The QTableWidget always scrolls to setColumn/RowCount automatically - pyqt5

Question

I am currently trying to add a file (that changes periodically) to a QTable widget. However, the row and column also changes permanently.
To delete old information:
self.tableWidget.setRowCount(0)
self.tableWidget.setColumnCount(0)
Change to new list length:
self.tableWidget.setRowCount(len(someList))
self.tableWidget.setColumnCount(4)
After that the scroll position is at the top. Although I also did the following:
self.tableWidget.setAutoScroll(False)
pos = self.tableWidget.verticalScrollBar().value()
#Change the column row size
#check max>=pos
self.tableWidget.verticalScrollBar().setValue(pos)
Everything is ignored and it scrolls up anyway.
My code example:
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QTimer
import sys
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(618, 510)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
self.gridLayout.setObjectName("gridLayout")
self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
self.scrollArea.setWidgetResizable(True)
self.scrollArea.setObjectName("scrollArea")
self.scrollAreaWidgetContents_2 = QtWidgets.QWidget()
self.scrollAreaWidgetContents_2.setGeometry(QtCore.QRect(0, 0, 594, 440))
self.scrollAreaWidgetContents_2.setObjectName("scrollAreaWidgetContents_2")
self.gridLayout_2 = QtWidgets.QGridLayout(self.scrollAreaWidgetContents_2)
self.gridLayout_2.setObjectName("gridLayout_2")
self.tableWidget = QtWidgets.QTableWidget(self.scrollAreaWidgetContents_2)
self.tableWidget.setObjectName("tableWidget")
self.tableWidget.setColumnCount(4)
self.tableWidget.setRowCount(20)
self.gridLayout_2.addWidget(self.tableWidget, 0, 0, 1, 1)
self.scrollArea.setWidget(self.scrollAreaWidgetContents_2)
self.gridLayout.addWidget(self.scrollArea, 0, 0, 1, 1)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 618, 25))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
self.qTimer = QTimer()
self.qTimer.setInterval(1000)
self.qTimer.timeout.connect(self.getData)
self.qTimer.start()
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
def getData(self):
self.tableWidget.setRowCount(0)
self.tableWidget.setColumnCount(0)
self.tableWidget.setColumnCount(4)
self.tableWidget.setRowCount(20)
#Problem: Scrolls to top
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())

Answer 1

Changing the layout of an item model requires a certain amount of time to the view that is showing it.
In order to ensure that the scroll bar is updated, you can ask Qt to "process" its current event queue:
def getData(self):
pos = self.tableWidget.verticalScrollBar().value()
self.tableWidget.setRowCount(0)
self.tableWidget.setColumnCount(0)
self.tableWidget.setColumnCount(4)
self.tableWidget.setRowCount(20)
QtWidgets.QApplication.processEvents()
self.tableWidget.verticalScrollBar().setValue(pos)
On the other hand, to minimize unnecessary requests on the table and avoid flickering, you should set the row count to the new amount instead of resetting it everytime. In this way you don't need to move the scroll bar everytime, as it will always try to keep its previous position, even if the new row count is less than before.
Note: you should not modify (nor try to mimic) the files generated by pyuic, as those files have to be imported in your main script(s) instead. Read more about using Designer.