eclipseRCP深入淺出（學習總結）2015.08.25

<span style="font-size:18px;">1、</span>

public class AddContactAction extends Action implements 
	ISelectionListener,ActionFactory.IWorkbenchAction {
	private final IWorkbenchWindow window;
	public static String ID = "com.eclipsercp.hyperbola.addContact";
	private IStructuredSelection selection;

	public AddContactAction(IWorkbenchWindow window){
		this.window = window;
		setId(ID);
		setText("&Add Contact...");
		setToolTipText("Add a Contact to your Contacts list.");
		setImageDescriptor(AbstractUIPlugin.imageDescriptorFromPlugin(
				"com.eclipsercp.hyperbola", IImageKeys.ADD_CONTACT));
		window.getSelectionService().addSelectionListener(this);
	}
	
	public void dispose(){
		window.getSelectionService().removeSelectionListener(this);
	}
	@Override
	public void selectionChanged(IWorkbenchPart part, ISelection selection) {

	}

}
<span style="font-size:18px;">這是添加聯繫人的action，其中ID有兩個作用，首先能夠唯一標識一個action，其次在<span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;">ApplicationActionBarAdvisor的<span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;"> fillMenuBar（）方法進行註冊action時會用到這個ID。</span></span></span>

<span style="font-size:18px;"><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;"><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;">2、action會註冊到selection listener中，可以看到AddContactAction是實現了ISelectionListener接口的，當treeviewer中的元素被選中時，selectionChanged（）方法就會通知對應的action：</span></span></span>

<span style="font-size:18px;"><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;"><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 18px; line-height: 26px;"></span></span></span><pre name="code" class="java">@Override
	public void selectionChanged(IWorkbenchPart part, ISelection incoming) {
		//selection containing elements
		if(incoming instanceof IStructuredSelection){
			selection = (IStructuredSelection)incoming;
			setEnabled(selection.size() == 1 &&
					selection.getFirstElement()instanceof ContactsGroup);
		}else {
			//other selections(containing text or other kinds)
			setEnabled(false);
		}
	}