我用Java编写一个简单的游戏，我需要处理KeyEvents。不幸的是，我的Java知识相当低，我无法使其工作。我在这做错了什么？我还尝试实施KeyListener，同时从JPanel延伸，看看它是否有效，我甚至覆盖了addNotify()
至requestFocus()，没有。其他一切都很好。
以下是应该处理事件的类：
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JComponent;
import javax.swing.KeyStroke;
public class BasicRobot extends JComponent{
public static enum FACING{
NORTH, WEST, SOUTH, EAST
}
int xLoc, yLoc;
FACING facing;
int beepers;
public BasicRobot(int xLoc, int yLoc, FACING facing, int beepers){
this.xLoc = xLoc;
this.yLoc = yLoc;
this.facing = facing;
this.beepers = beepers;
World w = new World(this);
addKeyListener();
setFocusable(true);
requestFocusInWindow();
}
public void move(){
switch(facing){
case NORTH:
yLoc++;
break;
case WEST:
xLoc--;
break;
case SOUTH:
yLoc--;
break;
case EAST:
xLoc++;
break;
}
}
public void turnLeft(){
switch(facing){
case NORTH:
facing=FACING.WEST;
break;
case WEST:
facing=FACING.SOUTH;
break;
case SOUTH:
facing=FACING.EAST;
break;
case EAST:
facing=FACING.NORTH;
break;
}
}
void addKeyListener(){
getInputMap(WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "move");
getActionMap().put("move", new AbstractAction(){
public void actionPerformed(ActionEvent e) {
move();
}
});
}
}
这是World类（不确定它有多相关，但也许我做了一些非常愚蠢的事情，所以在这里）：
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.RenderingHints;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.border.LineBorder;
public class World extends JPanel implements Runnable{
private final int ROWS=30, COLS=30, BLOCK_SCALE=24, WALL_WIDTH=BLOCK_SCALE/3;
private final Dimension DIMS = new Dimension(COLS*BLOCK_SCALE, ROWS*BLOCK_SCALE);;
private final JFrame frame = new JFrame("World");
private final Polygon NORTH_TRIANGLE = new Polygon(new int[]{5,BLOCK_SCALE/2,BLOCK_SCALE-5}, new int[]{BLOCK_SCALE-3,2,BLOCK_SCALE-3}, 3);
private final Polygon WEST_TRIANGLE = new Polygon(new int[]{1,BLOCK_SCALE-4,BLOCK_SCALE-4}, new int[]{BLOCK_SCALE/2,5,BLOCK_SCALE-5}, 3);
private final Polygon SOUTH_TRIANGLE = new Polygon(new int[]{5,BLOCK_SCALE/2,BLOCK_SCALE-5}, new int[]{3,BLOCK_SCALE-2,3}, 3);
private final Polygon EAST_TRIANGLE = new Polygon(new int[]{4,4,BLOCK_SCALE-1}, new int[]{BLOCK_SCALE-5,5,BLOCK_SCALE/2}, 3);
private final int obsticleMap[][] = new int[COLS][ROWS];
private final Wall obsticles[] = {
new Wall(1, 1, 5, WALL_WIDTH, Wall.ALIGNMENT_HORIZONTAL),
new Wall(1, 1, 5, WALL_WIDTH, Wall.ALIGNMENT_VERTICAL),
new Wall(1, 5, 3, WALL_WIDTH, Wall.ALIGNMENT_HORIZONTAL)
}; //The Wall class is just data nothing of interest there
BasicRobot robot;
public World(BasicRobot robot){
super(null);
this.robot = robot;
initThis();
initFrame();
initObsticleMap();
}
private void initThis(){
setBackground(Color.white);
setSize(DIMS);
setLocation(1, 1);
setBorder(new LineBorder(Color.black));
Thread t = new Thread(this);
t.start();
}
private void initFrame(){
frame.setContentPane(new Container(){
private static final long serialVersionUID = 1L;
public void paint(Graphics g){
super.paint(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHints(new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON));
