NativeScript Core

Chart Line Series

LineSeries are a type of CategoricalSeries that present categorical data as points connected with a line. The line chart usually visualizes a trend in data over intervals of time, but can also be used to show comparisons among discrete categories.

Setup

To display a Line Chart, you will need to:

  • Add a RadCartesianChart to your page.
  • Set the chart's horizontalAxis to a category axis (CategoricalAxis, DateTimeCategoricalAxis or DateTimeContinuousAxis).
  • Set the chart's verticalAxis to a value axis (LinearAxis or LogarithmicAxis).
  • Add at least one instance of LineSeries to the chart's series property and set its items property to a collection of data items, its categoryProperty set to the name of the property of the data items that will be used to determine their category and its valueProperty to the name of the property used to determine their value.

To illustrate this setup, let's create an example. First we will create a source with items:

Example 1: Define a source with data

get categoricalSource() {
    return [
        { Country: "Germany", Amount: 15, SecondVal: 14, ThirdVal: 24 },
        { Country: "France", Amount: 13, SecondVal: 23, ThirdVal: 25 },
        { Country: "Bulgaria", Amount: 24, SecondVal: 17, ThirdVal: 23 },
        { Country: "Spain", Amount: 11, SecondVal: 19, ThirdVal: 24 },
        { Country: "USA", Amount: 18, SecondVal: 8, ThirdVal: 21 }
    ];
}

We use an instance of this model to assign it as the bindingContext of the page we have put our Line series on:

Example 2: Update bindingContext

import { CategoricalDataModel } from "../../data-models/categorical-data-model";

export function onPageLoaded(args) {
    const page = args.object;
    page.bindingContext = new CategoricalDataModel();
}

And finally, in the XML definition of the page we put a RadCartesianChart, add a LineSeries instance to it and bind the series to the source of data:

Example 3: Add chart to page's markup

<navigation:ExamplePage xmlns:navigation="navigation/example-page" loaded="onPageLoaded" xmlns:chart="nativescript-ui-chart" xmlns="http://www.nativescript.org/tns.xsd">
    <chart:RadCartesianChart id="cartesianChart">
        <chart:RadCartesianChart.horizontalAxis>
            <chart:CategoricalAxis/>
        </chart:RadCartesianChart.horizontalAxis>
        <chart:RadCartesianChart.verticalAxis>
            <chart:LinearAxis/>
        </chart:RadCartesianChart.verticalAxis>
        <chart:RadCartesianChart.series>
            <chart:LineSeries items="{{ categoricalSource }}" categoryProperty="Country" valueProperty="Amount">
            </chart:LineSeries>
        </chart:RadCartesianChart.series>
    </chart:RadCartesianChart>
</navigation:ExamplePage>

Here's how your Line chart should look like:

Figure 1: Chart with LineSeries on Android (left) and iOS (right)

Cartesian chart: Line series Cartesian chart: Line series

References

Want to see this scenario in action? Check our SDK examples repo on GitHub. You will find this and many other practical examples with NativeScript UI.

Examples used in this article:

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