Java游戏雪碧卡住了

Question

I am having a problem with a stuck sprite as soon as I switch to another JPanel via CardLayout.

import java.awt.CardLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.util.ArrayList;
import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel;

public class Game extends JFrame implements Runnable {

    private viewA v1;
    private viewB v2;
    private viewC v3;
    private viewD v4;
    private Player player;
    private CardLayout c1;
    private JPanel contPanel;

    // ############## VIEW A BUTTONLISTENER
    public class ViewAButtonList implements ActionListener{

        public void actionPerformed(ActionEvent ev){
            try{
            c1.show(contPanel, "1");

            } catch (Exception ex){

            ex.printStackTrace();
            }

        }


    }
    // ############## VIEW B BUTTON LISTENER
    public class ViewBButtonList implements ActionListener{

        public void actionPerformed(ActionEvent ev){
            try{
            c1.show(contPanel, "2");

            } catch (Exception ex){

            ex.printStackTrace();
            }

        }


    }
    // ############## VIEWC BUTTON ACTIONEVENT
    public class ViewCButtonList implements ActionListener{

        public void actionPerformed(ActionEvent ev){
            try{
            c1.show(contPanel, "3");

            } catch (Exception ex){

            ex.printStackTrace();
            }

        }


    }
    // ############## VIEW D BUTTON ACTION EVENT
    public class ViewDButtonList implements ActionListener{

        public void actionPerformed(ActionEvent ev){
            try{
            c1.show(contPanel, "4");

            } catch (Exception ex){

            ex.printStackTrace();
            }

        }


    }





    public Game() {
        player = new Player();
        // load player settings from server
        //  ..
        //    contPanel = new JPanel();
     //load views    v1 = new ViewA(Player); v2=new ViewB(Player); v3 = new ViewC(Player); v4 =new ViewD(Player);

     c1 = new CardLayout();

     contPanel.setLayout(c1);


     contPanel.add(v1,"1");

     contPanel.add(v2,"2");

     contPanel.add(v3"3");

     contPanel.add(v4,"4");

        c1.show(contPanel, "2");
        currPos =2;

        this.add(contPanel);

        setSize(652, 480);
        setLocationRelativeTo(null);
        setTitle("GAME");
        setResizable(false);
        setVisible(true);//go to end of view B (x=0), change to View A, close view B


       // Create 4 of each button to place in each seperate view (to swtich back and forth)
      // ................


    }

    public static void main(String[] args) {
         javax.swing.SwingUtilities.invokeLater(new Runnable() {
             public void run() {
                 new Game();
             }
         });
    }

    @Override   public void run() {         // TODO Auto-generated method stub
    } }

Now.. everything works from the standpoint of switching between screens.. but my Player sprite gets stuck on screen after switch, but on initial load I can move the sprite around with the arrow keys. I am not sure if passing the Player on the new ViewA(Player) might be the culprit.. but I have a feeling that it is.. can't figure out what I am doing wrong..

Here's theplayer:

import java.awt.Image; import java.awt.Rectangle; import java.awt.event.KeyEvent;

import java.util.ArrayList;

import javax.swing.ImageIcon;

public class Player {

 private String playersprite = "playersprite.png"; private int dx; private int dy; private int x; private int y; private int width; private int height; private boolean isFired; private boolean visible; private Image image; private ArrayList missiles; public Player() { ImageIcon ii = new ImageIcon(this.getClass().getResource(playersprite)); image = ii.getImage(); width = image.getWidth(null); height = image.getHeight(null); missiles = new ArrayList(); visible = true; isFired=false; //default spawn location x = 600; y = 400; } public void move() { x += dx; y += dy; if(x<=0){x=0;} if(x>=640-20){x=640-20;} if(y<=0){y=0;} if(y>=400){y=400;} } public int getX() { return x; } public int getY() { return y; } public void setX(int x){ this.x=x; } public void setY(int y){ this.y=y; } public Image getImage() { return image; } public ArrayList getMissiles() { return missiles; } public void setVisible(boolean visible) { this.visible = visible; } public boolean isVisible() { return visible; } public Rectangle getBounds() { return new Rectangle(x, y, 32, 32); } public void keyPressed(KeyEvent e) { System.out.println("X: "+x+",Y: "+y); int key = e.getKeyCode(); if (key == KeyEvent.VK_SPACE) { if(isFired==false){ isFired=true; fire(); } else return; } if (key == KeyEvent.VK_LEFT) { dx = -2; } if (key == KeyEvent.VK_RIGHT) { dx = 2; } if (key == KeyEvent.VK_UP) { dy = -2; } if (key == KeyEvent.VK_DOWN) { dy = 2; } } public void fire() { System.out.println("Player used weapon"); // missiles.add(new Missile(x, y)); } public void keyReleased(KeyEvent e) { int key = e.getKeyCode(); if (key == KeyEvent.VK_LEFT) { dx = 0; } if (key == KeyEvent.VK_RIGHT) { dx = 0; } if (key == KeyEvent.VK_UP) { dy = 0; } if (key == KeyEvent.VK_DOWN) { dy = 0; } if (key == KeyEvent.VK_SPACE) { isFired=false; } } } 

Answer 1

KeyListener require that the component they are registered are focusable AND have focus, this means that when you click something like a JButton focus moves to the button and the component with a KeyListener no longer has keyboard focus and therefore will no longer receive key events.

Instead, it is recommended that you use Key Bindings as this API has the capacity to overcome these limitations