我无法创建一个正方形的动画，当按下其中一个箭头键时，该动画将以特定速度移动。我已经实现了keyPressed和actionPerformed方法，并且还在构造函数的末尾启动了计时器的滴答。但是方块仍然不会'移动..我做错了什么？
以下是JPanel。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class A3JPanel extends JPanel implements KeyListener, ActionListener{
public static final int JFRAME_AREA_WIDTH = A3Constants.JFRAME_AREA_WIDTH;
public static final int JFRAME_AREA_HEIGHT = A3Constants.JFRAME_AREA_HEIGHT;;
public static final Rectangle HOME_AREA = A3Constants.HOME_AREA;
public static final Rectangle LEO_LEFT_AREA = A3Constants.LEO_LEFT_AREA;
public static final Rectangle ALL_WALLS_AREA = A3Constants.ALL_WALLS_AREA;
public static final Rectangle EXITING_SLIDES_AREA = A3Constants.EXITING_SLIDES_AREA;
public static final Color NICE_GRAY_COLOUR = A3Constants.NICE_GRAY_COLOUR;
public static final Color GAME_SCREEN_COLOUR = A3Constants.GAME_SCREEN_COLOUR;
public static final Color SLIDES_AREA_COLOUR = A3Constants.SLIDES_AREA_COLOUR;
public static final Color LEO_AREA_COLOUR = A3Constants.LEO_AREA_COLOUR;
public static final Color HOME_AREA_COLOUR = A3Constants.HOME_AREA_COLOUR;
public static final Color WALL_COLOUR = A3Constants.WALL_COLOUR;
public static final int MAX_WALLS = A3Constants.MAX_WALLS;
public static final Font TINY_FONT = A3Constants.TINY_FONT;
public static final Font LARGE_FONT = A3Constants.LARGE_FONT;
public static final Font HUGE_FONT = A3Constants.HUGE_FONT;
public static final int LARGE_FONT_SIZE = A3Constants.LARGE_FONT_SIZE;
public static final int HUGE_FONT_SIZE = A3Constants.HUGE_FONT_SIZE;
public static final Point TICKS_POSITION = A3Constants.TICKS_POSITION;
public static final Point WINNER_LOSER_INFO_POSITION = A3Constants.WINNER_LOSER_INFO_POSITION;
public static final Point INFORMATION_POSITION1 = A3Constants.INFORMATION_POSITION1;
public static final Point INFORMATION_POSITION2 = A3Constants.INFORMATION_POSITION2;
public static final Point INFORMATION_POSITION3 = A3Constants.INFORMATION_POSITION3;
public static final int TICKS_ALLOWED = A3Constants.TICKS_ALLOWED;
public static final int UP = A3Constants.UP;
public static final int DOWN = A3Constants.DOWN;
public static final int LEFT = A3Constants.LEFT;
public static final int RIGHT = A3Constants.RIGHT;
private CoolCat coolCat;
private Timer t;
public A3JPanel() {
setBackground(Color.GREEN);
coolCat = new CoolCat(A3Constants.LEO_START_AREA.x, A3Constants.LEO_START_AREA.y);
addKeyListener(this);
t = new Timer(30,this);
t.start();
//t.addActionListener(this);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
drawGameArea(g);
coolCat.draw(g);
}
private void drawGameArea(Graphics g){
g.setColor(A3Constants.LEO_AREA_COLOUR);
g.fillRect(A3Constants.LEO_LEFT_AREA.x, A3Constants.LEO_LEFT_AREA.y, A3Constants.LEO_LEFT_AREA.width, A3Constants.LEO_LEFT_AREA.height);
g.setColor(A3Constants.WALL_COLOUR);
g.fillRect(A3Constants.ALL_WALLS_AREA.x, A3Constants.ALL_WALLS_AREA.y, A3Constants.ALL_WALLS_AREA.width, A3Constants.ALL_WALLS_AREA.height);
g.setColor(A3Constants.HOME_AREA_COLOUR);
g.fillRect(A3Constants.HOME_AREA.x, A3Constants.HOME_AREA.y, A3Constants.HOME_AREA.width, A3Constants.HOME_AREA.height);
}
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == KeyEvent.VK_UP){
coolCat.setDirection(A3Constants.UP);
}
if(e.getKeyCode() == KeyEvent.VK_DOWN){
coolCat.setDirection(A3Constants.DOWN);
}
if(e.getKeyCode() == KeyEvent.VK_LEFT){
coolCat.setDirection(A3Constants.LEFT);
}
if(e.getKeyCode() == KeyEvent.VK_RIGHT){
coolCat.setDirection(A3Constants.RIGHT);
}
}
public void keyReleased(KeyEvent e){}
public void keyTyped(KeyEvent e){}
public void actionPerformed(ActionEvent e){
coolCat.move();
repaint();
}
}
以下是另一个班级。
