GridBagLayout - 为什么只调整左键？

Question

为什么在更改框架宽度时仅调整左侧按钮的大小？ 如何将所有字段调整大小？ 我尝试使用Swing做灵活的计算器。 我应该使用fill = GridBagConstraints.BOTH;或者说不同的东西？

package zda;

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.Font;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.Dimension;
import java.awt.Insets;

public class CalcAlfa {

private JFrame frame;
private JTextField textField;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                CalcAlfa window = new CalcAlfa();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the application.
 */
public CalcAlfa() {
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 300, 462);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    GridBagLayout gridBagLayout = new GridBagLayout();
    gridBagLayout.columnWidths = new int[]{50, 50, 50, 50, 50};
    gridBagLayout.rowHeights = new int[]{50, 50, 50, 50, 50};
    gridBagLayout.columnWeights = new double[]{1.0, Double.MIN_VALUE};
    gridBagLayout.rowWeights = new double[]{0.0, 0.0, Double.MIN_VALUE};
    frame.getContentPane().setLayout(gridBagLayout);

    textField = new JTextField();
    GridBagConstraints gbc_textField = new GridBagConstraints();
    gbc_textField.insets = new Insets(0, 0, 5, 5);
    gbc_textField.fill = GridBagConstraints.BOTH;
    gbc_textField.gridwidth = 4;
    gbc_textField.gridx = 0;
    gbc_textField.gridy = 0;

    frame.getContentPane().add(textField, gbc_textField);
    textField.setColumns(10);

    JButton b1 = new JButton("C");
    GridBagConstraints gbc_b1 = new GridBagConstraints();
    gbc_b1.insets = new Insets(0, 0, 5, 5);
    gbc_b1.fill = GridBagConstraints.BOTH;
    gbc_b1.gridx = 4;
    gbc_b1.gridy = 0;
    frame.getContentPane().add(b1, gbc_b1);

    JButton b2 = new JButton("7");
    GridBagConstraints gbc_b2 = new GridBagConstraints();
    gbc_b2.insets = new Insets(0, 0, 5, 5);
    gbc_b2.fill = GridBagConstraints.BOTH;
    gbc_b2.gridx = 0;
    gbc_b2.gridy = 1;
    frame.getContentPane().add(b2, gbc_b2);
    JButton b3 = new JButton("8");
    GridBagConstraints gbc_b3 = new GridBagConstraints();
    gbc_b3.insets = new Insets(0, 0, 5, 5);
    gbc_b3.fill = GridBagConstraints.BOTH;
    gbc_b3.gridx = 1;
    gbc_b3.gridy = 1;
    frame.getContentPane().add(b3, gbc_b3);

    JButton b4 = new JButton("9");
    GridBagConstraints gbc_b4 = new GridBagConstraints();
    gbc_b4.insets = new Insets(0, 0, 5, 5);
    gbc_b4.fill = GridBagConstraints.BOTH;
    gbc_b4.gridx = 2;
    gbc_b4.gridy = 1;
    frame.getContentPane().add(b4, gbc_b4);
    JButton b5 = new JButton("/");
    GridBagConstraints gbc_b5 = new GridBagConstraints();
    gbc_b5.insets = new Insets(0, 0, 5, 5);
    gbc_b5.fill = GridBagConstraints.BOTH;
    gbc_b5.gridx = 3;
    gbc_b5.gridy = 1;
    frame.getContentPane().add(b5, gbc_b5);
    JButton b6 = new JButton("sqrt");
    GridBagConstraints gbc_b6 = new GridBagConstraints();
    gbc_b6.insets = new Insets(0, 0, 5, 5);
    gbc_b6.fill = GridBagConstraints.BOTH;
    gbc_b6.gridx = 4;
    gbc_b6.gridy = 1;
    frame.getContentPane().add(b6, gbc_b6);

}

}