的JComboBox在Java中，声明

错误我在Java中得到了下一个简单的程序，我知道了网上，因为我尝试学习Java，但不知道如何解决它：的JComboBox在Java中，声明

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

     public class java2 extends JPanel { 

      public java2() { 
       setLayout(new Gridlayout(2,1)); 
       JList lista = new JList(java2.ids); 
       add(new JScrollpane(lista)); 
       JComboBox combo=new JComboBox(); 
       for (int i=0;i<100 ;i++) { 
        combo.addItem(Integer.toString(i)); 
        add(combo); 
       } 
      } 
     public static void main(String args[]) { 
      java1 lista=new Java1(); 
      JFrame ventana=new JFrame(); 
      ventana.getContentPane().add(lista,BorderLayout.CENTER); 
      ventana.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent evt){System.exit(0);}}); 
      ventana.setSize(200,200); 
      ventana.setVisible(true); 
     } 
     }

即时得到下一问题我每次编译，就像我说的时候，即时通讯新的Java和可以说，我知道如何解决EM：

java2.java:8: error: cannot find symbol 
     setLayout(new Gridlayout(2,1)); 
        ^
    symbol: class Gridlayout 
    location: class java2 
java2.java:9: error: cannot find symbol 
     JList lista = new JList(java2.ids); 
            ^
    symbol: variable ids 
    location: class java2 
java2.java:10: error: cannot find symbol 
     add(new JScrollpane(lista)); 
       ^
    symbol: class JScrollpane 
    location: class java2 
java2.java:18: error: cannot find symbol 
    java1 lista=new Java1(); 
    ^
    symbol: class java1 
    location: class java2 
java2.java:18: error: cannot find symbol 
    java1 lista=new Java1(); 
        ^
    symbol: class Java1 
    location: class java2 
Note: java2.java uses unchecked or unsafe operations. 
Note: Recompile with -Xlint:unchecked for details. 
5 errors

来源

2012-08-29 Bladimir Ruiz

不应该有是**新的JScrollPane **？标记大写字母'P' –

错误专门告诉你这个问题。它找不到符号，因为你错误地指定了它们。在java.awt中有一个'GridLayout'而不是'Gridlayout'（注意大小写不同）。你其他的问题几乎相似:) – Sujay

试试这个：

import java.awt.BorderLayout; 
import java.awt.GridLayout; 
import java.awt.event.WindowAdapter; 
import java.awt.event.WindowEvent; 

import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JList; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 

public class JavaDemo extends JPanel { 

    public JavaDemo() { 
    setLayout(new GridLayout(2, 1)); 
    JList lista = new JList(new String[] {"1", "2", "3", "4"}); 
    add(new JScrollPane(lista)); 
    JComboBox combo = new JComboBox(); 
    for (int i = 0; i < 100; i++) { 
     combo.addItem(Integer.toString(i)); 
     add(combo); 
    } 
    } 

    public static void main(String args[]) { 
    JavaDemo lista = new JavaDemo(); 
    JFrame ventana = new JFrame(); 
    ventana.getContentPane().add(lista, BorderLayout.CENTER); 
    ventana.addWindowListener(new WindowAdapter() { 
     public void windowClosing(WindowEvent evt) { 
     System.exit(0); 
     } 
    }); 
    ventana.setSize(200, 200); 
    ventana.setVisible(true); 
    } 
}

来源

2012-08-29 19:18:11

的JComboBox在Java中，声明

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