Question

我想创建带有标题的饼图。当我将鼠标移到饼图上时，文本显示非常流畅。

enter image description here

public void naiveAddData(String name, double value)
    {
        pieChartData.add(new Data(name, value));

        caption = new Label();
        caption.setTextFill(Color.DARKORANGE);
        caption.setStyle("-fx-font: 24 arial;");

        for (final Data data : chart.getData())
        {
            data.getNode().addEventHandler(MouseEvent.MOUSE_MOVED,
                new EventHandler<MouseEvent>()
                {
                    @Override
                    public void handle(MouseEvent e)
                    {
                        caption.setTranslateX(e.getSceneX() + 15);
                        caption.setTranslateY(e.getSceneY());
                        caption.setText(String.valueOf(data.getPieValue()) + "%");
                    }
                });
        }
    }

但是当我将鼠标移到饼图外时，标题仍然存在。它没有删除。我怎么解决这个问题？

P.S我设法以这种方式解决问题：

data.getNode().addEventHandler(MouseEvent.MOUSE_MOVED,
                new EventHandler<MouseEvent>()
                {
                    @Override
                    public void handle(MouseEvent e)
                    {
                        caption.setTranslateX(e.getSceneX() + 15);
                        caption.setTranslateY(e.getSceneY());
                        caption.setText(String.valueOf(data.getPieValue()) + "%");
                        caption.setVisible(true);
                    }
                });

            data.getNode().addEventHandler(MouseEvent.MOUSE_EXITED,
                new EventHandler<MouseEvent>()
                {
                    @Override
                    public void handle(MouseEvent e)
                    {
                        caption.setVisible(false);
                    }
                });
        }

有没有更好的解决方案？

Answer 1

如果您拥有标题的父级，则可以在鼠标退出时将其从父级删除，并在鼠标输入时再次添加。

    Parent captionparent = ...
    ...
    data.getNode().addEventHandler(MouseEvent.MOUSE_EXITED,
        new EventHandler<MouseEvent>()
        {
            @Override
            public void handle(MouseEvent e)
            {
                captionparent.getChildren().remove(caption);
            }
        });

Answer 2

以下是使用工具提示的完整示例。

public class ChartingMain extends Application {

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

@Override
public void start(Stage stage) throws Exception {
    PieChart pc = new PieChart();
    pc.setTitle("Most popular programming languages");
    ObservableList<PieChart.Data> pcdata = FXCollections.<PieChart.Data>observableArrayList();
    pcdata.add(new PieChart.Data("C#", 20d));
    pcdata.add(new PieChart.Data("Java",800d));
    pcdata.add(new PieChart.Data("C/C++", 400d));
    final double total = 20d + 800d + 400d;
    pc.dataProperty().set(pcdata);
    stage.setScene(new Scene(pc));
    stage.show();
    for(PieChart.Data data : pc.getData()){
        final Tooltip t = new Tooltip(data.getName() + " : " + new DecimalFormat("#.##").format((data.getPieValue() / total) * 100) + " %");
        data.getNode().setOnMouseEntered(new EventHandler<MouseEvent>(){
            @Override
            public void handle(MouseEvent me) {
                if(me.getSource() instanceof Node){
                    Node sender = (Node) me.getSource();
                    Tooltip.install(sender, t);
                    sender.setEffect(new Glow(0.5));
                }
            }});
        data.getNode().setOnMouseExited(new EventHandler<MouseEvent>(){
            @Override
            public void handle(MouseEvent me) {
                if(me.getSource() instanceof Node){
                    Node sender = (Node) me.getSource();
                    sender.setEffect(null);
                    t.hide();
                }
            }});
    }
}

}

退出饼图时，标签显示不正确

2 个答案: