A SketchApp plugin that generates a Swift Extension or UIColor or a UIColor Objective-C Category class from your Sketch documents.
Download the zip for this project and extract it to a temporary folder. Copy the UIColor Category Generator folder your Sketch Plugin folder. You can get access to that folder by opening the Plugins menu, and choosing Reveal Plugins Folder....
Watch this short screencast for full description of how the plugin can be used.
Open the Plugins menu and choose UIColor Category Generator > Insert Color Swatch. Customize your colors then open the Plugins menu and choose UIColor Category Generator > Generate UIColor Category. The category .m and .h files will be placed in the same folder as your source .sketch file.