JavaFX LineChart

末蓝、 2023-10-15 17:01 52阅读 0赞

The JavaFX LineChart can draw line charts inside your JavaFX applications. The JavaFX LineChart component is represented by the class `javafx.scene.chart.LineChart` .

### LineChart X Axis and Y Axis ###

A JavaFX LineChart draws a line chart. A line chart is a two-dimensional graph, meaning the graph has an X axis and a Y axis. Line charts typically have two numerical axes. A numerical axis is represented by the JavaFX class `javafx.scene.chart.NumberAxis` .

You need to define the X axis and Y axis used by a `LineChart`. Here is an example of creating two JavaFX `NumberAxis` instances:

NumberAxis xAxis = new NumberAxis();
    xAxis.setLabel("No of employees");
    
    NumberAxis yAxis = new NumberAxis();
    yAxis.setLabel("Revenue per employee");

### Creating a LineChart ###

You create a JavaFX LineChart component by creating an instance of the `LineChart` class. You need to pass an X axis and Y axis to the `LineChart` constructor. Here is a JavaFX `LineChart` instantiation example:

NumberAxis xAxis = new NumberAxis();
    xAxis.setLabel("No of employees");
    
    NumberAxis yAxis = new NumberAxis();
    yAxis.setLabel("Revenue per employee");
    
    LineChart lineChart = new LineChart(xAxis, yAxis);

### LineChart Data Series ###

To get a JavaFX `LineChart` component to display any lines, you must provide it with a *data series*. A data series is a list of data points. Each data point contains an X value and a Y value. Here is an example of creating a data series and adding it to a `LineChart` component:

XYChart.Series dataSeries1 = new XYChart.Series();
    dataSeries1.setName("2014");
    
    dataSeries1.getData().add(new XYChart.Data( 1, 567));
    dataSeries1.getData().add(new XYChart.Data( 5, 612));
    dataSeries1.getData().add(new XYChart.Data(10, 800));
    dataSeries1.getData().add(new XYChart.Data(20, 780));
    dataSeries1.getData().add(new XYChart.Data(40, 810));
    dataSeries1.getData().add(new XYChart.Data(80, 850));
    
    lineChart.getData().add(dataSeries1);

First an `XYChart.Series` instance is created and given a name. Second, 6 `XYChart.Data` instances are added to the `XYChart.Series` object. Third, the `XYChart.Series` object is added to a `LineChart` object.

It is possible to add multiple data series to the `LineChart` . Just repeat the above code for additional data series.

### Adding a LineChart to the Scene Graph ###

To make a `LineChart` visible you must add it to the JavaFX scene graph. This means adding the `LineChart` to a `Scene` object or add the `LineChart` to a layout component which is added to a `Scene` object.

Here is an example that adds a `LineChart` to the JavaFX scene graph:

package com.jenkov.javafx.charts;
    
    import javafx.application.Application;
    import javafx.scene.Scene;
    import javafx.scene.chart.LineChart;
    import javafx.scene.chart.NumberAxis;
    import javafx.scene.chart.XYChart;
    import javafx.scene.layout.VBox;
    import javafx.stage.Stage;
    
    public class LineChartExperiments extends Application {
    
        @Override
        public void start(Stage primaryStage) throws Exception {
            primaryStage.setTitle("LineChart Experiments");
    
            NumberAxis xAxis = new NumberAxis();
            xAxis.setLabel("No of employees");
    
            NumberAxis yAxis = new NumberAxis();
            yAxis.setLabel("Revenue per employee");
    
            LineChart lineChart = new LineChart(xAxis, yAxis);
    
            XYChart.Series dataSeries1 = new XYChart.Series();
            dataSeries1.setName("2014");
    
            dataSeries1.getData().add(new XYChart.Data( 1, 567));
            dataSeries1.getData().add(new XYChart.Data( 5, 612));
            dataSeries1.getData().add(new XYChart.Data(10, 800));
            dataSeries1.getData().add(new XYChart.Data(20, 780));
            dataSeries1.getData().add(new XYChart.Data(40, 810));
            dataSeries1.getData().add(new XYChart.Data(80, 850));
    
            lineChart.getData().add(dataSeries1);
    
            VBox vbox = new VBox(lineChart);
    
            Scene scene = new Scene(vbox, 400, 200);
    
            primaryStage.setScene(scene);
            primaryStage.setHeight(300);
            primaryStage.setWidth(1200);
    
            primaryStage.show();
        }
    
    
        public static void main(String[] args) {
            Application.launch(args);
        }
    }

The application resulting from running this application would look similar to this:

![0ad8fe8ad30748a4b576febe4c5d4d85.png][]

[0ad8fe8ad30748a4b576febe4c5d4d85.png]: https://img-blog.csdnimg.cn/0ad8fe8ad30748a4b576febe4c5d4d85.png