Develop Reference

SWT selection event after deleting selection

I'm making a simple menu to delete items on a tree. However, after deleting the items, the tree does not receive a selection event, therefore, the code in the listener does not execute (the listener, in the full code, updates a part of the UI).
I have simplified the code below, leaving out details. It is something like this:
tree.addListener (SWT.Selection, new Listener(){
public void handleEvent(Event e) {
(....)
}
}
I also tried this:
tree.addSelectionListener (new SelectionListener(){
public void widgetDefaultSelected(SelectionEvent e){
(...)
}
public void widgetSelected(SelectionEvent e) {
(...)
}
}
On my menu action (delete selection), there is this:
TreeItem [] selected = tree.getSelection();
tree.deselectAll();
if (selected.length > 0)
{
for( TreeItem i : selected){
i.dispose();
}
}
After deleting the selection, my selection listener does not fire. It does fire if I deselect all itens using the ctrl+click combination.
What should I do? Is there a way to fire the SWT.Selection event to the tree after deleting the itens or should I isolate the code inside the listener to call it again? Shouldn't the tree.deselectAll() fire a Selection event?

You can send a selection event programmatically with:
Event event = new Event();
event.widget = tree;
event.display = tree.getDisplay();
event.type = SWT.Selection;
tree.notifyListeners(SWT.Selection, event);

Have same situation and found
this link mentioning, that programmatically setSelection may never send this event due to design, so always send it (if needed) programmatically after setting too

Jface TreeViewer add right click menu, depending on clicked node

There is a good thread on how to correctly hook up a right-click menu to a Jface TreeViewer depending on the selected item.
I would like to show the right click menu depending on: if the right-click was on a node or into "empty space". The problem is that TreeViewer does not automatically clear the selection if you click into empty space. Is there any clean way how to achieve this?
My current approach would be to simply hook up a MouseListener to the tree with the following mouseDown method:
#Override
public void mouseDown(MouseEvent e) {
TreeItem item = treeViewer.getTree().getItem(new Point(e.x, e.y));
if (item == null) {
treeViewer.getTree().deselectAll();
}
}
This seems to work quite well. What do you think of this?

Ok, I found a dirty workaround. So if you really want to do it, here is a possible solution:
final Tree tree = viewer.getTree();
final Menu menu = new Menu(tree);
tree.setMenu(menu);
menu.addMenuListener(new MenuAdapter()
{
#Override
public void menuShown(MenuEvent e)
{
Point point = tree.toControl(Display.getDefault().getCursorLocation());
boolean found = false;
for (TreeItem item : tree.getItems())
{
for (int i = 0; i < tree.getColumnCount(); i++)
if (item.getBounds(i).contains(point))
found = true;
}
System.out.println(found);
}
});

How to add popup menu to your SWT/JFace TreeViewer
Hi, in your applications main class (that extends ApplicationWindow) in protected Control createContents(Composite parent) method you should add code like this:
//Author: Darius Kucinskas (c) 2008-2009
//Email: d[dot]kucinskas[eta]gmail[dot]com
//Blog: http://blog-of-darius.blogspot.com/
//License: GPL
// Create the popup menu
MenuManager menuMgr = new MenuManager();
Menu menu = menuMgr.createContextMenu(mTreeViewer.getControl());
menuMgr.addMenuListener(new IMenuListener() {
#Override
public void menuAboutToShow(IMenuManager manager) {
if(mTreeViewer.getSelection().isEmpty()) {
return;
}
if(mTreeViewer.getSelection() instanceof IStructuredSelection) {
IStructuredSelection selection = (IStructuredSelection)mTreeViewer.getSelection();
DatabaseModelObject object = (DatabaseModelObject)selection.getFirstElement();
if (object.getType() == DATABASE_OBJECT_TYPE.TABLE){
manager.add(new ShowTableDataAction(SWTApp.this));
}
}
}
});
menuMgr.setRemoveAllWhenShown(true);
mTreeViewer.getControl().setMenu(menu);
DatabaseModelObject - is class from my problem domain (specific to my program). mTreeViewer - is object of TreeViewer class (JFace). Thanks, have a nice day!

java JTree deselecting a node that is already selected

I am developing a java application that uses a JTree. What i would like to archive is that when i click on a node that is already selected it gets deselected.
My current solution is to add a mouse listener and a tree selection listener to the jtree. But the problem is that valueChanged gets called only if there is a change in selection (and not if you select the same node twice). To fix this i added a boolean which indicated if the node was clicked for the first time and then i handle the deselect in the mouseReleased function. This works but the problem now is if the node has children and you want to expand it the node gets deselected and reselected again (which i dont want).
How could i fix this problem? Is there any better way of deselecting a already selected node?
The code:
public void initComponents()
{
elementsTree.addTreeSelectionListener(this);
elementsTree.addMouseListener(new MouseAdapter() {
public void mouseReleased(MouseEvent me) {
TreePath tp = elementsTree.getPathForLocation(me.getX(), me.getY());
if (tp != null)
{
if(!nodeSelected && elementsTree.getSelectionModel().isPathSelected(tp) )
{
elementsTree.getSelectionModel().removeSelectionPath(tp);
}
}
nodeSelected = false;
}
});
}
public void valueChanged(TreeSelectionEvent e)
{
nodeSelected = true;
}
Thanks!

Just use the method clearSelection() from JTree.

