如何使用ImageIcon制作可拖动的组件
我正在尝试为国际象棋游戏构建用户界面。我使用 GridBagLayout 填充 JLabels ，棋子是 JLabels 的 ImageIcons 。
现在我想通过在棋盘上拖动来移动棋子。有没有办法用 ImageIcons 来做到这一点？或者有更好的方法来解决问题吗？
编辑：这是一个示例代码。你可以注意到你可以移动iconImage，但它不会用鼠标“拖动”。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.HashMap;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class MainDebug extends JFrame implements MouseListener {
private JPanel BoardPanel;
private String buffercase_mousepressed;
private String buffercase_mouseentered;
private JLabel A8 = new JLabel("A8");
private JLabel B8 = new JLabel("B8");
private HashMap componentMap;
private ImageIcon RookIcon = createImageIcon("50px-Rook.png", "Rook");
public MainDebug(String name) {
super(name);
setResizable(true);
}
private ImageIcon createImageIcon(String path, String description) {
java.net.URL imgURL = getClass().getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL, description);
} else {
System.err.println("Couldn't find file: " + path);
return null;
}
}
public void addComponentsToPane(final Container pane) {
BoardPanel = new JPanel();
BoardPanel.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
Dimension dim50 = new Dimension(50,50);
A8.setOpaque(true);
A8.setBackground(Color.white);
A8.setPreferredSize(dim50);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 0;
BoardPanel.add(A8,c);
A8.setName("A8");
A8.addMouseListener(this);
B8.setOpaque(true);
B8.setBackground(Color.lightGray);
B8.setPreferredSize(dim50);
B8.setName("B8");
c.gridx=1;
BoardPanel.add(B8,c);
B8.addMouseListener(this);
A8.setIcon(RookIcon);
pane.add(BoardPanel, BorderLayout.CENTER);
createComponentMap();
}
private void createComponentMap() {
componentMap = new HashMap<String,Component>();
int max_components = BoardPanel.getComponentCount();
//Component[] components = BoardPanel.getComponentCount();
//Component[] components = BoardPanel.getContentPane().getComponents();
for (int i=0; i < max_components; i++) {
componentMap.put(BoardPanel.getComponent(i).getName(), BoardPanel.getComponent(i));
}
}
public Component getComponentByName(String name) {
if (componentMap.containsKey(name)) {
return (Component) componentMap.get(name);
}
else return null;
}
public void mousePressed(MouseEvent e) {
buffercase_mousepressed = e.getComponent().getName();
}
public void mouseReleased(MouseEvent e) {
moveIcon(buffercase_mousepressed,buffercase_mouseentered);
}
public void mouseEntered(MouseEvent e) {
buffercase_mouseentered = e.getComponent().getName();
}
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
public void moveIcon(String A, String B){
if ((A != null) && (B != null)){
JLabel Ja = (JLabel)getComponentByName(A);
JLabel Jb = (JLabel)getComponentByName(B);
Icon iconeA = Ja.getIcon();
Icon iconeB = Jb.getIcon();
if (iconeA != null && iconeB == null){
Ja.setIcon(null);
Jb.setIcon(iconeA);
}
}
buffercase_mousepressed = null;
buffercase_mouseentered = null;
}
private static void createAndShowGUI() {
//Create and set up the window.
MainDebug frame = new MainDebug("Test interface");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Set up the content pane.
frame.addComponentsToPane(frame.getContentPane());
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
3 个答案:
答案 0 :(得分：2)
几年前，我写了一个框架来自定义Swing控件。
也许您可以将它作为一个开始，并根据您的用例进行调整。
教程： http://softsmithy.sourceforge.net/lib/current/docs/tutorial/swing/customizer/index.html
的Javadoc：
http://softsmithy.sourceforge.net/lib/current/docs/api/softsmithy-lib-swing-customizer/index.html
的Maven：
<dependency>
<groupId>org.softsmithy.lib</groupId>
<artifactId>softsmithy-lib-swing-customizer</artifactId>
<version>0.3</version>
</dependency>
您可能希望实施替代CustomizerLayout以使用Chessboard布局替换InfiniteTableLayout，也可能扩展AbstractCustomizerLayout。
您可以使用JXIconCustomizer支持图片/图标。 您还可能希望从JXIconCustomizer的一组可自定义的预览中删除“width”和“height”，以防止用户更改图像的大小：http://softsmithy.sourceforge.net/lib/current/docs/api/softsmithy-lib-swing-customizer/org/softsmithy/lib/swing/customizer/AbstractCustomizer.html#getCustomizableProperties%28%29
您可以在此处找到有关最新版本的更多信息：http://puces-blog.blogspot.ch/2012/11/news-from-software-smithy-version-03.html
如果您认为这种方法由于某种原因不适合您，您可以查看源代码（该库是开源）以获得一些起点：
答案 1 :(得分：2)
好的，这是我对你问题的一点看法......
