#ifndef FILE_SYSTEM_WATCHER_H 

#define FILE_SYSTEM_WATCHER_H #include <QObject> #include <QMap> #include <QFileSystemWatcher> class FileSystemWatcher : public QObject { 　　Q_OBJECT public: 　　static void addWatchPath(QString path); public slots: 　　void directoryUpdated(const QString &path); // 目录更新时调用，path是监控的路径 　　void fileUpdated(const QString &path); // 文件被修改时调用，path是监控的路径 private: 　　explicit FileSystemWatcher(QObject *parent = 0); private: 　　static FileSystemWatcher *m_pInstance; // 单例 　　QFileSystemWatcher *m_pSystemWatcher; // QFileSystemWatcher变量 　　QMap<QString, QStringList> m_currentContentsMap; // 当前每个监控的内容目录列表 }; #endif // FILE_SYSTEM_WATCHER_H

#include <QDir>
#include <QFileInfo>
#include <qDebug>
#include "FileSystemWatcher.h"
FileSystemWatcher* FileSystemWatcher::m_pInstance = NULL;
FileSystemWatcher::FileSystemWatcher(QObject *parent) : QObject(parent)
{
}// 监控文件或目录
void FileSystemWatcher::addWatchPath(QString path)
{qDebug() << QString("Add to watch: %1").arg(path);if (m_pInstance == NULL){m_pInstance = new FileSystemWatcher();m_pInstance->m_pSystemWatcher = new QFileSystemWatcher();// 连接QFileSystemWatcher的directoryChanged和fileChanged信号到相应的槽connect(m_pInstance->m_pSystemWatcher, SIGNAL(directoryChanged(QString)), m_pInstance, SLOT(directoryUpdated(QString)));connect(m_pInstance->m_pSystemWatcher, SIGNAL(fileChanged(QString)), m_pInstance, SLOT(fileUpdated(QString)));}// 添加监控路径m_pInstance->m_pSystemWatcher->addPath(path);// 如果添加路径是一个目录，保存当前内容列表
    QFileInfo file(path);if (file.isDir()){const QDir dirw(path);m_pInstance->m_currentContentsMap[path] = dirw.entryList(QDir::NoDotAndDotDot | QDir::AllDirs | QDir::Files, QDir::DirsFirst);}
}// 只要任何监控的目录更新（添加、删除、重命名），就会调用。
void FileSystemWatcher::directoryUpdated(const QString &path)
{qDebug() << QString("Directory updated: %1").arg(path);// 比较最新的内容和保存的内容找出区别(变化)QStringList currEntryList = m_currentContentsMap[path];const QDir dir(path);QStringList newEntryList = dir.entryList(QDir::NoDotAndDotDot | QDir::AllDirs | QDir::Files, QDir::DirsFirst);QSet<QString> newDirSet = QSet<QString>::fromList(newEntryList);QSet<QString> currentDirSet = QSet<QString>::fromList(currEntryList);// 添加了文件QSet<QString> newFiles = newDirSet - currentDirSet;QStringList newFile = newFiles.toList();// 文件已被移除QSet<QString> deletedFiles = currentDirSet - newDirSet;QStringList deleteFile = deletedFiles.toList();// 更新当前设置 m_currentContentsMap[path] = newEntryList;if (!newFile.isEmpty() && !deleteFile.isEmpty()){// 文件/目录重命名if ((newFile.count() == 1) && (deleteFile.count() == 1)){qDebug() << QString("File Renamed from %1 to %2").arg(deleteFile.first()).arg(newFile.first());}}else{// 添加新文件/目录至Dirif (!newFile.isEmpty()){qDebug() << "New Files/Dirs added: " << newFile;foreach (QString file, newFile){// 处理操作每个新文件....
            }}// 从Dir中删除文件/目录if (!deleteFile.isEmpty()){qDebug() << "Files/Dirs deleted: " << deleteFile;foreach(QString file, deleteFile){// 处理操作每个被删除的文件....
            }}}
}// 文件修改时调用
void FileSystemWatcher::fileUpdated(const QString &path)
{QFileInfo file(path);QString strPath = file.absolutePath();QString strName = file.fileName();qDebug() << QString("The file %1 at path %2 is updated").arg(strName).arg(strPath);
}

#include "FileSystemWatcher.h" 

int main(int argc, char *argv[]) { 　　QApplication a(argc, argv); 　　FileSystemWatcher::addWatchPath("E:/Test"); 　　... 　　return a.exec();}