DnDDemo2.java Source code

Introduction

Here is the source code for DnDDemo2.java

Source

import java.awt.Color;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.TransferHandler;
import javax.swing.text.JTextComponent;

public class DnDDemo2 {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new JPanel());

        JTextField textField = new JTextField(25);
        textField.setText("Let's swing higher");
        frame.add(textField);

        JTextArea textArea = new JTextArea("Demonstrating\ndrag and drop");
        textArea.setForeground(Color.red);
        frame.add(new JScrollPane(textArea));

        textArea.setDragEnabled(true);
        textField.setDragEnabled(true);
        TextColorTransferHandler transferHandler = new TextColorTransferHandler();
        textArea.setTransferHandler(transferHandler);
        textField.setTransferHandler(transferHandler);
        frame.pack();
        frame.setVisible(true);
    }
}

class TextColorTransferHandler extends TransferHandler {

    public int getSourceActions(JComponent c) {
        return COPY_OR_MOVE;
    }

    protected Transferable createTransferable(JComponent component) {
        String text = ((JTextComponent) component).getText();
        Color color = component.getForeground();
        TextColor transferable = new TextColor(text, color);
        return transferable;
    }

    public boolean canImport(JComponent c, DataFlavor[] flavors) {
        return true;
    }

    public boolean importData(JComponent component, Transferable transferable) {
        String colorMimeType = DataFlavor.javaJVMLocalObjectMimeType + ";class=java.awt.Color";
        JTextComponent textComponent = (JTextComponent) component;
        try {
            DataFlavor colorFlavor = new DataFlavor(colorMimeType);
            Color color = (Color) transferable.getTransferData(colorFlavor);
            String text = (String) transferable.getTransferData(DataFlavor.stringFlavor);
            textComponent.setForeground(color);
            textComponent.setText(text);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return true;
    }
}

class TextColor implements Transferable {
    private String text;

    private Color color;

    private DataFlavor[] flavors;

    public TextColor(String text, Color color) {
        String colorMimeType = DataFlavor.javaJVMLocalObjectMimeType + ";class=java.awt.Color";
        DataFlavor colorFlavor = null;
        try {
            colorFlavor = new DataFlavor(colorMimeType);
        } catch (ClassNotFoundException e) {
        }
        flavors = new DataFlavor[2];
        flavors[0] = DataFlavor.stringFlavor;
        flavors[1] = colorFlavor;
        this.text = text;
        this.color = color;
    }

    public DataFlavor[] getTransferDataFlavors() {
        return (DataFlavor[]) flavors.clone();
    }

    public boolean isDataFlavorSupported(DataFlavor flavor) {
        for (int i = 0; i < flavors.length; i++) {
            if (flavor.equals(flavors[i])) {
                return true;
            }
        }
        return false;
    }

    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
        if (flavor.equals(flavors[0])) {
            return text;
        } else if (flavor.equals(flavors[1])) {
            return color;
        } else {
            throw new UnsupportedFlavorException(flavor);
        }
    }
}

//Reference:
//Java 6 New Features: A Tutorial
//by Budi Kurniawan 
//Brainy Software Corp. 2006
//Chapter 4 - Networking
//# ISBN-10: 0975212885
//# ISBN-13: 978-0975212882