eclipse popupMene高级教程:使用Visibility定制弹出菜单

这几天一直在研究popupMenu的Action,想要达到的目是选中不同的东西弹出不同的菜单。网上有很多介绍的文章，不过很多文章都是一些翻译过来并且作者没有自己实践过的东西,浪费了我很多时间，最后自己通过摸索，终于找出了这个问题的解决办法。 

1.文章类型: 
这是一篇解决问题的教程，不讨论技术的背景知识，比如运用到何种设计模式，以及实现背后的原理等问题。 

2.此文对您的帮助: 
看完此文后您将能够创建一个由选择内容指定弹出项的动态菜单。 

setp1.创建一个rcp工程，模板使用有一个view的 

step2.创建popupMenu 
step2_1.新建类Action1: 

package solonote.example.popupmenu;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.ui.IObjectActionDelegate;
import org.eclipse.ui.IWorkbenchPart;

public class Action1 implements IObjectActionDelegate {

    @Override
    public void setActivePart(IAction action, IWorkbenchPart targetPart) {
        // TODO Auto-generated method stub

    }

    @Override
    public void run(IAction action) {
        // TODO Auto-generated method stub

    }

    @Override
    public void selectionChanged(IAction action, ISelection selection) {
        // TODO Auto-generated method stub

    }

}

step2_2.添加扩展点: 

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>

   <extension
         id="application"
         point="org.eclipse.core.runtime.applications">
      <application>
         <run
               class="solonote.example.popupmenu.Application">
         </run>
      </application>
   </extension>
   <extension
         point="org.eclipse.ui.perspectives">
      <perspective
            name="Perspective"
            class="solonote.example.popupmenu.Perspective"
            id="solonote.example.popupMenu.perspective">
      </perspective>
   </extension>
   <extension
         point="org.eclipse.ui.views">
      <view
            name="View"
            class="solonote.example.popupmenu.View"
            id="solonote.example.popupMenu.view">
      </view>
   </extension>
   <!-- 弹出菜单的定义 -->
   <extension
         point="org.eclipse.ui.popupMenus">
      <objectContribution
            id="objectContribution"
            objectClass="java.lang.Object">
         <action
               class="solonote.example.popupmenu.Action1"
               id="solonote.example.popupMenu.action1"
               label="label">
         </action>
      </objectContribution>
   </extension>

</plugin>

step2_3设置弹出菜单的弹出位置 
修改View类 

package solonote.example.popupmenu;

import org.eclipse.jface.action.MenuManager;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.ITableLabelProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.ui.ISharedImages;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.part.ViewPart;

public class View extends ViewPart {
    public static final String ID = "solonote.example.popupMenu.view";

    private TableViewer viewer;

    /**
     * The content provider class is responsible for providing objects to the
     * view. It can wrap existing objects in adapters or simply return objects
     * as-is. These objects may be sensitive to the current input of the view,
     * or ignore it and always show the same content (like Task List, for
     * example).
     */
    class ViewContentProvider implements IStructuredContentProvider {
        public void inputChanged(Viewer v, Object oldInput, Object newInput) {
        }

        public void dispose() {
        }

        public Object[] getElements(Object parent) {
            return new SimpleDTO[] { new SimpleDTO("One"), new SimpleDTO("Two"),  new SimpleDTO("Three") };

        }
    }

    class ViewLabelProvider extends LabelProvider implements
            ITableLabelProvider {
        public String getColumnText(Object obj, int index) {
            SimpleDTO dto = (SimpleDTO) obj;
            return dto.getName();
        }

        public Image getColumnImage(Object obj, int index) {
            return getImage(obj);
        }

        public Image getImage(Object obj) {
            return PlatformUI.getWorkbench().getSharedImages().getImage(
                    ISharedImages.IMG_OBJ_ELEMENT);
        }
    }

    /**
     * This is a callback that will allow us to create the viewer and initialize
     * it.
     */
    public void createPartControl(Composite parent) {
        viewer = new TableViewer(parent, SWT.MULTI | SWT.H_SCROLL
                | SWT.V_SCROLL);
        viewer.setContentProvider(new ViewContentProvider());
        viewer.setLabelProvider(new ViewLabelProvider());
        viewer.setInput(getViewSite());

        //初始化弹出菜单
        MenuManager popupMenuManager = new MenuManager("#PopupMenu");
        popupMenuManager.setRemoveAllWhenShown(true);
        Menu popupMenu = popupMenuManager.createContextMenu(viewer.getTable());
        viewer.getTable().setMenu(popupMenu);
        //设置选择提供者和弹出菜单
        getSite().setSelectionProvider(viewer);
        getSite().registerContextMenu(popupMenuManager, viewer);
    }

    /**
     * Passing the focus request to the viewer's control.
     */
    public void setFocus() {
        viewer.getControl().setFocus();
    }
}

好的step2已经结束了，现在您可以运行一下程序，看看效果. 

接下来将要进行的是，只有选中Three时菜单才弹出，选择其他两个则不弹出。 
确切的说是只有选择Three时      
<objectContribution 
            id="objectContribution" 
            objectClass="java.lang.Object"> 
节点中的Action才显示. 

接下来: 
step3_1修改扩展点 增加visibility项 

<!-- 弹出菜单的定义 -->
 <extension
       point="org.eclipse.ui.popupMenus">
    <objectContribution
          id="objectContribution"
          objectClass="java.lang.Object">
       <action
             class="solonote.example.popupmenu.Action1"
             id="solonote.example.popupMenu.action1"
             label="label">
       </action>
       <visibility>
          <objectState
                name="name"
                value="Three">
          </objectState>
       </visibility>
    </objectContribution>
 </extension>

修改被选中的DTO，让其实现IActionFilter接口 

package solonote.example.popupmenu;

import org.eclipse.ui.IActionFilter;

/**
 * Viewer显示的项
 * @author solonote
 * @version 0.1.0 2007-12-26 上午11:49:41
 */
public class SimpleDTO implements IActionFilter{
    /**
     * 显示的名字
     */
    private String name;

    /**
     * 返回显示的名字
     * @return 显示的名字
     */
    public String getName() {
        return name;
    }

    /**
     * 设置显示的名字
     * @param name 显示的名字
     */
    public void setName(String name) {
        this.name = name;
    }

    public SimpleDTO(String name) {
        super();
        this.name = name;
    }

    /**
     * 选择时候是否显示Action的判断
     * <visibility>
            <objectState
                  name="name"
                  value="Three">
            </objectState>
         </visibility>
     * @param target 选择的东西
     * @param name plugin.xml里配置的name
     * @param value plugin.xml里配置的value
     */
    @Override
    public boolean testAttribute(Object target, String name, String value) {
        System.out.println(name);
        System.out.println(value);
        System.out.println(target);
        SimpleDTO dto = (SimpleDTO) target;
        if(dto.getName().equals(value))
            return true;
        return false;
    }


}

然后就完成了，当然实际运用中我运用了Adapter将DTO适配成IActionFilter接口，这样DTO就不用和IActionFilter接口耦合了，或许以后的文章会接受如何适配。