JAVA移动球

Question

我尝试编写一个程序，让屏幕上的球会自行移动。但问题是它不执行 repaint();

有什么解决办法吗？

(主类)Main.java:

import javax.swing.*;
import java.awt.*;

public class Main extends JFrame{
    static int x = 10;


    public static void main(String[] args){
        JFrame f = new JFrame("title");
        f.setVisible(true);
        f.setSize(300,250);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        sekon m = new sekon();
        f.add(m);

        antr t = new antr();
        Thread th = new Thread(t);
        th.start();
    }
}

(第二课)sekon.java:

import javax.swing.*;
import java.awt.*;

public class sekon extends JPanel{
    int xiu = 10;

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(Color.RED);
        g.fillOval(xiu, 10, 20, 20);

    }


    public void changeX(int b){
        this.xiu = b;
    }



}

     class antr extends JPanel implements Runnable{
         int xi = 10;
        sekon s = new sekon();
         public void run(){

             xi += 1;
             s.changeX(xi);
             JPanel p = new JPanel();
             p.repaint();

             try{
                 Thread.sleep(5);
                 }catch(Exception e){}
         }
    }

Answer 1

1) 代码中的 repaint() 被代码行 Thread.sleep(5);

阻止

2)您的代码不起作用，因为错过了...，在屏幕上移动 Oval 的所有坐标

3) 对于 Swing 容器，仅使用 Swing JComponent Swing Timer用于处理、移动、重新喷漆，

使用Runnable#Thread当然可以，但不是这样，

关于Swing Timer的示例

    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;

    public class AnimationJPanel extends JPanel {

        private static final long serialVersionUID = 1L;
        private int cx = 0;
        private int cy = 150;
        private int cw = 20;
        private int ch = 20;
        private int xinc = 1;
        private int yinc = 1;

        public static void main(String[] args) {
            EventQueue.invokeLater(new Runnable() {

                @Override
                public void run() {
                    AnimationJPanel panel = new AnimationJPanel();
                    panel.setPreferredSize(new Dimension(400, 300));
                    panel.animate();
                    JFrame frame = new JFrame("Test");
                    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                    frame.getContentPane().add(panel);
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                }
            });
        }

        public AnimationJPanel() {
            setLayout(new BorderLayout());
            JLabel label = new JLabel("This is an AnimationJPanel");
            label.setForeground(Color.RED);
            label.setHorizontalAlignment(SwingConstants.CENTER);
            add(label);
            setBackground(Color.BLACK);
            setForeground(Color.RED);
            setOpaque(true);
        }

        public void animate() {
            new Timer(15, new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent e) {
                    Rectangle oldCircle = new Rectangle(cx - 1, cy - 1, cw + 2, ch + 2);
                    cx += xinc;
                    cy += yinc;
                    if (cx >= getWidth() - cw || cx <= 0) {
                        xinc *= -1;
                    }
                    if (cy >= getHeight() - ch || cy <= 0) {
                        yinc *= -1;
                    }
                    repaint(oldCircle);
                    repaint(cx - 1, cy - 1, cw + 2, ch + 2);
                }
            }).start();
        }

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawOval(cx, cy, cw, ch);
        }
}