MotionBuilder Python startup "Deferred" Qt script

mobu_startup_qt_defer.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-

"""
"Hacky" example that shows how to use OnUIIdle callback to defer a function call until MotionBuilder UI is properly 
"""

from __future__ import print_function, division, absolute_import

try:
    from PySide.QtWidgets import QApplication, QMenuBar
except ImportError:
    from PySide2.QtWidgets import QApplication, QMenuBar

def get_main_qt_window():
    parent = QApplication.activeWindow()
    grand_parent = parent
    while grand_parent is not None:
        parent = grand_parent
        grand_parent = parent.parent()
    
    return parent
    

def _on_uiidle_fn(*args, **kwargs):
    main_window = get_main_qt_window()
    if not main_window:
        return
    # accessing QMenuBar using main_window.menuBar() can cause MotionBuilder to crash
    parent_menubar = main_window.findChild(QMenuBar)
    if not parent_menubar:
        return

    init_cpg()


def init():

    # this will be called once Qt is fully loaded and you will be able to access and interact with Qt main window menubar without
    # problems.
    # CODE_HERE
    
    fbsys.OnUIIdle.Remove(_on_uiidle_fn)
    
    
fbsys.OnUIIdle.Add(_on_uiidle_fn)

Thanks a lot for sharing this. 🙏