Package com.codename1.charts

package com.codename1.charts

The main ChartComponent Package

The charts package enables Codename One developers to add charts and visualizations to their apps without having to include external libraries or embedding web views. We also wanted to harness the new features in the graphics pipeline to maximize performance.

Device Support

Since the charts package makes use of 2D transformations and shapes, it requires some of the graphics features that are not yet available on all platforms. Currently the following platforms are supported:

  • Simulator

  • Android

  • iOS

Features

  • Built-in support for many common types of charts including bar charts, line charts, stacked charts, scatter charts, pie charts and more.

  • Pinch Zoom - The com.codename1.charts,ChartComponent class includes optional pinch zoom support.

  • Panning Support - The com.codename1.charts,ChartComponent class includes optional support for panning.

Chart Types

The com.codename1.charts package includes models and renderers for many different types of charts. It is also extensible so that you can add your own chart types if required. The following screen shots demonstrate a small sampling of the types of charts that can be created.

**

The above screenshots were taken from the ChartsDemo app. Y ou can start playing with this app by checking it out from our git repository.

How to Create A Chart

Adding a chart to your app involves four steps:

  • Build the model. You can construct a model (aka data set) for the chart using one of the existing model classes in the com.codename1.charts.models package. Essentially, this is just where you add the data that you want to display.

  • Set up a renderer. You can create a renderer for your chart using one of the existing renderer classes in the com.codename1.charts.renderers package. The renderer allows you to specify how the chart should look. E.g. the colors, fonts, styles, to use.

  • Create the Chart View. Use one of the existing view classes in the com.codename1.charts.views package.

  • **Create a com.codename1.charts,ChartComponent **. In order to add your chart to the UI, you need to wrap it in a com.codename1.charts,ChartComponent object.

You can check out the ChartsDemo app for specific examples, but here is a high level view of some code that creates a Pie Chart.

/**
 * Creates a renderer for the specified colors.
 */
private DefaultRenderer buildCategoryRenderer(int[] colors) {
    DefaultRenderer renderer = new DefaultRenderer();
    renderer.setLabelsTextSize(15);
    renderer.setLegendTextSize(15);
    renderer.setMargins(new int[]{20, 30, 15, 0});
    for (int color : colors) {
        SimpleSeriesRenderer r = new SimpleSeriesRenderer();
        r.setColor(color);
        renderer.addSeriesRenderer(r);
    }
    return renderer;
}

/**
 * Builds a category series using the provided values.
 *
 * @param titles the series titles
 * @param values the values
 * @return the category series
 */
protected CategorySeries buildCategoryDataset(String title, double[] values) {
    CategorySeries series = new CategorySeries(title);
    int k = 0;
    for (double value : values) {
        series.add("Project " + ++k, value);
    }

    return series;
}

public Form createPieChartForm() {
    // Generate the values
    double[] values = new double[]{12, 14, 11, 10, 19};

    // Set up the renderer
    int[] colors = new int[]{ColorUtil.BLUE, ColorUtil.GREEN, ColorUtil.MAGENTA, ColorUtil.YELLOW, ColorUtil.CYAN};
    DefaultRenderer renderer = buildCategoryRenderer(colors);
    renderer.setZoomButtonsVisible(true);
    renderer.setZoomEnabled(true);
    renderer.setChartTitleTextSize(20);
    renderer.setDisplayValues(true);
    renderer.setShowLabels(true);
    SimpleSeriesRenderer r = renderer.getSeriesRendererAt(0);
    r.setGradientEnabled(true);
    r.setGradientStart(0, ColorUtil.BLUE);
    r.setGradientStop(0, ColorUtil.GREEN);
    r.setHighlighted(true);

    // Create the chart ... pass the values and renderer to the chart object.
    PieChart chart = new PieChart(buildCategoryDataset("Project budget", values), renderer);

    // Wrap the chart in a Component so we can add it to a form
    ChartComponent c = new ChartComponent(chart);

    // Create a form and show it.
    Form f = new Form("Budget", new BorderLayout());
    f.add(BorderLayout.CENTER, c);
    return f;

}

The charts package is derived work from the excellent open source aChartEngine API.