QModelIndex QFileSystemModel::setRootPath(const QString & newPath)
Sets the directory that is being watched by the model to newPath by installing a file system watcher on it. Any changes to files and directories within this directory will be reflected in the model.
If the path is changed, the rootPathChanged() signal will be emitted.
Note: This function does not change the structure of the model or modify the data available to views. In other words, the "root" of the model is not changed to include only files and directories within the directory specified by newPath in the file system.
双击 或 单击 信号，后取当前 路径 设置 setRootPath
