movebutton.java

learning java的源代码。书中每个实例都有相关的代码example。

//file: MoveButton.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class MoveButton extends JPanel {
  JButton button = new JButton("I Move");

  public MoveButton(  ) {
    setLayout(null);
    add(button);
    button.setSize(button.getPreferredSize(  ));
    button.setLocation(20, 20);
    addMouseListener(new MouseAdapter(  ) {
      public void mousePressed(MouseEvent e) {
      button.setLocation(e.getX(), e.getY(  ));
      }
    });
  }

  public static void main(String[] args) {
    JFrame f = new JFrame("MoveButton");
    f.addWindowListener(new WindowAdapter(  ) {
      public void windowClosing(WindowEvent e) { System.exit(0); }
    });
    f.setSize(250, 200);
    f.setLocation(200, 200);
    f.setContentPane(new MoveButton(  ));
    f.setVisible(true);
  }
}