添加/從JPanel的

Question

這裏移除的JLabel是我的代碼：

public class GUI 
{ 
    JFrame frame; 
    JPanel squares[][]; 

    public void movePiece(int oriX, int oriY, int destX, int destY) 
    { 
     squares[destY][destX] = squares[oriY][oriX]; 
     squares[oriY][oriX] = null; 
     frame.setVisible(true); 

    } 


    /* Constructor credited to stackoverflow user ranzy 
     http://stackoverflow.com/questions/2535417/chess-board-in-java */ 
    public GUI() 
    { 
     frame = new JFrame("Chess"); 
     squares = new JPanel[8][8]; 
     frame.setSize(500, 500); 
     frame.setLayout(new GridLayout(8, 8)); 

     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

     for (int i = 0; i < 8; i++) { 
      for (int j = 0; j < 8; j++) { 
       squares[i][j] = new JPanel(); 

       if ((i + j) % 2 == 0) { 
        squares[i][j].setBackground(Color.white); 
       } else { 
        squares[i][j].setBackground(Color.orange); 
       } 
       frame.add(squares[i][j]); 
      } 
     } 

     ImageIcon pawnW = new ImageIcon(getClass().getResource("pawnW.png")); 
     ImageIcon knightW = new ImageIcon(getClass().getResource("knightW.png")); 
     ImageIcon bishopW = new ImageIcon(getClass().getResource("bishopW.png")); 
     ImageIcon rookW = new ImageIcon(getClass().getResource("rookW.png")); 
     ImageIcon queenW = new ImageIcon(getClass().getResource("queenW.png")); 
     ImageIcon kingW = new ImageIcon(getClass().getResource("kingW.png")); 

     ImageIcon pawnB = new ImageIcon(getClass().getResource("pawnB.png")); 
     ImageIcon knightB = new ImageIcon(getClass().getResource("knightB.png")); 
     ImageIcon bishopB = new ImageIcon(getClass().getResource("bishopB.png")); 
     ImageIcon rookB = new ImageIcon(getClass().getResource("rookB.png")); 
     ImageIcon queenB = new ImageIcon(getClass().getResource("queenB.png")); 
     ImageIcon kingB = new ImageIcon(getClass().getResource("kingB.png")); 



     squares[0][0].add(new JLabel(rookB)); 
     squares[0][1].add(new JLabel(knightB)); 
     squares[0][2].add(new JLabel(bishopB)); 
     squares[0][3].add(new JLabel(queenB)); 
     squares[0][4].add(new JLabel(kingB)); 
     squares[0][5].add(new JLabel(bishopB)); 
     squares[0][6].add(new JLabel(knightB)); 
     squares[0][7].add(new JLabel(rookB)); 

     squares[7][0].add(new JLabel(rookW)); 
     squares[7][1].add(new JLabel(knightW)); 
     squares[7][2].add(new JLabel(bishopW)); 
     squares[7][3].add(new JLabel(queenW)); 
     squares[7][4].add(new JLabel(kingW)); 
     squares[7][5].add(new JLabel(bishopW)); 
     squares[7][6].add(new JLabel(knightW)); 
     squares[7][7].add(new JLabel(rookW)); 

     for (int i = 0; i < 8; i++) 
     { 
      squares[1][i].add(new JLabel(pawnB)); 
      squares[6][i].add(new JLabel(pawnW)); 
     } 

     frame.setVisible(true); 
    } 

} 

當用戶移動一塊，我想方塊進行更新。即目標廣場現在應該保持原點廣場jlabel。我試圖用我的movePiece方法做到這一點。但是，這不是創造我正在尋找的變化。我需要使用添加/刪除方法嗎？另外 - 任何時候我更新電路板時是否需要致電frame.setVisible(true)？

Answer 1

可以使用拖放和拖放這一點，或者你可以使用的MouseListener和的MouseMotionListener。後者的一個實例中可以看出，在這裏我的代碼：

import java.awt.*; 
import java.awt.event.*; 
import java.awt.image.BufferedImage; 
import javax.swing.*; 

public class Chess2 { 
    private static void createAndShowUI() { 
     JFrame frame = new JFrame("Chess 2"); 
     frame.getContentPane().add(new Chess2Gui().getMainComponent()); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.pack(); 
     frame.setLocationRelativeTo(null); 
     frame.setVisible(true); 
    } 

    public static void main(String[] args) { 
     java.awt.EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      createAndShowUI(); 
     } 
     }); 
    } 
} 

class Chess2Gui { 
    private static final int RANKS = 8; 
    private static final int FILES = 8; 
    private static final Color DARK_COLOR = new Color(0, 100, 0); 
    private static final Color LIGHT_COLOR = new Color(200, 200, 200); 
    private static final Color DARK_PIECE_COLOR = Color.black; 
    private static final int SQR_WIDTH = 80; 
    private static final int PIECE_WIDTH = 60; 
    private static final Dimension SQR_SIZE = new Dimension(SQR_WIDTH, SQR_WIDTH); 

    private JLayeredPane mainLayeredPane = new JLayeredPane(); 
    private JPanel board = new JPanel(new GridLayout(RANKS, FILES)); 
    private JPanelSquare[][] jPanelSquareGrid = new JPanelSquare[RANKS][FILES]; 

    public Chess2Gui() { 
     for (int rank = 0; rank < RANKS; rank++) { 
     for (int file = 0; file < FILES; file++) { 
      Color bkgd = DARK_COLOR; 
      if (rank % 2 == file % 2) { 
       bkgd = LIGHT_COLOR; 
      } 
      jPanelSquareGrid[rank][file] = new JPanelSquare(rank, file, bkgd); 
      jPanelSquareGrid[rank][file].setPreferredSize(SQR_SIZE); 
      board.add(jPanelSquareGrid[rank][file]); 
     } 
     } 
     board.setSize(board.getPreferredSize()); 
     board.setLocation(0, 0); 
     mainLayeredPane.add(board, JLayeredPane.DEFAULT_LAYER); 
     mainLayeredPane.setPreferredSize(board.getPreferredSize()); 

