非静态方法的getContentPane（）不能从静态上下文错误中的Java Swing引用

Question

非静态方法的getContentPane（）不能从静态上下文错误中的Java Swing

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

public class Studentlogin extends JFrame{ 
    public static void main(String[] args) { 

    Container c = getContentPane(); 

    setTitle(" Staff Signin "); 
    setSize(400 , 300); 
    setLayout(new FlowLayout());  
    setVisible(true); 
    setLayout(null); 

    JLabel tun = new JLabel("UserName"); 
    tun.setBounds(10,10,140,25); 
    c.add(sun); 

    JTextField tuname = new JTextField(10); 
    tuname.setToolTipText("Enter your StaffId "); 
    tuname.setBounds(145,10,200,25); 
    c.add(tuname); 

    JLabel tpw = new JLabel("PassWord"); 
    tpw.setBounds(10,50,140,25); 
    c.add(tpw); 

    JPasswordField tpword = new JPasswordField(10); 
    tpword.setEchoChar('*'); 
    tpword.setBounds(145,50,200,25); 
    c.add(tpword); 
} 
} 

被引用在编译时这我得到这种类型的错误的任何人都可以找我有什么不对这个代码，因为我可以在actionlistrener段

Studentlogin.java:9: error: non-static method getContentPane() cannot be referen 
ced from a static context 
       Container c = getContentPane(); 
          ^
Studentlogin.java:11: error: non-static method setTitle(String) cannot be refere 
nced from a static context 
       setTitle(" Staff Signin "); 
       ^
Studentlogin.java:12: error: non-static method setSize(int,int) cannot be refere 
nced from a static context 
       setSize(400 , 300); 
       ^

Answer 1

你需要从静态到去非静态上下文中执行这个代码相同类型的格式。最简单的方法是创建你的类的实例，并调用一个方法，例如go。

public class Studentlogin extends JFrame{ 
    public static void main(String[] args) { 
     new Studentlogin().go(); 
    } 

    private void go() { 
     Container c = getContentPane(); 

     setTitle(" Staff Signin "); 
     setSize(400 , 300); 
     setLayout(new FlowLayout()); 
     setVisible(true); 
     setLayout(null); 

     JLabel tun = new JLabel("UserName"); 
     tun.setBounds(10,10,140,25); 
     c.add(sun); 

     JTextField tuname = new JTextField(10); 
     tuname.setToolTipText("Enter your StaffId "); 
     tuname.setBounds(145,10,200,25); 
     c.add(tuname); 

     JLabel tpw = new JLabel("PassWord"); 
     tpw.setBounds(10,50,140,25); 
     c.add(tpw); 

     JPasswordField tpword = new JPasswordField(10); 
     tpword.setEchoChar('*'); 
     tpword.setBounds(145,50,200,25); 
     c.add(tpword); 
    } 

}