关于java继承的另一个问题：我想知道两件事： 1）如何设置我的程序在使用继承类之间切换？ 2）我不确定为什么我的扩展类glidingObject.java没有响应我的按键
这是我的Game.java（运行游戏;我应该传递一些参数，允许用户选择正确使用哪个类 - 飞行物体或滑翔物体？我也是包括我的飞行物体和滑翔物体的两个类）
public class Game extends JPanel {
private static final long serialVersionUID = 1L;
public static int WIDTH = 800, HEIGHT = 750;
public static ArrayList<Rectangle> columns;
public static Random rand;
public static double score;
public static boolean gameOver, started; //two modes, started and gameover
public static String username;
public static String currTime;
public static Timer timer;
public static flyingObject obj;
private PropertyChangeSupport mPcs = new PropertyChangeSupport(this);
public Game(flyingObject object){
obj = object;
timer = new Timer(20, new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
tick();
} catch (IOException e1) {
e1.printStackTrace();
}
}
});
columns = new ArrayList<Rectangle>();
rand = new Random();
Background bk = new Background();
addColumn(true);
addColumn(true);
addColumn(true);
addColumn(true);
addMouseListener(new MouseAdapter() {
@Override
public void mouseReleased(MouseEvent e) {
started = true;
}
});
PropertyChangeListener listener = new PropertyChangeListener() {
@Override
public void propertyChange(PropertyChangeEvent evt) {
try {
scoreBoard.record();
} catch (IOException e) {
e.printStackTrace();
}
}
};
this.addPropertyChangeListener(listener);
getDate(); //get the date of the game played
mPcs.firePropertyChange("gameOver",false, true); //alert record() method when the game is over
timer.start();
}
//adding the column
public static void addColumn(boolean start) {
int space = 300;
int width = 100;
int height = 50 + rand.nextInt(300);
if (start) {
//add top and bottom
columns.add(new Rectangle(WIDTH + width + columns.size() * 300, HEIGHT - height - 120, width, height + 100));
columns.add(new Rectangle(WIDTH + width + (columns.size() - 1) * 300, 0, width, HEIGHT - height - space));
}
else
{
columns.add(new Rectangle(columns.get(columns.size() - 1).x + 600, HEIGHT - height - 120, width, height + 100));
columns.add(new Rectangle(columns.get(columns.size() - 1).x, 0, width, HEIGHT - height - space));
}
}
//paint the columns
public void paintColumn(Graphics g, Rectangle column) {
g.setColor(Color.white);
g.fillRect(column.x, column.y, column.width, column.height);
}
public static void reset() {
obj = new glidingObject(WIDTH / 2 - 10, HEIGHT / 2 - 10);
columns.clear();
score = 0.0;
addColumn(true);
addColumn(true);
addColumn(true);
addColumn(true);
gameOver = false;
}
public void tick() throws IOException {
if (started) {
int speed = 10;
glidingObject.move();
for (int i = 0; i < columns.size(); i ++) {
Rectangle column = columns.get(i);
column.x -= speed;
if (column.x + column.width < 0) {
columns.remove(column);
if (column.y == 0) {
addColumn(false);
}
}
}
for (Rectangle column: columns) {
if (column.x == glidingObject.X) {
score += 0.5;
}
if (column.intersects(glidingObject.getBounds())) {
gameOver = true;
//when the object crashes, it does not go through the column
if (glidingObject.X <= column.x) {
glidingObject.X = column.x - glidingObject.DIAMETER;
}
else if (glidingObject.Y < column.height) {
glidingObject.Y = column.height;
}
Main.gameOver();
}
}
if (glidingObject.Y > HEIGHT || glidingObject.Y < 0) {
gameOver = true;
//timer.stop();
Main.gameOver();
}
if (glidingObject.Y + glidingObject.YMotion >= HEIGHT) {
gameOver = true;
//timer.stop();
Main.gameOver();
}
}
//update the display
repaint();
}
public void getDate() {
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
currTime = dateFormat.format(date);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Background.paint(g);
glidingObject.paint(g);
