Question

我已经有很长一段时间没遇到这个问题了我试图制造一个太空射击但无济于事，我试图让子弹像太空入侵者一样在屏幕上移动当玩家按下空格键时，子弹应该出现在玩家的X位置，并在屏幕上向右移动。

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
public class game extends JFrame{

boolean run = true;
boolean fired = false;

Image player;
Image bullet;

int playerX = 100;
int playerY = 200;

int bulletX;
int bulletY;


public game(){
    //Load Images:
    ImageIcon playerI = new     ImageIcon("C:/Users/Dan/workspace/shooterProject/bin/shooterProject/ship.png");
    player = playerI.getImage();
    ImageIcon bulletI = new     ImageIcon("C:/Users/Dan/workspace/shooterProject/bin/shooterProject/bullet.png");
    bullet = bulletI.getImage();
    //Set up game

      addKeyListener(new AL());

       addMouseListener(new Mouse());

       init();

}

private Image dbImage;
private Graphics dbg;


public static void main(String[] args) {
  new game();
}


//When the program runs, thins are initialised here

public void init(){
    windowManager();
}
public void paintComponent(Graphics g){

    if(run == true){
        g.drawImage(player, playerX, playerY, this);
    }
    if(fired == true){
        g.drawImage(bullet, bulletX, bulletY, this);
    }

    repaint();

}

public void paint(Graphics g){
    dbImage = createImage(getWidth(), getHeight());
    dbg = dbImage.getGraphics();
    paintComponent(dbg);
    g.drawImage(dbImage,0,0,this);
}


public void bullet(){
    bulletX = playerX;
    bulletY = playerY;
    while(fired == true){
        bulletX = bulletX + 10;
        if(bulletX == 800){
            bullet = null;
            fired = false;
        }
    }

}


public void windowManager(){

      JFrame f = new JFrame();

      setTitle("Engine");
      setVisible(true);
      setResizable(false);
      setSize(800,400);
      setBackground(Color.BLACK);
      setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public class AL extends KeyAdapter{
    public void keyPressed(KeyEvent e){

        int keyCode = e.getKeyCode();
        if((keyCode == KeyEvent.VK_UP) && (run == true) && (playerY - 20 > 0)){
               playerY = playerY - 10;
        }else if((keyCode == KeyEvent.VK_DOWN) && (run == true) && (playerY + 20 < 400)){
            playerY = playerY + 10;
        }
        if((keyCode == KeyEvent.VK_SPACE) && (fired == false)){
            fired = true;
            if(fired == true){
                bullet();
            }
        } 
    }

    public void keyReleased(KeyEvent e){
    }
}

public class Mouse extends MouseAdapter {
public void mousePressed(MouseEvent e) {

    double x = e.getX();
    double y = e.getY();

}
}
}

无论其

当我在没有while循环的情况下运行代码时，子弹出现在玩家的X位置但当玩家按下X按钮时，while循环没有任何反应，子弹甚至不出现！

任何人都可以帮助我如何让子弹出现并在屏幕上移动？感谢

Answer 1

这是因为你没有在子弹超出范围之前吸引子弹，你不应该以这种方式使用while循环，你可能需要google for＆＃39; Game Loop＆＃39;但是直到你在这里做一个可能有帮助的狙击手，请注意非常糟糕但应该有效：

public void paintComponent(Graphics g){

    if(run == true){
        g.drawImage(player, playerX, playerY, this);

        if(fired == true) {
            bulletX = bulletX + 10;
            if(bulletX > 800 || bulletX < 0){
                fired = false;
            }

            g.drawImage(bullet, bulletX, bulletY, this);
        }

        repaint();
    }

}

public void bullet(){
    bulletX = playerX;
    bulletY = playerY;
}

最后一个注释，将这个代码在paint方法dbImage = createImage（getWidth（），getHeight（））中移动到构造函数或init（），因为你每帧都在创建一个新图像。

Java帮助：使图像在屏幕上移动

1 个答案: