Java GridBagConstraints gridx 和 gridy 不起作用?

I am trying to use the gridx and gridy constraints to position my button. But they do not work! If I change the gridx and gridy variables, nothing happens. If I change the fill to GridBagConstraints to NONE, it still does not work.

我错过了什么吗?

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

public class Window extends JFrame{
    private static final long serialVersionUID = 1L;

    JFrame frame = new JFrame("GUI");
    JTextField username = new JTextField(20);

    public void CreateWindow(){
        JPanel pane = new JPanel();
        pane.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();

        c.fill = GridBagConstraints.NONE;

        JButton button = new JButton("Button 1");
        c.weightx = 1.0;
        c.weighty = 1.0;
        c.gridx = 3;   //Has no effect
        c.gridy = 5;   //Has no effect
        c.anchor = GridBagConstraints.NORTHWEST;//If I remove this, it still does not work.
        pane.add(button, c);                    
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.setSize(400, 600);
        frame.setResizable(true);           
        frame.setLocationRelativeTo(null);          
        frame.add(pane);
        frame.setVisible(true);    
    }
}

如果这很难阅读，问题就出在这里:

JPanel pane = new JPanel();
            pane.setLayout(new GridBagLayout());
            GridBagConstraints c = new GridBagConstraints();

            c.fill = GridBagConstraints.NONE;

            JButton button = new JButton("Button 1");
            c.weightx = 1.0;
            c.weighty = 1.0;
            c.gridx = 3;   //Has no effect
            c.gridy = 5;   //Has no effect
            c.anchor = GridBagConstraints.NORTHWEST;    //If I remove this, it still does not work.
            pane.add(button, c);