Adding new Widgets in a seperate thread

[Cruz]

Hi!

I'm meaning to grab some data from a network connection, wrap the data into a QFrame and add those QFrames to my gui. The data comes slow, so it has to be a seperate process that doesn't block the gui. Also the user needs to have the possibility to stop the process in the middle. So what I did is this:

class FrameGrabber : QThread;
 
void GUI::on_startGrabButton_clicked()
{
	// Start the grabber thread.
	frameGrabber.start();
}

class FrameGrabber : QThread;

void GUI::on_startGrabButton_clicked()
{
	// Start the grabber thread.
	frameGrabber.start();
}

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And inside the frameGrabber thread:

class MyFrame : QFrame;
 
void FrameGrabber::run()
{
	int framesToGrab =1000;
 
	while(framesToGrab >= 0)
	{
		MyFrame* f = NetworkConnection::grabFrame();
		GUI->addFrame(f);
		framesToGrab--;
		msleep(10);
	}
 
	GUI->grabbingProcessFinished();
}

class MyFrame : QFrame;

void FrameGrabber::run()
{
	int framesToGrab =1000;

	while(framesToGrab >= 0)
	{
		MyFrame* f = NetworkConnection::grabFrame();
		GUI->addFrame(f);
		framesToGrab--;
		msleep(10);
	}

	GUI->grabbingProcessFinished();
}

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The NetworkConnection class will instantiate a MyFrame, which is derived from QFrame. However, since the NetworkConnection doesn't know anything about the GUI, it cannot pass QWidget* parent as an argument to the constructor, so it can't instantiate a full blown QFrame yet. Only when MyFrame is added to the GUI with GUI->addFrame(), I try to set the parent with the setParent() method:

void GUI::addFrame(MyFrame* f)
{
	f->setParent(ui.GrabbedFrameBufferArea);
}

void GUI::addFrame(MyFrame* f)
{
	f->setParent(ui.GrabbedFrameBufferArea);
}

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This was the plan anyhow, but it doesn't work. I get a lot of this:

QPixmap: It is not safe to use pixmaps outside the GUI thread
QObject::setParent: Cannot set parent, new parent is in a different thread

I don't quite get why it complains about a different thread adding Widgets to the gui. But in any case, what would be the right solution?

Thanks
Cruz