QT MDI子窗口遍历

 foreach (QMdiSubWindow *window, mdiArea->subWindowList())
 {
  MdiChild *mdiChild = qobject_cast<MdiChild *>(window);
  if ( mdiChild->windowTitle() == index.data().toString() + ".txt")
  {//如果已经打开过，则获得焦点
   mdiChild->showMaximized();
   bNeedOpen = false;
   break;
  }
 }