对于编程类，我必须在java中重新创建游戏Space Invaders。我已经走得很远，实际上差不多已经完成，但是当我的外星人中队降级时会出现问题。有趣的是它发生在我的外星人2D阵列的前两列。当中队作为一组下降时，第一次整个顶行向右移动，第二行的第一个外星人向左移动。在随后的所有跌落中，只有第二排的第一个外星人继续向左移动越来越远。最初我编写代码，以便每个外星人的x和y位置先改变，然后我调用重绘方法。认为这是问题我删除了双循环之外的y位置的变化。所以现在每个外星人的x位置都会发生变化，屏幕会被重新绘制，因此会向左或向右移动。然后，如果drop ready boolean（在for循环中为double）设置为true，则每个外星人的y位置向下移动，屏幕再次重新绘制。因此，对每种类型的更改都有一个单独的repaint（）调用。尽管如此，这对我来说并没有帮助。我的Alien类和Squadron类的代码如下所示。有谁知道为什么会这样？
异形课程：
public class Alien extends Invader{
private int alienType;//denotes the type of alien
private GamePanel gamePanel;
private Rectangle rectangle;//used to set bounds of each alien for collision
public Alien(int xLoc, int yLoc, GamePanel gp){
this();
gamePanel=gp;
rectangle = new Rectangle();
alienType=0;
}
public Alien(){
alienType = 0;
rectangle = new Rectangle();
//inherited properties
this.setSpeed(10);//number of pixels aliens move
this.setHeight(20);
this.setWidth(20);
this.setVisible(true);
this.setColor(Color.white);
this.setDirection(Direction.East);//initial direction
}
//moves the alien left
public void moveLeft(){
getLocation().x += getSpeed();
}
//moves the alien right
public void moveRight(){
getLocation().x -= getSpeed();
}
//moves the alien downward
public void moveDown(){
getLocation().y += 2*getSpeed();
//resets their direction
if(getDirection()==Direction.East)
setDirection(Direction.West);
else
setDirection(Direction.East);
}
//draws the different type of aliens
@Override
public void draw(Graphics g){
getRectangle().setBounds(getLocation().x, getLocation().y, getWidth(), getHeight());//setting bounds of rectangle to dimensions of alien
//determines visiblity of aliens
if(isVisible()){
g.setColor(getColor());
switch(getAlienType()){
case 1:
//type 1 alien is a circle with two smaller circles under it
g.fillOval(getLocation().x, getLocation().y, getWidth(), getHeight());
g.fillOval(getLocation().x, getLocation().y+getHeight(), getWidth()/2, getHeight()/2);
g.fillOval(getLocation().x + (getWidth()-getWidth()/2), getLocation().y+getHeight(), getWidth()/2, getHeight()/2);
break;
case 2:
//type 2 alien is a square with two oval on the bottom
g.fillRect(getLocation().x, getLocation().y, getWidth(), getHeight());
g.fillOval(getLocation().x, getLocation().y+getHeight(), getWidth(), getHeight()/4);
g.fillOval(getLocation().x+(getWidth()/2), getLocation().y+getHeight()+(getHeight()/4), getWidth()/2, getHeight()/4);
break;
case 3:
//type 3 alien is a triangle with a circle on top
Polygon triangle = new Polygon();
triangle.addPoint(getLocation().x+(getWidth()/2), getLocation().y+5);
triangle.addPoint(getLocation().x,getLocation().y+getHeight());
triangle.addPoint(getLocation().x+getWidth(), getLocation().y+getHeight());
g.fillPolygon(triangle);
g.drawOval(getLocation().x +(getWidth()/2), getLocation().y-5, getWidth()/2, getHeight()/2);
}
}
}
//mutator and accessor methods
}
中队班：
public class Squadron implements ActionListener{
private Alien[][] aliens = new Alien[5][12];//2D array of invading aliens
private Timer moveTimer;//controls movement of squadron
private int numVisible;//current number of aliens that have not been destroyed
private int moveCount;//denotes the number of squad moves
