Pop-up menus
The most straightforward way to implement a JPopupMenu is to create an inner class that extends MouseAdapter, then add an object of that inner class to each component that you want to produce pop-up behavior:
//: c14:Popup.java
// Creating popup menus with Swing.
// <applet code=Popup width=300 height=200></applet>
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import com.bruceeckel.swing.*;
public class Popup extends JApplet {
private JPopupMenu popup = new JPopupMenu();
private JTextField t = new JTextField(10);
public void init() {
Container cp = getContentPane();
cp.setLayout(new FlowLayout());
cp.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(((JApplet)e.getComponent())
.getContentPane(), e.getX(), e.getY());
}
}
public static void main(String[] args) {
Console.run(new Popup(), 300, 200);
}
} ///:~
The same ActionListener is added to each JMenuItem, so that it fetches the text from the menu label and inserts it into the JTextField.
