EasyConstraints

Suit of custom swift operators to create NSLayoutConstraints.

Why?

Sometimes you need to do auto layout in code, and many times it’s horrible. You need to use NSLayoutConstraint with a looong method or use auto layout format strings. I wanted to test swift custom operators and had a bad time with lot’s of lines of simple auto layout constraints. With this easy operators I’m able to reduce code and get a clear view of what I’m doing when I create a constraint.

Installation

Embedded frameworks require a minimum deployment target of iOS 8 or OS X Mavericks.

Easy to understand

You just need to learn 3 concepts:

<>

<> means first Item in constraint relation, equivalent to item parameter in NSLayoutConstraint.

*

* means oposite. For example, in a horizontal trailing relationship “<><” * would mean vertical “*<><”.

<^>

<^> means top, so if you want to make view1 top equals to view2 top you just need: “view1<^>(view2,0)”. And you are right, “*<^>” is bottom!

How to

EasyConstraints only includes some constraints, the ones I needed as this started as a learning project. All the operators take a view and a touple with view, constant and a optional NSLayoutRelation parameter. If you need to define a different NSLayoutRelation to Equal (default) you can use that paremeter.

This are the operators included in EasyConstraints now:

<^>

EasyConstraints:

view1<^>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 0)

*<^>

EasyConstraints:

view1*<^>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 0)

<<>

EasyConstraints:

view1<<>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 0)

<>>

EasyConstraints:

view1<>>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: 0)

><>

EasyConstraints:

view1><>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: 0)

<><

EasyConstraints:

view1<><(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 0)

*><>

EasyConstraints:

view1*><>(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 0)

*<><

EasyConstraints:

view1*<><(view2,0)

Using NSLayoutConstraint constructor:

NSLayoutConstraint(item: view1, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: view2, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 0)

Thanks

Maybe you hate this idea,love it or want to create a PR. Any feedback is welcome.