条形图中的中心条

Question

我修改了Oracle网站的条形图示例，并将每个系列的条形减少到1。不幸的是，条形图不会位于刻度线上方。

有没有人知道如何让条形水平居中于刻度线上方？

以下是代码：

public class BarChartDemo extends Application {
    final static String austria = "Austria";
    final static String brazil = "Brazil";
    final static String france = "France";

    @Override
    public void start(Stage stage) {
        stage.setTitle("Bar Chart Sample");
        final CategoryAxis xAxis = new CategoryAxis();
        final NumberAxis yAxis = new NumberAxis();
        final BarChart<String, Number> bc = new BarChart<String, Number>(xAxis, yAxis);
        bc.setTitle("Country Summary");

        xAxis.setLabel("Country");
        yAxis.setLabel("Value");

        XYChart.Series series1 = new XYChart.Series();
        series1.setName("2003");
        series1.getData().add(new XYChart.Data(austria, 25601.34));

        XYChart.Series series2 = new XYChart.Series();
        series2.setName("2004");
        series2.getData().add(new XYChart.Data(brazil, 41941.19));

        XYChart.Series series3 = new XYChart.Series();
        series3.setName("2005");
        series3.getData().add(new XYChart.Data(france, 18722.18));

        Scene scene = new Scene(bc, 800, 600);
        bc.getData().addAll(series1, series2, series3);
        stage.setScene(scene);
        stage.show();
    }

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

这就是它的样子：

非常感谢！

Answer 1

<强>问题

BarChart的问题在于您要添加3个系列，但每个系列中只有一个唯一的国家/地区。 BarChart固有地为另外两个系列留出了空间。

<强>解决方案

实现此目的的正确方法是使用一个 XYChart.Series，然后为每个条添加颜色。这是一个示例应用程序，它也是如此。

public class BarChartDemo extends Application {
    final static String austria = "Austria";
    final static String brazil = "Brazil";
    final static String france = "France";

    @Override
    public void start(Stage stage) {
        stage.setTitle("Bar Chart Sample");
        final CategoryAxis xAxis = new CategoryAxis();
        final NumberAxis yAxis = new NumberAxis();
        final BarChart<String, Number> bc = new BarChart<String, Number>(xAxis, yAxis);
        bc.setTitle("Country Summary");

        xAxis.setLabel("Country");
        yAxis.setLabel("Value");

        XYChart.Series series1 = new XYChart.Series();
        series1.setName("2003");
        final XYChart.Data<String, Number> dataAustria = new XYChart.Data(austria, 25601.34);
        final XYChart.Data<String, Number> dataBrazil = new XYChart.Data(brazil, 41941.19);
        final XYChart.Data<String, Number> dataFrance = new XYChart.Data(france, 35000.19);
        series1.getData().add(dataAustria);
        series1.getData().add(dataBrazil);
        series1.getData().add(dataFrance);
        Scene scene = new Scene(bc, 800, 600);
        bc.getData().addAll(series1);
        stage.setScene(scene);
        stage.show();
        dataAustria.getNode().setStyle("-fx-bar-fill: CHART_COLOR_1;");
        dataBrazil.getNode().setStyle("-fx-bar-fill: CHART_COLOR_2;");
        dataFrance.getNode().setStyle("-fx-bar-fill: CHART_COLOR_3;");
    }

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

输出看起来像你要找的东西：

注意：您需要在节点显示在舞台上后将样式应用于节点。或者，您可以使用xyChartData.nodeProperty().addListener()并在其中应用样式。

dataAustria.nodeProperty().addListener((ov, oldNode, newNode) -> {
    if(null != newNode) {
        newNode.setStyle("-fx-bar-fill: red;");
    }
});