Swing I - Java - page 955

24. It will not compile, but will give compiler error messages saying that, in effect,

the invocations of addActionListener such as

redButton.addActionListener( this );

have arguments of an incorrect type.
25. Clicking a JMenuItem fires an action event (that is, an object of the class Action-
Event ). This is the same as with a JButton .
26. JButton b = new JButton("Hello");
b.setActionCommand("Bye");

27. JMenuItem m = new JMenuItem (" Hello ");
m.setActionCommand("Bye");

28. To change the action command for a JMenuItem , you use the method set-
ActionCommand , just as you would for a JButton .
29. Yes, it is legal.
30. As many as you want. Only one can be added with the method setJMenuBar , but
any number of others can be added to using the add method.
31. setJMenuBar

32. JMenuItem aChoice = new JMenuItem("Exit");

33. m.add(mItem);
mBar.add(m);
setJMenuBar(mBar);

You could use the following instead of using setJMenuBar :

add(mBar);

This will all take place inside a constructor named MenuGUI .

34. Register all three types of listeners with blueChoice , as follows:

blueChoice.addActionListener( new RedListener());
blueChoice.addActionListener( new WhiteListener());
blueChoice.addActionListener( new BlueListener());

35. Replace the three inner classes with the following inner class:

private class ColorListener implements ActionListener
{
private JPanel thePanel;
private Color theColor;

public ColorListener(Color c, JPanel p)
{