
848 CHAPTER 12 Graphical User Interfaces
Figure 12.7
Running Example 12.4
In the constructor, at lines 40–41, we declare and instantiate the Button-
Handler event handler, bh. At lines 43–45, we call the addActionListener
method to register the handler on our two buttons.
The output of this example is shown in Figure 12.7. When you run this
example, try entering a valid number into the text field, and press each but-
ton. Then try to enter text that cannot be converted to a number. Also, try
deleting either statement that registers the event listener on the buttons
(line 44 or 45), and run the application again.
12.7 Radio Buttons and Checkboxes
If you ...