QT Cuncurrent With mail Client - c++

Question

Hi I already asked my question here and understand why it's not working, now I have modified source code by moving the Smptp object as class variable , but still not working.
What I need to implement is send mail from a thread I chose QtConcurrent::run() for doing this but the slot not getting called after sending button clicked.
mainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QSettings"
#include "QFuture"
#include "QtConcurrent/QtConcurrent"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
connect(ui->sendBtn, SIGNAL(clicked()),this, SLOT(test()));
connect(ui->exitBtn, SIGNAL(clicked()),this, SLOT(close()));
connect(ui->browseBtn, SIGNAL(clicked()), this, SLOT(browse()));
}
void MainWindow::browse()
{
files.clear();
QFileDialog dialog(this);
dialog.setDirectory(QDir::homePath());
dialog.setFileMode(QFileDialog::ExistingFiles);
if (dialog.exec())
files = dialog.selectedFiles();
QString fileListString;
foreach(QString file, files)
fileListString.append( "\"" + QFileInfo(file).fileName() + "\" " );
ui->file->setText( fileListString );
}
void MainWindow::test(){
QFuture<void> f4 = QtConcurrent::run(this,&MainWindow::sendMail); // this not work
//sendMail(); // this works
}
void MainWindow::sendMail()
{
smtp = new Smtp(ui->uname->text(), ui->paswd->text(), ui->server->text(), ui->port->text().toInt());
connect(smtp, SIGNAL(status(QString)), this, SLOT(mailSent(QString)));
if( !files.isEmpty() )
smtp->sendMail(ui->uname->text(), ui->rcpt->text() , ui->subject->text(),ui->msg->toPlainText(), files );
else
smtp->sendMail(ui->uname->text(), ui->rcpt->text() , ui->subject->text(),ui->msg->toPlainText());
}
void MainWindow::mailSent(QString status)
{
if(status == "Message sent")
QMessageBox::warning( 0, tr( "Qt Simple SMTP client" ), tr( "Message sent!\n\n" ) );
delete smtp;
}
MainWindow::~MainWindow()
{
delete ui;
}
mainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "smtp.h"
#include <QtWidgets/QMessageBox>
#include <QFileDialog>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void sendMail();
void mailSent(QString);
void browse();
void test();
private:
Ui::MainWindow *ui;
QStringList files;
Smtp* smtp ;
};
#endif // MAINWINDOW_H
If I call sendMail(); directly it works, but using QFuture<void> f4 = QtConcurrent::run(this,&MainWindow::sendMail); it's not working, not working means the slot not get called, how can I resolve this issue?
I am referring the code from here https://github.com/xcoder123/SimpleSmtp_SSL_QT5/tree/master/smtp_attachements
Thanks
Haris

Answer 1

A solution as I already mentioned here is to use a QThread instead of QtConcurrent::run.
There is a detailed example contained in the Qt documentation: http://doc.qt.io/qt-5/qthread.html#details
The following code adapts this example to your use case.
smtp is moved to the workerThread. The communication between the main thread and the workerThread is done using signals and slots.
Be aware that you are not allowed to call any GUI related functions (such as showing message boxes etc.) in Smtp anymore!
This has to be done in the main thread.
User name, password etc. should probably also be passed through the signal to Smtp::sendMail.
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtWidgets/QMessageBox>
#include <QFileDialog>
#include <QThread>
namespace Ui {
class MainWindow;
}
class Smtp;
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void sendMailButtonClicked();
void mailSent(QString);
void browse();
private:
Ui::MainWindow *ui;
QStringList files;
Smtp* smtp;
QThread workerThread;
signals:
void sendMail(const QString &from, const QString &to, const QString &subject, const QString &body, QStringList files);
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "smtp.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
connect(ui->sendBtn, SIGNAL(clicked()),this, SLOT(sendMailButtonClicked()));
connect(ui->exitBtn, SIGNAL(clicked()),this, SLOT(close()));
connect(ui->browseBtn, SIGNAL(clicked()), this, SLOT(browse()));
smtp = new Smtp(ui->uname->text(), ui->paswd->text(), ui->server->text(), ui->port->text().toInt());
smtp->moveToThread(&workerThread);
connect(this, SIGNAL(sendMail(QString,QString,QString,QString,QStringList)), smtp, SLOT(sendMail(QString,QString,QString,QString,QStringList)));
connect(smtp, SIGNAL(status(QString)), this, SLOT(mailSent(QString)));
workerThread.start();
}
void MainWindow::browse()
{
files.clear();
QFileDialog dialog(this);
dialog.setDirectory(QDir::homePath());
dialog.setFileMode(QFileDialog::ExistingFiles);
if (dialog.exec())
files = dialog.selectedFiles();
QString fileListString;
foreach(QString file, files)
fileListString.append( "\"" + QFileInfo(file).fileName() + "\" " );
ui->file->setText( fileListString );
}
void MainWindow::mailSent(QString status)
{
if(status == "Message sent")
QMessageBox::warning( 0, tr( "Qt Simple SMTP client" ), tr( "Message sent!\n\n" ) );
}
MainWindow::~MainWindow()
{
workerThread.quit();
workerThread.wait();
delete ui;
}
void MainWindow::sendMailButtonClicked()
{
emit sendMail(ui->uname->text(), ui->rcpt->text() , ui->subject->text(),ui->msg->toPlainText(), files );
}
in smtp.h: set sendMail to be a slot:
public slots:
void sendMail( const QString &from, const QString &to,
const QString &subject, const QString &body,
QStringList files = QStringList());