这是一个基本的例子…
通过将标签划分为3x3网格来工作，其中每个单元格代表图标的可能位置。
public class TestMouseDrag { public static void main(String[] args) { new TestMouseDrag(); } public TestMouseDrag() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException ex) { } catch (InstantiationException ex) { } catch (IllegalAccessException ex) { } catch (UnsupportedLookAndFeelException ex) { } Jframe frame = new Jframe(); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new DragMyIcon()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } protected class DragMyIcon extends JPanel { private JLabel label; public DragMyIcon() { ImageIcon icon = null; try { icon = new ImageIcon(ImageIO.read(getClass().getResource("/bomb.png"))); } catch (IOException ex) { ex.printStackTrace(); } label = new JLabel(icon); label.setHorizontalAlignment(JLabel.CENTER); label.setVerticalAlignment(JLabel.CENTER); setLayout(new BorderLayout()); add(label); MouseHandler handler = new MouseHandler(); label.addMouseListener(handler); label.addMouseMotionListener(handler); } } protected class MouseHandler extends MouseAdapter { private boolean active = false; @Override public void mousePressed(MouseEvent e) { JLabel label = (JLabel) e.getComponent(); Point point = e.getPoint(); active = getIconCell(label).contains(point); if (active) { label.setCursor(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR)); } else { label.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR)); } } @Override public void mouseReleased(MouseEvent e) { active = false; JLabel label = (JLabel) e.getComponent(); label.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR)); } @Override public void mouseDragged(MouseEvent e) { if (active) { JLabel label = (JLabel) e.getComponent(); Point point = e.getPoint(); int verticalAlign = label.getVerticalAlignment(); int horizontalAlign = label.getHorizontalAlignment(); if (isWithInColumn(label, point, 0)) { horizontalAlign = JLabel.LEFT; } else if (isWithInColumn(label, point, 1)) { horizontalAlign = JLabel.CENTER; } else if (isWithInColumn(label, point, 2)) { horizontalAlign = JLabel.RIGHT; } if (isWithInRow(label, point, 0)) { verticalAlign = JLabel.TOP; } else if (isWithInRow(label, point, 1)) { verticalAlign = JLabel.CENTER; } else if (isWithInRow(label, point, 2)) { verticalAlign = JLabel.BOTTOM; } label.setVerticalAlignment(verticalAlign); label.setHorizontalAlignment(horizontalAlign); label.invalidate(); label.repaint(); } } @Override public void mouseMoved(MouseEvent e) { } protected boolean isWithInColumn(JLabel label, Point p, int gridx) { int cellWidth = label.getWidth() / 3; int cellHeight = label.getHeight(); Rectangle bounds = new Rectangle(gridx * cellWidth, 0, cellWidth, cellHeight); return bounds.contains(p); } protected boolean isWithInRow(JLabel label, Point p, int gridY) { int cellWidth = label.getWidth(); int cellHeight = label.getHeight() / 3; Rectangle bounds = new Rectangle(0, cellHeight * gridY, cellWidth, cellHeight); return bounds.contains(p); } private Rectangle getIconCell(JLabel label) { Rectangle bounds = new Rectangle(); int cellWidth = label.getWidth() / 3; int cellHeight = label.getHeight() / 3; bounds.width = cellWidth; bounds.height = cellHeight; if (label.getHorizontalAlignment() == JLabel.LEFT) { bounds.x = 0; } else if (label.getHorizontalAlignment() == JLabel.CENTER) { bounds.x = cellWidth; } else if (label.getHorizontalAlignment() == JLabel.RIGHT) { bounds.x = cellWidth * 2; } else { bounds.x = 0; bounds.width = 0; } //if (label.getHorizontalAlignment() == JLabel.TOP) { // bounds.y = 0; //} else if (label.getHorizontalAlignment() == JLabel.CENTER) { // bounds.y = cellHeight; //} else if (label.getHorizontalAlignment() == JLabel.BOTTOM) { // bounds.y = cellHeight * 2; //} else { // bounds.y = 0; // bounds.height = 0; //} if (label.getVerticalAlignment() == JLabel.TOP) { bounds.y = 0; } else if (label.getVerticalAlignment() == JLabel.CENTER) { bounds.y = cellHeight; } else if (label.getVerticalAlignment() == JLabel.BOTTOM) { bounds.y = cellHeight * 2; } else { bounds.y = 0; bounds.height = 0; } return bounds; } }}根据反馈更新
这个例子基本上使用a
JLayerdPane来允许
JLabels在其容器内重新定位…
public class MoveMe { public static void main(String[] args) { new MoveMe(); } public MoveMe() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException ex) { } catch (InstantiationException ex) { } catch (IllegalAccessException ex) { } catch (UnsupportedLookAndFeelException ex) { } Jframe frame = new Jframe(); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new MoveMePane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class MoveMePane extends JLayeredPane { public MoveMePane() { int width = 400; int height = 400; for (int index = 0; index < 10; index++) { String text = "Label " + index; JLabel label = new JLabel(text); label.setSize(label.getPreferredSize()); int x = (int) Math.round(Math.random() * width); int y = (int) Math.round(Math.random() * height); if (x + label.getWidth() > width) { x = width - label.getWidth(); } if (y + label.getHeight() > width) { y = width - label.getHeight(); } label.setLocation(x, y); add(label); } MoveMeMouseHandler handler = new MoveMeMouseHandler(); addMouseListener(handler); addMouseMotionListener(handler); } @Override public Dimension getPreferredSize() { return new Dimension(400, 400); } } public class MoveMeMouseHandler extends MouseAdapter { private int xOffset; private int yOffset; private JLabel draggy; private String oldText; @Override public void mouseReleased(MouseEvent me) { if (draggy != null) { draggy.setText(oldText); draggy.setSize(draggy.getPreferredSize()); draggy = null; } } public void mousePressed(MouseEvent me) { JComponent comp = (JComponent) me.getComponent(); Component child = comp.findComponentAt(me.getPoint()); if (child instanceof JLabel) { xOffset = me.getX() - child.getX(); yOffset = me.getY() - child.getY(); draggy = (JLabel) child; oldText = draggy.getText(); draggy.setText("What a drag"); draggy.setSize(draggy.getPreferredSize()); } } public void mouseDragged(MouseEvent me) { if (draggy != null) { draggy.setLocation(me.getX() - xOffset, me.getY() - yOffset); } } }}