     ImageIcon icon = new ImageIcon(ImageUtils2.createImage(PIECE_WIDTH, DARK_PIECE_COLOR)); 
     JLabel chessPiece = new JLabel(icon, SwingConstants.CENTER); 

     jPanelSquareGrid[1][3].add(chessPiece); 

     MyMouseAdapter mouseAdapter = new MyMouseAdapter(); 
     mainLayeredPane.addMouseListener(mouseAdapter); 
     mainLayeredPane.addMouseMotionListener(mouseAdapter); 

    } 

    public JComponent getMainComponent() { 
     return mainLayeredPane; 
    } 

    private class MyMouseAdapter extends MouseAdapter { 
     private JLabel piece = null; 
     private Point delta = null; 
     private int oldRank = -1; 
     private int oldFile = -1; 

     @Override 
     public void mousePressed(MouseEvent e) { 
     Point p = e.getPoint(); 
     Component c = board.getComponentAt(p); 
     for (int rank = 0; rank < jPanelSquareGrid.length; rank++) { 
      for (int file = 0; file < jPanelSquareGrid[rank].length; file++) { 
       if (jPanelSquareGrid[rank][file] == c) { 
        if (jPanelSquareGrid[rank][file].getChessPiece() != null) { 

        // the jPanelSquares are derived from JPanel but have a 
        // few of their own methods 
        piece = jPanelSquareGrid[rank][file].getChessPiece(); 
        jPanelSquareGrid[rank][file].remove(piece); 
        oldRank = rank; 
        oldFile = file; 
        mainLayeredPane.add(piece, JLayeredPane.DRAG_LAYER); 
        int x = p.x - PIECE_WIDTH/2; 
        int y = p.y - PIECE_WIDTH/2; 
        piece.setLocation(x, y); 

        delta = new Point(p.x - x, p.y - y); 
        board.revalidate(); 
        mainLayeredPane.repaint(); 
        return; 
        } 
       } 
      } 
     } 

     oldFile = -1; 
     oldRank = -1; 
     } 

     @Override 
     public void mouseDragged(MouseEvent e) { 
     if (piece != null) { 
      Point p = e.getPoint(); 
      int x = p.x - delta.x; 
      int y = p.y - delta.y; 
      piece.setLocation(x, y); 
      mainLayeredPane.revalidate(); 
      mainLayeredPane.repaint(); 
     } 
     } 

     @Override 
     public void mouseReleased(MouseEvent e) { 
     if (piece != null) { 
      JPanelSquare sqr = (JPanelSquare) board.getComponentAt(e.getPoint()); 
      mainLayeredPane.remove(piece); 
      if (sqr == null || !validMove(sqr)) { 
       jPanelSquareGrid[oldRank][oldFile].add(piece); 
      } else { 
       sqr.add(piece); 
      } 

      piece = null; 
      delta = null; 

      oldRank = -1; 
      oldFile = -1; 

      board.revalidate(); 
      mainLayeredPane.repaint(); 
     } 
     } 

     // just a pawn's moves 
     private boolean validMove(JPanelSquare sqr) { 
     int rank = sqr.getRank(); 
     int file = sqr.getFile(); 

     if (file != oldFile) { 
      return false; 
     } 
     if (oldRank == 1 && (rank != 2 && rank != 3)) { 
      return false; 
     } 
     if (oldRank != 1 && rank != oldRank + 1) { 
      return false; 
     } 
     return true; 
     } 
    } 
} 

@SuppressWarnings("serial") 
class JPanelSquare extends JPanel { 
    private int rank; 
    private int file; 
    private JLabel chessPiece = null; 

    public JPanelSquare(int rank, int file, Color bkgrnd) { 
     this.rank = rank; 
     this.file = file; 
     setBackground(bkgrnd); 
     setLayout(new GridBagLayout()); 
    } 

    public int getRank() { 
     return rank; 
    } 

    public int getFile() { 
     return file; 
    } 

    @Override 
    public Component add(Component c) { 
     chessPiece = (JLabel) c; 
     return super.add(c); 
    } 

    @Override 
    public void remove(Component comp) { 
     chessPiece = null; 
     super.remove(comp); 
    } 

    public JLabel getChessPiece() { 
     return chessPiece; 
    } 
} 

class ImageUtils2 { 

    public static BufferedImage createImage(int size, Color color) { 
     BufferedImage img = new BufferedImage(size, size, BufferedImage.TYPE_INT_ARGB); 
     Graphics2D g2 = img.createGraphics(); 
     g2.setColor(color); 
     g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
     g2.fillOval(size/3, 0, size/3, size/3); 
     g2.fillOval(size/4, size/4, size/2, 2 * size/3); 
     g2.fillOval(size/6, 2 * size/3, 2 * size/3, size/2); 
     g2.dispose(); 
     return img; 
    } 

} 

此使用的JLayeredPane和當用戶選擇了一塊，這（一個JLabel）獲取從 板的JPanel取出並升高到的JLayeredPane的DRAG_LAYER，直到它在有效的的位置上發佈。

請注意，此代碼取自我以前的答案here。有關代碼的更多細節，請查看答案。

Answer 2

JFrame remove();方法如何？使用這樣的：

frame.remove(JLabelName);