g2d.drawRect(0, 0, DIMS.width+1, DIMS.height+1);
g2d.drawLine(0, DIMS.height+2, DIMS.width+1, DIMS.height+2);
g2d.setFont(new Font("Serif", Font.BOLD, 18));
g2d.drawString(String.format("Loc X = %d", robot.xLoc), 20, DIMS.height+22);
g2d.drawString(String.format("Loc Y = %d", robot.yLoc), 20, DIMS.height+42);
g2d.drawString(String.format("Beepers in bag = %d", robot.beepers), 150, DIMS.height+22);
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setPreferredSize(new Dimension(DIMS.width+2,DIMS.height+50));
frame.setResizable(false);
frame.getContentPane().add(this);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void initObsticleMap(){
for(int i=0; i<obsticles.length; i++){
switch(obsticles[i].alignment){
case Wall.ALIGNMENT_HORIZONTAL:
for(int j=0; j<obsticles[i].span; j++){
obsticleMap[obsticles[i].xLoc+j][obsticles[i].yLoc] = 1;
}
break;
case Wall.ALIGNMENT_VERTICAL:
for(int j=0; j<obsticles[i].span; j++){
obsticleMap[obsticles[i].xLoc][obsticles[i].yLoc+j] = 1;
}
break;
}
}
}
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
drawGrid(g2d);
drawObsticles(g2d);
drawRobot(g2d);
}
private void drawGrid(Graphics2D g){
for(int i=0; i<COLS; i++){
for(int j=0; j<ROWS; j++){
g.drawRect(i*BLOCK_SCALE, j*BLOCK_SCALE, BLOCK_SCALE-1, BLOCK_SCALE-1);
}
}
}
private void drawObsticles(Graphics2D g2d){
for(int i=0; i<obsticles.length; i++){
switch(obsticles[i].alignment){
case Wall.ALIGNMENT_HORIZONTAL:
g2d.fillRoundRect(obsticles[i].xLoc*BLOCK_SCALE-BLOCK_SCALE/2, (ROWS-obsticles[i].yLoc)*BLOCK_SCALE-obsticles[i].width/2, BLOCK_SCALE*obsticles[i].span, obsticles[i].width, 2, 2);
break;
case Wall.ALIGNMENT_VERTICAL:
g2d.fillRoundRect(obsticles[i].xLoc*BLOCK_SCALE-obsticles[i].width/2, (ROWS-obsticles[i].yLoc-obsticles[i].span+1)*BLOCK_SCALE-BLOCK_SCALE/2, obsticles[i].width, BLOCK_SCALE*obsticles[i].span, 2, 2);
break;
}
}
}
private void drawRobot(Graphics2D g){
Polygon translated;
switch(robot.facing){
case NORTH:
translated = new Polygon(NORTH_TRIANGLE.xpoints, NORTH_TRIANGLE.ypoints, 3);
break;
case WEST:
translated = new Polygon(WEST_TRIANGLE.xpoints, WEST_TRIANGLE.ypoints, 3);
break;
case SOUTH:
translated = new Polygon(SOUTH_TRIANGLE.xpoints, SOUTH_TRIANGLE.ypoints, 3);
break;
case EAST:
translated = new Polygon(EAST_TRIANGLE.xpoints, EAST_TRIANGLE.ypoints, 3);
break;
default:
translated = new Polygon(EAST_TRIANGLE.xpoints, EAST_TRIANGLE.ypoints, 3);
}
translated.translate(robot.xLoc*BLOCK_SCALE-BLOCK_SCALE/2, (ROWS-robot.yLoc)*BLOCK_SCALE-BLOCK_SCALE/2);
g.setColor(Color.yellow);
g.fillPolygon(translated);
g.setColor(Color.black);
g.drawPolygon(translated);
}
public void run() {
for(;;){
try{
frame.repaint();
Thread.sleep(40);
}catch(Exception e){e.toString();}
}
}
}
PS：首选方法是使用Key Bindings。谢谢！
答案 0 :(得分：3)
getInputMap(WHEN_IN_FOCUSED_WINDOW)删除任何与焦点相关的问题...... addKeyListener()，以便注册密钥绑定。Thread.sleep 事实上，这看起来很可疑......
public void run() {
for(;;){
try{
frame.repaint();
Thread.sleep(40);
}catch(Exception e){e.toString();}
}
}
看到你并没有真正更新任何状态，它所做的只是吸收可以更好地利用的CPU周期......
其他...
