Extreme confusion over Qthread and avoiding subclassing

jgv115

Hi everyone,

(I'm coding in python but the principles are the same)

So I'm developing a simple interface that reads a few values from an external device and pushes them to a few QLabels.

I did some research on QThreads and it seems like at the moment, I'm defining a Qthread in another class and executing code from the run method:

class worker(QThread):
    def __init__(self):
        Qthread.__init__(self)

    def run(self):
        do_work()
        a = 3

    def do_work(self):
        b = 2

        self.emit(SIGNAL("work_done"),b)

class MyApp(QtGui.QMainWindow):
    QtGui.QMainWindow.__init__(self, parent)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        self.worker_thread = worker()

        self.connect(self.worker,SIGNAL('work_done'),self.done)

        self.worker_thread.start()

    def done(self,b)

        print "the value from the worker is: " + str(b)

So I just have a few questions.

Does everything I execute in the run() method in my worker class execute in a different thread?
- I don't understand why it would not be as my UI is constantly updating while I do many many other calculations in the background
If it is bad practice, what are the potential pitfalls of this method
If I was to discard this code and redo it without subclassing the QThread, what is the proper way to do it?

Thanks all!

SGaist

Hi and welcome to devnet,

Yes, do_work will be called in your thread.

For such a use case, it's a bit overkill, QtConcurrent::run would likely be simpler and cleaner.