我正在尝试为我的Java课程制作一个Breakout游戏程序，其中包括一系列彩色块（Bricks）。我已经成功完成了这项工作，但现在我的导师希望我们添加不同的Bricks子类。他想要的一个子类是ColorBrick，它继承了Brick超类的所有行为，除了它有一个颜色数组，每5个刻度都会改变一次。构造函数采用颜色数组而不是单个颜色。
这就是我的Brick超类：
package Breakout;
import java.awt.Color;
import java.awt.Graphics;
public class Brick {
public int x, y, i, j;
public Color c;
Brick[][] brick;
public Brick() {
}
public Brick(Color c, Brick[][] brick, int i, int j) {
this.c = c;
this.brick = brick;
this.x = i * 40;
this.y = j * 10 + 50;
this.i = i;
this.j = j;
}
public void tick() {
}
public void paint(Graphics g) {
g.setColor(c);
g.fillRect(x, y, Breakout.brickWidth, Breakout.brickHeight);
}
public void hit(Ball b) {
if (b.yThen > y + Breakout.brickHeight) {
b.yv = -b.yv;
b.yNow = 2 * (y + Breakout.brickHeight) - b.yNow;
}
if (b.yThen < y) {
b.yv = -b.yv;
b.yNow = 2 * (y) - b.yNow;
}
if (b.xThen > x + Breakout.brickWidth) {
b.xv = -b.xv;
b.xNow = 2 * (x + Breakout.brickWidth) - b.xNow;
}
if (b.xThen < x) {
b.xv = -b.xv;
b.xNow = 2 * (x) - b.xNow;
}
brick[i][j] = null;
}
}
这是我到目前为止我的colorBrick子类：
package Breakout;
import java.awt.Color;
public class ColorBrick extends Brick {
Color colors[] = {Color.red, Color.green, Color.blue, Color.yellow};
public ColorBrick(Color[] colors, Brick[][] brick, int i, int j){
this.colors = colors;
this.brick = brick;
this.i = i;
this.j = j;
}
public void tick(){
}
}
此时我撞墙了，我不确定从这里做什么。我的导师说由于某种原因，tick方法在超类中需要为空。如果它需要是空的那么为什么他让我们把它放在那里？我也不确定应该在子类tick方法中加入什么。我是否正朝着正确的方向前进，或者我到目前为止所做的一切都完全错了？任何指导将非常感谢！
这是我的主突破代码，如果它有用：
package Breakout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Breakout extends javax.swing.JFrame {
public static final int fieldHeight = 600;
public static final int fieldWidth = 400;
public int diameter = 5;
public int xNow = 200 - (diameter / 2);
public int yNow = 300 - (diameter - 2);
public int paddleWidth = 50;
public int paddleHeight = 5;
public int platform = 580;
public static int mousex;
public int mousey;
public static int brickWidth = 40;
public static int brickHeight = 10;
public Random randoms = new Random();
Brick[][] bricks = new Brick[arrayWide][arrayHigh];
public static boolean startUp;
public static int arrayWide = 10;
public static int arrayHigh = 5;
Ball ball = new Ball(200 - (diameter / 2), 20 /*300 - (diameter /2)*/, 0, 0, diameter, Color.white);
Paddle myPaddle = new Paddle(platform, paddleWidth, paddleHeight);
/**
* Creates new form Breakout
*/
public Breakout() {
initComponents();
clock.start();
}
public class MyPanel extends JPanel {
@Override
public void paint(Graphics g) {
super.paint(g);
if (startUp) {
ball.paint(g);
}
myPaddle.paint(g);
for (int i = 0; i < arrayWide; i++) {
for (int j = 0; j < arrayHigh; j++) {
if (bricks[i][j] != null) {
bricks[i][j].paint(g);
}
}
}
// Insert code to paint the scene here.
