[news.eclipse.platform.swt] Re: Windows fires SelectionEvent on tree.set

[Fabian Zeindl <fabian@xxxxxxxxxxxxxxxxxxxxxx>]

Here you are...

fabian

Tom Schindl schrieb:
> Hi,
>
> Well you could try. If you need immediate help you can use IRC 
> (#eclipse-dev at irc.freenode.net, nick: tomsontom), I'm online today in 
> the late afternoon. So if you ping have snippet post it to this thread 
> and then ping me on IRC.
>
> Greetings from the western part of Austria :-)
>
> Tom
>
> Fabian Zeindl schrieb:
> > Tom Schindl schrieb:
> > > Looks like a timing issue or are do doing something with 
> > > Display#asyncExec()? From what you say I construct the following.
> > >
> > > You've got a TextWidget and TreeWidget and when entry text you are 
> > > updating the selection in your Tree and the other way round, right?
> >
> > true.
> >
> > > I guess we need some code to reproduce this. You should try to write 
> > > a small snippet you can paste here and we can run.
> >
> > ok I'll do that. Will you be online again at some time this weekend? 
> > Unfortunately my solution is due on monday :-/.
> >
> > greetings / GrÃÃe
> > fabian
> >
> > > Tom
> > >
> > > Fabian Zeindl schrieb:
> > > > Another strange problem: When I remove the SelectionListener right 
> > > > before the setSelection and add it afterwards it still gets called 
> > > > when calling setSelection. Why is that?
> > > > I don't know whether this helps, but the SelectionListener gets 
> > > > called _after_ the method which calls setSelection finished. The 
> > > > method itself is a ModifyListener.
> > > >
> > > > fabian
> > > >
> > > > Tom Schindl schrieb:
> > > > > It is a bug if SWT fires a SelectionEvent when setting a selection 
> > > > > programmatically!
> > > > >
> > > > > Tom
> > > > >
> > > > > Fabian Zeindl schrieb:
> > > > > > Hi,
> > > > > >  for some unknown reason Win32 fires a SelectionEvent when I do 
> > > > > > tree.setSelection(TreeItem item) where gnu/linux doesn't fire one.
> > > > > > Is there a reason for this behaviour? Funnily enough, when I 
> > > > > > change the code to be simpler, Windows doesn't fire an event on 
> > > > > > setSelection.
> > > > > > Is this an SWT-Bug?
> > > > > >
> > > > > > thanks in advance
> > > > > > fabian

import org.eclipse.swt.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.events.*;
import java.util.*;

public class Test
{
	public static void main(String[] args)
	{
		new Test();
	}

	private Text text1, text2;
	private Tree tree;
	private TextModifyListener textlistener = new TextModifyListener();
	private TreeSelectionListener treelistener = new TreeSelectionListener();
	private ArrayList<TreeItem> lastCreatedItems = new ArrayList<TreeItem>();

	public Test()
	{
		Display display = new Display();
		Shell shell = new Shell();
		shell.setLayout( new GridLayout(2,false) );

		// Text 1
		text1 = new Text(shell, SWT.BORDER);
		text1.setLayoutData( new GridData(SWT.NONE,SWT.NONE,true,true) );
		text1.addModifyListener(textlistener);

		// Tree
		tree = new Tree(shell, SWT.BORDER);
		tree.setLayoutData( new GridData(SWT.FILL,SWT.FILL,true,true,1,2) );
		tree.addSelectionListener(treelistener);

		// Kinder erzeugen
		TreeItem item = new TreeItem(tree, SWT.NONE);
		item.setText("parent1");
		item = new TreeItem(item, SWT.NONE);
		item.setText("child1");
		item = new TreeItem(tree, SWT.NONE);
		item.setText("parent2");
		item = new TreeItem(item, SWT.NONE);
		item.setText("child2");

		// Text 2
		text2 = new Text(shell, SWT.BORDER);
		text2.setLayoutData( new GridData(SWT.NONE,SWT.NONE,true,true) );
		text2.addModifyListener(textlistener);

		shell.open();
		while (!shell.isDisposed())
			if (!display.readAndDispatch())
				display.sleep();
	}

	private void createTreeItems(ArrayList<String> category)
	{
		// run through list to find last non-empty entry
		int lastNonEmptyLevel = -1;
		for (int i = (category.size()-1); i >= 0; i--)
		{
			if (!category.get(i).matches("\\s*"))
			{
				lastNonEmptyLevel = i;
				break;
			}
		}  

		// delete all manually created items
		for (TreeItem item : lastCreatedItems)
			item.dispose();
		lastCreatedItems.clear();

		// create TreeItems for category
		TreeItem parent = null;
		for (int i=0; i <= lastNonEmptyLevel; i++)
		{   
			// Search for matching item and created
			TreeItem item = getMatchingChild(parent, category.get(i));
			if (item == null)
			{   
				item = createChild(parent, category.get(i));
				lastCreatedItems.add( item );
			}

			// expand item
			if (parent != null)
				parent.setExpanded(true);

			parent = item;
		}  

		// Removing the Listener doesn't work
		// this.tree.removeSelectionListener( this.treelistener );

		// comment out -> no SelectionEvents
		if (parent != null) {
			tree.setSelection(parent);
		}

		// this.tree.addSelectionListener( this.treelistener );
	}

	private class TextModifyListener implements ModifyListener
	{   
		public void modifyText(ModifyEvent e)
		{   
			System.out.println( "text: ModifyEvent!" );

			ArrayList<String> list = new ArrayList<String>();
			list.add(text1.getText());
			list.add(text2.getText());
			createTreeItems( list );

			System.out.println( "text: ModifyEvent dispatched!" );
		}
	}

	private class TreeSelectionListener extends SelectionAdapter
	{   
		public void widgetSelected(SelectionEvent e)
		{   
			System.out.println( "tree: SelectionEvent: " + e.hashCode() );

			if (tree.getSelectionCount() > 0)
			{
				TreeItem selectedItem = tree.getSelection()[0];

				// depth of selection
				int depth = 0;
				TreeItem parent = selectedItem;
				while ((parent = parent.getParentItem()) != null)
					depth ++;

				// fill TextFields
				switch (depth)
				{   
					case 0:
						text1.setText( selectedItem.getText() );
						text2.setText("");
						break;
					case 1:
						text1.setText( selectedItem.getParentItem().getText() );
						text2.setText( selectedItem.getText() );
						break;
				}
			}

			System.out.println( "tree: SelectionEvent dispatched!" );
		}
	}

	private TreeItem getMatchingChild(TreeItem parent, String text)
	{   
		TreeItem[] children = (parent != null ? parent.getItems() : this.tree.getItems());

		for (TreeItem item : children)
		{   
			if (item.getText().equals(text))
			{   
				return item;
			}
		}

		return null;
	}

	private TreeItem createChild(TreeItem parent, String text)
	{   
		TreeItem[] children = (parent != null ? parent.getItems() : this.tree.getItems());

		int index=0;
		while (index < children.length && children[index].getText().compareTo(text) < 0)
		{   
			index++;
		}  

		TreeItem newItem = (parent != null ? new TreeItem(parent, SWT.NONE, index) : new TreeItem(this.tree, SWT.NONE, index));
		newItem.setText(text);

		return newItem;
	}
}