的Java找不到符號

Question

這是我的錯誤信息

test.java:17: cannot find symbol 
symbol : class MouseAdapter 
location: class test 
     private class click extends MouseAdapter 
            ^
test.java:19: cannot find symbol 
symbol : class MouseEvent 
location: class test.click 
       public void mouseEntered(MouseEvent e) 
             ^
test.java:14: cannot find symbol 
symbol : variable trayicon 
location: class test 
     trayicon.addMouseListener(new click()); 
     ^
3 errors 

---

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

public class test extends JFrame 
{ 

    private JFrame frame; 

    public void init() 
    { 
     trayicon.addMouseListener(new click()); 
    } 

     private class click extends MouseAdapter 
     { 
      public void mouseEntered(MouseEvent e) 
      { 
       { 
       frame.setVisible(true); 
      } 
     } 
    } 
} 

Answer 1

重現錯誤：

$cat >test.java <<. 
import javax.swing.*; 
import javax.swing.event.*; 
import java.awt.*; 

public class test extends JFrame 
{ 

    private JFrame frame; 

    public void init() 
    { 
     trayicon.addMouseListener(new click()); 
    } 

     private class click extends MouseAdapter 
     { 
      public void mouseEntered(MouseEvent e) 
      { 
       { 
       frame.setVisible(true); 
      } 
     } 
    } 
} 
. 
$javac test.java 
test.java:15: cannot find symbol 
symbol : class MouseAdapter 
location: class test 
     private class click extends MouseAdapter 
            ^
test.java:17: cannot find symbol 
symbol : class MouseEvent 
location: class test.click 
      public void mouseEntered(MouseEvent e) 
            ^
test.java:12: cannot find symbol 
symbol : variable trayicon 
location: class test 
     trayicon.addMouseListener(new click()); 
     ^
3 errors 

添加進口

$ed test.java 
431 
1i 
import java.awt.event.*; 
. 
wq 
456 
$javac test.java 
test.java:13: cannot find symbol 
symbol : variable trayicon 
location: class test 
     trayicon.addMouseListener(new click()); 
     ^
1 error 

在第13行

$ed test.java 
456 
13i 
     JLabel trayicon = new JLabel();// or something that makes sense 
. 
wq 
528 
$javac test.java 
$ 

固定聲明trayicon！

結果代碼：

$cat test.java 
import java.awt.event.*; 
import javax.swing.*; 
import javax.swing.event.*; 
import java.awt.*; 

public class test extends JFrame 
{ 

    private JFrame frame; 

    public void init() 
    { 
     JLabel trayicon = new JLabel();// or something that makes sense 
     trayicon.addMouseListener(new click()); 
    } 

     private class click extends MouseAdapter 
     { 
      public void mouseEntered(MouseEvent e) 
      { 
       { 
       frame.setVisible(true); 
      } 
     } 
    } 
} 

BTW，你不需要線26和21：

$ed test.java 
633 
26d 
21d 
wq 
605 
$javac test.java 
$ 
$cat test.java 
import java.awt.event.*; 
import javax.swing.*; 
import javax.swing.event.*; 
import java.awt.*; 

public class test extends JFrame 
{ 

    private JFrame frame; 

    public void init() 
    { 
     JLabel trayicon = new JLabel();// or something that makes sense 
     trayicon.addMouseListener(new click()); 
    } 

     private class click extends MouseAdapter 
     { 
      public void mouseEntered(MouseEvent e) 
      { 
       frame.setVisible(true); 
      } 
     } 
    } 

Answer 2

您需要：

import java.awt.event.*; 

編輯：

，你需要聲明trayicon：

JLabel trayicon = new JLabel(); 

Answer 3

增加mellamokb，您使用的是可變托盤圖標其不被任何聲明。

所以加

import java.awt.event.MouseAdapter; 
import java.awt.event.MouseEvent; 

，並宣佈托盤圖標