UIView++

UIView++.swift

import UIKit

public struct AnchoredConstraints {
    var top, leading, bottom, trailing, width, height: NSLayoutConstraint?
}

extension UIView {
    
    @available(iOS 9.0, *)
    @discardableResult
    public func anchor(superView: UIView? = nil,
                       top: NSLayoutYAxisAnchor? = nil,
                       leading: NSLayoutXAxisAnchor? = nil,
                       bottom: NSLayoutYAxisAnchor? = nil,
                       trailing: NSLayoutXAxisAnchor? = nil,
                       padding: UIEdgeInsets = .zero,
                       size: CGSize = .zero) -> AnchoredConstraints {
        if let superView = superView {
            superView.addSubview(self)
        }
        translatesAutoresizingMaskIntoConstraints = false
        var anchoredConstraints = AnchoredConstraints()
        
        if let top = top {
            anchoredConstraints.top = topAnchor.constraint(equalTo: top, constant: padding.top)
        }
        
        if let leading = leading {
            anchoredConstraints.leading = leadingAnchor.constraint(equalTo: leading, constant: padding.left)
        }
        
        if let bottom = bottom {
            anchoredConstraints.bottom = bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom)
        }
        
        if let trailing = trailing {
            anchoredConstraints.trailing = trailingAnchor.constraint(equalTo: trailing, constant: -padding.right)
        }
        
        if size.width != 0 {
            anchoredConstraints.width = widthAnchor.constraint(equalToConstant: size.width)
        }
        
        if size.height != 0 {
            anchoredConstraints.height = heightAnchor.constraint(equalToConstant: size.height)
        }
        
        [anchoredConstraints.top,
         anchoredConstraints.leading,
         anchoredConstraints.bottom,
         anchoredConstraints.trailing,
         anchoredConstraints.width,
         anchoredConstraints.height].forEach { $0?.isActive = true }
        
        return anchoredConstraints
    }
    
    @available(iOS 9.0, *)
    public func fillSuperview(superView: UIView? = nil, padding: UIEdgeInsets = .zero) {
        if let superView = superView {
            superView.addSubview(self)
        }
        translatesAutoresizingMaskIntoConstraints = false
        if let superviewTopAnchor = superview?.topAnchor {
            topAnchor.constraint(equalTo: superviewTopAnchor, constant: padding.top).isActive = true
        }
        
        if let superviewBottomAnchor = superview?.bottomAnchor {
            bottomAnchor.constraint(equalTo: superviewBottomAnchor, constant: -padding.bottom).isActive = true
        }
        
        if let superviewLeadingAnchor = superview?.leadingAnchor {
            leadingAnchor.constraint(equalTo: superviewLeadingAnchor, constant: padding.left).isActive = true
        }
        
        if let superviewTrailingAnchor = superview?.trailingAnchor {
            trailingAnchor.constraint(equalTo: superviewTrailingAnchor, constant: -padding.right).isActive = true
        }
    }
    
    @available(iOS 9.0, *)
    public func centerInSuperview(size: CGSize = .zero) {
        translatesAutoresizingMaskIntoConstraints = false
        if let superviewCenterXAnchor = superview?.centerXAnchor {
            centerXAnchor.constraint(equalTo: superviewCenterXAnchor).isActive = true
        }
        
        if let superviewCenterYAnchor = superview?.centerYAnchor {
            centerYAnchor.constraint(equalTo: superviewCenterYAnchor).isActive = true
        }
        
        if size.width != 0 {
            widthAnchor.constraint(equalToConstant: size.width).isActive = true
        }
        
        if size.height != 0 {
            heightAnchor.constraint(equalToConstant: size.height).isActive = true
        }
    }

    public func add<T: UIView>(_ view: T, then closure: ((T) -> Void)) {
         self.addSubview(view)
         closure(view)
     }
}

extension UIEdgeInsets {
     init(_ top: CGFloat = 0, _ left: CGFloat = 0, _ bottom: CGFloat = 0, _ right: CGFloat = 0) {
        self.init(top: top, left: left, bottom: bottom, right: right)
    }
}