Conflict of "addSelectionChangedListener" and "addDoubleClickListener" for TableViewer

Question

all related

With JFace TableViewer, I want to select some entry(e.g select a file) by single-click, and do some other operations(e.g go into a directory) by double-click.

Noticing addSelectionChangedListener() and addDoubleClickListener() via a webpage: http://javafact.com/2010/08/07/example-tableviewer-events/ , I add SelectionChangedListener and DoubleClickListener for my TableViwer, and find out: Either of the two listeners can work, but they can't work together - actually it's DoubleClickListener that can't work.

What's the problem? How I should implement listeners for single-click and double-clicks? Any comments is appreciated.

About code: I created a tableViewer, and want to show filesystem structure. The expected behavior: User can double click a directory entry and tableViewer will show the structure of selected directory; user select a generic file by single-click. For other operations, warning message dialog will be shown.

The following is just code related with event handlers.

tableView.addSelectionChangedListener( new ISelectionChangedListener() {
public void selectionChanged(SelectionChangedEvent event) {
      IStructuredSelection sel = (IStructuredSelection) tableView.getSelection();  
      File selFile = (File) sel.getFirstElement();
      if(selFile != null){
    if (selFile.isDirectory()) {
       MessageDialog.openWarning(getShell(), "Warning", "You select a directory");
               return;
            }
    System.out.println("Selected : "+ selFile.getAbsolutePath());
    selectFileName = selFile.getAbsolutePath();

  }
    }
 });

 tableView.addDoubleClickListener( new IDoubleClickListener() {

@Override
public void doubleClick(DoubleClickEvent arg0) {
   Object selected;
   IStructuredSelection selection = (IStructuredSelection) tableView.getSelection();
   if (selection.size() != 1) return;
   selected = selection.getFirstElement();
   File file = (File) selected;
   if (file.isFile()) {
     MessageDialog.openInformation(getShell(),"Warning", "You double-clicks a generic file");
     return;
   } 
  if (file.isDirectory()) {
    System.out.println("Clicked direcotry: " + file.getAbsolutePath());

    //applyNewDirectory(file);
  }
     }          
   }); 

Regards & Thanks from Sunzen

Answer 1

(prolog: still working with JFace/SWT here, so this might be of interest to someone)

The problem is that the API allows you to do this, but it does not work (oh SWT...). You cannot have both listeners on the TableView, as the SelectionChangedListener will always grab the click and consume the event.

The solution is to attach the SelectionChangedListener to the underlying table, and the DoubleClickListener to the TableViewer. This way you can have both, e.g.:

table.addSelectionChangedListener(new ISelectionChangedListener(...));
tableViewer.addDoubleClickListener(new IDoubleClickListener(...));