Multiple JTree is not appearing in JScrollPanel

Question

I am using the first example mentioned here for creating my JTree but I want to put more than one tree as root in the JscrollPanel. I just changed the layout of the box and create one more tree with the same code but when I run the program the tree is not appearing to me.

Here is my code

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

public class SimpleTree extends JFrame {
  public static void main(String[] args) {
    new SimpleTree();
  }

  public SimpleTree() {
    super("Creating a Simple JTree");
    Container content = getContentPane();
    Object[] hierarchy =
      { "javax.swing",
        "javax.swing.border",
        "javax.swing.colorchooser",
        "javax.swing.event",
        "javax.swing.filechooser",
        new Object[] { "javax.swing.plaf",
                       "javax.swing.plaf.basic",
                       "javax.swing.plaf.metal",
                       "javax.swing.plaf.multi" },
        "javax.swing.table",
        new Object[] { "javax.swing.text",
                       new Object[] { "javax.swing.text.html",
                                      "javax.swing.text.html.parser" },
                       "javax.swing.text.rtf" },
        "javax.swing.tree",
        "javax.swing.undo" };
    DefaultMutableTreeNode root = processHierarchy(hierarchy);
    DefaultMutableTreeNode root2 = processHierarchy(hierarchy);
    JTree tree = new JTree(root);
    JTree tree2 = new JTree(root2);
    content.setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
    content.add(new JScrollPane(tree));
    content.add(new JScrollPane(tree2));
    setSize(getPreferredSize());
    setVisible(true);
  }

  /** Small routine that will make node out of the first entry
   *  in the array, then make nodes out of subsequent entries
   *  and make them child nodes of the first one. The process is
   *  repeated recursively for entries that are arrays.
   */

  private DefaultMutableTreeNode processHierarchy(Object[] hierarchy) {
    DefaultMutableTreeNode node =
      new DefaultMutableTreeNode(hierarchy[0]);
    DefaultMutableTreeNode child;
    for(int i=1; i<hierarchy.length; i++) {
      Object nodeSpecifier = hierarchy[i];
      if (nodeSpecifier instanceof Object[])  // Ie node with children
        child = processHierarchy((Object[])nodeSpecifier);
      else
        child = new DefaultMutableTreeNode(nodeSpecifier); // Ie Leaf
      node.add(child);
    }
    return(node);
  }
}

Could someone please help me with this. All help would be really appreciated.

Thanks Ashish Tyagi

Reimeus · Accepted Answer · 2012-11-29T19:39:14.883

3

A JScrollPane has a view to a single child component in its ViewPort.

You could however place the 2 JScrollPane components on a single panel with say, an evenly split GridLayout(2, 1) and set the view of the JScrollPane to the new panel.

Aside: You should use the ContentPane as the container for BoxLayout:

content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));

edited Nov 29 '12 at 19:39

answered Nov 29 '12 at 19:24

Reimeus

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Thanks a lot. looks like my code is creating two different scroll panel, is there any way I can add both tree in one scroll panel. – Ashish Nov 29 '12 at 19:31

score 2 · Answer 2 · edited May 23 '17 at 11:48

2

have to accepting that JScrollPane isn't designated to hold more than one JComponents
you can to put JPanel into JScrollPane, put required numbers of JTrees to (in JScrollPane) JPanel, maybe to use GridLayout for JPanel
notice possible concurency for scrollable betweens parent JScrollPane and every JScrollPanes with JTrees

edited May 23 '17 at 11:48

Community

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1

answered Nov 29 '12 at 19:31

mKorbel

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Multiple JTree is not appearing in JScrollPanel

2 Answers2