title: How to add a listener for a array list of java.util.List
body: <p>I have created a array list and when the list item is selected using mouse down event a listener has to be added for it so how can this be done .The code for which i have created the array list ia as follows</p>
  
  <pre><code>final java.util.List&lt;Object&gt; listSort = new ArrayList&lt;&gt;();
  for(String key: descriptionMappernewer.keySet())
      listSort.add(key);
  
  final MyFilter filter = new MyFilter();
  
  final ListViewer viewer = new ListViewer(this);
  //viewer.getList();
  viewer.getList().setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
  //viewer.getList();
  viewer.setContentProvider(new ArrayContentProvider());
  viewer.setInput(listSort); 
  </code></pre>
  
  <p>and now I need to add mouse down event listener for it. Earlier I had written the mouse event listener of SWT but that has to changed now. The earlier SWT listener looks like this</p>
  
  <pre><code>list.addListener(SWT.Selection, new Listener(){
        public void handleEvent(Event e) {
            int index =  list.getSelectionIndex();
            txtMethodDescription.setText(descriptionMappernewer.get( list.getItem(index)));
        }
  });
  </code></pre>
  
  <p>So please help me how can we add the listener to array list of java.util.List </p>