组件不会出现

Question

I'm trying to output these components but they won't appear. I can't figure out what I did wrong.

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

public class Buttons extends JApplet {
  Container con;
  JPanel form;
  JButton oneB, twoB, threeB;
  public void init() {
    con = new Container();
    form = new JPanel();
    form.setLayout(new GridLayout(2, 2));
    oneB = new JButton("1B");
    form.add(oneB);
    twoB = new JButton("2B");
    form.add(twoB);
    threeB = new JButton("3B");
    form.add(threeB);
    con.add(form);
  }
}

Answer 1

You never added con to anything

In fact, it's not really needed, just add form to the applet...

  public void init() {
    form = new JPanel();
    form.setLayout(new GridLayout(2, 2));
    oneB = new JButton("1B");
    form.add(oneB);
    twoB = new JButton("2B");
    form.add(twoB);
    threeB = new JButton("3B");
    form.add(threeB);
    add(form);
  }

If you're just learning, I would highly encourage you NOT to use applets, they have their own issues which can make learning a real pain. Instead, try starting with window based components, like JFrame