Adding 'Collapse All' button to a view

Start by adding extension point to plugin.xml of plugin where View lives:

view plainprint?

1.    
2. <extension point="org.eclipse.ui.menus">  
3.     <menucontribution locationuri="toolbar:com.iwaysoftware.explorer.views.ExplorerView">  
4.        <command commandid="org.eclipse.ui.navigate.collapseAll"></command>  
5.     </menucontribution>  
6.  </extension>  

Then add service code to the View's createPartControl method:

view plainprint?

1. IWorkbenchPartSite site = getSite();  
2.        if (site != null) {  
3.         IHandlerService handlerService = (IHandlerService) site.getService(  
4.           IHandlerService.class);  
5.         if (handlerService != null) {  
6.          CollapseAllHandler fCollapseHandler = new CollapseAllHandler(viewer);  
7.          handlerService.activateHandler(CollapseAllHandler.COMMAND_ID ,  
8.            fCollapseHandler);  
9.         }  
10.        }  

 
 IWorkbenchPartSite site = getSite();
        if (site != null) {
         IHandlerService handlerService = (IHandlerService) site.getService(
           IHandlerService.class);
         if (handlerService != null) {
          CollapseAllHandler fCollapseHandler = new CollapseAllHandler(viewer);
          handlerService.activateHandler(CollapseAllHandler.COMMAND_ID ,
            fCollapseHandler);
         }
        }