添加到拖动图层后，鼠标拖动停止工作

Question

我正在尝试构建一个Scrabble游戏，以帮助您更熟悉构建GUI并练习一般的Java技能。该板主要由带有JPanels的JLayeredPane组成，包括电路板图像和电路板空间。我试图通过将tile添加到drag_layer然后从那里移动来将Tile对象（扩展JLabel）拖放到棋盘周围，类似于以下示例：dragging a jlabel around the screen。鼠标按下正在工作并正确地将图块添加到拖动图层，但在此之后，鼠标似乎完全停止了。我尝试在mouseDragged覆盖方法中打印“拖动”，但它甚至不打印。有两个相关的类 - Console和MouseInput，我将在下面展示，但如果你想拉动整个项目，我还会在最后添加到GitHub仓库的链接。

安慰：

public Console () throws IOException{
    // Create gameConsole
    gameConsole = new JFrame();
    final int frameWidth = 850;
    final int frameHeight = 950;
    gameConsole.setPreferredSize(new Dimension(frameWidth, frameHeight));
    gameConsole.setTitle("Scrabble");
    gameConsole.setLayout(new GridBagLayout());
    gameConsole.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    GridBagConstraints c = new GridBagConstraints();
    c.fill = GridBagConstraints.BOTH;
    c.ipadx = 810;
    c.ipady = 950;

    // Create center console panel and add to gameConsole
    centerConsole = new JPanel();
    centerConsole.setLayout(new BorderLayout());
    gameConsole.add(centerConsole,c);


    // Create layered pane that holds the board and playerbox
    gameContainer = new JLayeredPane();
    gameContainer.setBounds(0,0,810,950);
    gameContainer.addMouseListener(new MouseInput(gameContainer));
    gameContainer.addMouseMotionListener(new MouseInput(gameContainer));
    centerConsole.add(gameContainer, BorderLayout.CENTER);

    // Create board image label and add to JPanel
    BufferedImage scrabbleImage = ImageIO.read(Console.class.getResource("/board.jpg"));    
    JLabel background = new JLabel(new ImageIcon(scrabbleImage));
    boardImage = new JPanel();
    boardImage.setBounds(0, 0, 810, 810);
    boardImage.add(background);
    boardImage.setOpaque(true);


    // create JPanel with gridBagLayout
    boardGrid = new JPanel();
    boardGrid.setBounds(0, 3, 810, 810);
    boardGrid.setLayout(new GridBagLayout());
    boardGrid.setOpaque(false);

    // Create panels to add to boardGrid
    spaces = new BoardSpace [15][15];
    BoardSpace.setBoardSpaces(spaces);

    // Set grid constraints
    GridBagConstraints cGrid = new GridBagConstraints();
    for (int i = 0; i < 15; i++) {
        for (int j = 0; j < 15; j++) {
            // panel constraints
            cGrid.gridx = i;                // grid x location
            cGrid.gridy = j;                // grid y location
            cGrid.gridheight = 1;           // spans 1 row
            cGrid.gridwidth = 1;            // spans 1 column
            cGrid.weightx = 0.0;
            cGrid.weighty = 0.0;
            cGrid.fill = GridBagConstraints.BOTH;   // Resize veritically & horizontally

            // Set size of board space and add to grid
            spaces[i][j].setOpaque(false);
            spaces[i][j].setPreferredSize(new Dimension((int) Info.GRIDSIZE,(int) Info.GRIDSIZE));
            boardGrid.add(spaces[i][j], cGrid);
        }
    }

    // Add to layeredPane
    gameContainer.add(boardImage, new Integer(0),0);
    gameContainer.add(boardGrid, new Integer(1),0);


    // Create player box panel 
    playerPanel = new JPanel();
    playerPanel.setLayout(new GridBagLayout());
    playerBox = new JPanel();
    playerBox.setLayout(new GridLayout(1,7, 10, 0));

    // Create player box constraints
    GridBagConstraints cp = new GridBagConstraints();
    cp.ipadx = 50;
    cp.ipady = 50;

    // Create playerBox spaces
    playerSpaces = new BoardSpace [1][7];
    BoardSpace.setPlayerSpaces(playerSpaces);

    // Add playerSpaces to playerBox
    for (int j = 0; j < 7; j++) {
        // panel constraints
        cGrid.gridx = 0;                // grid x location
        cGrid.gridy = j;                // grid y location
        cGrid.gridheight = 1;           // spans 1 row
        cGrid.gridwidth = 1;            // spans 1 column
        cGrid.weightx = 0.0;
        cGrid.weighty = 0.0;
        cGrid.fill = GridBagConstraints.BOTH;   // Resize veritically & horizontally

        // Set size of board space and add to grid
        playerSpaces[0][j].setOpaque(false);
        playerSpaces[0][j].setPreferredSize(new Dimension((int) Info.GRIDSIZE,(int) Info.GRIDSIZE));
        playerBox.add(playerSpaces[0][j], cGrid);
    }

