Java swing画随机圆

import javax.swing.JPanel; import java.awt.Color; import java.util.Random; import java.awt.Graphics; public class MyPanel extends JPanel { private int n; private int cr,cg,cb; private int r; private int x,y; Random random = new Random(); public MyPanel() { n = random.nextInt(6) + 5; } public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(Color.BLACK); Circle[] circle = new Circle[n]; for (int i=0; i<n; i++) { cr = random.nextInt(256); cg = random.nextInt(256); cb = random.nextInt(256); // x = random.nextInt(600); r = random.nextInt(200)+1; y = random.nextInt(400-2*r); x = random.nextInt(550-2*r); circle[i] = new Circle(x, y, r, new Color(cr,cg,cb)); } for (int i=0; i<n; i++) { circle[i].draw(g); } } }