Defining different icons for TreeNode by extending DefaultTreeCellRenderer

Question

Hello all,
I'm using a JTree to display project, folder and files. I'd like to have different icons for open project, close project, open folder, close folders, and files
but i got for the root which is a project object a folder icon and for folder when it is not expanded i got project icon and the when i expand it i got a folder icon, can someone help me please
Here is my code :
public class MyTreeCellRenderer extends DefaultTreeCellRenderer {
     private Icon openIcon = null;
     private Icon closeIcon = null;
     private Icon leafIcon = null;
     private Icon projectOpenIcon = new ImageIcon("icons/book_open.png");
     private Icon projectCloseIcon = new ImageIcon("icons/book_blue.png");
     private Icon folderOpenIcon = new ImageIcon("icons/folder.png");
     private Icon folderCloseIcon = new ImageIcon("icons/folder_closed.png");
     private Icon fileIcon = new ImageIcon("icons/document.png");
     @Override
     public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected,
               boolean expanded, boolean leaf, int row, boolean hasFocus) {
          super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row,
                    hasFocus);
          LogescoTreeNode node =
               (LogescoTreeNode)value;
          Object obj = node.getUserObject();
          System.out.println(obj.getClass().toString());
          if(openIcon == null) {
               openIcon = this.getOpenIcon();
               if(openIcon != null) {
                    if(obj instanceof LProject) {
                         openIcon = projectOpenIcon;
                         this.setOpenIcon(openIcon);
                         openIcon = null;
                    } else if(obj instanceof LFolder) {
                         openIcon = folderOpenIcon;
                         this.setOpenIcon(openIcon);     
                         openIcon = null;
          if(closeIcon == null) {
               closeIcon = this.getClosedIcon();
               if(closeIcon != null) {
                    if(obj instanceof LProject) {
                         closeIcon = projectCloseIcon;
                         this.setClosedIcon(closeIcon);
                         closeIcon = null;
                    } else if(obj instanceof LFolder) {
                         closeIcon = folderCloseIcon;
                         this.setClosedIcon(closeIcon);
                         closeIcon = null;
          this.setLeafIcon(fileIcon);
          return this;
}Thank you.

Answer 1

Hi all,
I changed my code a bit knowing that the renderer is global to the tree so my (openIcon == null) is called only once for the first node.
Here is my new code :
public class MyTreeCellRenderer extends DefaultTreeCellRenderer {
     private Icon projectOpenIcon = new ImageIcon("icons/book_open.png");
     private Icon projectCloseIcon = new ImageIcon("icons/book_blue.png");
     private Icon folderOpenIcon = new ImageIcon("icons/folder.png");
     private Icon folderCloseIcon = new ImageIcon("icons/folder_closed.png");
     private Icon fileIcon = new ImageIcon("icons/document.png");
     @Override
     public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected,
               boolean expanded, boolean leaf, int row, boolean hasFocus) {
          super.getTreeCellRendererComponent(tree, value, selected,
                    expanded, leaf, row, hasFocus);
          LogescoTreeNode node =
               (LogescoTreeNode)value;
          Object obj = node.getUserObject();
          System.out.println(obj.getClass().toString());
          if(obj instanceof LProject) {
               this.setIcon(expanded ? projectOpenIcon : projectCloseIcon);
          } else if(obj instanceof LFolder) {
               this.setIcon(expanded ? folderOpenIcon : folderCloseIcon);
          } else {
               this.setIcon(fileIcon);
          return this;
     }