Qt 弹出系统本地目录选择目录或者文件夹

• 选择目录：  
  QString dir = QFileDialog::getExistingDirectory(this, tr("Open Directory"), "/home", QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);

• 选择文件
  

  QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "/home", tr("Images (*.png *.xpm *.jpg)"));