Qt creating children threads using QFuture error - qt

Question

I am trying to make a Collaborative Editor(I have to use Linux networking libraries for all the networking stuff), I have the main widget(custom made class that inherits QWidget) with all the components. In the constructor I create all the Widgets on this main Widget and at the end I try to create a new thread using QFuture(I use QFuture instead of QThread cause it allows me easily to call functions with any type of parameters, like QTextEdit, QTextCursor...) but it gives me this error at compilation:
"QObject: Cannot create children for a parent that is in a different thread.
(Parent is QTextDocument(0x1b064b0), parent's thread is QThread(0x1985750), current thread is QThread(0x1ae7610)".
How to solve the error?
Here is my code:
mainwindow.h:
...//includes
using namespace QtConcurrent;
...
namespace Ui {
class Widget;
class TextEdit;
}
class TextEdit;
class Widget;
class Widget : public QWidget {
Q_OBJECT
public:
Widget(QWidget *parent = 0);
~Widget();
...
QFuture<void> thread;
}
class TextEdit : public QTextEdit {
Q_OBJECT
...
}
static void receiveKeyPress(TextEdit *textedit, QTextCursor *secondUserCursor) {
unsigned long long int Number = NULL;
QMessageBox::information(textedit->parentWidget(), "UI Component", "This makes the thread to throw the error");
while(1) if(connected == 1) {
read(recvFileDescriptor, &Number, sizeof(unsigned long long int));
if( Number != NULL)
if( Number == Qt::Key_Home )
secondUserCursor->movePosition(QTextCursor::StartOfLine);
...
else {
QTextCharFormat backgroundFormat = textedit->textCursor().charFormat();
backgroundFormat.setBackground(QColor("lightGreen"));
//If I don't use QMessageBox up there, it breaks here on the next command
secondUserCursor->setCharFormat(backgroundFormat);
secondUserCursor->setPosition(textedit->textCursor().position());
secondUserCursor->insertText(QString::number(Number));
} //else
}//while
}//the function
And mainwindow.cpp:
#include "mainwindow.h"
Widget::Widget(QWidget *parent) {
...
thread = run(receiveKeyPress, this->edit1, this->edit1->secondUserCursor); //run is from QtConcurrent namespace
}
main.cpp:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget window;
...
window.show();
return a.exec();
}
I've read here on stackoverflow how others use QObject(which I never used and I don't get the idea of it) and QThread(the only combination) but I already tried to use QThread and I wasn't able to pass QTextEdit and QTextCursor to it.
Thanks in advance
Edit:
mainwindow.h
class TextEdit : public QTextEdit {
Q_OBJECT
...
public slots:
void receiveKeyPress(qulonglong);
...
};
mainwindow.cpp
void TextEdit::receiveKeyPress(qulonglong Number) {
if( Number == Qt::Key_Home )
...
}
recv-thread.h - created based on this link http://developer.qt.nokia.com/doc/qt-4.8/thread-basics.html#example-3-clock
#include <QThread>
#include "mainwindow.h" //To get TextEdit in here
class RecvThread : public QThread {
Q_OBJECT
signals:
void transferDataToSlot(qulonglong Data);
protected:
void run();
};
recv-thread.cpp
#include "recv-thread.h"
void RecvThread::run() {
unsigned long long int Number = NULL;
while(1) if(connected == 1) {
read(recvFileDescriptor, &Number, sizeof(unsigned long long int));
if( Number != NULL) {
emit transferDataToSlot(Number);
}
}
}
main.cpp
...
#include "recv-thread.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget window;
RecvThread recvThread;
...
QObject::connect(&recvThread, SIGNAL(transferDataToSlot(qulonglong)), window.edit1, SLOT(receiveKeyPress(qulonglong)), Qt::QueuedConnection); //line 38
recvThread.start();
//Displaying the window
window.show();
a.exec();
recvThread.quit();
recvThread.wait();
return 0;
}
Am I doing it right?