?
Solved

Refreshing JTree without using DefaultTreeModel

Posted on 2004-03-21
9
Medium Priority
?
899 Views
Last Modified: 2007-12-19
I need to dynamically change the display information of tree nodes (e.g. node text), and then refresh the entire JTree so that my changes are displayed.

DefaultTreeModel has lots of useful methods that I could use to refresh the tree (e.g. reload()), however, there is no guarantee that the JTree will be using DefaultTreeModel.

Is there a way to refresh the tree without using DefaultTreeModel?

I am temporarily using the following code for the refresh:
    if(tree.isExpanded(rootPath)) {
      // Note the currently selected path so that it can be
      // restored after the tree is refreshed.
      TreePath selectedPath = tree.getSelectionPath();

      // Do the "refresh".
      tree.collapsePath(rootPath);
      tree.expandPath(rootPath);
      // The selection path will now be set to rootPath.

      // Restore the old selection path.
      tree.setSelectionPath(selectedPath);
    }

But this will fire unwanted TreeSelectionEvents, so I would prefer another solution.
0
Comment
Question by:xelia
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 4
9 Comments
 
LVL 92

Expert Comment

by:objects
ID: 10647090
You have to fire the relevant events from the TreeModel, this does not have to be a DefaultTreeModel, but it needs to come from the model.
Any other solution, such as refreshing the model, would cause you to lose your selection as you have already experienced.
0
 

Author Comment

by:xelia
ID: 10655309
Thanks objects,

I'll ask the people who created the tree model if they are firing the event when the node's data changes.
0
 

Author Comment

by:xelia
ID: 10673233
Unfortunately their TreeModel is not firing events when the nodes' contents changes, and I don't have access to the source code.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:xelia
ID: 10673375
It would be nice to have a utility method to refresh any JTree, no matter what its model is doing:

public static void refreshAll(JTree tree) {
  // Do refresh here.
}
0
 
LVL 92

Accepted Solution

by:
objects earned 1200 total points
ID: 10674047
> It would be nice to have a utility method to refresh any JTree

There is: setModel().
0
 

Author Comment

by:xelia
ID: 10674349
This works, but like you were saying before, the selected path gets lost.  :(
0
 
LVL 92

Expert Comment

by:objects
ID: 10674364
yes, as the tree has no way of knowing whether the underlying model data has changed or not so it has to clear any state such as selection.
0
 

Author Comment

by:xelia
ID: 10674437
Thanks objects - that answered my next question (why changing the model was firing TreeSelectionEvents).
0
 
LVL 92

Expert Comment

by:objects
ID: 10700752
0

Featured Post

Enroll in October's Free Course of the Month

Do you work with and analyze data? Enroll in October's Course of the Month for 7+ hours of SQL training, allowing you to quickly and efficiently store or retrieve data. It's free for Premium Members, Team Accounts, and Qualified Experts!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Are you developing a Java application and want to create Excel Spreadsheets? You have come to the right place, this article will describe how you can create Excel Spreadsheets from a Java Application. For the purposes of this article, I will be u…
Introduction This article is the last of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers our test design approach and then goes through a simple test case example, how …
Viewers learn about the “for” loop and how it works in Java. By comparing it to the while loop learned before, viewers can make the transition easily. You will learn about the formatting of the for loop as we write a program that prints even numbers…
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Down…
Suggested Courses

649 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question