addtwoapplet.java

21天学会java 一书的源代码。参看此书必不可少的辅助

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class AddTwoApplet extends JApplet implements ActionListener {
    JTextField one = new JTextField("0", 5);
    JLabel plus = new JLabel("+");
    JTextField two = new JTextField("0", 5);
    JButton equals = new JButton("Add");
    JLabel result = new JLabel("???");

    public void init() {
        Container pane = getContentPane();
        FlowLayout flow = new FlowLayout();
        pane.setLayout(flow);
        equals.addActionListener(this);
        pane.add(one);
        pane.add(plus);
        pane.add(two);
        pane.add(equals);
        pane.add(result);
        setContentPane(pane);
    }

    public void actionPerformed(ActionEvent evt) {
        try {
            int value1 = Integer.parseInt(one.getText());
            int value2 = Integer.parseInt(two.getText());
            result.setText("" + (value1 + value2));
        } catch (NumberFormatException exc) {
            one.setText("0");
            two.setText("0");
            result.setText("0");
        }
    }
}