FlashLayout

FlashLayout wraps the system apis to make it easy to create or active NSLayoutContraint

Install

pod 'FlashLayout'

Swift Package Manager

Copy URL https://github.com/felix8888/FlashLayout as the Package URL

Use VFL for a single statement

Call the addConstraints to add and create constraints

Sample code

view.addConstraints("|[view]|", views: ["view": view])

Provde options

let views: [String: UIViiew] = [
    "leftView": leftView,
    "rightView": rightView,
]
view.addConstraints("|[leftView][rightView]|", options: [.alignAllTop, .alignAllBottom], views: views)

Same, you can add metrics parameter, it's default to nil

Use function builder

This simplified all kinds of ways to generate constraints

Sample

NSLayoutConstraint.activate(views: ["c": c, "d": d, "d": d]) {
    a.leftAnchor.constraint(equalTo: b.leftAnchor)
    "H:|[c][d]|".options(.alignAllTop)
    "V:|[c]|"
    d.flHeight <= c.flHeight * 0.5 + 100
    d.flWidth == 100
    existingConstraintsArray
}

If you only want to create constraints and won't active them directly, call this func

let constraints = NSLayoutConstraint.constraints(views: ["c": c, "d": d]) {
    a.leftAnchor.constraint(equalTo: b.leftAnchor)
    "H:|[c][d]|".options(.alignAllTop)
    "V:|[c]|"
    existingConstraintsArray
}

Note: FlashLayout provide some shorter names for LayoutAnchor, such as view.flWidth is view.widthAnchor If you don't like them, you could use the original name too

FlashLayout defines some math operators for constration creation, so the 3 lines below are same

a.flLeft == b.flCenterX + 100
a.leftAnchor == b.centerXAnchor + 100
a.leftAnchor.constraint(equalTo: b.centerXAnchor, constant: 100)

Available layout anchor math operators

• == equal to
• <= less than or equal to
• >= greater than or equal to
• * multiplier
• + additional constant