AWTでドラッグアンドドロップを試す

このサイトを参考にしています。

import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import java.awt.event.*;
import java.io.*;

/**
$Id: awt-dnd.html,v 1.1 2009/06/22 16:12:04 kishi Exp kishi $
*/

public class DNDTest implements DragGestureListener, DragSourceListener,
    DropTargetListener, Transferable {
    static final DataFlavor[] supportedFlavors = { null };

    static
    {
        try {
            supportedFlavors[ 0 ] = new DataFlavor( DataFlavor.javaJVMLocalObjectMimeType );
        } catch ( Exception ex ) {
            ex.printStackTrace();
        }
    }

    Object object;

    // Transferable methods.
    public Object getTransferData( DataFlavor flavor ) {
        if ( flavor.isMimeTypeEqual( DataFlavor.javaJVMLocalObjectMimeType ) )
            return object;
        else
            return null;
    }
    public DataFlavor[] getTransferDataFlavors() {
        return supportedFlavors;
    }
    public boolean isDataFlavorSupported( DataFlavor flavor ) {
        return flavor.isMimeTypeEqual( DataFlavor.javaJVMLocalObjectMimeType );
    }

    // DragGestureListener method.
    public void dragGestureRecognized( DragGestureEvent ev ) {
        ev.startDrag( null, this, this );
    }

    // DragSourceListener methods.
    public void dragDropEnd( DragSourceDropEvent ev ) { }
    public void dragEnter( DragSourceDragEvent ev ) { }
    public void dragExit( DragSourceEvent ev ) { }
    public void dragOver( DragSourceDragEvent ev ) {
        object = ev.getSource();
    }
    public void dropActionChanged( DragSourceDragEvent ev ) { }

    // DropTargetListener methods.
    public void dragEnter( DropTargetDragEvent ev ) { }
    public void dragExit( DropTargetEvent ev ) { }
    public void dragOver( DropTargetDragEvent ev ) {
        dropTargetDrag( ev );
    }
    public void dropActionChanged( DropTargetDragEvent ev ) {
        dropTargetDrag( ev );
    }
    void dropTargetDrag( DropTargetDragEvent ev ) {
        ev.acceptDrag( ev.getDropAction() );
    }

    public void drop( DropTargetDropEvent ev ) {
        ev.acceptDrop( ev.getDropAction() );
        try {
            Object target = ev.getSource();
            Object source = ev.getTransferable().getTransferData( supportedFlavors[ 0 ] );
            Component component = ( ( DragSourceContext ) source ).getComponent();
            Container oldContainer = component.getParent();
            Container container = ( Container ) ( ( DropTarget ) target ).getComponent();
            container.add( component );
            oldContainer.validate();
            oldContainer.repaint();
            container.validate();
            container.repaint();
        } catch ( Exception ex ) {
            ex.printStackTrace();
        }
        ev.dropComplete( true );
    }

    public static void main( String[] arg ) {
        Button button = new Button( "このボタンをドラッグしてください。" );
        Label label = new Label( "このラベルをドラッグしてください。" );
        Checkbox checkbox = new Checkbox( "このチェックボックスをドラッグしてください。" );

        Frame source = new Frame( "SOURCE" );
        source.setLayout( new FlowLayout() );
        source.add( button );
        source.add( label );
        source.addWindowListener( new WindowAdapter() {
                                      public void windowClosing( WindowEvent we ) {
                                          System.exit( 0 );
                                      }
                                  }
                                );

        Frame target = new Frame( "TARGET" );
        target.setLayout( new FlowLayout() );
        target.add( checkbox );
        target.addWindowListener( new WindowAdapter() {
                                      public void windowClosing( WindowEvent we ) {
                                          System.exit( 0 );
                                      }
                                  }
                                );

        DNDTest dndListener = new DNDTest();

        DragSource dragSource = new DragSource();
        DropTarget dropTarget1 = new DropTarget( source, DnDConstants.ACTION_MOVE, dndListener );
        DropTarget dropTarget2 = new DropTarget( target, DnDConstants.ACTION_MOVE, dndListener );
        DragGestureRecognizer dragRecognizer1 = dragSource.createDefaultDragGestureRecognizer( button, DnDConstants.ACTION_MOVE, dndListener );
        DragGestureRecognizer dragRecognizer2 = dragSource.createDefaultDragGestureRecognizer( label, DnDConstants.ACTION_MOVE, dndListener );
        DragGestureRecognizer dragRecognizer3 = dragSource.createDefaultDragGestureRecognizer( checkbox, DnDConstants.ACTION_MOVE, dndListener );

        source.setBounds( 0, 200, 400, 200 );
        target.setBounds( 420, 200, 400, 200 );
        source.show();
        target.show();
    }

}