UIView Extensions

UIView+Anchors.swift

import Foundation
import UIKit

extension UIView {
    
    func addConstraintsWithFormat(_ format: String, views: UIView...) {
        
        var viewsDictionary = [String: UIView]()
        for (index, view) in views.enumerated() {
            let key = "v\(index)"
            viewsDictionary[key] = view
            view.translatesAutoresizingMaskIntoConstraints = false
        }
        
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: format, options: NSLayoutFormatOptions(), metrics: nil, views: viewsDictionary))
    }
    
    func anchorFillSuperview() {
        translatesAutoresizingMaskIntoConstraints = false
        if let superview = superview {
            leftAnchor.constraint(equalTo: superview.leftAnchor).isActive = true
            rightAnchor.constraint(equalTo: superview.rightAnchor).isActive = true
            topAnchor.constraint(equalTo: superview.topAnchor).isActive = true
            bottomAnchor.constraint(equalTo: superview.bottomAnchor).isActive = true
        }
    }
    
    
    func anchorToTop(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil) {
        
        anchorWithConstantsToTop(top, left: left, bottom: bottom, right: right, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0)
    }
    
    func anchorWithConstantsToTop(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil, topConstant: CGFloat = 0, leftConstant: CGFloat = 0, bottomConstant: CGFloat = 0, rightConstant: CGFloat = 0) {
        
        _ = anchor(top, left: left, bottom: bottom, right: right, topConstant: topConstant, leftConstant: leftConstant, bottomConstant: bottomConstant, rightConstant: rightConstant)
    }
    
    func anchor(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil, topConstant: CGFloat = 0, leftConstant: CGFloat = 0, bottomConstant: CGFloat = 0, rightConstant: CGFloat = 0, widthConstant: CGFloat = 0, heightConstant: CGFloat = 0) {
        translatesAutoresizingMaskIntoConstraints = false
        
        var anchors = [NSLayoutConstraint]()
        
        if let top = top {
            anchors.append(topAnchor.constraint(equalTo: top, constant: topConstant))
        }
        
        if let left = left {
            anchors.append(leftAnchor.constraint(equalTo: left, constant: leftConstant))
        }
        
        if let bottom = bottom {
            anchors.append(bottomAnchor.constraint(equalTo: bottom, constant: -bottomConstant))
        }
        
        if let right = right {
            anchors.append(rightAnchor.constraint(equalTo: right, constant: -rightConstant))
        }
        
        if widthConstant > 0 {
            anchors.append(widthAnchor.constraint(equalToConstant: widthConstant))
        }
        
        if heightConstant > 0 {
            anchors.append(heightAnchor.constraint(equalToConstant: heightConstant))
        }
        
        anchors.forEach({$0.isActive = true})
    }
    
    public func anchor(width: CGFloat, height: CGFloat){
        anchor(nil, left: nil, bottom: nil, right: nil, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0, widthConstant: width, heightConstant: height)
    }
    
    public func anchorCenterXToSuperview(constant: CGFloat = 0) {
        translatesAutoresizingMaskIntoConstraints = false
        if let anchor = superview?.centerXAnchor {
            centerXAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        }
    }
    
    public func anchorCenterYToSuperview(constant: CGFloat = 0) {
        translatesAutoresizingMaskIntoConstraints = false
        if let anchor = superview?.centerYAnchor {
            centerYAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        }
    }
    
    public func anchorCenterSuperview() {
        anchorCenterXToSuperview()
        anchorCenterYToSuperview()
    }
    
    public func anchorLeftRight(left: NSLayoutXAxisAnchor? = nil, leftConstant: CGFloat, right: NSLayoutXAxisAnchor? = nil, rightConstant: CGFloat){
        anchor(nil, left: left, bottom: nil, right: right, topConstant: 0, leftConstant: leftConstant, bottomConstant: 0, rightConstant: rightConstant, widthConstant: 0, heightConstant: 0)
    }
    
    public func anchorCenter(to view: UIView, constantX: CGFloat = 0, constantY: CGFloat = 0){
        translatesAutoresizingMaskIntoConstraints = false
        let anchorX = view.centerXAnchor
        let anchorY = view.centerYAnchor
        centerXAnchor.constraint(equalTo: anchorX, constant: constantX).isActive = true
        centerYAnchor.constraint(equalTo: anchorY, constant: constantY).isActive = true
        
    }
    
}