extension UIButton {
    func setImage(named: String) {
        if let image = UIImage(named: named) {
            self.setImage(image, for: .normal)
        }
    }
}

extension UIImageView {
    func setImage(named: String) {
        if let image = UIImage(named: named) {
            self.image = image
        }
    }
}

struct Insets {
    let left: CGFloat
    let top: CGFloat
    let right: CGFloat
    let bottom: CGFloat

    static let zero = Insets(left: 0, top: 0, right: 0, bottom: 0)
}

extension UIView {

    func bindFrameToSuperviewBounds(insets: Insets? = nil) {
        guard let superview = self.superview else {
            debug("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
            return
        }
        self.translatesAutoresizingMaskIntoConstraints = false
        self.topAnchor.constraint(equalTo: superview.topAnchor, constant: insets?.top ?? 0).isActive = true
        self.bottomAnchor.constraint(equalTo: superview.bottomAnchor, constant: insets?.bottom ?? 0).isActive = true
        self.leadingAnchor.constraint(equalTo: superview.leadingAnchor, constant: insets?.left ?? 0).isActive = true
        self.trailingAnchor.constraint(equalTo: superview.trailingAnchor, constant: insets?.right ?? 0).isActive = true
    }

    func bindFrameToSuperviewHorizontal(insets: Insets? = nil) {
        guard let superview = self.superview else {
            debug("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
            return
        }
        self.translatesAutoresizingMaskIntoConstraints = false
        self.leadingAnchor.constraint(equalTo: superview.leadingAnchor, constant: insets?.left ?? 0).isActive = true
        self.trailingAnchor.constraint(equalTo: superview.trailingAnchor, constant: insets?.right ?? 0).isActive = true
    }

    func bindFrameWidthOfHorizontal(targetView: UIView, insets: Insets? = nil) {
        self.translatesAutoresizingMaskIntoConstraints = false
        self.leadingAnchor.constraint(equalTo: targetView.leadingAnchor, constant: insets?.left ?? 0).isActive = true
        self.trailingAnchor.constraint(equalTo: targetView.trailingAnchor, constant: insets?.right ?? 0).isActive = true
    }

    func bindFrameToSuperviewVertical(insets: Insets? = nil) {
        guard let superview = self.superview else {
            debug("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
            return
        }
        self.translatesAutoresizingMaskIntoConstraints = false
        self.topAnchor.constraint(equalTo: superview.topAnchor, constant: insets?.top ?? 0).isActive = true
        self.bottomAnchor.constraint(equalTo: superview.bottomAnchor, constant: insets?.bottom ?? 0).isActive = true
    }

    func fixedWidth(_ width: CGFloat) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1, constant: width)
    }
    func minWidth(_ width: CGFloat) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self, attribute: .width, relatedBy: .greaterThanOrEqual, toItem: nil, attribute: .width, multiplier: 1, constant: width)
    }
    func fixedHeight(_ height: CGFloat) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1, constant: height)
    }
    func snapOnRight(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: to,
                                  attribute: NSLayoutConstraint.Attribute.leading,
                                  relatedBy: .equal,
                                  toItem: self,
                                  attribute: .trailing,
                                  multiplier: 1,
                                  constant: constant)
    }
    func snapOnTop(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: to,
                                  attribute: NSLayoutConstraint.Attribute.top,
                                  relatedBy: .equal,
                                  toItem: self,
                                  attribute: .bottom,
                                  multiplier: 1,
                                  constant: constant)
    }
    func snapLeft(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.leading,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: .leading,
                                  multiplier: 1,
                                  constant: constant)
    }
    func snapRight(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.trailing,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: .trailing,
                                  multiplier: 1,
                                  constant: constant)
    }
    func snapBottom(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.bottom,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: .bottom,
                                  multiplier: 1,
                                  constant: constant)
    }
    func snapTop(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.top,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: .top,
                                  multiplier: 1,
                                  constant: constant)
    }
    func centerYinside(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.centerY,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: NSLayoutConstraint.Attribute.centerY,
                                  multiplier: 1,
                                  constant: constant)
    }
    func centerXinside(to: UIView, constant: CGFloat=0) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: NSLayoutConstraint.Attribute.centerX,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: NSLayoutConstraint.Attribute.centerX,
                                  multiplier: 1,
                                  constant: constant)
    }
    func constraint(to: UIView, attribute:NSLayoutConstraint.Attribute, constant: CGFloat=0, multiplier: CGFloat = 1) -> NSLayoutConstraint {
        return NSLayoutConstraint(item: self,
                                  attribute: attribute,
                                  relatedBy: .equal,
                                  toItem: to,
                                  attribute: attribute,
                                  multiplier: multiplier,
                                  constant: constant)
    }
}