Automatically resize columns when elements are expanded

Question

In a multi-column tree, how do I resize columns to content when expanding / collapsing and updating data?

Solving a similar question for tables does not work.

Same as:

  tree.addListener(SWT.Collapse, new Listener(){
   @Override
   public void handleEvent(Event e) {
    expandAndResize(false, (TreeItem) e.item);
   }
  });

  tree.addListener(SWT.Expand, new Listener() {
   @Override
   public void handleEvent(Event event) {
    expandAndResize(false, (TreeItem) event.item);
   }
  });

 private static void expandAndResize(Boolean expand_, TreeItem item_)
 {
  System.out.println( (expand_?"Expanding":"Collapsing") + "item={" + item_ + "}");
  item_.setExpanded(expand_);
  System.out.println(" Resizing columns");
  resizeTree(item_.getParent());
 }

 private static void resizeTree(Tree tree_)
 {
  for (TreeColumn tc: tree_.getColumns())
   resizeTreeColumn(tc);
 }

 private static void resizeTreeColumn(TreeColumn treeColumn_)
 {
  treeColumn_.pack();  
 }

This works for updating data (by calling resizeTree), but for extensions / dumps this is one step!

In particular, if I expand the element in the first column, and the base element is longer than the column width, resizing to this width will be performed the next time I reduce or expand any other element (or if I directly call resizeTree).

: TreeContentProvider ITableLabelProvider, , ITableLabelProvider ( , ?! )

X- Eclipse

Answer 1

A snippet, , .

, , , asyncExec, . ( -, ...)

: TreeItem.setExpanded(.). , Boolean, . , , . , . : ?

, :

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.*;

public class Snippet {

   public static void main( String[] args ) {
      final Display display = new Display();
      Shell shell = new Shell(display);
      shell.setLayout(new FillLayout());
      final Tree tree = new Tree(shell, SWT.BORDER);
      tree.setHeaderVisible(true);
      TreeColumn col1 = new TreeColumn(tree, 0);
      col1.setText("col1");
      TreeColumn col2 = new TreeColumn(tree, 0);
      col2.setText("col2");

      for ( int i = 0; i < 4; i++ ) {
         TreeItem iItem = new TreeItem(tree, 0);
         iItem.setText(new String[] { "TreeItem (0) -" + i, "x" });
         for ( int j = 0; j < 4; j++ ) {
            TreeItem jItem = new TreeItem(iItem, 0);
            jItem.setText(new String[] { "TreeItem (1) -" + i, "x" });
            for ( int k = 0; k < 4; k++ ) {
               TreeItem kItem = new TreeItem(jItem, 0);
               kItem.setText(new String[] { "TreeItem (2) -" + i, "x" });
               for ( int l = 0; l < 4; l++ ) {
                  TreeItem lItem = new TreeItem(kItem, 0);
                  lItem.setText(new String[] { "TreeItem (3) -" + i, "x" });
               }
            }
         }
      }

      col1.pack();
      col2.pack();

      Listener listener = new Listener() {

         @Override
         public void handleEvent( Event e ) {
            final TreeItem treeItem = (TreeItem)e.item;
            display.asyncExec(new Runnable() {

               @Override
               public void run() {
                  for ( TreeColumn tc : treeItem.getParent().getColumns() )
                     tc.pack();
               }
            });
         }
      };

      tree.addListener(SWT.Collapse, listener);
      tree.addListener(SWT.Expand, listener);

      shell.setSize(200, 200);
      shell.open();
      while ( !shell.isDisposed() ) {
         if ( !display.readAndDispatch() ) display.sleep();
      }
      display.dispose();
   }
}