使用IMenuCreator

IAction定义了setMenuCreator()和getMenuCreator(),他们的作用在于为IAction提供下拉框样式的Action,

通过IMenuCreator实现将多个相关Action组合在一起.

 

*代码参考

eclipse中的org.eclipse.ui.internal.ide.actions.OpenWorkspaceAction使用了这种样式实现,

下面的代码借用了他的IMenuCreator实现方式:

import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.ActionContributionItem;
import org.eclipse.jface.action.IContributionItem;
import org.eclipse.jface.action.IMenuCreator;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;

public class MenuCreatorActionTest extends Action implements IMenuCreator {

private MenuManager dropDownMenuMgr;

public MenuCreatorActionTest(){
		setText("MenuCreatorActionTest");
		setId("test.MenuCreatorActionTest");
		setMenuCreator(this);    //设置IMenuCreator
	}

public void run(){
		System.out.println("MenuCreatorActionTest");
	}

private void createDropDownMenuMgr() {
if (dropDownMenuMgr == null) {
			dropDownMenuMgr = new MenuManager();

			dropDownMenuMgr.add(new InnerAction("One"));
			dropDownMenuMgr.add(new InnerAction("Two"));
		}
	}

	@Override
public void dispose() {
if (dropDownMenuMgr != null) {
			dropDownMenuMgr.dispose();
			dropDownMenuMgr = null;
		}
	}

	@Override
public Menu getMenu(Control parent) {    //在工具栏被调用
		createDropDownMenuMgr();    
return dropDownMenuMgr.createContextMenu(parent);
	}

	@Override
public Menu getMenu(Menu parent) {    //在菜单栏被调用
		createDropDownMenuMgr();
		Menu menu = new Menu(parent);
		IContributionItem[] items = dropDownMenuMgr.getItems();
for (int i = 0; i < items.length; i++) {
			IContributionItem item = items[i];
			IContributionItem newItem = item;
if (item instanceof ActionContributionItem) {
				newItem = new ActionContributionItem(
						((ActionContributionItem) item).getAction());
			}
			newItem.fill(menu, -1);
		}
return menu;
	}

class InnerAction extends Action{
private String text;

public InnerAction(String text){
super(text);
this.text =text;
		}

public void run(){
			System.out.println(text);
		}
	}

}

效果截图