最近为一个程序写界面,需要更换JTree的默认图标,因为以前从没做过swing,走了不少弯路,现在把方法告诉大家,希望对你的工作能有所帮助.

     先来一个常见的图标更换方法,需要显示继承DefaultTreeCellRenderer类,代码引用自http://blog.blogchina.com/174500.html

private class MyRenderer extends DefaultTreeCellRenderer {
           ImageIcon htmlIcon;
           ImageIcon imageIcon;
           public MyRenderer() {
               htmlIcon = new ImageIcon("source/html.gif");
               imageIcon=new ImageIcon("source/image.gif");
           }

           public Component getTreeCellRendererComponent(
                               JTree tree,
                               Object value,
                               boolean sel,
                               boolean expanded,
                               boolean leaf,
                               int row,
                               boolean hasFocus) {

               super.getTreeCellRendererComponent(
                               tree, value, sel,
                               expanded, leaf, row,
                               hasFocus);
               if (leaf && isImage(value)) {
                   setIcon(imageIcon);
                   //setToolTipText("This book is in the Tutorial series.");
               }
               else if(leaf){
                   setIcon(htmlIcon);
               }

               return this;
           }

           protected boolean isImage(Object value) {
               Sitemarks.SitemarkEntry node =
                       (Sitemarks.SitemarkEntry)value;
               String name=
                       (String)(node.getName());

               if (name.endsWith(".jpg")||name.endsWith(".gif")) {
                   return true;
               }

               return false;
           }
       }

    实现起来太麻烦了,我只是想换个图标而已,java也太不讲人情了,需要写这么多代码.于是我尝试这样直接设置:

   JTree leftTree = new JTree();
   ((DefaultTreeCellRenderer)leftTree.getCellRenderer()).setClosedIcon(myClosedIcon);
   这样的问题是,如果你需要动态增删JTree的结点,调用UpdateUI()方法后,显示的图标又变为默认的图标.你还得在调用updateUI()后重新调用上面语句.

   最后我想到使用匿名类的方法如下:

           leftTree.setCellRenderer(new DefaultTreeCellRenderer(){
                 public Icon getClosedIcon() {
                         //返回你需要的图标
                         return myClosedIcon                         

                 }
           });