JScrollPanel中的Jtree不能正常工作

Question

DefaultMutableTreeNode myComputer = new DefaultMutableTreeNode("My Computer"); 
DefaultMutableTreeNode c = new DefaultMutableTreeNode("Local Disk(C:)"); 
DefaultMutableTreeNode vinod = new DefaultMutableTreeNode("Vinod"); 
DefaultMutableTreeNode swing = new DefaultMutableTreeNode("Swing"); 
DefaultMutableTreeNode tr = new DefaultMutableTreeNode("Tree"); 
DefaultMutableTreeNode a = new DefaultMutableTreeNode("3½ Floppy(A:)"); 
DefaultMutableTreeNode e = new DefaultMutableTreeNode("New Volume(E:)"); 
c.add(vinod); 
vinod.add(swing); 
swing.add(tr); 
myComputer.add(c); 
myComputer.add(a); 
myComputer.add(e); 


JTree tree = new JTree(myComputer); 
JScrollPane scrollPane = new JScrollPane(tree); 
jPanel1.add(scrollPane); 
tree.setVisible(true); 

我從網上得到了新的樹示例，但是當我嘗試顯示它時，它不會出現！我不知道爲什麼。有任何想法嗎？ 謝謝！

Answer 1

調整代碼到SSCCE，工作正常這裏

public static void main(String[] args) { 
    EventQueue.invokeLater(new Runnable() { 
     @Override 
     public void run() { 
     JFrame frame = new JFrame(); 

     DefaultMutableTreeNode myComputer = new DefaultMutableTreeNode("My Computer"); 
     DefaultMutableTreeNode c = new DefaultMutableTreeNode("Local Disk(C:)"); 
     DefaultMutableTreeNode vinod = new DefaultMutableTreeNode("Vinod"); 
     DefaultMutableTreeNode swing = new DefaultMutableTreeNode("Swing"); 
     DefaultMutableTreeNode tr = new DefaultMutableTreeNode("Tree"); 
     DefaultMutableTreeNode a = new DefaultMutableTreeNode("3½ Floppy(A:)"); 
     DefaultMutableTreeNode e = new DefaultMutableTreeNode("New Volume(E:)"); 
     c.add(vinod); 
     vinod.add(swing); 
     swing.add(tr); 
     myComputer.add(c); 
     myComputer.add(a); 
     myComputer.add(e); 


     JTree tree = new JTree(myComputer); 
     JScrollPane scrollPane = new JScrollPane(tree); 
     frame.getContentPane().add(scrollPane); 
     tree.setVisible(true); 

     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 
     frame.pack(); 
     frame.setVisible(true); 
     } 
    }); 
    }