Question

这个Java代码使用的是Swing。我正在尝试生成一个表单，以便在其中涵盖Swing basic。它有标签，按钮，文本字段但单选按钮不起作用。请告诉我里面的错误。是因为我没有在面板中添加单选按钮吗？

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class Swingtrial extends JFrame {

    final String[] sList
        = {
            "JANUARY",
            "FEBRUARY",
            "MARCH",
            "APRIL",
            "MAY",
            "JUNE",
            "JULY",
            "AUGUST",
            "SEPTEMBER",
            "OCTOBER",
            "NOVEMBER",
            "DECEMBER",};

    public Swingtrial() {
        callGUI();
    }

    public void callGUI() {
        int s[];
        JPanel panel = new JPanel();
        getContentPane().add(panel);
        setTitle("TRIAL FORM");

        panel.setLayout(null);
        panel.setSize(200, 200);
        JLabel lab = new JLabel("Name");
        lab.setBounds(200, 60, 100, 25);
        panel.add(lab);

        JTextField name = new JTextField("first name");
        name.setBounds(275, 60, 100, 25);
        panel.add(name);

        JTextField name1 = new JTextField("middle name");
        name1.setBounds(380, 60, 100, 25);
        panel.add(name1);

        JTextField name2 = new JTextField("last name");
        name2.setBounds(500, 60, 150, 25);
        panel.add(name2);

        JLabel age = new JLabel("Date of Birth");
        age.setBounds(200, 100, 150, 25);
        panel.add(age);

        JComboBox date = new JComboBox();
        date.setBounds(275, 100, 50, 25);
        date.setBackground(Color.LIGHT_GRAY);

        panel.add(date);
        for (int i = 1; i <= 31; i++) {
            extracted(date, i);
        }

        JComboBox drop = new JComboBox();
        drop.setBounds(350, 100, 85, 25);
        drop.setBackground(Color.LIGHT_GRAY);
        panel.add(drop);
        for (int iCtr = 0; iCtr < sList.length; iCtr++) {
            drop.addItem(sList[iCtr]);
        }

        JComboBox yr = new JComboBox();
        yr.setBounds(455, 100, 80, 25);
        yr.setBackground(Color.LIGHT_GRAY);
        panel.add(yr);
        for (int i = 1900; i <= 2014; i++) {
            extracted(yr, i);  // not understood?????? :(  
        }

        JLabel add = new JLabel("address");

        add.setBounds(200, 150, 100, 25);
        panel.add(add);

        JTextField address = new JTextField("Adress");
        address.setBounds(280, 150, 200, 40);
        panel.add(address);

        JRadioButton male = new JRadioButton("male");
        JRadioButton female = new JRadioButton("Female");
        ButtonGroup bG = new ButtonGroup();
        add(male);
        bG.add(female);
        this.setSize(100, 200);
        this.setLayout(new FlowLayout());
        this.add(male);
        this.add(female);
        male.setSelected(true);
        this.setVisible(true);

        JButton but = new JButton("ommm");
        but.setBounds(50, 60, 80, 30);
        panel.add(but);
        but.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
            }
        });
    }

    private void extracted(JComboBox month, int i) {
        month.addItem(i);
    }

    public static void main(String args[]) {
        Swingtrial mainFrame = new Swingtrial();
        mainFrame.setVisible(true);
    }
}

Answer 1

将male添加到ButtonGroup：

错误包含在注释行中：

    JRadioButton male = new JRadioButton("male");
    JRadioButton female = new JRadioButton("Female");
    ButtonGroup bG = new ButtonGroup();
    add(male);   //this adds the component to the JFrame not the button group
    bG.add(female);

可以使用以下方法修复：

bG.add(male);

单选按钮消失

1 个答案: