java - 限制和卡住按钮不起作用，也不会生成新球(动画)

Question

这是一个让球以对角线方式下降的用户界面，但每次我按下“动画它!”按钮时它不会创建一个新球。

• 另一个问题是“卡住”按钮无法按预期工作，因为它应该停止球，然后；如果你再按一次，它应该会让球再次移动。

• 最后，限制有问题，当球几乎触及底部时，它没有到达底部并弹到右侧。另外，当球“触及”正确的界限时，它就会上升。

• 此外，当调整框架大小时，限制不会更新。

请下载一个球并更改目录，以便程序可以找到您的球的分配位置。没有必要下载足球场，但如果您愿意，也可以。最后，我要感谢您花时间寻找这个故障。

Ball link: https://lapequeteria.cl/wp-content/uploads/2018/11/balon-adidas-2.jpeg (Make it png)

Pitch link: https://www.freejpg.com.ar/asset/900/9c/9ca2/F100004898.jpg

import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import java.io.File;

class Animation extends JFrame {  //Frame

  static boolean running = true;
  static Layout panel = new Layout();
  JButton animate, stop;
  Runnable runnable;
  Thread move;

    public Animation() {
      setLayout(new BorderLayout());  //BorderLayout disposition
      setTitle("Pelota en acción");      

        animate = new JButton("Animate it!");  //Button to create balls
          animate.setSize(120,30);
          animate.addActionListener(new ActionListener(){
            @Override
              public void actionPerformed(ActionEvent e) {
                  panel.createEllipse();
                  runnable = panel;
                  move = new Thread(runnable);
                   panel.X = 0;
                   panel.Y = 0;
                  move.start();
               }
          });

        stop = new JButton("Freeze");  //Botón para interrumpir hilo (aun no implementado)
          stop.setBounds(0,0,120,30);
          stop.addActionListener(new ActionListener(){
            @Override
              public void actionPerformed(ActionEvent e) {
                if(move.isAlive()){
                  stop.setText("Go");  //Pause
                    synchronized(move) {
                      try {
//                        running = false;
                        move.wait();
                      } catch (InterruptedException ex) {
                        System.out.println("Interrupted");
                      }
                    }
                }
                else {
                  stop.setText("Freeze");  //Play
                    synchronized(move) {
//                      running = true;
                      move.notifyAll();
                    }
                }
              }
        });

        JPanel subPanel = new JPanel();  //Layout with its buttons situated to the south
          subPanel.add(animate);
          subPanel.add(stop);
        add(subPanel,BorderLayout.SOUTH);

        add(panel);
    }

    public static void main(String[] args) {  //Frame construction
        Animation ventana = new Animation();
          ventana.setSize(850,625);
          ventana.setLocationRelativeTo(null);
          ventana.setVisible(true);
          ventana.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
}

class Layout extends JPanel implements Runnable {  //Layout and thread

  volatile double X,Y;  //Coordinates
  volatile double dX=1,dY=1;  //Direction
  static ArrayList<Image> balls = new ArrayList<>();  //Balls collection
  Image picture, ball;
  int width = 120,height = 120;

  @Override
    public void paintComponent(Graphics g) {  //Shows the ball and the pitch
      super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;

        soccerPitch();
        g2.drawImage(picture, 0, 0, null);
        for (Image ball : balls) {  //Balls added to the layout
          g2.drawImage(ball,(int)X,(int)Y,100,100,null);
        }
    }

    public void soccerPitch () {  //Builds the soccerPitch image
        try {
          picture = ImageIO.read(new File("C:\\Users\\Home\\Desktop\\NO BORRAR porfavor\\Cancha.jpg"));
        } catch (IOException ex) {
          System.out.println("Pitch image was not found");
        }
    }

    public void createEllipse () {  //Builds the ball image
        try {
          ball = ImageIO.read(new File("C:\\Users\\Home\\Desktop\\NO BORRAR porfavor\\Pelota.png"));
            System.out.println(ball.getWidth(null)+" "+ball.getHeight(null));
        } catch(IOException ex) {
          System.out.println("Any balls were found");
        }
        balls.add(ball);  //Balls are added to the collection
    }

    @Override
      public void run () {  //Moves the ball(coordinate system doesn't work)
        moveBall(Animation.panel.getBounds());
      }

    public void moveBall(Rectangle2D limits) {
        while(true) {
//        while(Animation.running) {
          System.out.println("X: "+X+"\tY: "+Y);
          System.out.println(limits.getBounds());
            X+=dX;  
            Y+=dY;

            if(X<limits.getMinX()){     
              X=limits.getMinX();   
              dX=-dX;
            }
            if(X + width>=limits.getMaxX()){    
              X=limits.getMaxX()-width; 
              dX=-dY;
            }
            if(Y<limits.getMinY()){ 
              Y=limits.getMinY();
              dY=-dY;
            }
            if(Y + height>=limits.getMaxY()){   
              Y=limits.getMaxY()-height;
              dY=-dY;
            }
            try {
              Thread.sleep(4);
            } catch (InterruptedException e) {
              System.out.println("Interrupted");
            }
            repaint();
        }
    }
}

以防万一你想帮助我；我不是要求完成工作，只是向我解释为什么它不起作用。

Answer 1

您似乎违反了 Concurrency in Swing 的基本规则。加号而不是 using LayoutManagers您手动设置组件的边界(这就是为什么当调整框架大小时，组件不在正确的位置)。

现在，您在线程中启动应用程序，对吧？在此线程中，您准备 GUI 并执行操作，然后在某个时刻 while(true)。当您 while(true) 时，线程将“卡在”while 循环内，因此无法发生 swing 事件。这就是为什么您必须 while(true) 并在另一个线程中创建动画。然而，在 Swing 中创建动画的最佳方法是 use a Swing Timer.

我创建了一个示例，其中动画每 100 毫秒在面板中创建一个新的随机矩形 (10x10)。使用它进行一些过期操作，并尝试将相同的逻辑调整到您的应用程序(毕竟，您不会发布代码并期望我们为您修复它:))。

这是示例:

public class Animation extends JFrame implements ActionListener {
    private Timer timer;
    private RectanglePanel panel;

    public Animation() {
        super("test");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        add(panel = new RectanglePanel());

        timer = new Timer(100, this); //every 100 ms add new Shape

        JButton button = new JButton("Start Animation");
        button.addActionListener(e -> timer.start()); //start animation timer
        add(button, BorderLayout.PAGE_END);
        pack();
        setSize(500, 500);
        setLocationRelativeTo(null);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        panel.createNewShape(); //add new shape
        panel.repaint();
    }

    private class RectanglePanel extends JPanel {
        private List<Rectangle> shapes;

        public RectanglePanel() {
            super();
            this.shapes = new ArrayList<>();
        }

        public void createNewShape() {
            int x = (int) (Math.random() * getWidth());
            int y = (int) (Math.random() * getHeight());
            x = Math.min(x, getWidth() - 10);
            y = Math.min(y, getHeight() - 10);
            Rectangle r = new Rectangle(x, y, 10, 10);
            System.out.println("New rectangle:" + r);
            shapes.add(r);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            for (Rectangle r : shapes) {
                g.setColor(randomColor());
                g.drawRect(r.x, r.y, r.width, r.height);
            }
        }

        private Color randomColor() {
            return new Color((int) (Math.random() * 255), (int) (Math.random() * 255), (int) (Math.random() * 255));
        }
    }

    public static void main(String[] args) {
        //All swing applications must run on their own thread
        SwingUtilities.invokeLater(() -> new Animation().setVisible(true));
    }
}

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