for (Rectangle column: columns) {
paintColumn(g, column);
}
g.setColor(Color.white);
g.setFont(new Font("Manaspace", 1, 60));
if (!started) {
g.drawString("Click to start!", 75, HEIGHT / 2 - 50);
}
if (gameOver) {
g.drawString("Game Over!", 200, HEIGHT / 2 - 50);
}
if (!gameOver && started) {
g.drawString(String.valueOf(score), WIDTH / 2 - 25, 100);
}
}
}
class flyingobject.java
public class flyingObject implements ActionListener, MouseListener, KeyListener {
static int DIAMETER = 25;
static int Y; // Y position of the unicorn
static int X; // X position of the unicorn
static int YMotion; // Y movement of the unicorn
//parameters are the initial positions
public flyingObject(int xpos, int ypos) {
X = xpos;
Y = ypos; // this changes
}
//getters
public int getX() {
return X;
}
public int getY() {
return Y;
}
//setters
public void setX(int newX) {
X = newX;
}
public void setY(int newY) {
Y = newY;
}
//the bounds of the object (rectangle)
public static Rectangle getBounds() {
return new Rectangle(X, Y, DIAMETER, DIAMETER);
}
//the visible component of the object - this can get overriden by subclasses
public static void paint(Graphics g){
g.setColor(Color.white);
g.fillRect(X, Y, DIAMETER, DIAMETER);
}
//the movement component of the object
public static void jump() {
if (Game.gameOver) {
Game.reset();
Game.gameOver = false;
}
if (!Game.started) {
Game.started = true;
}
else if (!Game.gameOver) {
if (YMotion > 0) {
YMotion = 0;
}
YMotion -= 14;
}
}
public static void move() {
if ((Y > 0) && (Y < Game.HEIGHT)) {
YMotion += 1.5; // gravity
Y += YMotion;
}
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
}
@Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_SPACE)
{
jump();
}
}
@Override
public void mouseClicked(MouseEvent e) {
jump();
}
@Override
public void mousePressed(MouseEvent e) {
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
}
@Override
public void mouseExited(MouseEvent e) {
}
@Override
public void actionPerformed(ActionEvent e) {
}
}
类glidingobject.java（game.java应该允许用户在使用飞行物体或扩展类滑翔物体之间进行选择）
public class glidingObject extends flyingObject{
//velocity of the object
private static int vx;
private static int vy;
private static int lives;
public glidingObject(int xpos, int ypos) {
super(xpos, ypos);
vx = 0;
vy = 0;
lives = 3;
}
//getter methods
public int getVx() {
return vx;
}
public int getVy() {
return vy;
}
//setter methods
public void setVx(int newVx) {
vx = newVx;
}
public void setVy(int newVy) {
vy = newVy;
}
//moves the object
public static void jump() {
X += vx;
Y += vy;
}
public static void paint(Graphics g) {
g.setColor(Color.CYAN);
g.fillOval(X, Y, DIAMETER, DIAMETER);
}
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT){
vx = 10;
}
if (e.getKeyCode() == KeyEvent.VK_LEFT){
vx = -10;
}
if (e.getKeyCode() == KeyEvent.VK_UP){
vy = 10;
}
if (e.getKeyCode() == KeyEvent.VK_DOWN){
vy = -10;
}
}
@Override
public void keyPressed(KeyEvent e) {
}
@Override
public void keyReleased(KeyEvent e) {
}
@Override
public void mouseClicked(MouseEvent e) {
}
@Override
public void mousePressed(MouseEvent e) {
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
}
@Override
public void mouseExited(MouseEvent e) {
}
@Override
public void actionPerformed(ActionEvent e) {
}
}
答案 0 :(得分：1)
我应该传递一些参数，允许用户选择正确使用哪个类 - 飞行物体还是滑翔物体？
这是interface变得如此强大的地方。飞行＆＃34;飞行＆＃34;和＆＃34;滑翔＆＃34;对象将共享一些共同的属性/功能，这些应该由接口描述。您Game应该只接受此interface的实例，它不应该关注实施的内容，只关注它们是否符合商定的interface。
这是＆＃34;接口代码的原则，而不是实现＆＃34;
这有多复杂取决于你，例如，你可以有抽象的实现来描述＆＃34; air＆＃34;基于实体和＆＃34;地面＆＃34;基于实体，您可以从中获得＆＃34; powered＆＃34;并且＆＃34;无动力＆＃34;抽象＆＃34; air＆＃34;的实现所有这些都将被绑定到游戏实体＆＃34; interface
我不确定为什么我的扩展类glidingObject.java没有响应我的按键
这是因为您正在使用KeyListener，因为它与焦点相关的问题而闻名。有关推荐的解决方案，请参阅How to Use Key Bindings