JavaFX How to get a (x, y) coordinate from a plotted dot on a chart with the mouse cursor?

Question

How to obtain the (x; y) coordinate XYChart.Data(x, y) from a plotted chart symbol by clicking on it or passing the mouse cursor above it?

A label has to receive the obtained coordinate if the mouse has selected it.

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.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class GetChartCoord extends Application {

@Override
    public void start(Stage stage) {

        VBox vbox = new VBox();

        // Creating a chart
        final NumberAxis xAxis = new NumberAxis();
        final NumberAxis yAxis = new NumberAxis();

        LineChart<Number, Number> lineChart = new LineChart<Number, Number>(xAxis, yAxis);

        XYChart.Series series = new XYChart.Series();
        series.setName("Example 1");

        for (int x = 0; x <= 100; x++) {
            double y = Math.random()*100;
            series.getData().add(new XYChart.Data(x, y));
        }
        lineChart.getData().add(series);

        // This label should receive the coordinate (x; y) from the dot that is
        // on the mouse cursor or very next to it
        Label labelXY = new Label();
        labelXY.setText("(x; y)");

        vbox.getChildren().addAll(lineChart, labelXY);
        Scene scene = new Scene(vbox, 800, 600);

        stage.setScene(scene);
        stage.show();
    }
}

EDIT:

The answer for that question mentioned by Sedrick solved my problem, but I had to adapt to adapt the code. So I will answer my own question by posting my modified code

Possible duplicate of [JavaFX LineChart Hover Values](https://stackoverflow.com/questions/14615590/javafx-linechart-hover-values) — SedJ601, Jan 25 '19 at 21:10
Not an exact duplicate, but you should be able to get your answer from there. — SedJ601, Jan 25 '19 at 21:10

Carlos Eduardo · Accepted Answer · 2019-02-04T16:52:53.653

Chart.java

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.stage.Stage;

public class ChangeSymbolSize extends Application {

@Override
public void start(Stage stage) {

    // Random chart
    // Defining the Axis
    final NumberAxis xAxis = new NumberAxis();
    final NumberAxis yAxis = new NumberAxis();
    // Creating the chart
    LineChart<Number, Number> lineChart = new LineChart(xAxis, yAxis);
    // Preparing the series
    XYChart.Series series = new XYChart.Series();
    series.setName("Grafico");

    for (double x = 0; x <= 10; x++) {
        double y = Math.random() * 100;
        XYChart.Data chartData;
        chartData = new XYChart.Data(x, y);
        chartData.setNode(new ShowCoordinatesNode(x, y));
        series.getData().add(chartData);
    }

    // Adding series to chart
    lineChart.getData().add(series);

    Scene scene = new Scene(lineChart, 800, 600);
    stage.setScene(scene);
    stage.show();
}

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

ShowCoordinatesNode.java

import java.text.DecimalFormat;
import javafx.event.EventHandler;
import javafx.scene.Cursor;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.StackPane;

public class ShowCoordinatesNode extends StackPane {

public ShowCoordinatesNode(double x, double y) {

    final Label label = createDataThresholdLabel(x, y);

    setOnMouseEntered(new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent mouseEvent) {
                setScaleX(1);
                setScaleY(1);
                getChildren().setAll(label);
                setCursor(Cursor.NONE);
                toFront();
        }
    });
    setOnMouseExited(new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent mouseEvent) {
                getChildren().clear();
                setCursor(Cursor.CROSSHAIR);
        }
    });
}

private Label createDataThresholdLabel(double x, double y) {
    DecimalFormat df = new DecimalFormat("0.##");
    final Label label = new Label("(" + df.format(x) + "; " + df.format(y) + ")");
    label.getStyleClass().addAll("default-color0", "chart-line-symbol", "chart-series-line");
    label.setStyle("-fx-font-size: 10; -fx-font-weight: bold;");
    label.setMinSize(Label.USE_PREF_SIZE, Label.USE_PREF_SIZE);
    return label;
}
}

JavaFX How to get a (x, y) coordinate from a plotted dot on a chart with the mouse cursor?

1 Answers1