xnike's blog

Cascades for Blackberry 10. Theme based asset selector

Upcoming Blackberry 10 release will have full theme support. According to the API Documentation there are Brigth and Dark themes:

The default theme is Bright. To change the application theme to Dark specify the following configuration value in the application`s bar-descriptor.xml file:

<env var="CASCADES_THEME" value="dark"/>

or previously


If You have, for example, a background image for each of the available themes - "asset:///images/bright/background.png" and "asset:///images/dark/background.png" - You can easily manage it by adding a globally available property:

import bb.cascades 1.0

Page {
    id: mainPage;
    // this property will contain string representation of the current application theme.
    property string theme: themeStyleToString(Application.themeSupport.theme.colorTheme.style);

    Container {
        ImageView {
            imageSource: "asset:///images/" + mainPage.theme + "/background.png"

    function themeStyleToString(style) {
        switch(style) {
            case VisualStyle.Bright:    return "bright"
            case VisualStyle.Dark:      return "dark"

        // will use dark as default in case of unknown
        return "dark"

Unfortunately, right now I know only one way to change the application theme - via bar-descriptor.xml.