Context menu for TreeViewer based on selected node - SWT

I need to create a context menu for a TreeViewer in an Eclipse plugin project. But, the menu should not contain constant items, they should vary depending on the type of the node that is selected. For example, my treeViewer has the following hierarchy:
Node A
|
--Node B
|
--Node C
For node A - I want to show a menu with an action, but for nodes B and C I don't want to show anything (no menu).
I managed to create the menu for node A, but then I can't get rid of it when some other type of node is selected. My code looks like:
treeViewer.addSelectionChangedListener(
new ISelectionChangedListener(){
public void selectionChanged(SelectionChangedEvent event) {
if(event.getSelection() instanceof IStructuredSelection) {
IStructuredSelection selection = (IStructuredSelection)event.getSelection();
Object o = selection.getFirstElement();
MenuManager menuMgr = new MenuManager();
if (o instanceof NodeA){
Menu menu = menuMgr.createContextMenu(treeViewer.getControl());
treeViewer.getControl().setMenu(menu);
getSite().registerContextMenu(menuMgr, treeViewer);
menuMgr.add(new SomeAction());
}else {
//what ?
}
}
}
}
);
On the else branch I tried to call dispose(),removeAll() on the MenuManager...nothing works!
Any help is appreciated, thanks.

As #jeeeyul mentioned, you should only create one MenuManager to use within your view.
You can use New>Plug-in Project and the view template to get an example of a context menu in a view using a viewer, but basically in your createPartControl(Composite) method you would hook up your context manager.
MenuManager menuMgr = new MenuManager();
menuMgr.setRemoveAllWhenShown(true);
menuMgr.addMenuListener(new IMenuListener() {
public void menuAboutToShow(IMenuManager manager) {
SampleView.this.fillContextMenu(manager);
}
});
Menu menu = menuMgr.createContextMenu(viewer.getControl());
viewer.getControl().setMenu(menu);
getSite().registerContextMenu(menuMgr, viewer);
Your fillContextMenu(MenuManager) method will have access to your viewer, so you can get the current selection from that. You can add whatever actions you want, even re-add actions after updating them with the current selection.
The registerContextMenu(*) call allows extension points like org.eclipse.ui.popupMenus and org.eclipse.ui.menus to contribute items to your context menu.

Just use single Menu Manager.
Do not make Menu Manager dynamically.
in theory, It's possible you tried, but it's inefficient and it's not general way.
Just make a Menu Manager and add all actions which you needs.
when selection has been changed, call Action#setVisible(true|false)to hide or show menu items.
You can also use Action#setEnable to enable/disable menu item.
ps.
Menu Manager is not a menu GUI(likes TreeViewer is a not tree)
It contributes Actions(business logic) to Menu(SWT). And It also manage visibility and enablement. We call this Contribution Manager. We can create a SWT menu very easy with this. (even we don't know about SWT, we just have to know only our business logic:Action) It's fundamental idea in JFace.
When you add an action into manu manager, action will be wrapped with ActionContributionItem. It hooks action's state to update UI(visibility, enablement for menu, button, toolbar and so on). It also hooks UI to launch action when it pressed.
If you are new to eclipse, It is easy to confuse role of SWT and JFace.

Thats the way I do it:
MenuManager menuMgr = new MenuManager();
Menu menu = menuMgr.createContextMenu(viewer.getControl());
menuMgr.addMenuListener(new IMenuListener() {
#Override
public void menuAboutToShow(IMenuManager manager) {
// IWorkbench wb = PlatformUI.getWorkbench();
// IWorkbenchWindow win = wb.getActiveWorkbenchWindow();
if (viewer.getSelection().isEmpty()) {
return;
}
if (viewer.getSelection() instanceof IStructuredSelection) {
IStructuredSelection selection = (IStructuredSelection) viewer.getSelection();
Node object = (Node)selection.getFirstElement();
if (object.getModel() instanceof NodeA) {
manager.add(new Action();
} else if (object.getModel() instanceof NodeB) {
manager.add(new OtherAction());
}
}
}
});
menuMgr.setRemoveAllWhenShown(true);
viewer.getControl().setMenu(menu);
I hope this helps ;)
It is important to set removeAllWhenShown property of menu manager to false, in order to hide all the other nodes actions ;)

Suppose that you know how to create Action and you are only interested in context menu following example worked for me hope this bunch of code will help you
private void hookContextMenu() {
MenuManager contextMenu = new MenuManager();
contextMenu.setRemoveAllWhenShown(true);
contextMenu.addMenuListener(new IMenuListener() {
#Override
public void menuAboutToShow(IMenuManager manager) {
IStructuredSelection sSelection = (IStructuredSelection) treeViewer.getSelection();
}
if(selectedObject instanceof A){
manager.add(action);
}
}
});

GWT: Editing Text Of Tree Item

When a user clicks a 'Add Node' button above a tree and the program adds a tree item below the selected node, I would like to insert the new tree item with the text highlight and ready for editing by the user... like labels in GMail. Any ideas?
--Kirt

Are you using the GWT default TreeItem? If so, when you add the node, you could add the TreeItem with a Widget which you write which contains a TextBox and a Button to save.
When the save button is clicked, it calls setText() on the tree item with the text box's text, thus removing the widgets from the tree item.
It may be an even better idea to subclass TreeItem to encapsulate this logic and provide more functionality.
edit: Here, just because I'm feeling generous...
public class EditableTreeItem extends TreeItem {
public EditableTreeItem() {
super();
TextBox textBox = new TextBox();
Button saveButton = new Button("Save");
saveButton.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent e) {
if (!textBox.getText().isEmpty()) {
EditableTreeItem.this.setText(textBox.getText());
}
}
});
}
}