Image object is not moving(Spaceship Game) - Java Swing
Image object is not moving(Spaceship Game) - Java Swing
所以我得到了继承自 JPanel 的 class 和实例化 Image 对象并使其水平移动的 Thread。问题是 Image 只是使用 Graphics class 和 drawImage() 方法绘制的，但保持静止不动。
MyJPanel.java
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MyJPanel extends JPanel implements ActionListener,Runnable
{
private static final long serialVersionUID = 1L;
private Timer timer;
private Image backgroundImage;
private Image player;
private int playerX, playerY;
private int projectileX,projectileY;
private Image projectileImage;
private ArrayList<Image> projectiles = new ArrayList<Image>();
boolean flag = false;
public MyJPanel(Image backgroundImage, Image player,Image projectileImage)
{
this.backgroundImage = backgroundImage;
this.player = player;
this.projectileImage = projectileImage;
this.setLayout(null);
timer = new Timer(50, this);
timer.start();
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
}
repaint();
}
});
// Mouse listener
this.addMouseMotionListener(new MouseMotionListener()
{
@Override
public void mouseMoved(MouseEvent e)
{
playerX = e.getX();
playerY = e.getY();
}
@Override
public void mouseDragged(MouseEvent e)
{
}
});
hideMouseCursor();
this.setFocusable(true);
this.setVisible(true);
} // End of JPanel constructor
public void paintComponent(Graphics graphics)
{
super.paintComponent(graphics);
graphics.drawImage(backgroundImage,0,0,this.getWidth(),this.getHeight(),null); // Draw the background
graphics.drawImage(player,playerX,playerY,null); // Draw the player
graphics.drawImage(projectileImage,projectileX,projectileY,null);
}
public void moveProjectile()
{
while (projectileX < this.getWidth())
{
this.projectileX += 2;
}
}
public void hideMouseCursor() // Hides the mouse cursor
{
//Transparent 16 x 16 pixel cursor image.
BufferedImage cursorbackgroundImgage = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB);
// Create a new blank cursor.
Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
cursorbackgroundImgage, new Point(0, 0), "Blank Cursor");
// Set the blank cursor to the JPanel.
this.setCursor(blankCursor);
}
@Override
public void actionPerformed(ActionEvent actionEvent) // Without the method and the repaint() the mouse listener will not work
{
repaint();
}
public class ProjectileThread extends Thread
{
Graphics graphics;
public ProjectileThread(int playerX,int playerY)
{
projectileX = playerX + player.getWidth(null);
projectileY = playerY + player.getHeight(null) / 2;
}
@Override
public void run()
{
graphics.drawImage(projectileImage,projectileX,projectileY,null);
while (projectileX < getWidth())
{
projectileX += 2;
}
try
{
Thread.sleep(500);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
public static void main(String[] args)
{
JFrame frame = new JFrame("A Game by me");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH); // Making the frame take a full screen
ImageIcon backgroundImageIcon = new ImageIcon("space_background_2.jpg");
Image backgroundImgage = backgroundImageIcon.getImage();
ImageIcon playerImageIcon = new ImageIcon("spaceship_1.png");
Image playerImage = playerImageIcon.getImage();
ImageIcon projectileIcon = new ImageIcon("spaceship_projectile_1.png");
Image projectileImage = projectileIcon.getImage();
frame.add(new MyJPanel(backgroundImgage,playerImage,projectileImage));
frame.setVisible(true);
}
@Override
public void run()
{
}
} // End of MyJPanel
有一些我不使用的变量和对象，请不要介意。
CS:
话题：
public class ProjectileThread extends Thread
{
Graphics graphics;
public ProjectileThread(int playerX,int playerY)
{
projectileX = playerX + player.getWidth(null);
projectileY = playerY + player.getHeight(null) / 2;
}
@Override
public void run()
{
graphics.drawImage(projectileImage,projectileX,projectileY,null);
while (projectileX < getWidth())
{
projectileX += 2;
}
try
{
Thread.sleep(500);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
每次 space 栏点击启动线程：
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
}
repaint();
}
});
我一直很安静地解决这个问题，如果我清楚地说 this.projectileX += 2;?
，我似乎不记得为什么它没有移动
如有任何建议，我们将不胜感激。谢谢。
答案：
简单地说，我需要创建一个线程并将其添加到 threds（射弹）列表中，每次按下 space 栏时我都想要 x，y 值。然后在 paintComponent() 方法中，我在线程列表上使用 foreach 循环移动并绘制它们。此外，我在移动射弹的 while 循环中添加了 Thread.sleep(10)，因此它不会移动得太快。
public class MyJPanel extends JPanel implements ActionListener
{
private static final long serialVersionUID = 1L;
private Timer timer;
private Image backgroundImage;
private Image player;
private int playerX, playerY;
private int projectileX,projectileY;
private Image projectileImage;
private ArrayList<ProjectileThread> projectiles = new ArrayList<ProjectileThread>();
static boolean gameLoop = true;
public MyJPanel(Image backgroundImage, Image player,Image projectileImage)
{
this.backgroundImage = backgroundImage;
this.player = player;
this.projectileImage = projectileImage;
this.setLayout(null);
timer = new Timer(50, this);
timer.start();
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
projectiles.add(projectileThread);
repaint();
}
}
});
// Mouse listener
this.addMouseMotionListener(new MouseMotionListener()
{
@Override
public void mouseMoved(MouseEvent e)
{
playerX = e.getX();
playerY = e.getY();
}
@Override
public void mouseDragged(MouseEvent e)
{
}
});
hideMouseCursor();
this.setFocusable(true);
this.setVisible(true);
} // End of JPanel constructor
public int getX()
{
return this.projectileX;
}
public int getY()
{
return this.projectileX;
}
public void paintComponent(Graphics graphics)
{
super.paintComponent(graphics);
graphics.drawImage(backgroundImage,0,0,this.getWidth(),this.getHeight(),null); // Draw the background
graphics.drawImage(player,playerX,playerY,null); // Draw the player
for (ProjectileThread projectileThread : projectiles)
{
graphics.drawImage(projectileImage,projectileThread.getX(),projectileThread.getY(),null);
}
}
public void hideMouseCursor() // Hides the mouse cursor
{
//Transparent 16 x 16 pixel cursor image.
BufferedImage cursorbackgroundImgage = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB);
// Create a new blank cursor.
Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
cursorbackgroundImgage, new Point(0, 0), "Blank Cursor");
// Set the blank cursor to the JPanel.
this.setCursor(blankCursor);
}
@Override
public void actionPerformed(ActionEvent actionEvent) // Without the method and the repaint() the mouse listener will not work
{
repaint();
}
public class ProjectileThread extends Thread
{
private int projectileX;
private int projectileY;
public ProjectileThread(int playerX,int playerY)
{
this.projectileX = playerX + player.getWidth(null);
this.projectileY = playerY + player.getHeight(null) / 2 - 28;
}
@Override
public void run()
{
try
{
while (projectileX < backgroundImage.getWidth(null) - projectileImage.getWidth(null))
{
projectileX += 2;
Thread.sleep(10);
repaint(); // Goes to paintComponent() method
}
projectiles.remove(this); // Remove the thread from the list
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public int getX()
{
return this.projectileX;
}
public int getY()
{
return this.projectileY;
}
}
public static void main(String[] args)
{
JFrame frame = new JFrame("A Game by me");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH); // Making the frame take a full screen
ImageIcon backgroundImageIcon = new ImageIcon("space_background_2.jpg");
Image backgroundImgage = backgroundImageIcon.getImage();
ImageIcon playerImageIcon = new ImageIcon("spaceship_1.png");
Image playerImage = playerImageIcon.getImage();
ImageIcon projectileIcon = new ImageIcon("spaceship_projectile_1.png");
Image projectileImage = projectileIcon.getImage();
frame.add(new MyJPanel(backgroundImgage,playerImage,projectileImage));
frame.setVisible(true);
while (gameLoop)
{
}
}
} // End of MyJPanel
所以我得到了继承自 JPanel 的 class 和实例化 Image 对象并使其水平移动的 Thread。问题是 Image 只是使用 Graphics class 和 drawImage() 方法绘制的，但保持静止不动。
