Above, Below, and Beyond Tech Talk

by Rahel Lüthy

May 3, 2016

Programmatic JavaFX Styling

JavaFX components can be styled via CSS. This is great, but sometimes wiring up a separate CSS file to set a simple background color is a bit over the top. That’s where the setStyle method comes in handy:

Label label = new Label("Hello");
label.setStyle("-fx-background-color: deeppink");

CSS classes are used to style more advanced components. A ScatterChart’s plot background can e.g. be styled via the chart-plot-background class. This is how the styling would look like in a CSS file:

.chart-plot-background {
    -fx-background-color: transparent;

Unfortunately, we cannot simply cram the same CSS into the setStyle method:

NumberAxis xAxis = new NumberAxis();
NumberAxis yAxis = new NumberAxis();
ScatterChart<Number, Number> chart = new ScatterChart<>(xAxis, yAxis);

        ".chart-plot-background {\n" +
        "    -fx-background-color: transparent;\n" +

Instead, the lookup method can be used to navigate the CSS hierarchy:

chart.lookup(".chart-plot-background").setStyle("-fx-background-color: transparent");

In case you were wondering why you would ever want to have a transparent chart background: The ScatterChart component does not support line connections. Using a StackPane to layer a ScatterChart and a LineChart can serve as a simple workaround. The chart in the top layer must then have a transparent background.