Swiftstraints
can turn verbose auto-layout code:
let constraint = NSLayoutConstraint(item: blueView,
attribute: NSLayoutAttribute.Width,
relatedBy: NSLayoutRelation.Equal,
toItem: redView,
attribute: NSLayoutAttribute.Width,
multiplier: 1.0,
constant: 0.0)
Into one just one line of code:
let constraint = blueView.widthAnchor == redView.widthAnchor
Or transform your less than consise visual format language code:
let constraints = NSLayoutConstraint.constraintsWithVisualFormat("H:|[leftView]-10-[rightView]|",
options: NSLayoutFormatOptions(0),
metrics: nil,
views: ["leftView":leftView, "rightView":rightView])
Into the following:
let constraints = NSLayoutConstraints("H:|[\(leftView)]-10-[\(rightView)]|")
That was easy!
Swiftstraints
is available through CocoaPods. To install, simply include the following lines in your podfile:
use_frameworks!
pod 'Swiftstraints'
Be sure to import the module at the top of your .swift files:
import Swiftstraints
Alternatively, clone this repo or download it as a zip and include the classes in your project.
With Swiftstraints
you can create constraints that look just Apple's generic constraint definition:
item1.attribute1 = multiplier Γ item2.attribute2 + constant
Swifstraints
utilizes the new layout anchors introduced in iOS 9:
let view = UIView()
view.widthAnchor
view.heightAnchor
view.trailingAnchor
view.centerXAnchor
etc...
Swiftstraints
implements operator overloading so that you can easily create custom constraints:
let blueView = UIView()
let redView = UIView()
let constraint = blueView.heightAnchor == redView.heightAnchor
Just as you would expect, you can specify a multiplier:
let constraint = blueView.heightAnchor == 2.0 * redView.heightAnchor
Or add a constant:
let constraint = blueView.heightAnchor == redView.heightAnchor + 10.0
You can specify inequalities:
let constraint = blueView.heightAnchor <= redView.heightAnchor
And you can define constant constraints if you so choose:
let constraint = blueView.heightAnchor == 100.0
Swiftstraints can readily compute relatively complex constraints:
let constraint = blueView.heightAnchor * 1.4 - 5.0 >= redView.heightAnchor / 3.0 + 400
It's really easy.
Apple provides an API that lets you create multiple constraints simultaneously with the Visual Format Language. As we saw before it can be a little cumbersome:
let constraints = NSLayoutConstraint.constraintsWithVisualFormat("H:|[leftView]-10-[rightView]|",
options: NSLayoutFormatOptions(0),
metrics: nil,
views: ["leftView":leftView, "rightView":rightView])
Swiftstraints
uses string interpolation to let you specify the same constraints in one line of code:
let constraints = NSLayoutConstraints("H:|[\(leftView)]-10-[\(rightView)]|")
Swiftstraints
also extends UIView
so that you can add constraints easily using the interpolated string format:
superview.addConstraints("H:|[\(leftView)]-10-[\(rightView)]|")
Super easy, super simple.
- 3.0.1 - Bug fixes and limited iOS 8 support (Thank you catjia1011)
- 3.0.0 - Updated to Swift 3
- 2.2.0 - Added support for UILayoutPriority
- 2.1.0 - Fixed a view reference bug and added a new convenience method for adding constraints
- 2.0.2 - Added support for tvOS target.
- 2.0.1 - Updated to include support for axis anchors, increased test coverage and more documentation.
- 2.0.0 - Updated for Swift 2.0 and iOS 9. Now uses layout anchors for simple constraints and string interpolation for Visual Format Language constraints.
- 1.1.0 - Minor API tweaks
- 1.0.0 - Initial Release
Brad Hilton, [email protected]
Swiftstraints is available under the MIT license. See the LICENSE file for more info.