MyJPanel.java
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MyJPanel extends JPanel implements ActionListener,Runnable
{
private static final long serialVersionUID = 1L;
private Timer timer;
private Image backgroundImage;
private Image player;
private int playerX, playerY;
private int projectileX,projectileY;
private Image projectileImage;
private ArrayList<Image> projectiles = new ArrayList<Image>();
boolean flag = false;
public MyJPanel(Image backgroundImage, Image player,Image projectileImage)
{
this.backgroundImage = backgroundImage;
this.player = player;
this.projectileImage = projectileImage;
this.setLayout(null);
timer = new Timer(50, this);
timer.start();
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
}
repaint();
}
});
// Mouse listener
this.addMouseMotionListener(new MouseMotionListener()
{
@Override
public void mouseMoved(MouseEvent e)
{
playerX = e.getX();
playerY = e.getY();
}
@Override
public void mouseDragged(MouseEvent e)
{
}
});
hideMouseCursor();
this.setFocusable(true);
this.setVisible(true);
} // End of JPanel constructor
public void paintComponent(Graphics graphics)
{
super.paintComponent(graphics);
graphics.drawImage(backgroundImage,0,0,this.getWidth(),this.getHeight(),null); // Draw the background
graphics.drawImage(player,playerX,playerY,null); // Draw the player
graphics.drawImage(projectileImage,projectileX,projectileY,null);
}
public void moveProjectile()
{
while (projectileX < this.getWidth())
{
this.projectileX += 2;
}
}
public void hideMouseCursor() // Hides the mouse cursor
{
//Transparent 16 x 16 pixel cursor image.
BufferedImage cursorbackgroundImgage = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB);
// Create a new blank cursor.
Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
cursorbackgroundImgage, new Point(0, 0), "Blank Cursor");
// Set the blank cursor to the JPanel.
this.setCursor(blankCursor);
}
@Override
public void actionPerformed(ActionEvent actionEvent) // Without the method and the repaint() the mouse listener will not work
{
repaint();
}
public class ProjectileThread extends Thread
{
Graphics graphics;
public ProjectileThread(int playerX,int playerY)
{
projectileX = playerX + player.getWidth(null);
projectileY = playerY + player.getHeight(null) / 2;
}
@Override
public void run()
{
graphics.drawImage(projectileImage,projectileX,projectileY,null);
while (projectileX < getWidth())
{
projectileX += 2;
}
try
{
Thread.sleep(500);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
public static void main(String[] args)
{
JFrame frame = new JFrame("A Game by me");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH); // Making the frame take a full screen
ImageIcon backgroundImageIcon = new ImageIcon("space_background_2.jpg");
Image backgroundImgage = backgroundImageIcon.getImage();
ImageIcon playerImageIcon = new ImageIcon("spaceship_1.png");
Image playerImage = playerImageIcon.getImage();
ImageIcon projectileIcon = new ImageIcon("spaceship_projectile_1.png");
Image projectileImage = projectileIcon.getImage();
frame.add(new MyJPanel(backgroundImgage,playerImage,projectileImage));
frame.setVisible(true);
}
@Override
public void run()
{
}
} // End of MyJPanel
有一些我不使用的变量和对象，请不要介意。
CS:
话题：
public class ProjectileThread extends Thread
{
Graphics graphics;
public ProjectileThread(int playerX,int playerY)
{
projectileX = playerX + player.getWidth(null);
projectileY = playerY + player.getHeight(null) / 2;
}
@Override
public void run()
{
graphics.drawImage(projectileImage,projectileX,projectileY,null);
while (projectileX < getWidth())
{
projectileX += 2;
}
try
{
Thread.sleep(500);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
每次 space 栏点击启动线程：
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
}
repaint();
}
});
我一直很安静地解决这个问题，如果我清楚地说 this.projectileX += 2;?
