popup.java

java程序设计源代码

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

public class Popup extends JPanel {
  JPopupMenu popup = new JPopupMenu();
  JTextField t = new JTextField(10);
  public Popup() {
    add(t);
    ActionListener al = new ActionListener() {
      public void actionPerformed(ActionEvent e){
        t.setText(
          ((JMenuItem)e.getSource()).getText());
      }
    };
    JMenuItem m = new JMenuItem("Hither");
    m.addActionListener(al);
    popup.add(m);
    m = new JMenuItem("Yon");
    m.addActionListener(al);
    popup.add(m);
    m = new JMenuItem("Afar");
    m.addActionListener(al);
    popup.add(m);
    popup.addSeparator();
    m = new JMenuItem("Stay Here");
    m.addActionListener(al);
    popup.add(m);
    PopupListener pl = new PopupListener();
    addMouseListener(pl);
    t.addMouseListener(pl);
  }
  class PopupListener extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      maybeShowPopup(e);
    }
    public void mouseReleased(MouseEvent e) {
      maybeShowPopup(e);
    }
    private void maybeShowPopup(MouseEvent e) {
      if(e.isPopupTrigger()) {
        popup.show(
          e.getComponent(), e.getX(), e.getY());
      }
    }
  }
  public static void main(String args[]) {
		JPanel p = new Popup();
		JFrame frame = new JFrame("TestPopup");
		frame.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e){
				System.exit(0);
			}
		});
		frame.getContentPane().add(
			p, BorderLayout.CENTER);
		frame.setSize(400,300);
		frame.setVisible(true);
  }
}