现在，而不是使用GridBagLayout，我设计了自己的布局管理器，这将允许我指定应放置一块的“网格”位置，并允许板和布局管理器计算物品的物理位置会出现。就个人而言，我认为你会发现它比使用GridBagLayout更容易。
代码有两种模式。它具有“捕捉”模式，这将导致棋子在开始拖动时想要“捕捉”到网格并且“自由”模式，这将允许棋子在拖动时“滑动”整个棋盘...
如果您选择继续使用GridBagLayout，则基本拖动过程不会更改。您可以使用GridBagLayout#setConstraint修改给定组件的约束
public class Chess {
public static void main(String[] args) {
new Chess();
}
public Chess() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new Board());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static final int GRID_SIZE = 50;
public static final boolean SNAP_TO_GRID = false;
public class Board extends JPanel {
private BufferedImage board;
private Point highlightCell;
public Board() {
setLayout(new BoardLayoutManager());
int width = GRID_SIZE * 8;
int height = GRID_SIZE * 8;
board = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = board.createGraphics();
g2d.setColor(Color.WHITE);
g2d.fill(new Rectangle(0, 0, width, height));
g2d.setColor(Color.BLACK);
for (int row = 0; row < 8; row++) {
int xPos = (row % 2 == 0) ? GRID_SIZE : 0;
for (int col = 0; col < 8; col += 2) {
g2d.fill(new Rectangle(xPos, row * GRID_SIZE, GRID_SIZE, GRID_SIZE));
xPos += (GRID_SIZE * 2);
}
}
JLabel piece = new JLabel();
try {
piece.setIcon(new ImageIcon(ImageIO.read(getClass().getResource("/Luke.png"))));
} catch (IOException ex) {
piece.setBackground(new Color(255, 0, 0, 64));
piece.setOpaque(true);
}
add(piece, new Point(0, 0));
MouseHandler mouseHandler = new MouseHandler(this);
addMouseListener(mouseHandler);
addMouseMotionListener(mouseHandler);
}
protected Rectangle getBoardBounds() {
return new Rectangle(getBoardOffset(), new Dimension(GRID_SIZE * 8, GRID_SIZE * 8));
}
public Point gridToPoint(Point grid) {
Point p = new Point();
if (grid != null) {
Point offset = getBoardOffset();
p.x = grid.x * GRID_SIZE + offset.x;
p.y = grid.y * GRID_SIZE + offset.y;
}
return p;
}
public Point pointToGrid(Point p) {
Point grid = null;
Rectangle board = getBoardBounds();
if (board.contains(p)) {
p.x = p.x - board.x;
p.y = p.y - board.y;
grid = new Point();
grid.x = p.x / GRID_SIZE;
grid.y = p.y / GRID_SIZE;
}
return grid;
}
public void setPieceGrid(Component comp, Point grid) {
((BoardLayoutManager) getLayout()).setPieceGrid(comp, grid);
invalidate();
revalidate();
repaint();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
protected Point getBoardOffset() {
int width = getWidth();
int height = getHeight();
Point p = new Point();
p.x = (width - board.getWidth()) / 2;
p.y = (height - board.getHeight()) / 2;
return p;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
Point p = getBoardOffset();
g2d.drawImage(board, p.x, p.y, this);
if (highlightCell != null) {
Point cell = gridToPoint(highlightCell);
Rectangle bounds = new Rectangle(cell.x, cell.y, GRID_SIZE, GRID_SIZE);
g2d.setColor(Color.RED);
g2d.draw(bounds);
}
g2d.dispose();
}
public void setHightlightCell(Point p) {
if (highlightCell != p) {
highlightCell = p;
repaint();
}
}
}
public class MouseHandler extends MouseAdapter {
private Component dragComponent;
private Board board;
private Point dragOffset;
public MouseHandler(Board board) {
this.board = board;
}
public Board getBoard() {
return board;
}
@Override
public void mousePressed(MouseEvent e) {
Component comp = getBoard().getComponentAt(e.getPoint());
if (comp != null) {
dragComponent = comp;
dragOffset = new Point();
dragOffset.x = e.getPoint().x - comp.getX();
dragOffset.y = e.getPoint().y - comp.getY();
}
}
@Override
public void mouseReleased(MouseEvent e) {
if (dragComponent != null) {
Board board = getBoard();
Point p = board.pointToGrid(e.getPoint());
System.out.println(p);
board.setPieceGrid(dragComponent, p);
dragComponent = null;
board.setHightlightCell(null);
}
}
@Override
public void mouseDragged(MouseEvent e) {
if (dragComponent != null) {
Board board = getBoard();
Point grid = board.pointToGrid(e.getPoint());
if (SNAP_TO_GRID) {
Point p = board.gridToPoint(grid);
dragComponent.setLocation(p);
} else {
Point dragPoint = new Point();
dragPoint.x = e.getPoint().x - dragOffset.x;
dragPoint.y = e.getPoint().y - dragOffset.y;
dragComponent.setLocation(dragPoint);
}
board.setHightlightCell(grid);
}
}
}
public class BoardLayoutManager implements LayoutManager2 {
private Map<Component, Point> mapGrid;
public BoardLayoutManager() {
mapGrid = new HashMap<>(25);
}
public void setPieceGrid(Component comp, Point grid) {
mapGrid.put(comp, grid);
}
@Override
public void addLayoutComponent(Component comp, Object constraints) {
if (constraints instanceof Point) {
mapGrid.put(comp, (Point) constraints);
} else {
throw new IllegalArgumentException("Unexpected constraints, expected java.awt.Point, got " + constraints);
}
}
@Override
public Dimension maximumLayoutSize(Container target) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public float getLayoutAlignmentX(Container target) {
return 0.5f;
}
@Override
public float getLayoutAlignmentY(Container target) {
return 0.5f;
}
@Override
public void invalidateLayout(Container target) {
}
@Override
public void addLayoutComponent(String name, Component comp) {
}
@Override
public void removeLayoutComponent(Component comp) {
mapGrid.remove(comp);
}
@Override
public Dimension preferredLayoutSize(Container parent) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public Dimension minimumLayoutSize(Container parent) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public void layoutContainer(Container parent) {
Point offset = ((Board) parent).getBoardOffset();
for (Component comp : parent.getComponents()) {
Point p = mapGrid.get(comp);
if (p == null) {
comp.setBounds(0, 0, 0, 0); // Remove from sight :P
} else {
int x = p.x * GRID_SIZE + offset.x;
int y = p.y * GRID_SIZE + offset.y;
comp.setBounds(x, y, GRID_SIZE, GRID_SIZE);
}
}
}
}
}
答案 2 :(得分：1)
我想知道最简单的方法
使用标准的Swing DnD支持属性（虽然远不如@ Mad的解决方案:-)，基本上是：
- 将棋盘构建为JLabels网格
- 根据需要将各个图块设置为标签
- 实现自定义TransferHandler，它导出/导入图标属性并控制移动
- 注册一个开始拖动的mouseListener
类似的东西：
// the shared mouseListener
MouseListener listener = new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
JComponent c = (JComponent) e.getSource();
TransferHandler handler = c.getTransferHandler();
handler.exportAsDrag(c, e, TransferHandler.COPY);
}
};
// the shared TransferHandler
// super supports copy only, so it needs to do the move itself
// taking the lazy way of null the icon on the source
TransferHandler handler = new TransferHandler("icon") {
private JComponent source;
@Override
public void exportAsDrag(JComponent comp, InputEvent e, int action) {
super.exportAsDrag(comp, e, action);
}
@Override
public boolean canImport(TransferSupport support) {
// empty fields only
return (((JLabel) support.getComponent()).getIcon() == null)
&& super.canImport(support);
}
@Override
protected void exportDone(JComponent source, Transferable data,
int action) {
((JLabel) source).setIcon(null);
}
};
// lazy me: a one row board
JComponent board = new JPanel(new GridLayout(0, 8));
Color[] colors = new Color[] {Color.WHITE, Color.BLACK};
for (int column = 0; column < 8; column++) {
// filled with labels as fields
board.add(createField(colors[column % 2], listener, handler));
}
Icon figure = XTestUtils.loadDefaultIcon();
((JLabel) board.getComponent(0)).setIcon(figure);
// create and configure a JLabel as field
private JLabel createField(Color color, MouseListener listener,
TransferHandler handler) {
JLabel label = new JLabel();
label.setOpaque(true);
label.setBackground(color);
label.addMouseListener(listener);
label.setTransferHandler(handler);
return label;
}
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