    // Add player box to south panel
    playerPanel.add(playerBox, cp);

    // Add player box to bottom of layeredPane
    playerPanel.setBounds(0,825,810,75);
    gameContainer.add(playerPanel, new Integer(0),0);

    gameConsole.pack();

    // Make gameConsole visible
    gameConsole.setVisible(true);
}

鼠标适配器：

public class MouseInput extends MouseAdapter {
/**
 * 
 */
private Component mouseArea;
private boolean dragging;
private Tile draggingTile;
private BoardSpace currentSpace;
private BoardSpace startingSpace;
private Component selectedObject;
Component [] panelObjects;
private JLayeredPane dragLayer;
private Point dragPoint;
private int dragWidth;
private int dragHeight;

public MouseInput(Component mouseArea) {
    // TODO Auto-generated constructor stub
    super();
    mouseArea = this.mouseArea;
}


void eventOutput(String eventDescription, MouseEvent e) {
    Point p = e.getPoint();
    System.out.println(eventDescription
            + " (" + p.getX() + "," + p.getY() + ")"
            + " detected on "
            + e.getComponent().getClass().getName()
            + "
");
}

public void mouseMoved(MouseEvent e) {
    //eventOutput("Mouse moved", e);
}

public void mouseDragged(MouseEvent e) {

    if (dragging) {
        System.out.println("Dragging");
    }

    if (!dragging) {
        return;
    } else {
        System.out.println("Dragging " + Tile.getLetter(draggingTile));
        int x = e.getPoint().x - dragWidth;
        int y = e.getPoint().y - dragHeight;
        draggingTile.setLocation(x, y);

        draggingTile.repaint();
    }
}


@Override
public void mouseClicked(MouseEvent e) {
    // TODO Auto-generated method stub
    //eventOutput("Mouse Clicked", e);
}


@Override
public void mouseEntered(MouseEvent e) {
    /*
    dragPoint = e.getPoint();
    selectedObject = e.getComponent().getComponentAt(dragPoint);
    // Get the current space

    while (!selectedObject.getClass().getSimpleName().equals("BoardSpace")) {
        try {
            dragPoint = selectedObject.getMousePosition();
            selectedObject = selectedObject.getComponentAt(dragPoint);
        } catch (NullPointerException illegalSpace){
            currentSpace = startingSpace;
            break;
        }
    }

    if (selectedObject.getClass().getSimpleName().equals("BoardSpace")) {
        currentSpace = (BoardSpace) selectedObject;
        System.out.println(BoardSpace.getID(currentSpace));
    } */
}


@Override
public void mouseExited(MouseEvent e) {
    // TODO Auto-generated method stub
    //eventOutput("Mouse Exited", e);
}


@Override
public void mousePressed(MouseEvent e) {
    dragLayer = (JLayeredPane) e.getSource();
    dragPoint = e.getPoint();
    selectedObject = e.getComponent().getComponentAt(dragPoint);

    // Get the current space
    while (!selectedObject.getClass().getSimpleName().equals("BoardSpace")) {
        try {
            dragPoint = selectedObject.getMousePosition();
            selectedObject = selectedObject.getComponentAt(dragPoint);
        } catch (NullPointerException illegalSpace){
            return;
        }
    }

    currentSpace = (BoardSpace) selectedObject;
    startingSpace = currentSpace;

    // If the boardspace has a tile, remove Tile from boardspace and add to dragging layer
    if (BoardSpace.Taken(currentSpace)) {
        // get dragging tile
        draggingTile = BoardSpace.getTile(currentSpace);
        dragging = true;

        // remove tile and repaint space
        BoardSpace.removeTile(currentSpace, draggingTile);
        currentSpace.revalidate();
        currentSpace.repaint();

        // Add tile to dragging layer
        dragWidth = draggingTile.getWidth() / 2;
        dragHeight = draggingTile.getHeight() / 2;
        int x = e.getPoint().x - dragWidth;
        int y = e.getPoint().y - dragHeight;

        draggingTile.setLocation(x, y);
        dragLayer.add(draggingTile, JLayeredPane.DRAG_LAYER);
        draggingTile.revalidate();
        draggingTile.repaint();

        System.out.println("Selected Tile " + Tile.getLetter(draggingTile));
    } else {
        return;
    }

}


@Override
public void mouseReleased(MouseEvent e) {
    /*
    // TODO Auto-generated method stub
    if (!BoardSpace.Taken(currentSpace)) {
        return;
    } else {
        dragging = false; 
        BoardSpace.setTile(currentSpace, draggingTile);
        draggingTile = null;
        currentSpace.repaint();
        currentSpace.revalidate();
    } */
  }

}

完整代码可以从：https://github.com/jowarren13/scrabble.git中提取