JavaFX CSS Layout

JavaFX is a powerful framework for building desktop applications, and one of its key features is the ability to style and layout user interfaces using CSS. This allows developers to separate the visual design of an application from its logic, making it easier to maintain and update the look and feel of the UI.

In this article, we will explore how to use CSS to layout JavaFX controls and containers. We will cover the various layout options available, such as positioning, sizing, and alignment, and provide code examples to demonstrate each concept.

CSS Layout Properties

JavaFX provides a set of CSS properties that can be used to control the layout of UI elements. These properties can be applied to individual controls or to containers that hold multiple controls. Here are some of the most commonly used CSS layout properties:

  • fx-margin and fx-padding: These properties control the spacing around a control or container. The fx-margin property sets the space outside the border, while the fx-padding property sets the space inside the border.

  • fx-alignment: This property controls the alignment of a control within its parent container. Values can be CENTER, TOP_LEFT, TOP_CENTER, TOP_RIGHT, CENTER_LEFT, CENTER_RIGHT, BOTTOM_LEFT, BOTTOM_CENTER, or BOTTOM_RIGHT.

  • fx-hgrow and fx-vgrow: These properties control how a control or container should grow or shrink to fill the available space. The fx-hgrow property specifies horizontal growth, while the fx-vgrow property specifies vertical growth. Values can be ALWAYS, NEVER, or SOMETIMES.

  • fx-alignment-inset: This property controls the alignment of a control within its parent container's content area. Values can be TOP_LEFT, TOP_CENTER, TOP_RIGHT, CENTER_LEFT, CENTER_RIGHT, BOTTOM_LEFT, BOTTOM_CENTER, or BOTTOM_RIGHT.

These are just a few examples of the CSS layout properties available in JavaFX. For a complete list, refer to the official JavaFX CSS documentation.

CSS Layout Examples

Let's walk through some code examples to see how CSS layout properties can be used in practice. We will start with a simple JavaFX application that contains a button and a label. Our goal is to position and style these controls using CSS.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class CSSLayoutExample extends Application {
    @Override
    public void start(Stage primaryStage) {
        Button button = new Button("Click me!");
        Label label = new Label("Hello, JavaFX!");

        StackPane root = new StackPane();
        root.getChildren().addAll(button, label);

        Scene scene = new Scene(root, 300, 200);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());

        primaryStage.setTitle("CSS Layout Example");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

In the above code, we create a Button and a Label and add them to a StackPane. We then create a Scene with the root StackPane and load a CSS file called "styles.css". Finally, we set the scene on the primary stage and show it.

Now let's take a look at the CSS file "styles.css" and apply some layout properties to our controls:

.button {
    -fx-font-size: 18px;
    -fx-padding: 10px 20px;
    -fx-background-color: #1E90FF;
    -fx-text-fill: white;
}

.label {
    -fx-font-size: 24px;
    -fx-alignment: center;
    -fx-padding: 10px;
}

In the CSS file, we use the class selectors .button and .label to target the Button and Label controls, respectively. We then apply various layout properties such as font size, padding, background color, and text color.

By running the application and applying the CSS styles, we can see that the button is styled with a blue background, white text, and larger font size. The label is centered and has a larger font size as well.

Conclusion

In this article, we have explored how to use CSS layout properties in JavaFX to style and position UI controls. We have covered some of the most commonly used layout properties and provided code examples to demonstrate their usage.

Using CSS for layout in JavaFX allows for a separation of concerns, making it easier to maintain and update the visual design of an application. By leveraging the power of CSS, developers can create visually appealing and responsive user interfaces in JavaFX.

For more information on JavaFX CSS layout properties, refer to the official JavaFX CSS documentation. Happy coding!

References

  • [JavaFX CSS Documentation](