因为你永远不会将BasicRobot添加到显示的任何内容（如窗口），所以它永远不会将它的监听器注册到事件队列中，这意味着，键绑定永远不会起作用。
不应该从BasicRobot扩展JComponent，而应该只是不从任何内容扩展它，没有获得任何好处。
相反，将密钥绑定注册到World并从那里调用BasicRobot#move
例如......对不起，我的代码可能会稍微退一步，但基本的想法是......
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class World extends JPanel implements Runnable {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
new World(new BasicRobot(0, 0, BasicRobot.FACING.SOUTH, 100));
}
});
}
private final int ROWS = 30, COLS = 30, BLOCK_SCALE = 24, WALL_WIDTH = BLOCK_SCALE / 3;
private final Dimension DIMS = new Dimension(COLS * BLOCK_SCALE, ROWS * BLOCK_SCALE);
private final JFrame frame = new JFrame("World");
private final Polygon NORTH_TRIANGLE = new Polygon(new int[]{5, BLOCK_SCALE / 2, BLOCK_SCALE - 5}, new int[]{BLOCK_SCALE - 3, 2, BLOCK_SCALE - 3}, 3);
private final Polygon WEST_TRIANGLE = new Polygon(new int[]{1, BLOCK_SCALE - 4, BLOCK_SCALE - 4}, new int[]{BLOCK_SCALE / 2, 5, BLOCK_SCALE - 5}, 3);
private final Polygon SOUTH_TRIANGLE = new Polygon(new int[]{5, BLOCK_SCALE / 2, BLOCK_SCALE - 5}, new int[]{3, BLOCK_SCALE - 2, 3}, 3);
private final Polygon EAST_TRIANGLE = new Polygon(new int[]{4, 4, BLOCK_SCALE - 1}, new int[]{BLOCK_SCALE - 5, 5, BLOCK_SCALE / 2}, 3);
private final int obsticleMap[][] = new int[COLS][ROWS];
// private final Wall obsticles[] = {
// new Wall(1, 1, 5, WALL_WIDTH, Wall.ALIGNMENT_HORIZONTAL),
// new Wall(1, 1, 5, WALL_WIDTH, Wall.ALIGNMENT_VERTICAL),
// new Wall(1, 5, 3, WALL_WIDTH, Wall.ALIGNMENT_HORIZONTAL)
// }; //The Wall class is just data nothing of interest there
BasicRobot robot;
public World(BasicRobot robot) {
super(null);
this.robot = robot;
initThis();
initFrame();
initObsticleMap();
}
private void initThis() {
setBackground(Color.white);
setSize(DIMS);
setLocation(1, 1);
setBorder(new LineBorder(Color.black));
// Thread t = new Thread(this);
// t.start();
initKeyBindings();
}
private void initFrame() {
frame.setContentPane(new Container() {
private static final long serialVersionUID = 1L;
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHints(new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON));
g2d.drawRect(0, 0, DIMS.width + 1, DIMS.height + 1);
g2d.drawLine(0, DIMS.height + 2, DIMS.width + 1, DIMS.height + 2);
g2d.setFont(new Font("Serif", Font.BOLD, 18));
g2d.drawString(String.format("Loc X = %d", robot.xLoc), 20, DIMS.height + 22);
g2d.drawString(String.format("Loc Y = %d", robot.yLoc), 20, DIMS.height + 42);
g2d.drawString(String.format("Beepers in bag = %d", robot.beepers), 150, DIMS.height + 22);
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setPreferredSize(new Dimension(DIMS.width + 2, DIMS.height + 50));
frame.setResizable(false);
frame.getContentPane().add(this);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void initObsticleMap() {
// for (int i = 0; i < obsticles.length; i++) {
// switch (obsticles[i].alignment) {
// case Wall.ALIGNMENT_HORIZONTAL:
// for (int j = 0; j < obsticles[i].span; j++) {
// obsticleMap[obsticles[i].xLoc + j][obsticles[i].yLoc] = 1;
// }
// break;
// case Wall.ALIGNMENT_VERTICAL:
// for (int j = 0; j < obsticles[i].span; j++) {
// obsticleMap[obsticles[i].xLoc][obsticles[i].yLoc + j] = 1;
