Java 通过单击鼠标按钮绘制和存储对象

我试图在每次单击时绘制圆形对象，然后将每个圆形对象存储到Arraylist中，我不知道为什么我的程序不工作！如果我删除了arraylist和创建新圆形对象的线条，程序将正常工作。如何使程序将所有回路对象存储到Arraylist中

 import javax.swing.JPanel;
    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.event.MouseAdapter;
    import java.awt.event.MouseEvent;
    import java.util.ArrayList;
    import java.util.Random;

    public class CircleObj extends JPanel {
        private int rColor;
        private int gColor;
        private int bColor;
        private int radius;
        private Random rand = new Random();
        private int xStart;
        private int yStart;
        ArrayList <Circle> xxx ;

        public CircleObj () {
        xxx =  new ArrayList<Circle>();

        addMouseListener(new MouseAdapter() {

            public void mouseClicked (MouseEvent e) {

            xStart = e.getX();
            yStart = e.getY();
            rColor = rand.nextInt(256);
            gColor = rand.nextInt(256);
            bColor = rand.nextInt(256);
            radius = rand.nextInt(20);


            repaint();
            }
        }); // end addMouseListener
        }

        public void paintComponent (Graphics g) {
        super.paintComponent(g);
        g.setColor(new Color(rColor, gColor, bColor));
        g.fillOval(xStart, yStart, radius, radius);
        xxx.add(new Circle());
        }

        private class Circle {
            private int x;
            private int y;
            private int r;
            private int rcol;
            private int gcol;
            private int bcol;

            public Circle()
                {
                x=xStart;
                y=yStart;
                r=radius;
                rcol= rColor;
                gcol= gColor;
                bcol= bColor;

                }




        }

    }

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不要在

paintComponent

方法中添加新形状，

paintComponent

可以出于多种原因调用，其中许多原因您无法控制，而是在触发

mouseClicked

事件时创建它

public void mouseClicked (MouseEvent e) {

    xStart = e.getX();
    yStart = e.getY();
    rColor = rand.nextInt(256);
    gColor = rand.nextInt(256);
    bColor = rand.nextInt(256);
    radius = rand.nextInt(20);

    xxx.add(new Circle(xStart, yStart, new Color(rColor, gColor, bColor), radius));

    repaint();
}

然后在

paintComponent

中，在

ArrayList

中循环并绘制圆

public void paintComponent (Graphics g) {
    super.paintComponent(g);
    for (Circle c : xxx) {
        g.setColor(c.getColor());
        g.fillOval(c.getX(), c.getY(), c.getRadius(), c.getRadius());
    }
}

现在，您必须修改

Circle

类，以提供

CircleObj

可以用来实际绘制圆的getter

public void paintComponent (Graphics g) {
    super.paintComponent(g);
    for (Circle c : xxx) {
        g.setColor(c.getColor());
        g.fillOval(c.getX(), c.getY(), c.getRadius(), c.getRadius());
    }
}

---

或者，您可以使用Java中提供的

Shape

s API…查看更多详细信息…

非常感谢兄弟。