为了调整大小,我查看了类属性,找不到任何东西,可以触发。最好的解决方案是这样的。
package groupleyaut;
import java.awt.EventQueue;
import javax.swing.JFrame;
import  javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class gfg {
`enter code here`private JFrame frame;
/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                gfg window = new gfg();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}
/**
 * Create the application.
 */
public gfg() {
    initialize();
}
/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 807, 325);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JPanel panel = new JPanel();
    panel.setBackground(Color.BLACK);
    frame.getContentPane().add(panel, BorderLayout.CENTER);
    JPanel panel_1 = new JPanel();
    panel_1.setPreferredSize(new Dimension(10, 100));
    JPanel panel_2 = new JPanel();
    panel_2.setPreferredSize(new Dimension(200, 50));
    GroupLayout gl_panel = new GroupLayout(panel);
    gl_panel.setHorizontalGroup(
        gl_panel.createParallelGroup(Alignment.LEADING)
            .addGroup(gl_panel.createSequentialGroup()
                .addContainerGap()
                .addComponent(panel_1, GroupLayout.PREFERRED_SIZE, panel_1.getPreferredSize().width, GroupLayout.PREFERRED_SIZE)
                .addGap(64)
                .addComponent(panel_2, GroupLayout.PREFERRED_SIZE, 492, GroupLayout.PREFERRED_SIZE)
                .addContainerGap(166, Short.MAX_VALUE))
    );
    gl_panel.setVerticalGroup(
        gl_panel.createParallelGroup(Alignment.LEADING)
            .addGroup(gl_panel.createSequentialGroup()
                .addContainerGap()
                .addGroup(gl_panel.createParallelGroup(Alignment.LEADING)
                    .addComponent(panel_2, GroupLayout.PREFERRED_SIZE, 128, GroupLayout.PREFERRED_SIZE)
                    .addComponent(panel_1, GroupLayout.PREFERRED_SIZE, panel_1.getPreferredSize().height, GroupLayout.PREFERRED_SIZE))
                .addGap(66))
    );
    panel_2.setLayout(null);
    JButton btnNewButton = new JButton("New button");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            panel_1.setPreferredSize(new Dimension(10, 200));
            GroupLayout gl_panel = new GroupLayout(panel);
            gl_panel.setHorizontalGroup(
                gl_panel.createParallelGroup(Alignment.LEADING)
                    .addGroup(gl_panel.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(panel_1, GroupLayout.PREFERRED_SIZE, panel_1.getPreferredSize().width, GroupLayout.PREFERRED_SIZE)
                        .addGap(64)
                        .addComponent(panel_2, GroupLayout.PREFERRED_SIZE, 492, GroupLayout.PREFERRED_SIZE)
                        .addContainerGap(166, Short.MAX_VALUE))
            );
            gl_panel.setVerticalGroup(
                gl_panel.createParallelGroup(Alignment.LEADING)
                    .addGroup(gl_panel.createSequentialGroup()
                        .addContainerGap()
                        .addGroup(gl_panel.createParallelGroup(Alignment.LEADING)
                            .addComponent(panel_2, GroupLayout.PREFERRED_SIZE, 128, GroupLayout.PREFERRED_SIZE)
                            .addComponent(panel_1, GroupLayout.PREFERRED_SIZE, panel_1.getPreferredSize().height, GroupLayout.PREFERRED_SIZE))
                        .addGap(66))
            );
            panel.setLayout(gl_panel);
        }
    });
    btnNewButton.setBounds(147, 42, 89, 23);
    panel_2.add(btnNewButton);
    panel.setLayout(gl_panel);
}
}