// }
// break;
// }
// }
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
drawGrid(g2d);
drawObsticles(g2d);
drawRobot(g2d);
}
private void drawGrid(Graphics2D g) {
for (int i = 0; i < COLS; i++) {
for (int j = 0; j < ROWS; j++) {
g.drawRect(i * BLOCK_SCALE, j * BLOCK_SCALE, BLOCK_SCALE - 1, BLOCK_SCALE - 1);
}
}
}
private void drawObsticles(Graphics2D g2d) {
// for (int i = 0; i < obsticles.length; i++) {
// switch (obsticles[i].alignment) {
// case Wall.ALIGNMENT_HORIZONTAL:
// g2d.fillRoundRect(obsticles[i].xLoc * BLOCK_SCALE - BLOCK_SCALE / 2, (ROWS - obsticles[i].yLoc) * BLOCK_SCALE - obsticles[i].width / 2, BLOCK_SCALE * obsticles[i].span, obsticles[i].width, 2, 2);
// break;
// case Wall.ALIGNMENT_VERTICAL:
// g2d.fillRoundRect(obsticles[i].xLoc * BLOCK_SCALE - obsticles[i].width / 2, (ROWS - obsticles[i].yLoc - obsticles[i].span + 1) * BLOCK_SCALE - BLOCK_SCALE / 2, obsticles[i].width, BLOCK_SCALE * obsticles[i].span, 2, 2);
// break;
// }
// }
}
private void drawRobot(Graphics2D g) {
Polygon translated;
switch (robot.facing) {
case NORTH:
translated = new Polygon(NORTH_TRIANGLE.xpoints, NORTH_TRIANGLE.ypoints, 3);
break;
case WEST:
translated = new Polygon(WEST_TRIANGLE.xpoints, WEST_TRIANGLE.ypoints, 3);
break;
case SOUTH:
translated = new Polygon(SOUTH_TRIANGLE.xpoints, SOUTH_TRIANGLE.ypoints, 3);
break;
case EAST:
translated = new Polygon(EAST_TRIANGLE.xpoints, EAST_TRIANGLE.ypoints, 3);
break;
default:
translated = new Polygon(EAST_TRIANGLE.xpoints, EAST_TRIANGLE.ypoints, 3);
}
translated.translate(robot.xLoc * BLOCK_SCALE - BLOCK_SCALE / 2, (ROWS - robot.yLoc) * BLOCK_SCALE - BLOCK_SCALE / 2);
g.setColor(Color.yellow);
g.fillPolygon(translated);
g.setColor(Color.black);
g.drawPolygon(translated);
}
public void run() {
// for (;;) {
// try {
// frame.repaint();
// Thread.sleep(40);
// } catch (Exception e) {
// e.toString();
// }
// }
}
public void initKeyBindings() {
getInputMap(WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "move");
getActionMap().put("move", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
System.out.println("move");
robot.move();
repaint();
}
});
}
public static class BasicRobot {
public static enum FACING {
NORTH, WEST, SOUTH, EAST
}
int xLoc, yLoc;
FACING facing;
int beepers;
public BasicRobot(int xLoc, int yLoc, FACING facing, int beepers) {
this.xLoc = xLoc;
this.yLoc = yLoc;
this.facing = facing;
this.beepers = beepers;
}
public void move() {
// try {
// Thread.sleep(300);
// } catch (Exception e) {
// e.toString();
// }
switch (facing) {
case NORTH:
yLoc++;
break;
case WEST:
xLoc--;
break;
case SOUTH:
yLoc--;
break;
case EAST:
xLoc++;
break;
}
}
public void turnLeft() {
// try {
// Thread.sleep(300);
// } catch (Exception e) {
// e.toString();
// }
switch (facing) {
case NORTH:
facing = FACING.WEST;
break;
case WEST:
facing = FACING.SOUTH;
break;
case SOUTH:
facing = FACING.EAST;
break;
case EAST:
facing = FACING.NORTH;
break;
}
}
}
}
<强>更新...
这是个人的事情，但我更喜欢使用KeyEvent虚拟密钥代码......
getInputMap(WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "move");
否则我认为你可能需要使用（但我不是100％肯定）
getInputMap(WHEN_IN_FOCUSED_WINDOW).put("pressed UP, "move");