Storyboards are great to use, save time and allows developers to visualise the whole (or part) of app, in terms of screen relationships.

####Problem: Storyboards fail at runtime, note compile time

Using storyboards means also accessing storyboards created items programmatically. Such as:

  1. Segue identifiers.
  2. Cell reuse identifiers.
  3. View Controllers identifiers.
    When changing an identifier in storyboard, developer should also change the identifier in the code.
    This is prone to error.

####Solution: Auto Generated Constants from Storyboard
Square have recently wrote in Square Engineering Blog about a new tool they have released: objc-codegenutils. and specifically: objc-identifierconstants.

This “generates string identifiers into-compiler checked constants”. AKA a file for every storyboard that contains:
NSString *const <StoryBoardFileName>MySegueIdentifier or:
NSString *const <StoryBoardFileName>MyCellIdentifier.

Using constants avoid typos.


  1. Clone the project at objc-codegenutils.

  2. Open the cloned project.

  3. Choose identifierconstants as target:
    ![alt text](/images/posts/codegen-22.2.14.png =300x)

  4. Build and find the built product:
    ![alt text](/images/posts/show-in-finder-22.2.14.png =300x)

  5. Copy objc-identifierconstants into your project. (I place under <ProjectRoot>/objc-codegen-utils/).

  6. Add it as a run script on every build:

     objc-codegen-utils/objc-identifierconstants -o ${SRCROOT}/Classes/GeneratedIdentifiers/ ${SRCROOT}/Classes/en.lproj/MainStoryboard.storyboard

I output the files into ${SRCROOT}/Classes/GeneratedIdentifiers/ and ${SRCROOT}/Classes/en.lproj/MainStoryboard.storyboard is the path to my storyboard file.
7. Build your project and add the generated files to the project.
8. Replace string identifiers with new constants.

No more typos.