How to keep track of thread progress in Python without freezing the PyQt GUI?

Question

Questions:

1. What is the best practice for keeping track of a tread\'s progress without locking the GUI (\"Not Responding\")?
2. Gene

Answer 1

Native python queues won't work because you have to block on queue get(), which bungs up your UI.

Qt essentially implements a queuing system on the inside for cross thread communication. Try this call from any thread to post a call to a slot.

QtCore.QMetaObject.invokeMethod()

It's clunky and is poorly documented, but it should do what you want even from from a non-Qt thread.

You can also use event machinery for this. See QApplication (or QCoreApplication) for a method named something like "post".

Edit: Here's a more complete example...

I created my own class based on QWidget. It has a slot that accepts a string; I define it like this:

@QtCore.pyqtSlot(str)
def add_text(self, text):
   ...

Later, I create an instance of this widget in the main GUI thread. From the main GUI thread or any other thread (knock on wood) I can call:

QtCore.QMetaObject.invokeMethod(mywidget, "add_text", QtCore.Q_ARG(str,"hello world"))

Clunky, but it gets you there.

Dan.