标签未显示在鼠标事件JavaFx上 [英] Label not showing on mouse event JavaFx

问题描述

我有一个饼图，我使用本指南添加了一个鼠标监听器：

I have a pie chart where i have added a mouse listener using this guide:

饼图的Oracle指南

然而，当我运行我的程序并点击图表它不做任何事情。

However when i run my program and click on the chart it doesnt do anything.

我试过System.out.println（caption.getText（））;并且标签的文字是正确的，但标签没有显示。

I have tried to System.out.println(caption.getText()); and the text of the label is correct however the label is just not showing up.

我的代码如下：

public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("Imported Fruits");
        stage.setWidth(500);
        stage.setHeight(500);

        ObservableList<PieChart.Data> pieChartData =
                FXCollections.observableArrayList(
                new PieChart.Data("Grapefruit", 13),
                new PieChart.Data("Oranges", 25),
                new PieChart.Data("Plums", 10),
                new PieChart.Data("Pears", 22),
                new PieChart.Data("Apples", 30));
        final PieChart chart = new PieChart(pieChartData);
        chart.setTitle("Imported Fruits");

        ((Group) scene.getRoot()).getChildren().add(chart);

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

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

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

}

谁能告诉我我做了什么错误？

Can anyone tell me what i did wrong?

推荐答案

您忘了将标题'caption'添加到根节点中的子项列表中： - ）

You forgot to add the label 'caption' to the list of children in your root node :-)

public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("Imported Fruits");
        stage.setWidth(500);
        stage.setHeight(500);

        ObservableList<PieChart.Data> pieChartData =
                FXCollections.observableArrayList(
                new PieChart.Data("Grapefruit", 13),
                new PieChart.Data("Oranges", 25),
                new PieChart.Data("Plums", 10),
                new PieChart.Data("Pears", 22),
                new PieChart.Data("Apples", 30));
        final PieChart chart = new PieChart(pieChartData);
        chart.setTitle("Imported Fruits");
        final ObservableList<Node> children = ((Group) scene.getRoot()).getChildren();

        children.add(chart);

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

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

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

我已做出上述更改并可验证其是否有效（如下所示）如下图所示）

I have made the above change and can verify that it works (as depicted by the image below)

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