Arranging Components on a User Interface - Java 6 - page 312

The ActionListener interface includes only one method:

public void actionPerformed(Action evt) {
// more to come

}

This method is called when a component being listened to generates an action event. In
the SurveyPanel class, this happens whenever a button is clicked.

In SurveyPanel , this method uses an instance variable that keeps track of which card to
display:

int currentCard = 0;

Every time a button is clicked and actionPerformed() is called, this variable is incre-
mented, and the card layout manager's show( Container , String ) method is called to
display a new card. If the last card has been displayed, the Finish button is disabled.

Here's the complete method:

public void actionPerformed(ActionEvent evt) {
currentCard++;
if (currentCard >= ask.length) {
ask[2].finalButton.setEnabled(false);

}
cards.show(this, “Card “ + currentCard);

}

Listing 11.5 shows the full SurveyWizard class.

LISTING 11.5 The Full Text of SurveyWizard.java

1: import java.awt.*;
2: import java.awt.event.*;
3: import javax.swing.*;
4:
5: public class SurveyWizard extends JPanel implements ActionListener {
6: int currentCard = 0;
7: CardLayout cards = new CardLayout();
8: SurveyPanel[] ask = new SurveyPanel[3];
9:
10: public SurveyWizard() {
11: super();
12: setSize(240, 140);
13: setLayout(cards);
14: // set up survey
15: String question1 = “What is your gender?”;
16: String[] responses1 = { “female”, “male”, “not telling” };