java JavaFX | PieChart 类

JavaFX | PieChart 类

原文:https://www.geeksforgeeks.org/javafx-piechart-class/

PieChart 类是 JavaFX 的一部分。PieChart 类用于创建饼图。图表内容由基于饼图数据集的饼图切片填充。默认情况下，饼图的布局设置为顺时针。饼图继承了图表类。

该类的构造函数为:

饼图():创建饼图的空实例。
饼图(观察列表数据):用给定的数据创建饼图实例。

常用方法:

方法	说明
getData()	返回饼图的数据
getLabelLineLength()	返回饼图的标签长度
getLabelsVisible()	指示是否绘制饼图切片标签
getStartAngle()	返回饼图的起始角度
isClockwise()	返回饼图是顺时针还是逆时针
设置顺时针(布尔 v)	传递真值时，将饼图方向设置为顺时针
设置数据(观察列表数据)	设置属性数据的值。
setLabelLineLength(double v)	设置饼图的标签线长度。
setLabelsVisible（boolean v）	设置标签可见属性的值。
setStartAngle(双 v)	设置饼图的开始角度

下面的程序将说明 PieChart 类的使用:

Java program to create a pie chart with some specified data: This program creates a PieChart. A PieChart.Data will be created that will be added to the pie chart as an observable list.T he PieChart will be created inside a scene, which in turn will be hosted inside a stage. The function setTitle() is used to provide title to the stage. Then a Group is created, and the pie chart is attached. The group is attached to the scene. Finally, the show() method is called to display the final results.

```java // Java program to create a pie chart // with some specified data import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.chart.PieChart; import javafx.scene.layout.; import javafx.event.ActionEvent; import javafx.scene.AmbientLight; import javafx.scene.shape.Sphere; import javafx.scene.control.; import javafx.stage.Stage; import javafx.scene.Group; import javafx.scene.PerspectiveCamera; import javafx.scene.paint.Color; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.collections.FXCollections;

public class pie_chart_1 extends Application {

// launch the application     public void start(Stage stage)     {         // set title for the stage         stage.setTitle("Creating Pie Chart");

// piechart data         PieChart.Data data[] = new PieChart.Data[5];

// string and integer data         String status[] = {"Correct Answer", "Wrong Answer",                            "Compilation Error", "Runtime Error",                            "Others" };

int values[] = {20, 30, 10, 4, 2};

for (int i = 0; i < 5; i++) {             data[i] = new PieChart.Data(status[i], values[i]);         }

// create a pie chart         PieChart pie_chart = new                 PieChart(FXCollections.observableArrayList(data));

// create a Group         Group group = new Group(pie_chart);

// create a scene         Scene scene = new Scene(group, 500, 300);

// set the scene         stage.setScene(scene);

stage.show();     }

// Main Method     public static void main(String args[])     {

// launch the application         launch(args);     } } ```

输出:
Java program to create a pie chart with some specified data, with visible labels and a defined start angle, and ordered in anticlockwise direction: This program creates a PieChart. A PieChart.Data will be created that will be added to the pie chart as an observable list. The PieChart will be created inside a scene, which in turn will be hosted inside a stage. The function setTitle() is used to provide title to the stage. Then a Group is created, and the pie chart is attached. The group is attached to the scene. Finally, the show() method is called to display the final results.we will set label line length of pie chart using setLabelLineLength() function, we will set the start angle and the clockwise orientation using setStartAngle() and setClockwise() function respectively . we can make the labels visible using setLabelsVisible() function.

```java // Java program to create a pie chart with // some specified data, with visible labels // and a defined start angle, and ordered // in anticlockwise direction import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.chart.PieChart; import javafx.scene.layout.; import javafx.event.ActionEvent; import javafx.scene.AmbientLight; import javafx.scene.shape.Sphere; import javafx.scene.control.; import javafx.stage.Stage; import javafx.scene.Group; import javafx.scene.PerspectiveCamera; import javafx.scene.paint.Color; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.collections.FXCollections;

public class pie_chart_2 extends Application {

// launch the application     public void start(Stage stage)     {         // set title for the stage         stage.setTitle("Creating Pie Chart");

// piechart data         PieChart.Data data[] = new PieChart.Data[5];

// string and integer data         String status[] = {"Correct Answer", "Wrong Answer",                            "Compilation Error", "Runtime Error",                            "Others"};

int values[] = {20, 30, 10, 4, 2};

for (int i = 0; i < 5; i++) {             data[i] = new PieChart.Data(status[i], values[i]);         }

// create a pie chart         PieChart pie_chart = new                 PieChart(FXCollections.observableArrayList(data));

// set line length of label         pie_chart.setLabelLineLength(10.0f);

// make labels visible         pie_chart.setLabelsVisible(true);

// set start angle         pie_chart.setStartAngle(20.0f);

// set anticlockwise         pie_chart.setClockwise(false);

// create a Group         Group group = new Group(pie_chart);

// create a scene         Scene scene = new Scene(group, 500, 500);

// set the scene         stage.setScene(scene);

stage.show();     }

// Main Method     public static void main(String args[])     {

// launch the application         launch(args);     } } ```

输出: