JavaFX 饼图

表示圆圈中的数据的图表，每个切片表示百分比。

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.chart.PieChart;
import javafx.scene.chart.PieChart.Data;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class Main extends Application {
    public static void main(String[] args) {
        launch(args);
    }
    @Override
    public void start(Stage primaryStage) {
        PieChart pieChart = new PieChart();
        pieChart.setData(getChartData());
        primaryStage.setTitle("PieChart");
        StackPane root = new StackPane();
        root.getChildren().add(pieChart);
        primaryStage.setScene(new Scene(root, 400, 250));
        primaryStage.show();
    }
    private ObservableList<Data> getChartData() {
        ObservableList<Data> answer = FXCollections.observableArrayList();
        answer.addAll(new PieChart.Data("java", 17.56),
                      new PieChart.Data("JavaFx", 31.37));
        return answer;
    }
}

创建饼图

要创建饼图，我们需要PieChart类。
饼图数据包裹在PieChart.Data对象中。
每个PieChart.Data对象有两个字段:饼图扇区的名称及其对应的值。

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Side;
import javafx.scene.Scene;
import javafx.scene.chart.PieChart;
import javafx.scene.chart.PieChart.Data;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class Main extends Application {
    public static void main(String[] args) {
        launch(args);
    }
    @Override
    public void start(Stage primaryStage) {
        PieChart pieChart = new PieChart();
        pieChart.setData(getChartData());
        pieChart.setTitle("Title");
        pieChart.setLegendSide(Side.LEFT);
        pieChart.setClockwise(false);
        pieChart.setLabelsVisible(false);
        StackPane root = new StackPane();
        root.getChildren().add(pieChart);
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
    }
    private ObservableList<Data> getChartData() {
        ObservableList<Data> answer = FXCollections.observableArrayList();
        answer.addAll(new PieChart.Data("java", 17),
                      new PieChart.Data("JavaFx",31),
                      new PieChart.Data("Swing",10),
                      new PieChart.Data("IO",20),
                      new PieChart.Data("NIO",21)
                     );
        return answer;
    }
}

处理饼图的事件

以下代码创建一个EventHandler对象来处理落入特定图表切片的MOUSE_PRESSED事件。

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.scene.chart.*;
import javafx.scene.Group;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
public class Main extends Application {
    @Override
    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 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()) 
                                                                   + "%");
                                               }
                                           });
        }
        ((Group) scene.getRoot()).getChildren().addAll(chart, caption);
        stage.setScene(scene);
        //scene.getStylesheets().add("piechartsample/Chart.css");
        stage.show();
    }
    public static void main(String[] args) {
        launch(args);
    }
}