为什么按钮的大小和位置改变不了

Question

为什么开始测试可以调整但是查询不能

public class UserFrame extends JFrame {
    JButton button_submit;
    JButton button_query;
    JTextField textField_name;
    JTextField textField_sno;
    JTextField textField_major;
    JTextField textField_className;

    public UserFrame() {
        setTitle("添加学生");
        setLayout(null);
        setLocationRelativeTo(null);
        setSize(440,350);
        initComponents();
        setVisible(true);
    }

    private void initComponents() {
        JLabel label1 = new JLabel("姓名");
        label1.setBounds(75, 20, 80, 20);
        add(label1);
        textField_name = new JTextField();
        textField_name.setBounds(140, 20, 215, 26);
        add(textField_name);

        JLabel label2 = new JLabel("学号");
        label2.setBounds(75, 65, 80, 20);
        add(label2);
        textField_sno = new JTextField();
        textField_sno.setBounds(140, 65, 215, 26);
        add(textField_sno);

        JLabel label3 = new JLabel("专业");
        label3.setBounds(75, 110, 80, 20);
        add(label3);
        textField_major = new JTextField();
        textField_major.setBounds(140, 110, 215, 26);
        add(textField_major);

        JLabel label4 = new JLabel("班级");
        label4.setBounds(75, 155, 80, 20);
        add(label4);
        textField_className = new JTextField();
        textField_className.setBounds(140, 155, 215, 26);
        add(textField_className);

        JPanel panel = new JPanel(new FlowLayout(FlowLayout.CENTER));
        panel.setBounds(0, 200, getWidth(), 35);
        add(panel);

        /*panel.add(new JLabel("或输入姓名查询成绩"));
        textField = new JTextField();
        textField.setPreferredSize(new Dimension(175,26));
        panel.add(textField);*/

        button_query = new JButton("查询");
        setLayout( null );
        button_query.setBounds(170, 230, 140, 40);
        panel.add(button_query);
        button_query.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                queryTest();
            }
        });

        button_submit = new JButton("开始测试");
        setLayout( null );
        button_submit.setBounds(70, 230, 140, 40);
        add(button_submit);
        //button_submit.setBounds(165, 260, 105, 35);
        button_submit.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                start();
            }
        });
    }

Answer 1

你的查询按钮，被添加到 panel 父容器里面了，你的开始测试按钮没有使用 panel.add

你可以再用一个新的父容器 panelB 去添加：开始测试按钮就好了