Trascinare componenti (drag)

[claujava]

Ciao ragazzi =) mi kiedevo come si potesse realizzare un semplice Jframe all interno del quale fosse possibile spostare (tramite trascinamento col mouse) JButton o JLabel
..ad esempio supponiamo di voler rendere mobile un JButton..se scrivo questo codice ottengo spostamenti imprecisi..come bisogna fare??grazie a ki sarà disponibile a risp =)



[
JButton x =new JButton ("prova");
x.addMouseListener(drag);


MouseListener drag = new MouseListener ()
{





@Override
public void mouseClicked(MouseEvent arg0) {}

@Override
public void mouseEntered(MouseEvent arg0) {}

@Override
public void mouseExited(MouseEvent arg0) {}
@Override
public void mousePressed(MouseEvent arg0) {}
@Override
public void mouseReleased(MouseEvent me) {
int x=me.getX();
int y=me.getY();
JLabel comp = (JLabel) me.getSource ();

comp.setLocation(x,y);


}
};]

[andbin]

Originariamente inviato da claujava
ad esempio supponiamo di voler rendere mobile un JButton

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class DragComponentTestFrame extends JFrame {
    public DragComponentTestFrame() {
        super("Test drag di componenti");
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(400, 300);

        Container contentPane = getContentPane();
        contentPane.setLayout(null);    // Nessun layout manager

        JButton b = new JButton("JButton");
        b.setBounds(40, 50, 90, 40);
        ComponentDragHandler.register(b);

        JLabel l = new JLabel("JLabel");
        l.setOpaque(true);
        l.setBackground(Color.LIGHT_GRAY);
        l.setHorizontalAlignment(SwingConstants.CENTER);
        l.setBounds(190, 120, 80, 30);
        ComponentDragHandler.register(l);

        contentPane.add(b);
        contentPane.add(l);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new DragComponentTestFrame().setVisible(true);
            }
        });
    }
}

class ComponentDragHandler extends MouseAdapter implements MouseMotionListener {
    private int baseX;
    private int baseY;

    public void mousePressed(MouseEvent e) {
        baseX = e.getX();
        baseY = e.getY();
    }

    public void mouseDragged(MouseEvent e) {
        Component comp = e.getComponent();

        Point compPoint = comp.getLocation();
        Point clickPoint = e.getPoint();

        int x = compPoint.x + clickPoint.x - baseX;
        int y = compPoint.y + clickPoint.y - baseY;

        comp.setLocation(x, y);
    }

    public void mouseMoved(MouseEvent e) {}

    public static void register(Component c) {
        ComponentDragHandler handler = new ComponentDragHandler();
        c.addMouseListener(handler);
        c.addMouseMotionListener(handler);
    }
}