给个例子,LZ看看 import java.awt.*; import java.awt.datatransfer.*; import java.awt.event.*; import java.awt.dnd.*; import java.io.*; import java.util.*; import javax.swing.*;/** This is a test class to test drag and drop behavior. Drop items into the text area to see the MIME types of the drop target. */ public class DropTargetTest { public static void main(String[] args) { JFrame frame = new DropTargetFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }/** This frame contains a text area that is a simple drop target. */ class DropTargetFrame extends JFrame { public DropTargetFrame() { setTitle("DropTarget"); setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); JTextArea textArea = new JTextArea("Drop items into this text area.\n"); new DropTarget(textArea, new TextDropTargetListener(textArea)); add(new JScrollPane(textArea), "Center"); } private static final int DEFAULT_WIDTH = 300; private static final int DEFAULT_HEIGHT = 300; }/** This listener displays the properties of a dropped object. */ class TextDropTargetListener implements DropTargetListener { /** Constructs a listener. @param aTextArea the text area in which to display the properties of the dropped object. */ public TextDropTargetListener(JTextArea aTextArea) { textArea = aTextArea; } public void dragEnter(DropTargetDragEvent event) { int a = event.getDropAction(); if ((a & DnDConstants.ACTION_COPY) != 0) textArea.append("ACTION_COPY\n"); if ((a & DnDConstants.ACTION_MOVE) != 0) textArea.append("ACTION_MOVE\n"); if ((a & DnDConstants.ACTION_LINK) != 0) textArea.append("ACTION_LINK\n"); if (!isDragAcceptable(event)) { event.rejectDrag(); return; } } public void dragExit(DropTargetEvent event) { } public void dragOver(DropTargetDragEvent event) { // you can provide visual feedback here } public void dropActionChanged(DropTargetDragEvent event) { if (!isDragAcceptable(event)) { event.rejectDrag(); return; } } public void drop(DropTargetDropEvent event) { if (!isDropAcceptable(event)) { event.rejectDrop(); return; } event.acceptDrop(DnDConstants.ACTION_COPY); Transferable transferable = event.getTransferable(); DataFlavor[] flavors = transferable.getTransferDataFlavors(); for (int i = 0; i < flavors.length; i++) { DataFlavor d = flavors[i]; textArea.append("MIME type=" + d.getMimeType() + "\n"); try { if (d.equals(DataFlavor.javaFileListFlavor)) { java.util.List<File> fileList = (java.util.List<File>) transferable.getTransferData(d); for (File f : fileList) { textArea.append(f + "\n"); } } else if (d.equals(DataFlavor.stringFlavor)) { String s = (String) transferable.getTransferData(d); textArea.append(s + "\n"); } } catch (Exception e) { textArea.append(e + "\n"); } } textArea.append("\n"); event.dropComplete(true); } public boolean isDragAcceptable(DropTargetDragEvent event) { // usually, you check the available data flavors here // in this program, we accept all flavors return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0; } public boolean isDropAcceptable(DropTargetDropEvent event) { // usually, you check the available data flavors here // in this program, we accept all flavors return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0; } private JTextArea textArea; }
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.dnd.*;
import java.io.*;
import java.util.*;
import javax.swing.*;/**
This is a test class to test drag and drop behavior. Drop items into the text area to see the
MIME types of the drop target.
*/
public class DropTargetTest
{
public static void main(String[] args)
{
JFrame frame = new DropTargetFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}/**
This frame contains a text area that is a simple drop target.
*/
class DropTargetFrame extends JFrame
{
public DropTargetFrame()
{
setTitle("DropTarget");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); JTextArea textArea = new JTextArea("Drop items into this text area.\n"); new DropTarget(textArea, new TextDropTargetListener(textArea));
add(new JScrollPane(textArea), "Center");
} private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 300;
}/**
This listener displays the properties of a dropped object.
*/
class TextDropTargetListener implements DropTargetListener
{
/**
Constructs a listener.
@param aTextArea the text area in which to display the
properties of the dropped object.
*/
public TextDropTargetListener(JTextArea aTextArea)
{
textArea = aTextArea;
} public void dragEnter(DropTargetDragEvent event)
{
int a = event.getDropAction();
if ((a & DnDConstants.ACTION_COPY) != 0)
textArea.append("ACTION_COPY\n");
if ((a & DnDConstants.ACTION_MOVE) != 0)
textArea.append("ACTION_MOVE\n");
if ((a & DnDConstants.ACTION_LINK) != 0)
textArea.append("ACTION_LINK\n"); if (!isDragAcceptable(event))
{
event.rejectDrag();
return;
}
} public void dragExit(DropTargetEvent event)
{
} public void dragOver(DropTargetDragEvent event)
{
// you can provide visual feedback here
} public void dropActionChanged(DropTargetDragEvent event)
{
if (!isDragAcceptable(event))
{
event.rejectDrag();
return;
}
} public void drop(DropTargetDropEvent event)
{
if (!isDropAcceptable(event))
{
event.rejectDrop();
return;
} event.acceptDrop(DnDConstants.ACTION_COPY); Transferable transferable = event.getTransferable(); DataFlavor[] flavors = transferable.getTransferDataFlavors();
for (int i = 0; i < flavors.length; i++)
{
DataFlavor d = flavors[i];
textArea.append("MIME type=" + d.getMimeType() + "\n"); try
{
if (d.equals(DataFlavor.javaFileListFlavor))
{
java.util.List<File> fileList
= (java.util.List<File>) transferable.getTransferData(d);
for (File f : fileList)
{
textArea.append(f + "\n");
}
}
else if (d.equals(DataFlavor.stringFlavor))
{
String s = (String) transferable.getTransferData(d);
textArea.append(s + "\n");
}
}
catch (Exception e)
{
textArea.append(e + "\n");
}
}
textArea.append("\n");
event.dropComplete(true);
} public boolean isDragAcceptable(DropTargetDragEvent event)
{
// usually, you check the available data flavors here
// in this program, we accept all flavors
return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0;
} public boolean isDropAcceptable(DropTargetDropEvent event)
{
// usually, you check the available data flavors here
// in this program, we accept all flavors
return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0;
} private JTextArea textArea;
}
看不懂就再问吧
看懂了要记得评论啊