Question

我试图在周末解决这个问题，但无济于事。我似乎无法直接使用QFileSystemWatcher::Files()找到一个例子，所以我想我会问。

我有一个程序：

让用户选择“来源”文件夹。
按一个按钮开始观看新文件的源文件夹
使用'directoryChanged（）'发出信号，每次添加或删除文件时我都会尝试更新计数。

我会断言我的QfileSystemWatcher实现可能不正确。但是这段代码工作正确并触发信号/插槽。但计数始终为零...

来自mainwindow.cpp ...

信号：

//connect push buttons
QObject::connect(ui->startButton, SIGNAL(clicked()),
                 this, SLOT(startButtonClicked()));

//link qfilesystemwatcher with signals and slots
    QObject::connect(&hotfolder, SIGNAL(directoryChanged(QString)), this, SLOT(hotfolderChanged()));

插槽：

void MainWindow::startButtonClicked(){

  //start the file system watcher using the 'source folder button'
   //first, get the resulting text from the source folder button
   QString sourceText = ui->sourceBtnLineEdit->text();
   ui->statusbar->showMessage(sourceText);

   //convert the text from source button to a standard string.
   string filePath = sourceText.toStdString();
   cout << filePath << endl;

   //call method to add source path to qfilesystemwatcher
   startWatching(sourceText);

}

void MainWindow::hotfolderChanged(){

    int fileCount = filesWatched();
    ui->statusbar->showMessage(QString::number(fileCount));

}

#ifndef MAGICKWATCHER_H
#define MAGICKWATCHER_H

#include <QFileSystemWatcher>
#include <mainwindow.h>

//create the qFileSystemWatcher
QFileSystemWatcher hotfolder;

//add folder to qfilesystemwatcher
//starts watching of folder path
int startWatching( QString folder){

    hotfolder.addPath(folder);
    cout << "hotfolder created!" << endl;
    return 0;
}

//get file list of folder being watched
int filesWatched(){
    QStringList watchedList = hotfolder.files();

    //report out each line of file list
    for (int i = 0; i < watchedList.size(); ++i){
             cout << watchedList.at(i).toStdString() << endl;
             cout << "is this looping?!!" << endl;
    }
    return watchedList.count();
}


#endif // MAGICKWATCHER_H

如何使用QFileSystemWatcher获取被监视文件夹的文件数？我知道QDir及其选项，但想具体了解如何使用QFileSystemWatcher。

我仍然总体上围绕着c ++，所以感谢你提出任何建议或提示。我想也许我的问题是我如何实现QFileSystemWatcher。

我使用的一些相关链接：

QFileSystemWatcher working only in main()

http://doc.qt.io/qt-5/qfilesystemwatcher.html#files

Answer 1

您可以在监控目录中获取有关文件的信息，例如使用QDir::entryInfoList并filters适用于您的情况。至少QDir::Files和可能QDir::NoDotAndDotDot是有意义的。

//get file list of folder being watched
int filesWatched() {
    QString folder = "/path/to/hotfolder/";
    QDir monitoredFolder(folder);
    QFileInfoList watchedList = 
        monitoredFolder.entryInfoList(QDir::NoDotAndDotDot | QDir::Files);

    QListIterator<QFileInfo> iterator(watchedList);
    while (iterator.hasNext())
    {
        QFileInfo file_info = iterator.next();
        qDebug() << "File path:" << file_info.absoluteFilePath();
    }

    return watchedList.count();
}

使用QFileSystemWatcher :: Files（）获取监视文件夹示例的文件数？计数总是0？

1 个答案: