java - 我如何在java中删除球、改变颜色和改变球的类型

Question

帮我找到一个代码来更改颜色，更改球的类型，以及从 Canvas 上删除球。我已经尝试了很多次，但总是出错。

package bouncetugas;

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

public class BounceTugas {

public static void main(String[] args) {

  EventQueue.invokeLater(new Runnable()
            {
                public void run()
                {
                    JFrame frame = new BounceFrame();
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.setVisible(true);
                }
            });
    }
}
/** A runnable animate a bouncing ball*/

class BallRunnable implements Runnable 
{


public BallRunnable(Ball aBall, Component aComponent)
{
    ball = aBall;
    component = aComponent;
}

public void run()
{

    try {

        for (int i = 1; i <= STEPS; i++)
        {
            ball.move(component.getBounds());
            component.repaint();
            Thread.sleep(DELAY);
        }
    }
    catch (InterruptedException e)
    {
    }
}

private Ball ball;
private Component component;
public static final int STEPS = 1000;
public static final int DELAY = 5;
}

//The frame with panel and buttons.

class BounceFrame extends JFrame
{

/*Constructs the frame with the component for showing 
the bouncing ball and Start and Close buttons*/
public BounceFrame()
{
    setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
    setTitle("Bounce Latihan");

    comp = new BallComponent();
    add(comp, BorderLayout.CENTER);
    JPanel buttonPanel = new JPanel();
     addButton(buttonPanel, "Add Ball", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });

      addButton(buttonPanel, "Remove Ball", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            removeBall();
        }
    });

       addButton(buttonPanel, "Change Color", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            changeColor();
        }
    });
        addButton(buttonPanel, "Change Type", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            changeBall();
        }
    });
          addButton(buttonPanel, "Start", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            startBall();
        }
    });

         addButton(buttonPanel, "Pause", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            pauseBall();
        }
    });

         addButton(buttonPanel, "Close", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            System.exit(0);
        }
    });
    add(buttonPanel, BorderLayout.SOUTH);
}

//Adds a button to a container.
public void addButton(Container c, String title, ActionListener listener)
{
    JButton button = new JButton(title);
    c.add(button);
    button.addActionListener(listener);
}

//Adds a bouncing ball to the canvas and starts a thread to make it bounce
public void addBall()
{
    Ball b = new Ball();
    comp.add(b);
    Runnable r = new BallRunnable(b, comp);
    Thread t = new Thread(r);
    t.start();
}

 public void removeBall()
{
    //Ball.remove(Ball.size() - 1);    
}

 public void changeColor()
 {  
   if (g2.getColor() = Color.RED){
            .g2.setColor(Color.GREEN);
        }
        else{
            g2.setColor(Color.RED);
        }

        this.repaint();
 }

 public void startBall()
{
    Thread r = new Thread();
    r.start();
    synchronized(r) {
        r.notify(); 
    }
}

public void pauseBall() {
   synchronized (this) {
    try {
    wait(); 
    } catch (InterruptedException e) {
    }
    }
}

private BallComponent comp;
public static final int DEFAULT_WIDTH = 650;
public static final int DEFAULT_HEIGHT = 450;
public static final int STEPS = 1000;
public static final int DELAY = 3;
} 

类球

import java.awt.geom.*;

class Ball {


//Moves the ball to the next position, 
//reversing direction if it hits one of the edges
 public void move(Rectangle2D bounds)
   {
       x += dx;
       y += dy;
       if (x < bounds.getMinX())
       {
           x = bounds.getMinX();
           dx = -dx;
       }
       if (x + XSIZE >= bounds.getMaxX())
       {
           x = bounds.getMaxX() - XSIZE;
           dx = -dx;
       }
       if (y < bounds.getMinY())
       {
           y = bounds.getMinY();
           dy = -dy;
       }
       if (y + YSIZE >= bounds.getMaxY())
       {
           y = bounds.getMaxY() - YSIZE;
           dy = -dy;
       }
   }

//Gets the shape of the ball at its current position.
public Ellipse2D getShape()
{
return new Ellipse2D.Double(x,y, XSIZE, YSIZE);
}

private static final int XSIZE = 15;
private static final int YSIZE = 15;
private double x = 0;
private double y = 0;
private double dx = 1;
private double dy = 1;
}

BallComponent 类

import java.awt.*;
import java.util.*;
import javax.swing.*;
/**
 *
 * @author Fahmi
 */
//The component that draws the balls.
class BallComponent extends JPanel {

//Add a ball to the component
public void add(Ball b)
{
   balls.add(b); 
}

public void paintComponent(Graphics g)
{
    super.paintComponent(g); //erase back
    Graphics2D g2 = (Graphics2D) g;
    for (Ball b : balls)
    {
        g2.setColor(Color.RED);
        g2.fill(b.getShape());
    }
}
private ArrayList<Ball> balls = new ArrayList<Ball>();
}

我在 1 个包中创建了 3 个文件:BounceTugas、Ball 和 BallComponent。我希望任何人都可以解决这个问题

Answer 1

我修改了你的类(class)。

这里是空方法的实现。

• 更改球大小 (BounceTugas.java)

  public void changeBallSize(){
      if(Ball.getXSIZE()==15){
          Ball.setXSIZE(45);
      }else{
          Ball.setXSIZE(15);
      }
      if(Ball.getYSIZE()==15){
          Ball.setYSIZE(45);
      }else{
          Ball.setYSIZE(15);
      }
  
      Ball.setCircle(!Ball.isCircle());
  
      comp.repaint();
  }
  

• 改变球类型(BouceTugas.java)

  public void changeBallType(){
      Ball.setCircle(!Ball.isCircle());
  
      comp.repaint();
  }
  

• 移除球 (BounceTugas.java)

  public void removeBall() {
      if(comp.getBalls().size()>0){
          comp.getBalls().remove(0);
      }
      comp.repaint();
  }
  

• 更改球颜色(BounceTugas.java)

  public void changeColor() {
  
      if (comp.getColor() == Color.RED) {
          comp.setColor(Color.GREEN);
      } else {
          comp.setColor(Color.RED);
      }
  
      comp.repaint();
  }
  

• BallComponent.java

  public void paintComponent(Graphics g) {
      super.paintComponent(g); // erase back
      Graphics2D g2 = (Graphics2D) g;
      for (Ball b : balls) {
          g2.setColor(color);
          g2.fill(b.getShape());
      }
  }
  
  private ArrayList<Ball> balls = new ArrayList<Ball>();
  
  private Color color = Color.RED;
  
  public Color getColor() {
      return color;
  }
  
  public void setColor(Color color) {
      this.color = color;
  }
  
  public ArrayList<Ball> getBalls() {
      return balls;
  }
  

• Ball.java

  public Shape getShape() {
      if(circle){
          return new Ellipse2D.Double(x, y, XSIZE, YSIZE);
      }else{
          return new Rectangle((int)x,(int)y,XSIZE,YSIZE);
      }
  }
  
  private static boolean circle=true;
  private static int XSIZE = 15;
  private static int YSIZE = 15;
  
  public static int getXsize() {
      return XSIZE;
  }
  
  public static int getYsize() {
      return YSIZE;
  }
  
  public static int getXSIZE() {
      return XSIZE;
  }
  
  public static void setXSIZE(int xSIZE) {
      XSIZE = xSIZE;
  }
  
  public static int getYSIZE() {
      return YSIZE;
  }
  
  public static void setYSIZE(int ySIZE) {
      YSIZE = ySIZE;
  }
  
  public static boolean isCircle() {
      return circle;
  }
  
  public static void setCircle(boolean circle) {
      Ball.circle = circle;
  }