Styjun

I am using Python3.6 and PySide2

I have a treewidget-A populated with employee list.
on click on employee (treewidget-A item) a another treeWidget-B will populate.

Now if I click on empty area (deselect item) but treeWidget-B still showing last clicked employee item details.

This is to populate treewidget items

self.treeWidget_A.itemClicked.connect(self.populate_employee)
self.treeWidget_A.currentItemChanged.connect(self.populate_employee)

How to execute clear_employee_data() function on click on empty area of QtreeWidget ?

def clear_employee_data(self):
 self.treeWidget_B.clear()

You have to detect the click and verify that there is not an item:

from PySide2 import QtCore, QtWidgets

class TreeWidget(QtWidgets.QTreeWidget):
 emptyClicked = QtCore.Signal()

 def __init__(self, parent=None):
 super(TreeWidget, self).__init__(parent)
 for i in range(2):
 it = QtWidgets.QTreeWidgetItem(self, ["item-".format(i)])
 for j in range(3):
 child_it = QtWidgets.QTreeWidgetItem(it, ["item--".format(i, j)])
 self.expandAll()

 def mousePressEvent(self, event):
 super(TreeWidget, self).mousePressEvent(event)
 if not self.indexAt(event.pos()).isValid():
 self.emptyClicked.emit()

@QtCore.Slot()
def on_empty_clicked():
 print("clicked")

if __name__ == '__main__':
 import sys
 app = QtWidgets.QApplication(sys.argv)
 w = TreeWidget()
 w.emptyClicked.connect(on_empty_clicked)
 w.resize(640, 480)
 w.show()
 sys.exit(app.exec_())

With Qt Designer use eventfilter:

from PySide2 import QtCore, QtGui, QtWidgets

from design import Ui_MainWindow

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
 emptyClicked = QtCore.Signal()

 def __init__(self, parent=None):
 super(MainWindow, self).__init__(parent)
 self.setupUi(self)
 self.treeWidget_A.viewport().installEventFilter(self)
 self.emptyClicked.connect(self.on_emptyClicked)

 def eventFilter(self, obj, event):
 if obj is self.treeWidget_A.viewport() and event.type() == QtCore.QEvent.MouseButtonPress:
 if not self.treeWidget_A.indexAt(event.pos()).isValid():
 self.emptyClicked.emit()
 return super(MainWindow, self).eventFilter(obj, event)

 @QtCore.Slot()
 def on_emptyClicked(self):
 print("empty")

if __name__ == "__main__":
 import sys
 app = QtWidgets.QApplication(sys.argv)
 w = MainWindow()
 w.show()
 sys.exit(app.exec_())