Hello Toni,
judging from the error message the problem ist not in the code you postet,
but in the way you use the callback. Like the error message states: you
shouldn't call methods of QObjects from other threads. Even if you don't
use threads explicitly that happens easily if you use another
framework/module that makes use of threads internally. So your callback is
probably invoked in another thread.
You can work around that by using signals.
Define your own signal... for example
my_signal = QtCore.pyqtSignal()
and in your callback function you trigger the signal
my_signal.emit()
In your GUI code you connect your new signal with the update function
my_signal.connect(lambda: self.text.setText('Hello world!'))
If the concept is new to you, here's a tutorial:
http://pythoncentral.io/pysidepyqt-tutorial-creating-your-own-signals-and-slots/
<http://pythoncentral.io/pysidepyqt-tutorial-creating-your-own-signals-and-slots/>
Regards
Sebastian
Am Donnerstag, 20. Juli 2017 14:49:18 UTC+2 schrieb Toni:
>
> Hi everyone,
>
> I'm trying to update the text inside a TextItem object from a callback, so
> that I can stream float values that come from outside my python script.
> The problem I'm facing is that once my callback is invoked from the
> framework I'm using, the following error is thrown:
>
> QObject: Cannot create children for a parent that is in a different thread.
>>
>
> I don't know how to avoid that and I'm not sure if there is actually a way
> to do what I want,
>
> This is the code I have written until now:
>
> QtGui.QApplication([])
>
> ## Create window with GraphicsView widget
>
> win = pg.GraphicsLayoutWidget()
> win.show() ## show widget alone in its own window
> win.setWindowTitle('...')
>
> # ... window settings
>
> ## Create image item
> self.vis = pg.ImageItem()
>
> # ... image settings
>
> ## Create obstacle histogram
> plot = pg.PlotItem()
>
> # ... plot settings
>
> self.text = pg.TextItem('Loading...')
> self.view.addItem(self.text)
>
>
> And from the callback mentioned above (where the problem is) I do:
>
> self.text.setText('Hello world!')
>
>
> Does anyone know how to avoid this problem and implement this behavior?
>
> Thank you in advance for your answers, I hope the question is clear.
>
>
>
>
>
>
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