JFrame /面板未显示

Question

I should be displaying a row of 2 buttons but that doesn't seem to be the case.

import java.util.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class Studying extends JFrame{

JButton button = new JButton("Word");
JButton button1 = new JButton("MoreWords");

public void Studying(){

JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(1,2));
p1.add(button);
p1.add(button1);
add(p1);

}

 public static void main(String[] args){
Studying frame = new Studying();
frame.setTitle("test");
frame.setSize(500,200);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

Answer 1

The constructor is not an actual constructor, it is being treated as a method, causing the classes default constructor to be used. Constructors do not specify a return type, even void .

Fixed Constructor

public Studying(){

    JPanel p1 = new JPanel();
    p1.setLayout(new GridLayout(1,2));
    p1.add(button);
    p1.add(button1);
    add(p1);

}

Answer 2

The function Studying() isn't a class, so Studying frame = new Studying(); refers to public class Studying extends JFrame and public void Studying() is never called. Move the creation of the buttons to the static main, and append them to the frame, and the buttons will be visible.

public class Studying extends JFrame {

static JButton button = new JButton("Word");
static JButton button1 = new JButton("MoreWords");

public static void main(String[] args) {
    Studying frame = new Studying();
    frame.setTitle("test");
    frame.setSize(500, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLayout(new GridLayout(1, 2));
    frame.add(button);
    frame.add(button1);
    frame.setVisible(true);

}
}

Answer 3

This should work:

import java.util.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class Studying extends JFrame{

JButton button = new JButton("Word");
JButton button1 = new JButton("MoreWords");

public Studying(){

JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(1,2));
p1.add(button);
p1.add(button1);
add(p1);

}

 public static void main(String[] args){
Studying frame = new Studying();
frame.setTitle("test");
frame.setSize(500,200);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);

}