I try to implement the progressBar for the file upload window on the basis of the http example, now it works for each file separately. I would like the progress bar to be the same for all downloaded files from 0 to 100, and not for each file separately. Here is the code:

httpwindow.h

 #ifndef HTTPWINDOW_H #define HTTPWINDOW_H #include <QProgressDialog> #include <QNetworkAccessManager> #include <QUrl> QT_BEGIN_NAMESPACE class QFile; class QLabel; class QLineEdit; class QPushButton; class QSslError; class QAuthenticator; class QNetworkReply; class QCheckBox; QT_END_NAMESPACE class ProgressDialog : public QProgressDialog { Q_OBJECT public: explicit ProgressDialog(const QUrl &url, QWidget *parent = Q_NULLPTR); public slots: void networkReplyProgress(qint64 bytesRead, qint64 totalBytes); }; class HttpWindow : public QDialog { Q_OBJECT public: explicit HttpWindow(QWidget *parent = Q_NULLPTR); void startRequest(const QUrl &requestedUrl); private slots: void downloadFile(); void cancelDownload(); void httpFinished(); void httpReadyRead(); void enableDownloadButton(); void slotAuthenticationRequired(QNetworkReply*,QAuthenticator *); #ifndef QT_NO_SSL void sslErrors(QNetworkReply*,const QList<QSslError> &errors); #endif private: QFile *openFileForWrite(const QString &fileName); QLabel *statusLabel; QLineEdit *urlLineEdit; QPushButton *downloadButton; QCheckBox *launchCheckBox; QLineEdit *defaultFileLineEdit; QLineEdit *downloadDirectoryLineEdit; QUrl url; QNetworkAccessManager qnam; QNetworkReply *reply; QFile *file; bool httpRequestAborted; }; #endif

