[英]Java awt Why can I only remove most recent addition to Linked List
我正在為大學計算機科學項目用Java awt創建一個太空射擊游戲。
我通過計時器每3秒鍾產生一次的敵人被添加到LinkedList
,並且for loop
將它們全部渲染。
在我為玩家的子彈對象准備的課程中,有if
語句來檢查激光是否進入敵人的范圍,如果它們全部成立,它將從LinkedList
移除敵人。
但是,僅刪除了LinkedList
最新添加的內容。 子彈穿過其他子彈,什么也沒發生。 這是我第一次玩游戲,也是我第一次使用LinkedList
,因此請諒解。
控制器類控制敵人, Laser
類是子彈, Enemy
類是Enemy
。 還有一個播放器,Main和GUI類。
import java.awt.*;
import java.util.LinkedList;
import java.util.Timer;
import java.util.TimerTask;
public class Controller
{
private LinkedList<Enemy> e = new LinkedList<Enemy>();
Enemy tempEnemy, tempEnemy2
;
Main main;
int refreshSpawn = 3000; //move timer refresh rate
int xpos;
int width;
int ypos;
int height;
Timer spawnTimer = new Timer();
public Controller(Main main)
{
this.main = main;
spawn();
}
public void spawn()
{
spawnTimer.schedule(new TimerTask()
{
public void run() //run method and timer
{
addEnemy(new Enemy(main, (int)(Math.random()*4+2)));
}
}, 0, refreshSpawn);
}
public void render(Graphics g)
{
for(int i = 0; i < e.size(); i++)
{
tempEnemy = e.get(i);
xpos = tempEnemy.getX();
width = tempEnemy.getXsize();
ypos = tempEnemy.getY();
height = tempEnemy.getYsize();
tempEnemy.render(g);
}
}
public void update()
{
for(int i = 0; i < e.size(); i++)
{
tempEnemy2 = e.get(i);
tempEnemy2.move();
}
}
public void addEnemy(Enemy enemy)
{
e.add(enemy);
System.out.println(e.size());
//spawn();
}
public void removeEnemy()
{
e.remove(tempEnemy);
}
public int getX()
{
return xpos;
}
public int getY()
{
return ypos;
}
public int getXsize()
{
return width;
}
public int getYsize()
{
return height;
}
public Enemy getEnemy()
{
return tempEnemy;
}
}
import java.awt.*;
public class Enemy
{
Image ship; //image of enemy ship
int x, y; //ship position
int speed;
public Enemy(Main main, int speed) //constructing enemy
{
this.speed = speed;
ship = main.getImage(main.getDocumentBase(), "enemyShip"+(int)(Math.random()*6+1)+".png"); //picture for enemy ship
x = (int)(Math.random()*900+1); //enemy has a starting position at a random x point
y = -100; //start ship slightly off screen so it doesn't suddenly appear
}
public void move()
{
y += speed;
if(y > 600)
{
y = -100;
x = (int)(Math.random()*900);
}
}
public void render(Graphics g)
{
g.drawImage(ship, x, y, null);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public int getXsize()
{
return ship.getWidth(null);
}
public int getYsize()
{
return ship.getHeight(null);
}
}
import java.awt.*;
public class Laser
{
Image img; //image of laser
int laserSpeed = 10; //speed of laser
int x, y; //position of laser
int xSize, ySize; //size of laser
Controller cont;
GUI gui;
public Laser(Image img, int x, int y, Controller cont, GUI gui) //constructing laser
{
this.cont = cont;
this.img = img; //setting laser image
this.gui = gui;
xSize = x; //size of laser
ySize = y; //size of laser
}
public void shoot(int x, int y, int shipSize)
{
this.x = x + (shipSize/2) - (xSize/2);
this.y = y;
}
public void move()
{
y -= laserSpeed;
if(x <= cont.getX() + cont.getXsize() && x + xSize >= cont.getX() - cont.getXsize())
{
if(y <= cont.getY() + cont.getYsize() && y > 0)
{
remove();
cont.removeEnemy();
gui.scoreUp(5);
}
}
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public int getXSize()
{
return xSize;
}
public int getYSize()
{
return ySize;
}
public Image getImage()
{
return img;
}
public void remove()
{
y = -ySize;
x = -100;
}
}
據我所知, tempEnemy
由render
方法分配給LinkedList
的最后一個元素。 這意味着,當您調用removeEnemy
它將刪除最后一個渲染的對象(可能是您添加的最后一個對象)。
您應該做的就是告訴Controller
它應該使用哪個Enemy
,當您調用它時,它絕對不知道您的意圖是什么...
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