菜鸟求助，马士兵贪吃蛇代码问题
在看马士兵的贪吃蛇视频，跟着视频写了一部分代码，目前可以实现只有一节的蛇移动起来，应该是可以改变方向的，但我的却只会沿着初始化的方向一直走，按方向键没反应，大神们看看问题出在哪
//Yard.java
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Yard extends Frame {
public static final int ROWS = 50;
public static final int COLS = 50;
public static final int BLOCK_SIZE = 10;
private boolean gameOver = false;
Snake s = new Snake();
Image offScreenImage = null;
public void lauch() {
this.setLocation(300, 300);
this.setSize(COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent arg0) {
System.exit(0);
}
});
this.setVisible(true);
new Thread(new PaintThread()).start();
}
public static void main(String[] args) {
new Yard().lauch();
}
public void paint(Graphics g) {
Color c = g.getColor();
g.setColor(Color.GRAY);
g.fillRect(0, 0, COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);
g.setColor(Color.DARK_GRAY);
for(int i=1; i<ROWS; i++) {
g.drawLine(0, BLOCK_SIZE * i, COLS * BLOCK_SIZE, BLOCK_SIZE * i);
}
for(int i=1; i<COLS; i++) {
g.drawLine(BLOCK_SIZE * i, 0, BLOCK_SIZE * i, BLOCK_SIZE * ROWS);
}
g.setColor(c);
s.draw(g);
}
public void update(Graphics g) {
if(offScreenImage == null) {
offScreenImage = this.createImage(COLS * BLOCK_SIZE, ROWS * BLOCK_SIZE);
}
Graphics gOff = offScreenImage.getGraphics();
paint(gOff);
g.drawImage(offScreenImage, 0, 0, null);
}
private class PaintThread implements Runnable{
public void run() {
while(true) {
repaint();
try {
Thread.sleep(50);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
private class KeyMonitor extends KeyAdapter{
public void keyPressed(KeyEvent e) {
s.keyPressed(e);
}
}
}
//Snake.java
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
public class Snake {
Node head = null;
Node tail = null;
int size = 0;
Node n = new Node(20, 30, Dir.L);
public Snake() {
head = n;
tail = n;
size = 1;
}
public class Node {
int w = Yard.BLOCK_SIZE;
int h = Yard.BLOCK_SIZE;
int row, col;
Dir dir = Dir.L;
Node next = null;
Node prev = null;
Node(int row, int col, Dir dir) {
this.row = row;
this.col = col;
this.dir = dir;
}
public void draw(Graphics g) {
Color c = g.getColor();
g.setColor(Color.BLACK);
g.fillRect(Yard.BLOCK_SIZE * col, Yard.BLOCK_SIZE * row, w, h);
g.setColor(c);
}
}
public void addToTail() {
Node node = null;
switch(tail.dir) {
case L:
node = new Node(tail.row, tail.col + 1, tail.dir);
break;
case U:
node = new Node(tail.row + 1, tail.col, tail.dir);
break;
case R:
node = new Node(tail.row, tail.col - 1, tail.dir);
break;
case D:
node = new Node(tail.row - 1, tail.col, tail.dir);
break;
}
tail.next = node;
node.prev = tail;
tail = node;
size++;
}
public void addToHead() {
Node node = null;
switch(head.dir) {
case L:
node = new Node(head.row, head.col - 1, head.dir);
break;
case U:
node = new Node(head.row - 1, head.col, head.dir);
break;
case R:
node = new Node(head.row, head.col + 1, head.dir);
break;
case D:
node = new Node(head.row + 1, head.col, head.dir);
break;
}
node.next = head;
head.prev = node;
head = node;
size++;
}
public void draw(Graphics g) {
if (size <= 0) return;
move();
for(Node n = head; n != null; n = n.next) {
n.draw(g);
}
}
private void move() {
addToHead();
deleteFromTail();
}
private void deleteFromTail() {
if(size ==0) return;
tail = tail.prev;
tail.next = null;
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
switch(key) {
case KeyEvent.VK_LEFT:
head.dir = Dir.L;
break;
case KeyEvent.VK_UP:
head.dir = Dir.U;
break;
case KeyEvent.VK_RIGHT:
head.dir = Dir.R;
break;
case KeyEvent.VK_DOWN:
head.dir = Dir.D;
break;
}
}
}
//Dir.java
public enum Dir {
L, U, R, D
}
[最优解释]
没监听键盘事件，
在lauch()里面加一行：
addKeyListener(new KeyMonitor());
[其他解释]
你的程序里面没有键盘监听。
而且仅仅加了键盘监听还是不管用的。。
你还得添加一个焦点，把焦点置为键盘监听。
借用楼上的代码
frame.addKeyListener(new KeyMonitor())//后面的你自己写把
另外焦点程序也是必须的。。
[其他解释]
哈哈 ，马士兵的声音很有磁性。。。。
[其他解释]
键盘没反应就是没有监听到，前几天我写马士兵的视频时候也碰到这问题，楼主握手握手！！！最近这阶段都在学java，感觉生活很充实！
[其他解释]
马士兵的视频我看过很好啊。你自己好好看看是否少写了一些类似于按钮监听等事件啊，还有你调试一下一步一步的跟着代码走，总能发现问题的，调试程序也是一种衡量程序员的标准之一。
[其他解释]
键盘没反应就是没有监听到，前几天我写马士兵的视频时候也碰到这问题，楼主握手握手！！！最近这阶段都在学java，感觉生活很充实！
楼上说的对
[其他解释]
没监听到的原因就是因为你没有把你的那个frame或者jpanel设置为焦点。
[其他解释]
我也在看马士兵的，正在学习中
[其他解释]
解决了，谢谢啊