Nome della Classe:

 1 package mousedragtesto;
 2 
 3 import java.awt.Dimension;
 4 import java.awt.EventQueue;
 5 import java.awt.Font;
 6 import java.awt.Graphics;
 7 import java.awt.Point;
 8 import java.awt.event.MouseAdapter;
 9 import java.awt.event.MouseEvent;
10 import java.awt.event.MouseMotionAdapter;
11 import javax.swing.JFrame;
12 import javax.swing.JPanel;
13 
14 
15 public class MouseDragTesto extends JPanel {
16 
17     private static final String TITLE = "Drag me!";
18     private static final int W = 640;
19     private static final int H = 480;
20     private Point textPt = new Point(W / 2, H / 2);
21     private Point mousePt;
22 
23     public MouseDragTesto() {
24         this.setFont(new Font("Serif", Font.ITALIC + Font.BOLD, 32));
25         this.addMouseListener(new MouseAdapter() {
26 
27             @Override
28             public void mousePressed(MouseEvent e) {
29                 mousePt = e.getPoint();
30                 repaint();
31             }
32         });
33         this.addMouseMotionListener(new MouseMotionAdapter() {
34 
35             @Override
36             public void mouseDragged(MouseEvent e) {
37                 int dx = e.getX() - mousePt.x;
38                 int dy = e.getY() - mousePt.y;
39                 textPt.setLocation(textPt.x + dx, textPt.y + dy);
40                 mousePt = e.getPoint();
41                 repaint();
42             }
43         });
44     }
45 
46     @Override
47     public Dimension getPreferredSize() {
48         return new Dimension(W, H);
49     }
50 
51     @Override
52     public void paintComponent(Graphics g) {
53         super.paintComponent(g);
54         int w2 = g.getFontMetrics().stringWidth(TITLE) / 2;
55         g.drawString(TITLE, textPt.x - w2, textPt.y);
56     }
57 
58     public static void main(String[] args) {
59         EventQueue.invokeLater(new Runnable() {
60 
61             @Override
62             public void run() {
63                 JFrame f = new JFrame(TITLE);
64                 f.add(new MouseDragTesto());
65                 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
66                 f.pack();
67                 f.setLocationRelativeTo(null);
68                 f.setVisible(true);
69             }
70         });
71     }
72 }