无法完成饼图的圆圈

Question

我正在制作一个包含4个不同元素的饼图.我可以让元素出现在JFrame中,但我无法完成饼图圈.这些是元素:

public static class PieChart extends JComponent { 

        IAPieChart[] pieValue = {new IAPieChart(5, Color.green),
                                new IAPieChart(4, Color.orange),
                                new IAPieChart(3, Color.blue),
                                new IAPieChart(2, Color.red)

        };

现在元素被实例化并加载到数组中,我使用这个方法来绘制它们:

public void paintComponent(Graphics g) {

            drawPie((Graphics2D) g, getBounds(),  pieValue);

        }

这个方法将元素放在JFrame上,但只给了我大约120度的圆.:

void drawPie(Graphics2D g, Rectangle area, IAPieChart[] pieValue){

            double sum = 0.0;
            for (int i = 0; i < pieValue.length; i++) {

                sum += pieValue[i].arcValue;
            }

            double endPoint =  0.0D;
            int arcStart = 0; 
            for (int i = 0; i < pieValue.length; i++){

                endPoint = (int) (endPoint * 360 / sum);
                int radius = (int) (pieValue[i].arcValue * 360/ sum);
                g.setColor(pieValue[i].color);
                g.fillArc(area.x, area.y, area.width, area.height, arcStart , radius);
                radius += pieValue[i].arcValue;
            }

        }
    }

我不知所措.我用Java大约需要10周时间,所以这主要是反复试验.我正在寻找一种方法来完成这个圈子.我将值减少到可以显示所有颜色的最低点.任何更大的东西都会消除一种颜色或另一种颜色.

我希望你能提供帮助.这是完整的程序IAPieChart:

package iapiechart;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JComponent;
import javax.swing.JFrame;



class IAPieChart{

    double arcValue;        // passes a value for the calculation of the arc.
    Color color;            // holds value for color (expressed as an integer 

    public IAPieChart(double value, Color color){

        this.arcValue = value;
        this.color = color;
    }


    public static class PieChart extends JComponent { 

        IAPieChart[] pieValue = {new IAPieChart(5, Color.green),
                                new IAPieChart(4, Color.orange),
                                new IAPieChart(3, Color.blue),
                                new IAPieChart(2, Color.red)

        };

        public void paintComponent(Graphics g) {

            drawPie((Graphics2D) g, getBounds(),  pieValue);

        }

        void drawPie(Graphics2D g, Rectangle area, IAPieChart[] pieValue){

            double sum = 0.0;
            for (int i = 0; i < pieValue.length; i++) {

                sum += pieValue[i].arcValue;
            }

            double endPoint =  0.0D;
            int arcStart = 0; 
            for (int i = 0; i < pieValue.length; i++){

                endPoint = (int) (endPoint * 360 / sum);
                int radius = (int) (pieValue[i].arcValue * 360/ sum);
                g.setColor(pieValue[i].color);
                g.fillArc(area.x, area.y, area.width, area.height, arcStart , radius);
                radius += pieValue[i].arcValue;
            }

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

        JFrame frame = new JFrame();

        frame.getContentPane().add(new PieChart());
        frame.setSize(300, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
        frame.setVisible(true);

        }
 }

Answer 1

你有

            double endPoint =  0.0D;
            int arcStart = 0; 
            for (int i = 0; i < pieValue.length; i++){

            endPoint = (int) (endPoint * 360 / sum);
            ...

然而，每次乘以零时，这总是会给出 endPoint = 0 。尝试制作一下

             endPoint += (int) (endPoint * 360 / sum);