StackOverflow2013

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POHow to expand JTree nodes (in advance), but keep them invisible
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copied!<p>I seems to me that when i call </p> <blockquote> <p>JTree.expandPath( path )</p> </blockquote> <p>That by default all its parents are expanded as well. But what i actually want to do is, set up specific invisible children to be expanded in advance. So that when a node is expanded that its complete sub-tree pops-out.</p> <p>I've found that internally in JTree <code>expandedState.put(path, Boolean.TRUE);</code> records the expanded nodes, but i can't get access to it. (p.s. i don't want to use reflection :)</p> <p>Installing listener for the expansion event, would result in a lot of run-time updates beeing fired. That's why i prefer to let JTree record the expanded states.</p> <p>Hope that there are other ways of doing it.<br> Any help is appreciated?</p> <h2>Accepted the Listener solution. Option 2</h2> <h3>Option 1 Overriding :</h3> <p>One nasty drawBack..it is depending on the implementation of setExpandedState()</p> <pre><code>private boolean cIsExpandingHidden = false; private TreePath cExpandingPath; public void expandBranchHidden(DefaultMutableTreeNode node) { TreeNode[] mPathSections = mNode.getPath(); TreePath mPath = new TreePath(mPathSections); // if (!cTree.isVisible(mPath)){ cIsExpandingHidden = true; } cExpandingPath = mPath; try{ expandPath(mPath); }finally{ cExpandingPath = null; cIsExpandingHidden = false; } } @Override public boolean isExpanded(TreePath path) { // override the questions whether the node parents of // 'the currently expanded node' to return TRUE if (cIsExpandingHidden){ if (path.isDescendant(cExpandingPath)){ return true; // just claim it doesn't need expanding } } return super.isExpanded(path); } @Override public void fireTreeExpanded(TreePath path) { // the treeUI must not to know.. bad luck for any other listeners if (!cIsExpandingHidden){ super.fireTreeExpanded(path); } } </code></pre> <h3>Option 2 Listener</h3> <pre><code>/* code where new nodes are received */ { // only if direct parent is expanded.. else expansionListener will pick it up if (cTree.isExpanded(mCreator.getParentTreeNode())){ for (TreeNode mNode : mAddNodes) { if (mNode.isDefaultExpanded()) { cTree.expandBranch(mNode); mNode.setDefaultExpanded(false); } } } } /* expansion listener */ { if (cRecursiveExpand){ return; } // walk through children, expand and clear its preference cRecursiveExpand = true; IExtendedTreeNode[] mNodes = cTree.getChildrenOfCurrentNode(); for (IExtendedTreeNode mNode : mNodes) { TreeNode mTreeNode = (TreeNode)mNode; if (mTreeNode.isDefaultExpanded()){ cTree.expandBranch(mTreeNode); mTreeNode.setDefaultExpanded(false); } } cRecursiveExpand = false; } </code></pre>

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