More on listeners - An Introduction to Graphical User Interfaces with Java Swing - page 86

File: its/CounterInterfaceGUI/CounterInterfacePanel.Java

1. package its.CounterInterfaceGUI;
2.
3. import javax.swing.JPanel;
4. import javax.swing.JButton;
5. import javax.swing.JLabel;
6. import java.awt.BorderLayout;
7. import javax.swing.SwingConstants;
8. import java.awt.event.ActionListener;
9. import java.awt.event.ActionEvent;
10.
11.

public class CounterInterfacePanel extends JPanel

12.

implements ActionListener{

13.
14.

private CounterModel counter;

15.

private JLabel valueLabel;

16.
17. public CounterInterfacePanel() {

18.

counter = new CounterModel();

19.
20.

BorderLayout bordLay = new BorderLayout();

21. this .setLayout(bordLay);

22.
23.

JButton upButton = new JButton("Up");

24. JButton downButton = new JButton("Down");

25. valueLabel = new JLabel(""+counter.getValue(),SwingConstants.CENTER);

26.
27.

this .add(upButton,BorderLayout.WEST);

28.

this .add(downButton,BorderLayout.EAST);

29.

this .add(valueLabel,BorderLayout.CENTER);

30.
31.

// A CounterInterfacePanel is now

32.

// also an ActionListener. Therefore, it

33.

// is assigned to the buttons using ”this”.

34.

upButton.addActionListener( this );

35.

downButton.addActionListener( this );

36.

}

37.
38.

public void increment(){

39.

counter.increment();

40.

valueLabel.setText(""+counter.getValue());

41. }

42.
43.

public void decrement(){

44. counter.decrement();