public class OlderAdderApplet extends Applet implements ActionListener
1:
2: import java.awt.BorderLayout;
3: import java.awt.Button;
4: import java.awt.Color;
5: import java.awt.FlowLayout;
6: import java.awt.Panel;
7: import java.awt.TextField;
8: import java.awt.event.ActionEvent;
9: import java.awt.event.ActionListener;
10: import java.applet.Applet;
11:
12: public class OlderAdderApplet extends Applet implements ActionListener
13: {
14: private TextField inputOutputField;
15: private double sum = 0;
16:
17: public void init()
18: {
19: setLayout(new BorderLayout());
20:
21: Panel buttonPanel = new Panel();
22: buttonPanel.setBackground(Color.gray);
23: buttonPanel.setLayout(new FlowLayout());
24: Button addButton = new Button("Add");
25: addButton.addActionListener(this);
26: buttonPanel.add(addButton);
27: Button resetButton = new Button("Reset");
28: resetButton.addActionListener(this);
29: buttonPanel.add(resetButton);
30: add(buttonPanel, BorderLayout.SOUTH);
31:
32: Panel textPanel = new Panel();
33: textPanel.setBackground(Color.blue);
34: textPanel.setLayout(new FlowLayout());
35: inputOutputField = new TextField("Numbers go here.", 30);
36: inputOutputField.setBackground(Color.white);
37: textPanel.add(inputOutputField);
38: add(textPanel, BorderLayout.CENTER);
39: }
40:
41: public void actionPerformed(ActionEvent e)
42: {
43: if (e.getActionCommand( ).equals("Add"))
44: {
45: sum = sum +
46: stringToDouble(inputOutputField.getText( ));
47: inputOutputField.setText(Double.toString(sum));
48: }
49: else if (e.getActionCommand( ).equals("Reset"))
50: {
51: sum = 0;
52: inputOutputField.setText("0.0");
53: }
54: else
55: inputOutputField.setText("Error in adder code.");
56: }
57:
58: private static double stringToDouble(String stringObject)
59: {
60: return Double.parseDouble(stringObject.trim( ));
61: }
62: }
63: