How to use signals and slots in Slicer 3d?

[jamesobutler (James Butler)]

A previous post of mine mentioned some about basics of using Qt signals and slots with python.

Dynamically Updating UI

Doing some like a=qt.QPushButton() is already the python interface that you can use in Slicer to interact with Qt which is C++ based. Slicer uses PythonQt and not PyQt. They are similar in syntax, but with different licensing. How are you currently connecting the button press to updating the label? I generally connect actions using the newer style of a=qt.QPushButton() a.clicked.connect(slotName)

Essentially the syntax is something like {object}.{signal_name}.connect({slot_name}).

So something that is based on QProgressBar will have these signals such as valueChanged. Therefore

def printMyNewValue(value):
  print("The progress bar value is now: {}".format(value))

import qt
progress_bar = qt.QProgressBar()
progress_bar.setMaximum(10)
progress_bar.valueChanged.connect(printMyNewValue)
progress_bar.setValue(4)  # will then print "The progress bar value is now: 4"