JavaFX：在PieChart切片上显示百分比

Question

我试图在饼图的每个切片上定位百分比，但是我无法将它们放在正确的位置。我只找到了鼠标悬停在鼠标位置标注标签的示例，但是我希望保持始终可见的百分比。这里有什么问题？

这是我的代码：

public class PieChartExperiments extends Application implements {
@Override
public void start(Stage primaryStage) throws Exception {
primaryStage.setTitle("StackedBarChart Experiments");

Map<String, Double> pieChartData = new TreeMap<String, Double>(new SeriesComparator());
double click = 75;
double clickAndCredential = 16.67F;
double clickOnly = click - clickAndCredential;
double noClick = 100 - click;

pieChartData.put(JUST_CLICK_LABEL, clickOnly);
pieChartData.put(CREDENTIAL_LABEL, clickAndCredential);
pieChartData.put(NO_CLICK_LABEL, noClick);

CategoryAxis xAxis = new CategoryAxis();
// xAxis.setLabel("Devices");

NumberAxis yAxis = new NumberAxis();
// yAxis.setLabel("Visits");

List<PieChart.Data> pieChartDataList = pieChartData.entrySet().stream()
    .map(e -> new PieChart.Data(e.getKey(), e.getValue())).collect(Collectors.toList());

ObservableList<PieChart.Data> pieChartDataOL = FXCollections.observableArrayList(pieChartDataList);

/*
 * Create the PieChart object
 */
final PieChart pieChart = new PieChart(pieChartDataOL);
pieChart.setTitle("Overall Click Results");
pieChart.setLegendSide(Side.TOP);

VBox vbox = new VBox(pieChart);

Scene scene = new Scene(vbox, 1200, 720);
System.out.println("Resource: " + this.getClass().getResource("/javafx/style/PieChart.css"));

scene.getStylesheets().add(this.getClass().getResource("/javafx/style/PieChart.css").toExternalForm());

// SET THE PIE SLICES COLOR AFTER CREATING THE SCENE
for (Data data : pieChart.getData()) {
    Node node = data.getNode();
    String dataName = data.getName();
    double percentage = data.getPieValue();
    double x = node.getLayoutX();
    double y = node.getLayoutY();
    Label label = new Label(String.format("%.2f", percentage) + "%");
    label.setLabelFor(node);
    label.setLayoutX(x);
    label.setLayoutY(y);

    vbox.getChildren().add(label);
}

primaryStage.setScene(scene);
primaryStage.setHeight(720);
primaryStage.setWidth(1200);

primaryStage.show();
}

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