[PyQt] how to set up a timer to call a method after a delay?

Steve Castellotti sc at puzzlebox.info
Wed Jun 30 12:46:36 BST 2010

Hello all-

    I have written a simple socket server based around
QtNetwork.QTcpServer which I want to use to send a single stream of
information to multiple connected clients, with updates pushed at a
specific frequency (lets say once per second).

    I am a little confused how to set up a timer which will emit a
signal that is connected to my method for sending the data.

    For example, under Python Twisted, I might have something like this:

def sendData(self, timer):
    data = self.getCurrentData()
    reactor.callLater(timer, self.sendData, timer)

    ...whereby the "callLater" function makes sure the function happens
at a regular interval.

    I have tried setting up a QTimer object in the __init__ method of my
socket server's class:

self.timer = QtCore.QTimer()
self.timer.connect(self.timer, QtCore.SIGNAL("timeout()"),
self.timer.start(1000) # 1 second

    ...but received an exception that "QTimer can only be used with
threads started with QThread" which leads me to believe I will need to
implement threading for my server (also I expected to need to send
"parent=self" when instantiating the QTimer object so I know I must be
doing something wrong).

    Is there an easier way to accomplish what I am trying to do?

    If there is obvious documentation which I have overlooked please
just point me in the right direction.

Thanks in advance.

Steve Castellotti

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