DropTest2.java Source code

Introduction

Here is the source code for DropTest2.java

Source

/*
Java Swing, 2nd Edition
By Marc Loy, Robert Eckstein, Dave Wood, James Elliott, Brian Cole
ISBN: 0-596-00408-7
Publisher: O'Reilly 
*/
// DropTest2.java
//Another simple drag & drop tester application.
//

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextArea;

public class DropTest2 extends JFrame implements DropTargetListener {

    DropTarget dt;

    JTextArea ta;

    public DropTest2() {
        super("Drop Test");
        setSize(300, 300);

        getContentPane().add(new JLabel("Drop a list from your file chooser here:"), BorderLayout.NORTH);
        ta = new JTextArea();
        ta.setBackground(Color.white);
        getContentPane().add(ta, BorderLayout.CENTER);

        // Set up our text area to recieve drops...
        // This class will handle drop events
        dt = new DropTarget(ta, this);
        setVisible(true);
    }

    public void dragEnter(DropTargetDragEvent dtde) {
        System.out.println("Drag Enter");
    }

    public void dragExit(DropTargetEvent dte) {
        System.out.println("Drag Exit");
    }

    public void dragOver(DropTargetDragEvent dtde) {
        System.out.println("Drag Over");
    }

    public void dropActionChanged(DropTargetDragEvent dtde) {
        System.out.println("Drop Action Changed");
    }

    public void drop(DropTargetDropEvent dtde) {
        try {
            // Ok, get the dropped object and try to figure out what it is
            Transferable tr = dtde.getTransferable();
            DataFlavor[] flavors = tr.getTransferDataFlavors();
            for (int i = 0; i < flavors.length; i++) {
                System.out.println("Possible flavor: " + flavors[i].getMimeType());
                // Check for file lists specifically
                if (flavors[i].isFlavorJavaFileListType()) {
                    // Great! Accept copy drops...
                    dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
                    ta.setText("Successful file list drop.\n\n");

                    // And add the list of file names to our text area
                    java.util.List list = (java.util.List) tr.getTransferData(flavors[i]);
                    for (int j = 0; j < list.size(); j++) {
                        ta.append(list.get(j) + "\n");
                    }

                    // If we made it this far, everything worked.
                    dtde.dropComplete(true);
                    return;
                }
                // Ok, is it another Java object?
                else if (flavors[i].isFlavorSerializedObjectType()) {
                    dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
                    ta.setText("Successful text drop.\n\n");
                    Object o = tr.getTransferData(flavors[i]);
                    ta.append("Object: " + o);
                    dtde.dropComplete(true);
                    return;
                }
                // How about an input stream?
                else if (flavors[i].isRepresentationClassInputStream()) {
                    dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
                    ta.setText("Successful text drop.\n\n");
                    ta.read(new InputStreamReader((InputStream) tr.getTransferData(flavors[i])),
                            "from system clipboard");
                    dtde.dropComplete(true);
                    return;
                }
            }
            // Hmm, the user must not have dropped a file list
            System.out.println("Drop failed: " + dtde);
            dtde.rejectDrop();
        } catch (Exception e) {
            e.printStackTrace();
            dtde.rejectDrop();
        }
    }

    public static void main(String args[]) {
        new DropTest2();
    }
}