How to connect the signal and slot in multi-thread program?

justforfun

The mainwindow.cpp:

@#include "ui_mainwindow.h"
#include <QtCore>

/* ****** Thread part ****** */
myThread::myThread(QObject *parent)
: QThread(parent)
{
}

void myThread::run()
{
while(1){
qDebug("thread one----------");
emit threadSignal1();
usleep(100000);
}
exec();
}

myThread2::myThread2(QObject *parent)
: QThread(parent)
{
}

void myThread2::run()
{
while(1){
qDebug("thread two");
emit threadSignal2();
usleep(100000);
}
exec();
}
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

onethread = new myThread(this);
onethread->start(QThread::NormalPriority);

twothread = new myThread2(this);
twothread->start(QThread::NormalPriority);

connect(onethread, SIGNAL(onethread->threadSignal1()),
        this, SLOT(mySlot1()));
connect(twothread, SIGNAL(threadSignal2()),
        this, SLOT(mySlot2()),Qt::QueuedConnection);

}

void MainWindow::mySlot1()
{
ui->textEdit1->append("This is thread1");
}

void MainWindow::mySlot2()
{
ui->textEdit1->append("This is thread2");
}

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

void MainWindow::on_pushButton_clicked()
{
ui->textEdit1->append("textEdit1");
ui->textEdit2->append("textEdit2");
}@

The mainwindow.h:

@#define MAINWINDOW_H

#include <QMainWindow>
#include <QThread>

namespace Ui {
class MainWindow;
}

class myThread : public QThread
{
Q_OBJECT

public:
myThread(QObject *parent = 0);
void run();

signals:
void threadSignal1();
};

class myThread2 : public QThread
{
Q_OBJECT

public:
myThread2(QObject *parent = 0);
void run();

signals:
void threadSignal2();
};

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
void mySlot1();
void mySlot2();

private slots:
void on_pushButton_clicked();

private:
Ui::MainWindow *ui;
myThread *onethread;
myThread2 *twothread;
};

#endif // MAINWINDOW_H@

Please check the above code. It can give the qDebug output normally while the textEdit1/2 have no any output. And it seems to be a multi-thread signal/slot connect issue. Who can help? Thanks!

podsvirov

You provide the code - it is good. But I can not understand what you want?
In mainwindow.h file put slots in the public section:

@
public slots:
void mySlot1();
void mySlot2();
@

Without this, these methods are not slots, so do not working in connection.

justforfun

Yes, you are right. This is the root cause! After correcting it, the code can work now. Thank you!

podsvirov

Glad to help!
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