java - 从 jpanel 中绘制和删除 jlabel

Question

我正在制作一个国际象棋游戏 GUI，方法是设置一个 jpanels 网格，顶部带有 jlabel(棋子图像)。我设置了板子，每个方 block (jpanel)都有一个空的 jlabel，可见性设置为 false。然后，我浏览每个 jpanels，并将 jlabel 图片设置为与我的其中一幅作品相对应的图像。我知道是否要画一 block ，因为我有一个变量 _board[8][8] 告诉我该位置是否被占用以及被谁占用。这就是我创建原始板的方式:

编辑:

我实际上对此做了很大的改变，这样我就不必每次都重新加载图像:

public ChessGameGUI(Square[][] board) throws IOException 
    {
        Dimension size = new Dimension(500, 400);
        Dimension boardSize = new Dimension(400, 400);

        layeredPane = new JLayeredPane();
        getContentPane().add(layeredPane);
        layeredPane.setPreferredSize(size);

        theBoard = new JPanel();
        layeredPane.add(theBoard, JLayeredPane.DEFAULT_LAYER);
        layeredPane.addMouseListener(this);

        GridLayout chessBoardLayout = new GridLayout(8,8);
        theBoard.setLayout(chessBoardLayout);
        theBoard.setPreferredSize(boardSize);
        theBoard.setBounds(0, 0, boardSize.width, boardSize.height);

        boolean drawWhite = true;

        // setup initial squares
        for(int y = 0; y < 8; y++)
        {
            for(int x = 0; x < 8; x++)
            {
                BorderLayout squareBorder = new BorderLayout();
                JPanel aChessSquare = new JPanel(squareBorder);

                if(drawWhite) aChessSquare.setBackground(Color.WHITE);
                else aChessSquare.setBackground(Color.GRAY);

                // load initial images
                if(board[x][y]._isOccupied)
                {
                    BufferedImage logo = null;

                    try{
                        // load the image
                        String path = findPieceImagePath(board, x, y);
                        logo = ImageIO.read(new File(path));
                        ImageIcon pieceImage = new ImageIcon(logo);

                        JLabel pieceJLabel = new JLabel();
                        pieceJLabel.setIcon(pieceImage); // new
                        pieceJLabel.setVisible(true); // new

                        aChessSquare.add(pieceJLabel);
                    } 
                    catch (IOException e)
                    { 
                        e.printStackTrace(); 
                    } // end try catch
                }// end if
                else
                {
                    JLabel pieceJLabel = new JLabel();
                    pieceJLabel.setVisible(false);
                    aChessSquare.add(pieceJLabel);
                }

                theBoard.add(aChessSquare);

                // alternate background colors
                if(x == 7);
                else drawWhite = !drawWhite;
            }
        }

        System.out.println("the number of components = " + theBoard.getComponentCount());

    }

这可以很好地加载初始板，但是我似乎无法获得特定的组件。当我点击其中一 block 时，该方 block 应该亮起。唯一获得绿色轮廓的方 block 是左上角的方 block (0, 0)。

public void mousePressed(MouseEvent e) 
    {
        System.out.println("mouse press x = " + e.getX() + " y = " + e.getY());

        // find which piece on the board is being clicked
        int gameX, gameY;
        gameX = e.getX() / 50;
        gameY = e.getY() / 50;

        System.out.println("gameX = " + gameX + " gameY = " + gameY);

        // out of bounds
        if(gameX < 0 || gameY < 0) return;

        // true if selected a piece on this team
        if(myGame._board[gameX][gameY]._isOccupied && !_pieceSelected && myGame._board[gameX][gameY]._team == myGame._turn) 
        {
            System.out.println("selected new piece");
            JPanel curSquare = (JPanel)theBoard.getComponentAt(gameX, gameY);
            curSquare.setBorder(BorderFactory.createLineBorder(Color.green));
            _pieceSelected = !_pieceSelected;



            return;
        }

我想我在这行上遇到了问题:JPanel curSquare = (JPanel)theBoard.getComponentAt(gameX, gameY);

但是，gameX 和 gameY 值已正确设置。

谢谢

Answer 1

我认为您缺少一行来将标签添加到每个面板。在“//设置初始方 block ”期间:

curLabel.setVisible(false);

应该是:

curLabel.setVisible(false);aChessSquare.add(curLabel);