如有任何建议，我们将不胜感激。谢谢。
答案：
简单地说，我需要创建一个线程并将其添加到 threds（射弹）列表中，每次按下 space 栏时我都想要 x，y 值。然后在 paintComponent() 方法中，我在线程列表上使用 foreach 循环移动并绘制它们。此外，我在移动射弹的 while 循环中添加了 Thread.sleep(10)，因此它不会移动得太快。
public class MyJPanel extends JPanel implements ActionListener
{
private static final long serialVersionUID = 1L;
private Timer timer;
private Image backgroundImage;
private Image player;
private int playerX, playerY;
private int projectileX,projectileY;
private Image projectileImage;
private ArrayList<ProjectileThread> projectiles = new ArrayList<ProjectileThread>();
static boolean gameLoop = true;
public MyJPanel(Image backgroundImage, Image player,Image projectileImage)
{
this.backgroundImage = backgroundImage;
this.player = player;
this.projectileImage = projectileImage;
this.setLayout(null);
timer = new Timer(50, this);
timer.start();
this.addKeyListener(new KeyAdapter() // Listens for a keyboard event
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_SPACE) // If pressing space - shoot
{
ProjectileThread projectileThread = new ProjectileThread(playerX,playerY);
projectileThread.start(); // Create a Thread and call run() method
projectiles.add(projectileThread);
repaint();
}
}
});
// Mouse listener
this.addMouseMotionListener(new MouseMotionListener()
{
@Override
public void mouseMoved(MouseEvent e)
{
playerX = e.getX();
playerY = e.getY();
}
@Override
public void mouseDragged(MouseEvent e)
{
}
});
hideMouseCursor();
this.setFocusable(true);
this.setVisible(true);
} // End of JPanel constructor
public int getX()
{
return this.projectileX;
}
public int getY()
{
return this.projectileX;
}
public void paintComponent(Graphics graphics)
{
super.paintComponent(graphics);
graphics.drawImage(backgroundImage,0,0,this.getWidth(),this.getHeight(),null); // Draw the background
graphics.drawImage(player,playerX,playerY,null); // Draw the player
for (ProjectileThread projectileThread : projectiles)
{
graphics.drawImage(projectileImage,projectileThread.getX(),projectileThread.getY(),null);
}
}
public void hideMouseCursor() // Hides the mouse cursor
{
//Transparent 16 x 16 pixel cursor image.
BufferedImage cursorbackgroundImgage = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB);
// Create a new blank cursor.
Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
cursorbackgroundImgage, new Point(0, 0), "Blank Cursor");
// Set the blank cursor to the JPanel.
this.setCursor(blankCursor);
}
@Override
public void actionPerformed(ActionEvent actionEvent) // Without the method and the repaint() the mouse listener will not work
{
repaint();
}
public class ProjectileThread extends Thread
{
private int projectileX;
private int projectileY;
public ProjectileThread(int playerX,int playerY)
{
this.projectileX = playerX + player.getWidth(null);
this.projectileY = playerY + player.getHeight(null) / 2 - 28;
}
@Override
public void run()
{
try
{
while (projectileX < backgroundImage.getWidth(null) - projectileImage.getWidth(null))
{
projectileX += 2;
Thread.sleep(10);
repaint(); // Goes to paintComponent() method
}
projectiles.remove(this); // Remove the thread from the list
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public int getX()
{
return this.projectileX;
}
public int getY()
{
return this.projectileY;
}
}
public static void main(String[] args)
{
JFrame frame = new JFrame("A Game by me");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH); // Making the frame take a full screen
ImageIcon backgroundImageIcon = new ImageIcon("space_background_2.jpg");
Image backgroundImgage = backgroundImageIcon.getImage();
ImageIcon playerImageIcon = new ImageIcon("spaceship_1.png");
Image playerImage = playerImageIcon.getImage();
ImageIcon projectileIcon = new ImageIcon("spaceship_projectile_1.png");
Image projectileImage = projectileIcon.getImage();
frame.add(new MyJPanel(backgroundImgage,playerImage,projectileImage));
frame.setVisible(true);
while (gameLoop)
{
}
}
} // End of MyJPanel