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UIView+AutoLayout

The ultimate API for creating Auto Layout constraints -- impressively simple, immensely powerful. Comprised of categories on UIView, NSArray, and NSLayoutConstraint.

UIView+AutoLayout provides a developer-friendly interface for the vast majority of Auto Layout use cases. It is designed for clarity and simplicity, taking inspiration from the Auto Layout UI options available in Interface Builder but delivering far more flexibility and capability. The API is also highly efficient, adding only a thin layer of third party code and being engineered for maximum performance (for example, automatically adding constraints to the nearest ancestor view).

API Cheat Sheet

This is just a handy overview of the core API methods. Check out the header file for the full API and documentation. A couple notes:

  • All of the API methods begin with auto... for easy autocompletion!
  • All methods that generate constraints also automatically add the constraint(s) to the correct view, then return the newly created constraint(s) for you to optionally store for later adjustment or removal.
  • *Many methods below also have a variant which includes a relation: parameter to make the constraint an inequality.

UIView

  • + autoRemoveConstraint(s):
  • - autoRemoveConstraintsAffectingView
  • - autoRemoveConstraintsAffectingViewAndSubviews
  • + autoSetPriority:forConstraints:
  • - autoCenterInSuperview:
  • - autoAlignAxisToSuperviewAxis:
  • - autoPinEdge(s)ToSuperviewEdge(s):withInset(s):
  • - autoPinEdge:toEdge:ofView:(withOffset:)
  • - autoAlignAxis:toSameAxisOfView:(withOffset:)
  • - autoMatchDimension:toDimension:ofView:(withOffset:)(withMultiplier:)
  • - autoSetDimension(s)ToSize:
  • - autoConstrainAttribute:toAttribute:ofView:(withOffset:)(withMultiplier:)
  • - autoPinToTopLayoutGuideOfViewController:withInset:
  • - autoPinToBottomLayoutGuideOfViewController:withInset:

NSArray

  • - autoAlignViewsToEdge:
  • - autoAlignViewsToAxis:
  • - autoMatchViewsDimension:
  • - autoSetViewsDimension:toSize:
  • - autoDistributeViewsAlongAxis:withFixedSpacing:alignment:
  • - autoDistributeViewsAlongAxis:withFixedSize:alignment:

NSLayoutConstraint

  • - autoRemove

Setup

Note: you must be developing for iOS 6.0 or later to use Auto Layout.

Manually from GitHub

  1. Download the UIView+AutoLayout.h and UIView+AutoLayout.m files and add them to your Xcode project

  2. #import UIView+AutoLayout.h wherever you need it

    (Hint: adding the import to your precompiled header file once will allow you to access the API from anywhere in your app!)

  3. Start joyfully creating constraints in code!

Using CocoaPods

  1. Add the pod UIView+AutoLayout to your Podfile.

     platform :ios, '6.0'
 pod 'UIView+AutoLayout'

  2. Run pod install from Terminal.

  3. Open your app's .xcworkspace file to launch Xcode and start joyfully creating constraints in code!

Releases

Releases are tagged in the git commit history using semantic versioning. Check out the releases and release notes for each version.

Usage

Example Project

Check out the example project included in the repository. It contains a few demos of the API in use for various scenarios. While running the app, tap on the screen to cycle through the demos. You can rotate the device to see the constraints in action (as well as toggle the taller in-call status bar in the iOS Simulator).

Tips and Tricks

Check out some Tips and Tricks to keep in mind when using the API.

Limitations

  • Will need to use the NSLayoutConstraint SDK API directly for some uncommon advanced use cases

UIView+AutoLayout vs. the rest

An overview of the Auto Layout options available, ordered from the lowest- to highest-level of abstraction.

  • Apple NSLayoutConstraint SDK API
    • Pros: Raw power
    • Cons: Extremely verbose, tedious to write, difficult to read
  • Apple Visual Format Language
    • Pros: Concise, convenient
    • Cons: Doesn't support some use cases, incomplete compile-time checks, must learn syntax, hard to debug
  • Apple Interface Builder
    • Pros: Visual, simple
    • Cons: Difficult for complicated layouts, cannot dynamically set constraints, not always WYSIWYG
  • UIView+AutoLayout
    • Pros: Simple, efficient, built directly on the iOS SDK, minimal third party code
    • Cons: Not the most concise or pure expression of layout code
  • High-level layout frameworks (Masonry, KeepLayout)
    • Pros: Very clean, simple, and convenient
    • Cons: Cannot mix with SDK APIs, total dependency on third party code, potential compatibility issues when SDK changes

Problems, Suggestions, Pull Requests?

Bring 'em on! :)

I'm especially interested in hearing about any common use cases that this API does not currently address. Feel free to add feature requests (and view current work in progress) on the Feature Requests page of the wiki for this project.

Meta

Designed & maintained by Tyler Fox (@smileyborg). Distributed with the MIT license.