import java.awt.*;
public class CoolCat {
public static final Rectangle LEO_START_AREA = A3Constants.LEO_START_AREA;
public static final int GAME_SCREEN_AREA_TOP = A3Constants.GAME_SCREEN_AREA_TOP;
public static final int GAME_SCREEN_AREA_BOTTOM = A3Constants.GAME_SCREEN_AREA_BOTTOM;
public static final int GAME_SCREEN_AREA_LEFT = A3Constants.GAME_SCREEN_AREA_LEFT;
public static final int GAME_SCREEN_AREA_RIGHT = A3Constants.GAME_SCREEN_AREA_RIGHT;
public static final int UP = A3Constants.UP;
public static final int DOWN = A3Constants.DOWN;
public static final int LEFT = A3Constants.LEFT;
public static final int RIGHT = A3Constants.RIGHT;
private Rectangle area;
private int speed;
private int direction;
public CoolCat(int x, int y){
this.speed = speed;
speed = (int)(Math.random() * (8 - 4 + 1)) + 4;
area = new Rectangle(A3Constants.LEO_START_AREA.x, A3Constants.LEO_START_AREA.y);
direction = RIGHT;
}
public Rectangle getArea(){
area = new Rectangle(LEO_START_AREA.x, LEO_START_AREA.y, LEO_START_AREA.width, LEO_START_AREA.height);
return area;
}
public void setDirection(int direction){
this.direction = direction;
}
//public boolean hasReachedHome(Rectangle zhomeArea){}
public void move(){
if(direction == A3Constants.UP){
area.y -= speed;
} else if(direction == A3Constants.DOWN){
area.y += speed;
} else if(direction == A3Constants.LEFT){
area.x -= speed;
} else if(direction == A3Constants.RIGHT){
area.x += speed;
}
}
public void draw(Graphics g){
g.setColor(Color.RED);
g.fillOval(A3Constants.LEO_START_AREA.x, A3Constants.LEO_START_AREA.y, A3Constants.LEO_START_AREA.width, A3Constants.LEO_START_AREA.height);
}
}
答案 0 :(得分：1)
您正在将一个KeyListener添加到JPanel，该组件默认情况下无法接受焦点，并且关键侦听器需要关注。
一个简单的解决方案是让你的JPanel接受焦点，然后请求焦点。
更好的解决方案是避免在Swing应用程序中使用KeyListeners，而是使用Key Bindings（正如之前在类似问题中讨论的那样很多次）。例如，请查看：How to make an image move while listening to a keypress in Java.
答案 1 :(得分：0)
尝试这样的事情。我刚刚做了这个，所以请原谅任何错误。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class g{
public static void main(String args){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
create();
}
});
}
public static MyPanel my;
public static void create(){
JFrame f = new JFrame("test");
my = new MyPanel();
f.add(my);
f.setSize(1000,1000);
f.setVisible(true);
f.addKeyListener(new KeyListener(){
@Override
public void keyPressed(KeyEvent e){
if(e.getKeyCode == 37){ //left
my.move(4); //1 = up, 2 = right, 3 = down, 4 = left
}
if(e.getKeyCode == 39){ //left
my.move(2); //1 = up, 2 = right, 3 = down, 4 = left
}
if(e.getKeyCode == 38){ //left
my.move(1); //1 = up, 2 = right, 3 = down, 4 = left
}
if(e.getKeyCode == 40){ //left
my.move(3); //1 = up, 2 = right, 3 = down, 4 = left
}
}
@Override
public void keyReleased(KeyEvent e){
//do nothings
}
@Override
public void keyTyed(KeyEvent e){
//do nothing
}
});
}
}
public class MyPanel extends JPanel implements ActionListener{
public static Timer time1;
public Square s;
public MyPanel(){
time1 = new Timer(50, this);
time1.start();
}
public void actionPerformed(ActionEvent e){
repaint();
}
public void move(int d){
if(d == 1){
s.setY(s.getY()-1);
}
if(d == 2){
s.setX(s.getX() + 1);
}
if(d == 3){
s.setY(s.getY() + 1);
}
if(d == 4){
s.setX(set.getX() - 1);
}
repaint();
}
public void paintComponent(Graphics g){
super.paintComponent(g);
s.paintSquare(g);
}
}
public class Square{
public int x;
public int y;
public void setX(int xPos){
this.x = xPos;
}
public int getX(){
return x;
}
public void setY(int yPos){
this.y = yPos;
}
public int getY(){
return y;
}
public void paintSquare(Graphics g){
g.setColor(Color.WHITE);
g.fillRect(0,0,1000,1000);
g.setColor(Color.RED);
g.fillRect(x,y,30,30);
}
}