Installation

• tns plugin add @nativescript-community/css-theme

Be sure to run a new build after adding plugins to avoid any issues.

Usage

The theme will style your application using Element selectors - you don't need to add CSS classes on every element you need to style.

import "@nativescript-community/css-theme";

This JS takes care of updating several classes on the app root elements, something that got included in @nativescript/core in {N} 6.1.

Setting Dark or Light mode

Setting the theme mode from light to dark is now easier - instead of loading a new file, just find the root view and set .ns-dark class to it - this will change all colorization to dark tones. For instance, if your page root is RadSideDrawer, just add a class to it, like this:

<drawer:RadSideDrawer class="ns-dark" xmlns:drawer="nativescript-ui-sidedrawer">
    ...
</drawer:RadSideDrawer>

If your root is a frame, you can do this

<Frame class="ns-dark" defaultPage="root"></Frame>

For Angular, if your root is a page-router-outlet, you can set the .ns-dark class on it - it will pass it down to the Frame it renders.

Setting Dark or Light mode from JavaScript

Setting the theme mode from JavaScript is also much easier now - just import the theme and call Theme.setMode() with your preferred mode - either Theme.Light or Theme.Dark, like this:

import Theme from "@nativescript-community/css-theme";

Theme.setMode(Theme.Dark); // Or Theme.Light

Keep in mind that in {N} 6.2 these changes will override the default system mode. To restore it, use Theme.Auto (available since Theme 2.3.0):

import Theme from "@nativescript-community/css-theme";

Theme.setMode(Theme.Auto);

Additionally there is another helper method - toggleMode, which can be used without parameters to just toggle the mode or with a boolean parameter to ensure light or dark mode is set:

import Theme from "@nativescript-community/css-theme";

Theme.toggleDarkMode(); // to toggle between the modes

// or

Theme.toggleDarkMode(true);  // to ensure dark mode
Theme.toggleDarkMode(false); // to ensure light mode

A note of warning

Due to limitation in Playground the JS Theme API cannot be imported like an ES6 module in a TS/Angular projects. You'll have to resort to requiring it:

const Theme = require("@nativescript-community/css-theme");

Theme.setMode(Theme.Dark); // Or Theme.Light

More root classes

In addition to .ns-light and .ns-dark classes, the theme's little JavaScript file introduces .ns-root on the root element, .ns-android/.ns-ios depending on the current platform (which the theme extensively uses) and additionally .ns-portrait/.ns-landscape and .ns-phone/.ns-tablet, which should be self-explanatory. Of course .ns-portrait/.ns-landscape get updated on orientation change, so you can use it to show a two pane layout in landscape, for instance.

Using Theme variables

There are several functions and mixins in the core theme, that can be used in your projects, as long as you're using SASS/SCSS.

If you need to access specific theme variables like simple colors or sizes, do it through the const function:

Button {
    background-color: const(forest);
    height: const(btn-height);
}

You can get light/dark colors:

Button {
    color: light(primary);

    .ns-dark & {
        color: dark(primary);
    }
}