JFrame /面板不顯示

Question

我應該顯示一排2個按鈕，但似乎並非如此。

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

構造函數不是實際的構造函數，它被視爲一種方法，導致使用類的默認構造函數。構造函數不指定返回類型，即使void。

固定構造

public Studying(){ 

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

} 

Answer 2

函數學習（）不是一個類，因此Studying frame = new Studying();指public class Studying extends JFramepublic void Studying()和永遠不會調用。將按鈕的創建移動到靜態主體，並將它們附加到框架，並且按鈕將可見。

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

這應該工作：

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); 

}