如何将图像从一个面板拖动到另一个面板

我创建了一个框架，然后在其中创建了面板。 我在一个面板中放置了一个图像，现在我需要将该图像拖到另一个面板上。 我怎么能这样做 作为初学者，请逐步解释。

使用纯java， DragGestureListener ， DropTargetAdapter和TransferHandler快速示例，用于DnD支持一个面板上的图像到另一个面板：

在单击和拖动任何形状之前：

在此处输入图像描述

选择绿色形状并将其拖到上面的空面板上后：

在此处输入图像描述

 import java.awt.BorderLayout; import java.awt.Component; import java.awt.Dimension; import java.awt.Point; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.awt.dnd.DnDConstants; import java.awt.dnd.DragGestureEvent; import java.awt.dnd.DragGestureListener; import java.awt.dnd.DragSource; import java.awt.dnd.DropTarget; import java.awt.dnd.DropTargetAdapter; import java.awt.dnd.DropTargetDropEvent; import java.io.IOException; import java.net.URL; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.TransferHandler; import javax.swing.TransferHandler.TransferSupport; import javax.swing.border.TitledBorder; public class Test { public static void main(String[] args) { createAndShowJFrame(); } public static void createAndShowJFrame() { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { JFrame frame = createJFrame(); frame.setVisible(true); } }); } private static JFrame createJFrame() { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.setTitle("Test"); JPanel panel = createEmptyJPanel(); new MyDropTargetListener(panel);//this must be done or we wont be able to drop any image onto the empty panel frame.add(panel, BorderLayout.CENTER); try { frame.add(createJLabelPanel(), BorderLayout.SOUTH); } catch (Exception ex) { ex.printStackTrace(); } frame.pack(); return frame; } private static JPanel createEmptyJPanel() { final JPanel p = new JPanel() { @Override public Dimension getPreferredSize() { return new Dimension(300, 300); } }; p.setBorder(new TitledBorder("Drag Image onto this panel")); TransferHandler dnd = new TransferHandler() { @Override public boolean canImport(TransferSupport support) { if (!support.isDrop()) { return false; } //only Strings if (!support.isDataFlavorSupported(DataFlavor.imageFlavor)) { return false; } return true; } @Override public boolean importData(TransferSupport support) { if (!canImport(support)) { return false; } Transferable tansferable = support.getTransferable(); Icon ico; try { ico = (Icon) tansferable.getTransferData(DataFlavor.imageFlavor); } catch (Exception e) { e.printStackTrace(); return false; } p.add(new JLabel(ico)); return true; } }; p.setTransferHandler(dnd); return p; } private static JPanel createJLabelPanel() throws Exception { JPanel panel = new JPanel(); panel.setBorder(new TitledBorder("Drag Image from here to Panel above")); JLabel label1 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/gJmeJ.png"))); JLabel label2 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/8BGfi.png"))); JLabel label3 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/1lgtq.png"))); MyDragGestureListener dlistener = new MyDragGestureListener(); DragSource ds1 = new DragSource(); ds1.createDefaultDragGestureRecognizer(label1, DnDConstants.ACTION_COPY, dlistener); DragSource ds2 = new DragSource(); ds2.createDefaultDragGestureRecognizer(label2, DnDConstants.ACTION_COPY, dlistener); DragSource ds3 = new DragSource(); ds3.createDefaultDragGestureRecognizer(label3, DnDConstants.ACTION_COPY, dlistener); panel.add(label1); panel.add(label2); panel.add(label3); return panel; } } class MyDropTargetListener extends DropTargetAdapter { private DropTarget dropTarget; private JPanel p; public MyDropTargetListener(JPanel panel) { p = panel; dropTarget = new DropTarget(panel, DnDConstants.ACTION_COPY, this, true, null); } @Override public void drop(DropTargetDropEvent event) { try { DropTarget test = (DropTarget) event.getSource(); Component ca = (Component) test.getComponent(); Point dropPoint = ca.getMousePosition(); Transferable tr = event.getTransferable(); if (event.isDataFlavorSupported(DataFlavor.imageFlavor)) { Icon ico = (Icon) tr.getTransferData(DataFlavor.imageFlavor); if (ico != null) { p.add(new JLabel(ico)); p.revalidate(); p.repaint(); event.dropComplete(true); } } else { event.rejectDrop(); } } catch (Exception e) { e.printStackTrace(); event.rejectDrop(); } } } class MyDragGestureListener implements DragGestureListener { @Override public void dragGestureRecognized(DragGestureEvent event) { JLabel label = (JLabel) event.getComponent(); final Icon ico = label.getIcon(); Transferable transferable = new Transferable() { @Override public DataFlavor[] getTransferDataFlavors() { return new DataFlavor[]{DataFlavor.imageFlavor}; } @Override public boolean isDataFlavorSupported(DataFlavor flavor) { if (!isDataFlavorSupported(flavor)) { return false; } return true; } @Override public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException { return ico; } }; event.startDrag(null, transferable); } }
  1. 可能有很多方法可以达到你想要的效果。 您可以使用玻璃窗格或JXLayer
  2. 停止将两个面板视为单独的元素，更像是将它们放入大型虚拟空间中。
  3. 该示例基本上将父组件视为两个图像窗格是窗口的“虚拟空间”。
  4. 它们共享相同的图像和图像位置详细信息。 他们个人将图像位置（在虚拟坐标中）转换为本地坐标，并绘制与其上显示的图像一样多的图像…
  5. 鼠标控件由父级维护。 这大大简化了流程，因为它可以同时通知两个面板

