Here, you’ll find how to make components' stylization on iOS' projects.


Inside Beagle’s library for iOS, there’s an AppTheme class that allows you to personalize components used on your application.

This class also can map application’s styles so it can be referenced on BFF to build a Server-Driven screen.

It makes possible to personalize, for example:

  • Texts' styles;
  • Button’s styles;
  • TabBar’s styles;
  • Container’s styles;

It’s importante to make it clear that iOS doesn’t map all the components' attributes. However, the most important ones are already mapped, so they can be modified if necessary.

Customized attributes

Not all customization’s attributes can be stylized. On the list below you will know which one can be personalized through Beagle.

Another important point is that styles created on iOS and related to componentes that came from backend. On these cases, you can configure the styles so each of them can be referenced, just like the example below:

    let theme = AppTheme(styles: [
    Styles.customButton.key    :,
    Styles.customText.key      :,
    Styles.customTab.key      :,
    Style.customContainer.key :,
    Style.customTextInput.key :

    dependencies.theme = theme

Besides reference styles, you have to create a key value pair defining a name to each style created:

struct StylePair {
    var key: String
    var style: Any
class Styles {
    static let customText = StylePair(key: "CustomText", style: customText)
    static let customButton = StylePair(key: "CustomButton", style: customButton)
    static let customTab = StylePair(key: "CustomTab", style: customTab)
    static let customContainer =  StylePair(key: "CustomContainer", style: customContainer)
    static let customTextInput = StylePair(key: "CustomTextInput", style: customTextInput)


The text components for Beagle iOS are totally customizable. To make any attribute change, follow the example below:

private static func textH1() -> (UITextView?) -> Void {
    BeagleStyle.text(font: .boldSystemFont(ofSize: 32), 
    color: UIColor(named: "ColorText")!)


Besides the complete text personalization, the Button component can be customized by another attribute: the withTitleColor, which personalizes the button’s color.

On Swift, you can also add extra styles to a component by using the <> note, according to the example below:

static func defaultStylishButton() -> (UIButton?) -> Void {
    return BeagleStyle.button(withTitleColor: .white)
        <> {
            $0?.titleLabel |> BeagleStyle.label(withFont: .systemFont(ofSize: 16, weight: .regular))
            $0?.layer.cornerRadius = 6
            $0?.clipsToBounds = true
            $0?.backgroundColor = UIColor(hex: "#3C3737")


Beagle’s TabBar component for iOS can be stylized with these attributes:

  1. backgroundColor: attributes a different color to tab background.
  2. indicatorColor: attributes a color to a selected background.
  3. selectedTextColor: attributes a text color to a selected tab.
  4. unselectedTextColor: attributes a text color to a unselected tab.
  5. selectedIconColor: attributes a icon color to a unselected tab.
  6. unselectedIconColor: attributes a icon color to a unselected tab.
static func customTab() -> (UIView?) -> Void {
        return BeagleStyle
                .tabBar(backgroundColor: .blue, 
                        indicatorColor: .white)


Beagle’s Container component for iOS can be styled any way you want, for example you can insert an image as a background.

static func customContainer() -> (UIView?) -> Void {
        return {
            guard let container = $0 else { return }
            UIGraphicsBeginImageContext(CGSize(width: 100, height: 100))
            UIImage(named: "image")?.draw(in: CGRect(x: 0, y: 0, width: 100, height: 100))
            guard let image = UIGraphicsGetImageFromCurrentImageContext() else { return }
            container.backgroundColor = UIColor(patternImage: image)


Beagle’s TextInput component for iOS can be stylized with these attributes:

  1. validInputColor: attributes a color to border given a valid input.
  2. invalidInputColor: attributes a color to border given a invalid input.
  3. borderStyle: attributes a style for TextInput’s border.
  4. borderWidth: attributes a width for TextInput’s border.
  5. cornerRadius: attributes a cornerRadius for TextInput’s border.
    static func customTextInput() -> (UITextField?) -> Void {
        return BeagleStyle.textInput(validInputColor: .gray, invalidInputColor: .red, borderStyle: .roundedRect, borderWidth: 1)

Last modified April 23, 2021: adding styleId to container (#482) (25c8eac0)