Qt利用QFileSystemWatcher对文件或目录监听fileChanged

相关资料：

https://blog.csdn.net/liang19890820/article/details/51849252

.pro

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += 
    main.cpp 
    mainwindow.cpp

HEADERS += 
    mainwindow.h

FORMS += 
    mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

#include <QFileSystemWatcher>
#include <QDebug>
#include <QFile>
#include <QStringList>
#include <QString>


QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

    void SaveCameraConfig(QStringList strliConfig);

private slots:
    void on_fileChanged(const QString &path);
    void on_directoryChanged(const QString &path);

    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;

    QFileSystemWatcher *m_FileWatcher;
    QStringList m_listOfConfig;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    m_FileWatcher = new QFileSystemWatcher();
    m_FileWatcher->addPath("d:/");
    m_FileWatcher->addPath("d:/log.txt");

    connect(m_FileWatcher, &QFileSystemWatcher::fileChanged, this, &MainWindow::on_fileChanged);
    connect(m_FileWatcher, &QFileSystemWatcher::directoryChanged, this, &MainWindow::on_directoryChanged);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::SaveCameraConfig(QStringList strliConfig)
{
    QStringList strList;
    QString strFileName = "d:/log.txt";
    QFile file(strFileName);
    if (file.open(QFile::WriteOnly)) {
        for (int i = 0; i < strliConfig.size(); i++) {
            QString str = strliConfig[i] + "
";
            file.write(str.toStdString().c_str());
        }
        file.close();
    }
}

void MainWindow::on_directoryChanged(const QString &path)
{
    qDebug() << QStringLiteral("目录发生改变--") << path;
}

void MainWindow::on_fileChanged(const QString &path)
{
    qDebug() << QStringLiteral("file发生改变--") << path;
}

void MainWindow::on_pushButton_clicked()
{
    int num = m_listOfConfig.size();
    m_listOfConfig.append(QString::number(num));
    SaveCameraConfig(m_listOfConfig);
}