SwiftStylish is a Swift framework for iOS that lets you style UI elements in a convenient way using style files.

Requirements

• iOS 13.0+
• Xcode 11.0+
• Swift 5.0+

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:

$ gem install cocoapods

To integrate SwiftStylish into your Xcode project using CocoaPods, specify it in your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '8.0'
target 'TargetName' do
pod 'SwiftStylish'
end 

Then, run the following command:

$ pod install

Usage

Add import "SwiftStylish" to where you are going to use the framework.

Frameworks provides you with SwiftStylisher wrapper.

• Apply style class to an element:

try SwiftStylisher.default.loadFile(filename: "HomeStyle", bundle: styleFileBundle)
try SwiftStylisher.default.applyStyle(className: ".nameLabel", forObject: self.usernameLabel)

• Apply style class with variables:

  1. Load variables from file and load style file.
  2. Apply style.

try SwiftStylisher.default.loadVariablesFile(filename: "StyleVariables", bundle: styleFileBundle)
try SwiftStylisher.default.loadFile(filename: "HomeStyle", bundle: styleFileBundle)

try SwiftStylisher.default.applyStyle(className: ".nameLabel", forObject: self.usernameLabel)

Check How SwiftStylish Works for information about applying styles .

Variables

Framework supports variables, stored in a separate from style classes files. Any file type can be used.
Variables must be split into root-level groups using keys:

• @colors - Color
• @fonts - Font
• @numbers - Float

Variables won't be parsed in cases:

• Variable's type doesn't match group's type.
• Parsed with class parser method.

Wrong:
title_font value won't be parsed.

{
	"_description": "wrong colors",
    "@colors":{
        "title_font": { "name": "Arial", "size": 16 },
    }
}

Right:

{
    
    "@colors":{
        "light_background": "#6ef2d1",
        "dark_background": "#0e9a8e"
    },
    "@fonts":{
        "title_font": { "name": "Arial", "size": 16 },
        "selected_cell_font": { "name": "Arial", "size": 12 }
    },
    "@numbers":
    {
        "label_number_of_lines": 3,
        "pading": 10,
        "width": 170
    }
}

Commentaries and includes of other files are supported.

{
	"_description": "Blue theme includes.",
    "@include": ["BlueThemeColors", "BlueThemeFonts", "BlueThemeNumbers"]
}

File Loader

To apply styles you first need to load them from a file. The framework provides you with loaders for JSON and Plist files.
Loader for another file type can be created by implementing protocol LoaderProtocol.

Supported File Formats

By default, SwiftStylish supports filetypes:

• JSON - JSONLoader
• Plist - PlistLoader

You can't refer to or inherit from a file with a different file type. Recommended using one file type for a project. Style file with different file type is allowed to use if it has no reference to files with another file type.

Example:

JSON format is used in the project. You want to use PLIST for some screen. This Plist file can't refer to JSON file. A parser will search for a file with a similar type, which is PLIST.

Style Repository

After parser finishes its work, all parsed values are stored in StyleRepository.

Description

Commentaries can be added using _description key. This key doesn't affect anything. You are free to add it everywhere inside JSON body.

{
    "_description": "this is a description for style file.",
    "@classes": {
        "_description": "This is a base rounded button class.",
        ".roundedButton": {
        		"_description": "Red background color property.",
        		"background-color": "#ff0000"
        }
    }
}

System Keys

Supported system keys:

• @classes
• @preload
• @state
• @include

Classes (@classes)

Every style file must contain root element @classes with dictionary value.
All root classes of the file are the keys in this base dictionary.

{  
   "_description":"this is a description for style file.",
   "@classes":{  
      "_description":"base rounded button style definition.",
      ".roundedButton":{  
         "_description":"Red background color property.",
         "background-color":"#ff0000",
         ".saveButton":{  
            "@preload":".roundedButton",
            "text":"Save"
         },
         ".deleteButton":{  
            "@preload":".roundedButton",
            "text":"Delete"
         }
      },
      ".tableView":{  
         "background-color":"#30a9f2",
         ".header":{  
            "background-color":"clear"
         }
      }
   }
}

Class Inheritance(@preload & @include)

Style classes can be inherited using @preload key. Inheritance is supported from a single class and multiple ones.

Syntax:

"@preload": [ String ]

"@preload": String

Accepts full class path as String or an array of them.

Classes from other files can be included using @include key.
Pass array of filenames with the same type of current style file.

Syntax:

"@include": [ String ]

Attributes from parent style are loaded to the repo and applied first, then other properties from child style are set.

Example:

{  
   "@include":[  
      "ParserTests1"
   ],
   "@classes":{  
      "_description":"Description for root class.",
      ".root":{  
         ".class1":{  
            "background-color":"#0000ff",
            "color":"#ff0"
         },
         ".class2":{  
            "@preload":".root.class1",
            "background-color":"#00ff00"
         },
         ".class3":{  
            "@preload":[  
               ".root.class1",
               ".root.class2"
            ],
            "background-color":"#ff0000"
         }
      }
   }
}

In this example the result backgrounColor value in class3 is #ff0000.

Control state (@state )

Control state can be specified using @state key for any UI element supporting it.

See Control State for details.

Supported style keys & values

Check Supported Keys for all supported style keys.

Check Values for all supported value types.

License

SwiftStylish is released under the MIT license. See LICENSE for details.