JAVA移动球

Question

我试图制作一个程序，在屏幕上球会自动移动。但问题是它没有重绘（）;

有任何建议如何修复它？

（主要类）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

您的代码中的

1）被代码行repaint()

阻止Thread.sleep(5);

2）你的代码不起作用，因为错过了...，所有在屏幕上移动Oval的坐标

3）对于Swing容器，Swing JComponent仅使用Swing Timer进行分析，移动，重新绘制，

确定可以使用Runnable#Thread，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);
        }
}

Answer 2

sekon对象拥有的antr实例与添加到GUI的实例不同。

Answer 3

研究以下教学示例，了解如何导致重绘动画。

public static void main(String args[]) throws Exception {
new JFrame("AnimationStudy") {
  int    x = 0;
  JPanel j = new JPanel() {
    protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.setColor(Color.RED);
      g.fillOval(x, 10, 20, 20);
      g.setColor(Color.BLACK);
      g.drawChars(("" + x).toCharArray(), 0, ("" + x).length(), x, 10);
    }
  };
  {
    setSize(300, 100);
    setLocation(300, 300);
    setVisible(true);
    setLayout(new BorderLayout());
    add(j);
    new Thread(new Runnable() {
      public void run() {
        int t = 250;
        for (x = 10; x < t; x += 1) {
          j.repaint();
          try {
            Thread.sleep((t - x) / 4);
          } catch (Exception e) {
            e.printStackTrace();
          }
        }
        System.exit(0);
      }
    }).start();
  }
};
}

Answer 4

您的班级antr和主班级使用不同的sekon实例。您应该将main方法中创建的实例传递给antr类。