图像未显示在JPanel上？

Question

我在获取程序中创建的两个正方形时遇到了一些麻烦，导入的ImageIcon显示在我的JPanel上。我已经有一段时间了，并且仍然无法弄清楚我能做些什么来让它们显示出来，并且允许玩家图像移动。这是我的代码的第一部分是迷宫类：

public class Maze extends JPanel{ 
int[][][] mazeArray; //will be defined in the loop depending on how many rectangles are spawned, also for making sure the player can't walk over the walls (first is what number wall it is, second is the x coordiante of the wall, and third is the y coordinate of the wall) 
//depending on whether or not the rctangle is vertical or horizontal it will use both values for its height and width (vertical would have sideX for the height, and sideY for the width; this would be the opposite for the horizontal rectangle) 
int sideX = 50; //x side length 
int sideY = 50; //y side length 
int x; 
int y; 
//setters and getters for use later (for changing the rctangles location and size) 
public void setSideX(int sideX){ 
    this.sideX = sideX; 
} 
public int getSideX(){ 
    return sideX; 
} 

public void setSideY(int sideY){ 
    this.sideY = sideY; 
} 
public int getSideY(){ 
    return sideY; 
} 

public void setCoordinates(int x, int y){ 
    this.x = x; 
    this.y = y; 
} 

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; 
} 
//end setters and getters 
public void generateMaze(){ 
    //the left side of the maze 
    for(int i = 0; i < 10; i++){ //ten blocks on the left side 
     setX(0); //x is always 0 for the left side 
     setY(getY() + 50); //adds 50 to the previous Y coordinate amount, m making it go down the whole left side 
    } 
    setY(0); //set y back to zero to be able to start the right column of blocks 
    //the right side of the maze 
    for(int i = 0; i < 10; i++){ 
     setX(500); //x is always 500 for the right side 
     setY(getY() + 50); //does the same as it did on the left side, except on the right 
    } 
    setY(0); //set y to zero again 
    setX(50); //start x at 50 since there is no need to remake the corners 
    for(int i = 0; i < 8; i++){ //only goes up to 8 this this time because the corners of the maze can be ignored 
     setY(0); //just in case y changes back 
     setX(getX() + 50); //x increases by 50 each time 
    } 
    setY(500); 
    setX(50); 
    for(int i = 0; i < 8; i++){ //same as above except for the bottom 
     setY(500); 
     setX(getX() + 50); 
    } 
    //the maze walls are now generated 
} 
public void paintComponent(Graphics g){ //for painting the rectangles 
    super.paintComponent(g); 
    g.setColor(Color.BLACK); 
    g.fillRect(getX(), getY(), sideX, sideY); //uses x and y coordinates defined in the generateMaze loop, and the uses whatever current value for the two side, depending on what type of rectangle it is 
} 
} 

这是我用来创建迷宫墙。现在到了与选手图像涉及Player类，玩家坐标，玩家的移动速度：

public class Player { 
//Player starts in the top left corner 
int playerX = 50; 
int playerY = 50; 
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; 
} 
} 

下一个就是我觉得这个问题是出现在玩家的图像（迷宫，我认为它是什么在迷宫类本身，虽然也可以在布局类的问题以及）：

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

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

public Layout() { 
    panel = new JPanel(); 
    panel.setLayout(new FlowLayout()); //same as the JFrame 
    panel.addKeyListener(new Move(p)); 
    panel.setFocusable(true); 
    panel.setBackground(Color.YELLOW); //background of the maze 
    m.generateMaze(); //create the maze 
} 

//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 JPanel getPanel(){ 
    return panel; 
} 
@Override //so it can repaint as needed 
protected void paintComponent(Graphics g){ 
    super.paintComponent(g); 
    g.drawImage(p.getPlayerImage(), p.getPlayerX(), p.getPlayerY(), this); 
} 

public void actionPerformed(ActionEvent ae){ 
    repaint(); 
} 
} 

class Move implements KeyListener { //for player movement 
final Player p; 
Move(Player p){ 
    this.p = p; 
} 

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) 
} 
} 

最后是运行它的类，但我不认为有任何的问题在这里，但只是在不管怎样我都会把它扔到这里：

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

public static void play() { 
    JFrame f = new JFrame(); 
    Layout l = new Layout(); 
    JPanel j = l.getPanel(); 

    f.setTitle("Maze Game for final project"); 
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    f.setSize(l.getX(), l.getY()); //size can be changed in layout 
    f.setVisible(true); 
    f.add(j); //adds the panel 
} 
} 

我试图让玩家的图像在50,50的时候产生，然后启动时也会产生墙壁。但是，目前唯一显示的JPanel是黄色背景。帮助将不胜感激！

新更新的代码在这里：

public static void play() { 
    JFrame f = new JFrame(); 
    Layout l = new Layout(); 

    f.setTitle("Maze Game for final project"); 
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    f.setSize(l.getX(), l.getY()); //size can be changed in layout 
    f.add(new Layout()); //adds the panel 
    f.setVisible(true); 
} 

，也为布局构造

public Layout() { 
    setLayout(new FlowLayout()); 
    addKeyListener(new Move(p)); 
    setFocusable(true); 
    setBackground(Color.YELLOW); 
    m.generateMaze(); 
} 

Answer 1

我不能说我已经通过所有的代码了，但有一点没有罢工我：

您的布局类扩展JPanel并重写paintComponet，但您从不使用此类作为JPanel。相反，您可以在其中使用其他一些名为panel的JPanel变量。摆脱那个变量，而是使用布局类本身的JPanel，并且至少一些您的问题可能会被修复。

例如，

public class Layout extends JPanel implements ActionListener { 
    Maze m = new Maze(); 
    Player p = new Player(); 
    int x = 500; 
    int y = 500; 
    Image player; 

    // JPanel panel; 

    public Layout() { 
     // panel = new JPanel(); 
     // panel.setLayout(new FlowLayout()); //same as the JFrame 
     // panel.addKeyListener(new Move(p)); 
     // panel.setFocusable(true); 
     // panel.setBackground(Color.YELLOW); //background of the maze 

     setLayout(new FlowLayout()); 
     addKeyListener(new Move(p)); 
     setFocusable(true); 
     setBackground(Color.YELLOW); 
     m.generateMaze(); 
    } 

    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 JPanel getPanel() { 
    // return panel; 
    // } 

    @Override 
    protected void paintComponent(Graphics g) { 
     super.paintComponent(g); 
     g.drawImage(p.getPlayerImage(), p.getPlayerX(), p.getPlayerY(), this); 
    } 

    public void actionPerformed(ActionEvent ae) { 
     repaint(); 
    } 
} 

的另一个问题是你KeyListeners的使用，因为按键绑定将是非常理想在这里，但我会离开，你的下一个问题。

此外，您将JPanel添加到JFrame 之后在JPanel上调用setVisible(true) - 不要这样做。只有在添加完所有组件后才能拨打setVisible(true)。