IntellijIdea插件开发之创建项目层级的右键菜单

@Override 
public void update(AnActionEvent event) {//根据扩展名是否是jar，显示隐藏此Action 
 String extension = getFileExtension(event.getDataContext()); 
 this.getTemplatePresentation().setEnabled(extension != null && "jar".equals(extension)); 
} 

import com.intellij.openapi.actionSystem.*; 
import com.intellij.openapi.project.Project; 
import com.intellij.openapi.ui.Messages; 
import com.intellij.openapi.vfs.VirtualFile; 
 
/** 
 * Created by ABC on 16/8/17. 
 */ 
public class FirstAction extends AnAction { 
 
 private Project mProject; 
 
 @Override 
 public void actionPerformed(AnActionEvent event) { 
  mProject = event.getData(PlatformDataKeys.PROJECT); 
  DataContext dataCOntext= event.getDataContext(); 
  if ("jar".equals(getFileExtension(dataContext))) {//根据扩展名判定是否进行下面的处理 
   //获取选中的文件 
   VirtualFile file = DataKeys.VIRTUAL_FILE.getData(event.getDataContext()); 
   if (file != null) { 
    Messages.showMessageDialog(mProject, file.getName(), "select file", Messages.getInformationIcon()); 
   } 
  } 
 } 
 
 @Override 
 public void update(AnActionEvent event) { 
  //在Action显示之前,根据选中文件扩展名判定是否显示此Action 
  String extension = getFileExtension(event.getDataContext()); 
  this.getTemplatePresentation().setEnabled(extension != null && "jar".equals(extension)); 
 } 
 
 public static String getFileExtension(DataContext dataContext) { 
  VirtualFile file = DataKeys.VIRTUAL_FILE.getData(dataContext); 
  return file == null &＃63; null : file.getExtension(); 
 } 
}