// Use methods in the Graphics class to do the painting
// Remember coordinates use (0,0) at the top left
}
}
public Timer clock = new Timer(50, new ActionListener() { // 50ms delay between ticks
public void actionPerformed(ActionEvent e) {
tick(); // Write a method named tick to advance your game
jPanel1.repaint();
}
}); // panel is the name of the JPanel that displays the game
public void launchball() {
}
public void tick() {
ball.move();
Brick brick2 = brickAt(ball);
if (brick2 != null) {
brick2.hit(ball);
}
myPaddle.move(mousex);
myPaddle.bounce(ball);
System.out.println();
}
public Brick brickAt(Ball b) {
int j = (int) (b.yNow - 50) / 10;
int i = (int) (b.xNow / 40);
if (i < arrayWide && i >= 0 && j < arrayHigh && j >= 0) {
return (bricks[i][j]);
}
return null;
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPopupMenu1 = new javax.swing.JPopupMenu();
jPanel2 = new javax.swing.JPanel();
jPanel1 = new MyPanel();
jLabel1 = new javax.swing.JLabel();
start = new javax.swing.JButton();
org.jdesktop.layout.GroupLayout jPanel2Layout = new org.jdesktop.layout.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 100, Short.MAX_VALUE)
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 100, Short.MAX_VALUE)
);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBackground(new java.awt.Color(0, 0, 0));
jPanel1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
public void mouseMoved(java.awt.event.MouseEvent evt) {
mouseMove(evt);
}
});
org.jdesktop.layout.GroupLayout jPanel1Layout = new org.jdesktop.layout.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 400, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 600, Short.MAX_VALUE)
);
jLabel1.setFont(new java.awt.Font("Hobo Std", 1, 24)); // NOI18N
jLabel1.setForeground(new java.awt.Color(153, 51, 255));
jLabel1.setText("Breakout");
start.setFont(new java.awt.Font("Hobo Std", 0, 13)); // NOI18N
start.setForeground(new java.awt.Color(255, 51, 0));
start.setText("Start");
start.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
startActionPerformed(evt);
}
});
org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.add(164, 164, 164)
.add(jLabel1))
.add(layout.createSequentialGroup()
.add(15, 15, 15)
.add(jPanel1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
.add(layout.createSequentialGroup()
.add(175, 175, 175)
.add(start)))
.addContainerGap(17, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.add(16, 16, 16)
.add(jLabel1)
.addPreferredGap(org.jdesktop.layout.LayoutStyle.UNRELATED)
.add(jPanel1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(org.jdesktop.layout.LayoutStyle.UNRELATED)
.add(start)
.addContainerGap(10, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void mouseMove(java.awt.event.MouseEvent evt) {
mousex = evt.getX();
mousey = evt.getY();
}
private void startActionPerformed(java.awt.event.ActionEvent evt) {
startUp = true;
ball.xNow = 200 - (diameter / 2);
ball.yNow = 300 - (diameter - 2);
ball.xv = 0;
ball.yv = 8;
for (int i = 0; i < arrayWide; i++) {
for (int j = 0; j < arrayHigh; j++) {
if ((j % 2 == 0 && i % 2 == 0) || (j % 2 == 1 && i % 2 == 1)) {
bricks[i][j] = new Brick(Color.magenta, bricks, i, j);
} else {
bricks[i][j] = new Brick(Color.gray, bricks, i, j);
}
}
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Breakout.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Breakout.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Breakout.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Breakout.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Breakout().setVisible(true);
}
});
}
答案 0 :(得分：0)
因为这听起来像homework.classwork，所以我不打算详细介绍。
据推测，某事（TBD）会每隔5秒（或定期）调用tick（）。正常Brick什么都不做。您的ColorBrick应每5秒换一次颜色。不知何故，它需要知道它的当前颜色并改变到下一个颜色。
答案 1 :(得分：0)
tick中需要一个空的Brick方法，以便另一个类只需要处理砖块;调用tick的班级不需要知道它是Brick还是ColorBrick。 tick的行为由运行时类指定;这是多态性 - 相关类对同一方法调用做出不同反应的能力。
子类tick方法需要跟踪已生成的滴答数。如果需要，它将更改颜色变量c。
我可能会在您的ColorBrick构造函数中进行一项额外更改：利用super调用超类构造函数，以免复制代码。
此外，声明您的实例变量（c，x，y等等。）protected，以便只有类本身和子类可以直接访问它们。
答案 2 :(得分：0)
tick方法需要存在于超类中，因为我猜测的意图是对于每个存在的Brick，将调用tick（）（可能在主Breakout类中，可能在循环中）。超类中的tick（）方法指定了“默认”行为，它不执行任何操作。对于ColorBrick类，当调用tick时，颜色需要每五个刻度更改一次，因此您需要在子类（ColorBrick）中指定此特殊行为。
要做到这一点，ColorBrick需要一种方法来保持tick（）被调用的次数。一旦你添加了一些可以做到这一点的代码，你就可以考虑在某些刻度上改变ColorBrick的颜色：你的ColorBrick已经“知道”它当前的颜色，因为它从Brick扩展，它具有Color属性（ c），所以这是在某些刻度上改变该值的情况。
我故意模糊不清，因为我不想为你完成任务，但请随时提出任何问题。
答案 3 :(得分：0)
您需要在tick中实施ColorBrick方法，如下所示：
private int i = 0;
public void tick(){
c = colors[i++ % colors.length];
}
现在，在制作图形应用程序时，您只需使用Brick类创建ColorBricks。例如，添加多个砖块来制作墙壁：
Brick[][] wall = new Brick[5][5];
上面数组中的部分Brick可能是ColorBrick。这允许为每个tick()对象具有通用接口，即Brick方法。但对于ColorBrick，此方法实际上会更改Brick的颜色 - 就像在其他Brick中一样，它什么都不做！
您可以执行更多DancingBrick之类的内容，这些内容会在每tick后更改大小。您的图形实现不需要进行大幅度更改，以便添加不同类型的Brick，因为它使用基本类型为Brick。