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