R.swift

Get strong typed, autocompleted resources like images, fonts and segues in Swift projects

Why use this?

It makes your code that uses resources:

• Fully typed, less casting and guessing what a method will return
• Compile time checked, no more incorrect strings that make your app crash at runtime
• Autocompleted, never have to guess that image name again

Currently you type:

let icon = UIImage(named: "settings-icon")
let font = UIFont(name: "San Francisco", size: 42)
let color = UIColor(named: "indicator highlight")
let viewController = CustomViewController(nibName: "CustomView", bundle: nil)
let string = String(format: NSLocalizedString("welcome.withName", comment: ""), locale: NSLocale.current, "Arthur Dent")

With R.swift it becomes:

let icon = R.image.settingsIcon()
let font = R.font.sanFrancisco(size: 42)
let color = R.color.indicatorHighlight()
let viewController = CustomViewController(nib: R.nib.customView)
let string = R.string.localizable.welcomeWithName("Arthur Dent")

Check out more examples or hear about how Fabric.app uses R.swift!

Demo

Autocompleted images:

Compiletime checked images:

This is only the beginning, check out more examples!

CocoaHeadsNL presentation

Mathijs Kadijk presented R.swift at the September 2016 CocoaHeadsNL meetup.
Talking about the ideas behind R.swift and demonstrating how to move from plain stringly-typed iOS code to statically typed code.

Features

After installing R.swift into your project you can use the R-struct to access resources. If the struct is outdated just build and R.swift will correct any missing/changed/added resources.

R.swift currently supports these types of resources:

• Images
• Fonts
• Resource files
• Colors
• Localized strings
• Storyboards
• Segues
• Nibs
• Reusable cells
• Project
• Entitlements
• Info.plist

Runtime validation with R.validate():

• If all images used in storyboards and nibs are available
• If all named colors used in storyboards and nibs are available
• If all view controllers with storyboard identifiers can be loaded
• If all custom fonts can be loaded

Q&A

• Why was R.swift created?
• Why should I choose R.swift over alternative X or Y?
• What are the requirements to run R.swift?
• How to fix missing imports in the generated file?
• How to use classes with the same name as their module?
• Can I ignore resources?
• Can I use R.swift in a library?
• How does R.swift work?
• How to upgrade to a new major version?
• How can I only run specific generators?

Installation

As of Rswift 7, Swift Package Manager is the recommended method of installation.

Demo video: Updating from R.swift 6 to Rswift 7 (Starting at 1:06, this describes the installation of Rswift 7).

Xcode project using SPM (Recommended)

Demo Video: Install R.swift in Xcode with SPM

1. In Project Settings, on the tab “Package Dependencies”, click “+”, search for https://github.com/mac-cain13/R.swift and click “Add Package”.
2. Select the target that will use R.swift next to “RswiftLibrary” and click “Add Package”.
3. Now click on your target, on the tab “Build Phases”, in the section “Run Build Tool Plug-ins”, click “+” and add RswiftGenerateInternalResources. (Screenshot)
4. Now the R struct should be available in your code, use auto-complete to explore all static references.

Note: The first build you might need to approve the new plugin by clicking the build error warning you about the new plugin.

R.swift on Xcode Cloud or any other CI

On your CI server you can’t explicitly allow the build plugin to run, so you need to disable plugin validation to be able to build without user interaction:

5. Run a script on your CI that runs: defaults write com.apple.dt.Xcode IDESkipPackagePluginFingerprintValidatation -bool YES before Xcode starts building.

On Xcode Cloud you can add a custom build script in ci_scripts/ci_post_clone.sh with this line that Xcode will run.

Package.swift based SPM project

1. Add a dependency in Package.swift:

   dependencies: [
       .package(url: "https://github.com/mac-cain13/R.swift.git", from: "7.0.0")
   ]
   

2. For each relevant target, add a dependency and a plugin

   .target(
       name: "Example",
       dependencies: [.product(name: "RswiftLibrary", package: "R.swift")],
       plugins: [.plugin(name: "RswiftGeneratePublicResources", package: "R.swift")]
   )
   

3. Build your project, now the R struct should be available in your code, use auto-complete to explore all static references

CocoaPods

1. Add pod 'R.swift' to your Podfile and run pod install
2. In Xcode: Click on your project in the file list, choose your target under TARGETS, click the Build Phases tab and add a New Run Script Phase by clicking the little plus icon in the top left
3. Drag the new Run Script phase above the Compile Sources phase and below Check Pods Manifest.lock, expand it and paste the following script:

   "$PODS_ROOT/R.swift/rswift" generate "$SRCROOT/R.generated.swift"
   

4. Add $SRCROOT/R.generated.swift to the “Output Files” of the Build Phase
5. Uncheck “Based on dependency analysis” so that R.swift is run on each build
6. Build your project, in Finder you will now see a R.generated.swift in the $SRCROOT-folder, drag the R.generated.swift files into your project and uncheck Copy items if needed

Screenshot of the Build Phase can be found here

Tip: Add the *.generated.swift pattern to your .gitignore file to prevent unnecessary conflicts.

Manually

0. Add the R.swift library to your project
1. Download a R.swift release, unzip it and put it into your source root directory
2. In Xcode: Click on your project in the file list, choose your target under TARGETS, click the Build Phases tab and add a New Run Script Phase by clicking the little plus icon in the top left
3. Drag the new Run Script phase above the Compile Sources phase, expand it and paste the following script:

   "$SRCROOT/rswift" generate "$SRCROOT/R.generated.swift"
   

4. Add $SRCROOT/R.generated.swift to the “Output Files” of the Build Phase
5. Uncheck “Based on dependency analysis” so that R.swift is run on each build
6. Build your project, in Finder you will now see a R.generated.swift in the $SRCROOT-folder, drag the R.generated.swift files into your project and uncheck Copy items if needed

Screenshot of the Build Phase can be found here

Tip: Add the *.generated.swift pattern to your .gitignore file to prevent unnecessary conflicts.

Contribute

We’ll love contributions, read the contribute docs for info on how to report issues, submit ideas and submit pull requests!

License

R.swift is created by Mathijs Kadijk and Tom Lokhorst released under a MIT License.