嘗試使用KeyListeners和ImageIcons時出錯？

Question

我目前正在努力爲學校製作一款迷宮遊戲，而且我爲什麼會遇到這些錯誤感到困惑。這是涉及的代碼段。還需要導入的所有內容都已導入。首先是具有玩家位置的玩家類，然後是他們的圖像。

public class Player { 
int playerX; 
int playerY; 
int moveSpeed = 5; //I can edit move speed here 
Image character; 

//getters and setters to utilize the player's location and image 
public Player(){ //constructor for initial starting points 
    playerX = 50; 
    playerY = 50; 
    ImageIcon player = new ImageIcon("E://Workspace//Maze//images//Player.jpg"); 
    character = player.getImage(); 
} 

public void setPlayerX(int playerX){ 
    this.playerX = playerX; 
} 
public int getPlayerX(){ 
    return playerX; 
} 

public void setPlayerY(int playerY){ 
    this.playerY = playerY; 
} 
public int getPlayerY(){ 
    return playerY; 
} 

public void setMoveSpeed(int moveSpeed){ 
    this.moveSpeed = moveSpeed; 
} 
public int getMoveSpeed(){ 
    return moveSpeed; 
} 

public Image getPlayerImage(){ 
    return character; 
} 
} 

現在是創建的JPanel的佈局類，並且應該是什麼最終繪製選手圖像進入遊戲，也是什麼是應該讓玩家移動。

public class Layout extends JPanel implements ActionListener { //GUI with a  non null FlowLayout 
Player p = new Player(); 
Maze m = new Maze(); 

//500 x 500 seemed like a good size for the maze game 
int x = 500; 
int y = 500; 

public Layout(){ 
    setLayout(new FlowLayout()); 
    addKeyListener(new Move()); 
    setFocusable(true); 
} 

//for use in setting and getting the borders of the game 
public void setX(int x){ 
    this.x = x; 
} 
public int getX(){ 
    return x; 
} 

public void setY(int y){ 
    this.y = y; 
} 
public int getY(){ 
    return y; 
} 

public void paintGame(Graphics g){ 
    super.paint(g); 
    g.drawImage(p.getPlayerImage(), p.getPlayerX(), p.getPlayerY(), null); 
} 
@Overrride 
public void actionPerformed(ActionEvent ae){ 
    repaint(); 
} 
} 

class Move extends Layout implements KeyListener { //Inheritance 
public void keyPressed(KeyEvent press) { //for the movement in the game 
    //I used both keys so that if the player woukld like to use WASD or the arrow keys either will work 
    if(press.getKeyCode() == KeyEvent.VK_W || press.getKeyCode() == KeyEvent.VK_UP){ 
     //move up 
     p.setPlayerY(p.getPlayerY() - p.getMoveSpeed()); 
    } 
    else if(press.getKeyCode() == KeyEvent.VK_S || press.getKeyCode() == KeyEvent.VK_DOWN){ 
     //move down 
     p.setPlayerY(p.getPlayerY() + p.getMoveSpeed()); 
    } 
    else if(press.getKeyCode() == KeyEvent.VK_A || press.getKeyCode() == KeyEvent.VK_LEFT){ 
     //move left 
     p.setPlayerX(p.getPlayerX() - p.getMoveSpeed()); 
    } 
    else if(press.getKeyCode() == KeyEvent.VK_D || press.getKeyCode() == KeyEvent.VK_RIGHT){ 
     //move right 
     p.setPlayerX(p.getPlayerX() + p.getMoveSpeed()); 
    } 
} 


public void keyReleased(KeyEvent release) { 
    //nothing is needed here 
} 

public void keyTyped(KeyEvent e) { 
    //does nothing if a key is type (no need for it) 
} 
} 

最後是應該運行遊戲的遊戲類（目前我只是試圖讓玩家跨越一個空格移動，而不尚未實現地圖）。

public class Play { 
public static void main(String[]args) { 
    play(); 
} 

public static void play(){ 
    Layout l = new Layout(); 
    Player p = new Player(); 
    Maze m = new Maze(); 

    l.setSize(l.getX(), l.getY()); //size can be changed in layout 
    l.setVisible(true); 
} 
} 

由於某種原因，當我嘗試運行此操作時，出現大量錯誤。我希望很快得到解決，所以我可以開始實施我的迷宮地圖。下面是我收到的錯誤：

Exception in thread "main" java.lang.StackOverflowError 
at java.lang.ref.SoftReference.get(Unknown Source) 
at sun.misc.SoftCache$ValueCell.strip(Unknown Source) 
at sun.misc.SoftCache$ValueCell.access$300(Unknown Source) 
at sun.misc.SoftCache.get(Unknown Source) 
at sun.awt.SunToolkit.getImageFromHash(Unknown Source) 
at sun.awt.SunToolkit.getImage(Unknown Source) 
at javax.swing.ImageIcon.<init>(Unknown Source) 
at javax.swing.ImageIcon.<init>(Unknown Source) 
at mazeGame.Player.<init>(Player.java:16) 
at mazeGame.Layout.<init>(Layout.java:11) 
at mazeGame.Move.<init>(Layout.java:49) 
at mazeGame.Layout.<init>(Layout.java:20) 

的：at mazeGame.Move.<init>(Layout.java:49) at mazeGame.Layout.<init>(Layout.java:20)仍在繼續爲atleast 20行的Eclipse停止outputing錯誤之前。 請幫我解決這個問題，因爲我目前一直在關注如何讓玩家移動，並需要開始創建迷宮地圖。對不起，真的很長的帖子，但我想發佈任何可能會給我的錯誤。

Answer 1

問題是你的構造函數中有無限遞歸。 Layout()調用addKeyListener(new Move());和Move延伸Layout，所以Move的構造函數也調用Layout()，它又調用Move()。

您需要重構代碼才能避免這種情況。一個簡單的方法將使移動不擴展布局，並將玩家作爲構造參數傳遞給Move。

class Move implements KeyListener { 
    final Player p; 
    Move(Player p) { 
     this.p = p; 
    } 
    ... 
} 

和Layout：

addKeyListener(new Move(p)); 

還要考慮使用key bindings，而不是一個關鍵聽衆。這通常是一種更好的方法。

Answer 2

嘗試更換線路：通過使用媒體跟蹤監視裝載

character = ImageIO.read(new File("E://Workspace//Maze//images//Player.jpg")); 

我認爲，問題可能是由ImageIcon的的異步加載的原因（圖像將被預裝：

ImageIcon player = new ImageIcon("E://Workspace//Maze//images//Player.jpg"); 
character = player.getImage(); 

與）http://docs.oracle.com/javase/7/docs/api/javax/swing/ImageIcon.html