private GamePanel gamePanel;
private boolean dropReady;//determines if squadron is ready to drop
public Squadron(GamePanel gp){
dropReady = false;
moveCount=0;
//initializes all aliens
for(int i=0; i<aliens.length; i++){
for(int j=0; j<aliens[i].length; j++){
aliens[i][j] = new Alien(0, 0, gp);
//sets location based on position in the array
aliens[i][j].getLocation().x = (j*2) * (aliens[i][j].getWidth() + aliens[i][j].getWidth()/2);
aliens[i][j].getLocation().y = (i*2) * ((aliens[i][j].getHeight() + aliens[i][j].getHeight()/2));
aliens[i][j].getLocation().y+= gp.getHeight()/6;//shifts aliens downward away from spaceship
//sets the type of alien based in row position
if(i==0){
aliens[i][j].setAlienType(1);
aliens[i][j].setPointValue(40);
}
else if(i>0 && i<3){
aliens[i][j].setAlienType(2);
aliens[i][j].setPointValue(20);
}
else if(i>=3){
aliens[i][j].setAlienType(3);
aliens[i][j].setPointValue(10);
}
}
}
moveTimer = new Timer(1000,this);
numVisible = 60;//set to initial number of aliens
gamePanel = gp;
moveTimer.start();
}
public void actionPerformed(ActionEvent e){
if(gamePanel.isEnabled()){
loop: for(int i=0; i<getAliens().length; i++){
for(int j =0; j<getAliens()[i].length; j++){
//alien lateral and vertical movements are based on if any aliens in a given row/column are visible
//moves aliens to the east
if(getAliens()[i][j].getDirection() == Direction.East && !dropReady && aliens[i][j].isVisible()){
getAliens()[i][j].moveLeft();
}
//moves alien to the west
else if(getAliens()[i][j].getDirection() == Direction.West && !dropReady && aliens[i][j].isVisible()){
getAliens()[i][j].moveRight();
}
//moves alien down
if(getAliens()[i][j].getLocation().x>= getGamePanel().getWidth()-aliens[i][j].getWidth() || getAliens()[i][j].getLocation().x<0){
dropReady=true;
}
//stops when alien reaches the bottom
if(getAliens()[i][j].getLocation().y+getAliens()[i][j].getHeight() >= getGamePanel().getHeight()-gamePanel.getLaserCanon().getHeight()){
getMoveTimer().stop();
gamePanel.gameOver();
}
}
}
moveCount++;
getGamePanel().repaint();
if(dropReady){
drop();
gamePanel.repaint();
}
//increases speed every 4 lateral moves
if(moveCount%4==0){
faster();
}
}
}
//reduces delay time in order to increase speed
public void faster(){
int delay = moveTimer.getDelay();
delay -=25;
if(delay>0)
moveTimer.setDelay(delay);
}
//calls move down method for each alien and resets dropReady flag
public void drop(){
for(int i=0; i<aliens.length; i++){
for(int j=0; j<aliens[i].length; j++){
aliens[i][j].moveDown();
}
}
dropReady=false;
}
//used when reset button is pressed. Sets aliens their initial position and redraws all aliens
public void resetPos(){
for(int i=0; i<aliens.length; i++){
for(int j=0;j<aliens[i].length; j++){
aliens[i][j].getLocation().x = (j*2) * (aliens[i][j].getWidth() + aliens[i][j].getWidth()/2);
aliens[i][j].getLocation().y = (i*2) * ((aliens[i][j].getHeight() + aliens[i][j].getHeight()/2));
aliens[i][j].getLocation().y+= gamePanel.getHeight()/6;
aliens[i][j].setVisible(true);
}
}
gamePanel.repaint();
}
//mutator and accessor methods
}
我意识到另一个与我相似的question已经被问到了，但是在阅读它时我觉得我已经实施了他们的建议无济于事，所以其他东西必然会导致问题。任何帮助表示赞赏