Java Swing - 如何使用GridBagConstraints每个步骤一个值...

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.image.BufferedImage;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Main {
  public static void main(String[] args) {
    JPanel gui = new JPanel(new BorderLayout(2, 2));
    BufferedImage bi = new BufferedImage(600, 200, BufferedImage.TYPE_INT_RGB);
    gui.add(new JLabel(new ImageIcon(bi)));

    JFrame myframe = new JFrame();
    JPanel myPanel = new JPanel();
    gui.add(myPanel, BorderLayout.PAGE_END);
    myPanel.setLayout(new GridLayout(2, 0, 0, 0));

    int x = 0;
    int y = 5;

    for (char alphabet = 'A'; alphabet <= 'Z'; alphabet++) {
      myPanel.add(new JButton(alphabet + ""));
      x++;
      if (x > 15) {
        y = 6;
        x = 0;
      }
    }
    myframe.add(gui);
    myframe.pack();
    myframe.setVisible(true);

    myframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}