/** * @version 1.00 1999-09-11 * @author Cay Horstmann */ import java.awt.*; import java.awt.datatransfer.*; import java.awt.event.*; import java.awt.dnd.*; import java.io.*; import java.util.*; import javax.swing.*; public class DropTargetTest { public static void main(String[] args) { JFrame frame = new DropTargetFrame(); frame.show(); } } class DropTargetFrame extends JFrame { public DropTargetFrame() { setTitle("DropTarget"); setSize(300, 300); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } } ); Container contentPane = getContentPane(); JTextArea textArea = new JTextArea("Drop items into this text area.\n"); new DropTarget(textArea, new TextDropTargetListener(textArea)); contentPane.add(new JScrollPane(textArea), "Center"); } } class TextDropTargetListener implements DropTargetListener { public TextDropTargetListener(JTextArea ta) { textArea = ta; } 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 fileList = (java.util.List) transferable.getTransferData(d); Iterator iterator = fileList.iterator(); while (iterator.hasNext()) { File f = (File)iterator.next(); textArea.append(f + "\n"); } } else if (d.equals(DataFlavor.stringFlavor)) { String s = (String) transferable.getTransferData(d); textArea.append(s + "\n"); } else if (d.isMimeTypeEqual("text/plain")) { String charset = d.getParameter("charset"); InputStream in = (InputStream) transferable.getTransferData(d); boolean more = true; int ch; if (charset.equals("ascii")) { do { ch = in.read(); if (ch != 0 && ch != -1) textArea.append("" + (char)ch); else more = false; } while (more); } else if (charset.equals("unicode")) { boolean littleEndian = true; // if no byte ordering mark, we assume // Windows is the culprit do { ch = in.read(); int ch2 = in.read(); if (ch != -1 && littleEndian) ch = (ch & 0xFF) | ((ch2 & 0xFF) << 8); if (ch == 0xFFFE) littleEndian = false; else if (ch != 0 && ch != -1) textArea.append("" + (char)ch); else more = false; } while (more); } textArea.append("\n"); } } catch(Exception e) { textArea.append("Error: " + e + "\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; }