An easy way to set custom styles to any UIResponder from the Interface Builder written in swift.

If you need the Objective-C version of this library, you are looking for MGEStyles.

As an iOS developer, I feel very often frustrated with how difficult is to set consistent styles to my views in the Xcode Interface Builder. If you think in a UILabel, you can use the same style (font, color and size) for a set of labels in different UIViewController. If, some time later, the design changes you'll have to change the properties of all these labels one by one, which is a tedious work. I try to solve this issue by developing Goya. This library, inspired by the android styles system, simplify this task, giving you the chance of define a totally custom styles in one single place and using it all over your project, using the Inerface Builder or by code.

Goya is provided in two flavours, Default and Lite. The only difference is that the default version add an inspectable attribute in the interface builder, and lite version doesn't. For more details, please go to the applying styles section

Add the following to your Podfile:

pod 'Goya'

or if you prefer the Lite flavour:

pod 'Goya/Lite'

If you want the Swift 2 version, you can use the old version of the library:

pod 'Goya', '~> 1.0'

Then run $ pod install.

If you don't have CocoaPods installed or integrated into your project, you can learn how to do so here.

Import the library by doing import Goya.

Clone or donwload the project and copy the contents of the Goya folder into your project. Then, you can remove the inspectable folder if you prefer the Lite flavour.

The library works in 3 steps:

1 - You have to create the styles you need

2 - You have to register all the stlyes that you want to use in your application.

3 - Apply these styles in your UIResponder in the interface builder or with code.

In this library, the styles are Style objects. Each style will have a configuration block, which will tell the library what to do with the UIResponder. For example, if you want to create a style for UILabels you would do:

let baseStyle = Style<UILabel> { (label) in
        label.font = .boldSystemFont(ofSize: 50)
        label.numberOfLines = 0
}

Goya allows inheritance. When a Style has a parent, the parent's configuration block is executed before the own block. As an example, we can create a child for the previous style with this method:

let titleStyle = Style<UILabel>(parent: baseStyle) { (label) in
    label.textColor = .red
    label.textAlignment = .Center
}

Registering a Style is very easy. You just have to call the following method:

public func register(name: String)

For example, if we want to register the defined titleStyle we'll do:

titleStyle.register("style")

The styles should be registered at application launch, so application:didFinishLaunchingWithOptions: might seems a good place to do it. Anyway, in order to keep the AppDelegate as clean as possible, creating a helper class to create and register all the styles and call this class from the AppDelegate is strongly recommended.

The final step is to apply the styles. There is 2 ways to do it:

When you use the Default flavour, a new property appears in the attribute inspector in the interface builder. It is called Style Name. Here you should provide the key of the registered style you want to apply:

If are using the Lite flavour or your version of Xcode doesn't supoort IBInspectables you can achieve the same result by addign a new attribute in the User defined runtime attributes section. The name must be gy_styleName, the type must be String and the Value must be the key of your registered style:

Goya provides a category which allow apply a style to any UIResponder. If you want to apply the registered style to a label, you can do it by typing:

let label = UILabel()
label.gy_styleName = "style"

You can also apply a no registered style:

let label = UILabel()
let titleStyle = Style<UILabel>(parent: baseStyle) { (label) in
    label.textColor = .red
    label.textAlignment = .Center
}
label.gy_style = titleStyle

@ManueGE

Goya is available under the MIT License. See LICENSE.