httpwindow.cpp

 #include <QtWidgets> #include <QtNetwork> #include <QUrl> #include "httpwindow.h" #include "ui_authenticationdialog.h" #ifndef QT_NO_SSL static const char defaultUrl[] = "https://qt-project.org/"; #else static const char defaultUrl[] = "http://qt-project.org/"; #endif static const char defaultFileName[] = "index.html"; ProgressDialog::ProgressDialog(const QUrl &url, QWidget *parent) : QProgressDialog(parent) { setWindowTitle(tr("Download Progress")); setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint); setLabelText(tr("Downloading %1.").arg(url.toDisplayString())); setMinimum(0); setValue(0); setMinimumDuration(0); } void ProgressDialog::networkReplyProgress(qint64 bytesRead, qint64 totalBytes) { setMaximum(totalBytes); setValue(bytesRead); } HttpWindow::HttpWindow(QWidget *parent) : QDialog(parent) , statusLabel(new QLabel(tr("Please enter the URL of a file you want to download.\n\n"), this)) , urlLineEdit(new QLineEdit(defaultUrl)) , downloadButton(new QPushButton(tr("Download"))) , launchCheckBox(new QCheckBox("Launch file")) , defaultFileLineEdit(new QLineEdit(defaultFileName)) , downloadDirectoryLineEdit(new QLineEdit) , reply(Q_NULLPTR) , file(Q_NULLPTR) , httpRequestAborted(false) { setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint); setWindowTitle(tr("HTTP")); connect(&qnam, &QNetworkAccessManager::authenticationRequired, this, &HttpWindow::slotAuthenticationRequired); #ifndef QT_NO_SSL connect(&qnam, &QNetworkAccessManager::sslErrors, this, &HttpWindow::sslErrors); #endif QFormLayout *formLayout = new QFormLayout; urlLineEdit->setClearButtonEnabled(true); connect(urlLineEdit, &QLineEdit::textChanged, this, &HttpWindow::enableDownloadButton); formLayout->addRow(tr("&URL:"), urlLineEdit); QString downloadDirectory = QStandardPaths::writableLocation(QStandardPaths::DownloadLocation); if (downloadDirectory.isEmpty() || !QFileInfo(downloadDirectory).isDir()) downloadDirectory = QDir::currentPath(); downloadDirectoryLineEdit->setText(QDir::toNativeSeparators(downloadDirectory)); formLayout->addRow(tr("&Download directory:"), downloadDirectoryLineEdit); formLayout->addRow(tr("Default &file:"), defaultFileLineEdit); launchCheckBox->setChecked(true); formLayout->addRow(launchCheckBox); QVBoxLayout *mainLayout = new QVBoxLayout(this); mainLayout->addLayout(formLayout); mainLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding)); statusLabel->setWordWrap(true); mainLayout->addWidget(statusLabel); downloadButton->setDefault(true); connect(downloadButton, &QAbstractButton::clicked, this, &HttpWindow::downloadFile); QPushButton *quitButton = new QPushButton(tr("Quit")); quitButton->setAutoDefault(false); connect(quitButton, &QAbstractButton::clicked, this, &QWidget::close); QDialogButtonBox *buttonBox = new QDialogButtonBox; buttonBox->addButton(downloadButton, QDialogButtonBox::ActionRole); buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole); mainLayout->addWidget(buttonBox); urlLineEdit->setFocus(); } void HttpWindow::startRequest(const QUrl &requestedUrl) { url = requestedUrl; httpRequestAborted = false; reply = qnam.get(QNetworkRequest(url)); connect(reply, &QNetworkReply::finished, this, &HttpWindow::httpFinished); connect(reply, &QIODevice::readyRead, this, &HttpWindow::httpReadyRead); ProgressDialog *progressDialog = new ProgressDialog(url, this); progressDialog->setAttribute(Qt::WA_DeleteOnClose); connect(progressDialog, &QProgressDialog::canceled, this, &HttpWindow::cancelDownload); connect(reply, &QNetworkReply::downloadProgress, progressDialog, &ProgressDialog::networkReplyProgress); connect(reply, &QNetworkReply::finished, progressDialog, &ProgressDialog::hide); progressDialog->show(); statusLabel->setText(tr("Downloading %1...").arg(url.toString())); } void HttpWindow::downloadFile() { const QString urlSpec = urlLineEdit->text().trimmed(); if (urlSpec.isEmpty()) return; const QUrl newUrl = QUrl::fromUserInput(urlSpec); if (!newUrl.isValid()) { QMessageBox::information(this, tr("Error"), tr("Invalid URL: %1: %2").arg(urlSpec, newUrl.errorString())); return; } QString fileName = newUrl.fileName(); if (fileName.isEmpty()) fileName = defaultFileLineEdit->text().trimmed(); if (fileName.isEmpty()) fileName = defaultFileName; QString downloadDirectory = QDir::cleanPath(downloadDirectoryLineEdit->text().trimmed()); if (!downloadDirectory.isEmpty() && QFileInfo(downloadDirectory).isDir()) fileName.prepend(downloadDirectory + '/'); if (QFile::exists(fileName)) { if (QMessageBox::question(this, tr("Overwrite Existing File"), tr("There already exists a file called %1 in " "the current directory. Overwrite?").arg(fileName), QMessageBox::Yes|QMessageBox::No, QMessageBox::No) == QMessageBox::No) return; QFile::remove(fileName); } file = openFileForWrite(fileName); if (!file) return; downloadButton->setEnabled(false); // schedule the request startRequest(newUrl); } QFile *HttpWindow::openFileForWrite(const QString &fileName) { QScopedPointer<QFile> file(new QFile(fileName)); if (!file->open(QIODevice::WriteOnly)) { QMessageBox::information(this, tr("Error"), tr("Unable to save the file %1: %2.") .arg(QDir::toNativeSeparators(fileName), file->errorString())); return Q_NULLPTR; } return file.take(); } void HttpWindow::cancelDownload() { statusLabel->setText(tr("Download canceled.")); httpRequestAborted = true; reply->abort(); downloadButton->setEnabled(true); } void HttpWindow::httpFinished() { QFileInfo fi; if (file) { fi.setFile(file->fileName()); file->close(); delete file; file = Q_NULLPTR; } if (httpRequestAborted) { reply->deleteLater(); reply = Q_NULLPTR; return; } if (reply->error()) { QFile::remove(fi.absoluteFilePath()); statusLabel->setText(tr("Download failed:\n%1.").arg(reply->errorString())); downloadButton->setEnabled(true); reply->deleteLater(); reply = Q_NULLPTR; return; } const QVariant redirectionTarget = reply->attribute(QNetworkRequest::RedirectionTargetAttribute); reply->deleteLater(); reply = Q_NULLPTR; if (!redirectionTarget.isNull()) { const QUrl redirectedUrl = url.resolved(redirectionTarget.toUrl()); if (QMessageBox::question(this, tr("Redirect"), tr("Redirect to %1 ?").arg(redirectedUrl.toString()), QMessageBox::Yes | QMessageBox::No) == QMessageBox::No) { downloadButton->setEnabled(true); return; } file = openFileForWrite(fi.absoluteFilePath()); if (!file) { downloadButton->setEnabled(true); return; } startRequest(redirectedUrl); return; } statusLabel->setText(tr("Downloaded %1 bytes to %2\nin\n%3") .arg(fi.size()).arg(fi.fileName(), QDir::toNativeSeparators(fi.absolutePath()))); if (launchCheckBox->isChecked()) QDesktopServices::openUrl(QUrl::fromLocalFile(fi.absoluteFilePath())); downloadButton->setEnabled(true); } void HttpWindow::httpReadyRead() { // this slot gets called every time the QNetworkReply has new data. // We read all of its new data and write it into the file. // That way we use less RAM than when reading it at the finished() // signal of the QNetworkReply if (file) file->write(reply->readAll()); } void HttpWindow::enableDownloadButton() { downloadButton->setEnabled(!urlLineEdit->text().isEmpty()); } void HttpWindow::slotAuthenticationRequired(QNetworkReply*,QAuthenticator *authenticator) { QDialog authenticationDialog; Ui::Dialog ui; ui.setupUi(&authenticationDialog); authenticationDialog.adjustSize(); ui.siteDescription->setText(tr("%1 at %2").arg(authenticator->realm(), url.host())); // Did the URL have information? Fill the UI // This is only relevant if the URL-supplied credentials were wrong ui.userEdit->setText(url.userName()); ui.passwordEdit->setText(url.password()); if (authenticationDialog.exec() == QDialog::Accepted) { authenticator->setUser(ui.userEdit->text()); authenticator->setPassword(ui.passwordEdit->text()); } } #ifndef QT_NO_SSL void HttpWindow::sslErrors(QNetworkReply*,const QList<QSslError> &errors) { QString errorString; foreach (const QSslError &error, errors) { if (!errorString.isEmpty()) errorString += '\n'; errorString += error.errorString(); } if (QMessageBox::warning(this, tr("SSL Errors"), tr("One or more SSL errors has occurred:\n%1").arg(errorString), QMessageBox::Ignore | QMessageBox::Abort) == QMessageBox::Ignore) { reply->ignoreSslErrors(); } } #endif

    2 answers 2

    You are missing the total size of all files intended for download. To get this information you need to send HEAD requests for all files ( int QHttp::head(const QString & path) ), they will return only the headers, without body. In them look at the size, after summing up get your total.

      Recommend:

      1. separate the network part from the UI.
      2. setReadBufferSize for each QNetworkReply, otherwise Qt writes everything to memory, for small files it is not critical, and if the file is gigabyte, then the consequences are obvious. After this, it is necessary to read in portions on the signal QNetworkReply :: readyRead