而代码是…… 

 import java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.Image; import java.awt.Point; import java.awt.Rectangle; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import javax.imageio.ImageIO; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; import javax.swing.border.EmptyBorder; import javax.swing.border.LineBorder; public class CrossImage { public static void main(String[] args) { new CrossImage(); } public CrossImage() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new TestPane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class TestPane extends JPanel { private BufferedImage img; private ImagePane left; private ImagePane right; private Point imagePoint; public TestPane() { setBorder(new EmptyBorder(10, 10, 10, 10)); setLayout(new GridLayout(0, 2, 10, 10)); left = new ImagePane(); right = new ImagePane(); imagePoint = new Point(10, 10); left.setImageLocation(imagePoint); right.setImageLocation(imagePoint); try { img = ImageIO.read(new File("Background.jpg")); left.setImage(img); right.setImage(img); } catch (IOException ex) { ex.printStackTrace(); } add(left); add(right); MouseAdapter mouseHandler = new MouseAdapter() { private Point delta; @Override public void mousePressed(MouseEvent e) { Point origin = e.getPoint(); Rectangle bounds = new Rectangle(imagePoint, new Dimension(img.getWidth(), img.getHeight())); if (bounds.contains(origin)) { delta = new Point(origin.x - imagePoint.x, origin.y - imagePoint.y); } } @Override public void mouseDragged(MouseEvent e) { if (delta != null) { imagePoint = e.getPoint(); imagePoint.translate(-delta.x, -delta.y); left.setImageLocation(imagePoint); right.setImageLocation(imagePoint); } } @Override public void mouseReleased(MouseEvent e) { delta = null; } }; addMouseListener(mouseHandler); addMouseMotionListener(mouseHandler); } } public class ImagePane extends JPanel { private Image image; private Point imageLocation; public ImagePane() { setBorder(new LineBorder(Color.DARK_GRAY)); } @Override public Dimension getPreferredSize() { return image == null ? super.getPreferredSize() : new Dimension(image.getWidth(this), image.getHeight(this)); } public void setImage(Image image) { this.image = image; repaint(); } public void setImageLocation(Point imageLocation) { this.imageLocation = imageLocation; repaint(); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); if (image != null && imageLocation != null) { Point p = SwingUtilities.convertPoint(getParent(), imageLocation, this); g.drawImage(image, px, py, this); } } } }

希望这能帮到你。非常类似的问题和一个很好的答案。

是否可以在JFrame中使用JButton，JTextField等“可移动”/“可拖动”组件？

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