JavaFX PieChart Tooltip not showing despite being installed

问题

I tried displaying a tooltip for each "slice" of a PieChart similar to this in chart.js:

I found this answer basically trying to achieve the same in the same framework. It has two upvotes and the same seemed to work on other chart types judging by other (accepted) answers. However the code would not really work for me in the sense that there was no tooltip showing up.

Example code showing the problem:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.PieChart;
import javafx.scene.control.Button;
import javafx.scene.control.Tooltip;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;


public class Main extends Application {

    @Override
    public void start(Stage primaryStage) {
        BorderPane pane = new BorderPane();

        PieChart chart = new PieChart();

        Button randomValues = new Button();
        randomValues.setOnAction(ae -> {
            chart.getData().clear();
            List<PieChart.Data> data = randomValues().stream().map(i -> new PieChart.Data("Test" + i % 10, i)).collect(Collectors.toList());
            data.forEach(d -> {
                Tooltip tip = new Tooltip();
                tip.setText(d.getPieValue() + "");
                Tooltip.install(d.getNode(), tip);
            });
            chart.getData().addAll(data);
        });

        pane.setCenter(chart);
        pane.setBottom(randomValues);
        primaryStage.setScene(new Scene(pane));
        primaryStage.show();
    }

    private List<Integer> randomValues() {
        return new Random().ints(5).boxed().collect(Collectors.toList());
    }

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

I expected a popup similar to the picture but there is literally nothing showing up. Any help is much appreciated!

回答1:

I simply moved

chart.getData().addAll(data);

above

data.forEach(d -> {
    Tooltip tip = new Tooltip();
    tip.setText(d.getPieValue() + "");
    Tooltip.install(d.getNode(), tip);
});

Complete code:

import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.PieChart;
import javafx.scene.control.Button;
import javafx.scene.control.Tooltip;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class Main extends Application
{

    @Override
    public void start(Stage primaryStage)
    {
        BorderPane pane = new BorderPane();

        PieChart chart = new PieChart();

        Button randomValues = new Button();
        randomValues.setOnAction(ae -> {
            chart.getData().clear();

            List<PieChart.Data> data = randomValues().stream().map(i -> new PieChart.Data("Test" + i % 10, i)).collect(Collectors.toList());
            chart.getData().addAll(data);
            data.forEach(d -> {
                Tooltip tip = new Tooltip();
                tip.setText(d.getPieValue() + "");
                Tooltip.install(d.getNode(), tip);
            });

        });

        pane.setCenter(chart);
        pane.setBottom(randomValues);
        primaryStage.setScene(new Scene(pane));
        primaryStage.show();
    }

    private List<Integer> randomValues()
    {
        return new Random().ints(5).boxed().collect(Collectors.toList());
    }

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

来源：https://stackoverflow.com/questions/48346230/javafx-piechart-tooltip-not-showing-despite-being-installed