import UnityEngine as unity
from PySide2 import QtWidgets
class TestUI(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        QtWidgets.QMainWindow.__init__(self, parent)
        # win
        self.setWindowTitle("TestQ")
        # ui part
        main_widget = QtWidgets.QWidget()
        self.setCentralWidget(main_widget)
        main_layout = QtWidgets.QVBoxLayout()
        main_widget.setLayout(main_layout)
        
        test_btn = QtWidgets.QPushButton("List Object")
        main_layout.addWidget(test_btn)
        # connection
        test_btn.clicked.connect(self.list_items)
    # function
    def list_items(self):
        print('hello in python, not shown in unity. - from TestQ')
        self.u_print('hello in unity. - from TestQ')
        obj_list = unity.Object.FindObjectsOfType(unity.GameObject)
        for each_obj in obj_list:
            self.u_print(each_obj.name)
    def u_print(self, info):
        unity.Debug.Log(info)
# fix QApplication singleton issue for run python inside some app
if not QtWidgets.QApplication.instance():
    app = QtWidgets.QApplication([])
else:
    app = QtWidgets.QApplication.instance()
main_ui = TestUI()
main_ui.show()