from PyQt5.QtWidgets import QApplication, QComboBox, QMainWindow
from PyQt5.QtWidgets import QWidget, QVBoxLayout
from PyQt5.QtGui import QStandardItemModel
from PyQt5.QtCore import Qt
import sys
 
# creating checkable combo box class
class CheckableComboBox(QComboBox):
    def __init__(self):
        super(CheckableComboBox, self).__init__()
        self.view().pressed.connect(self.handle_item_pressed)
        self.setModel(QStandardItemModel(self))
 
    # when any item get pressed
    def handle_item_pressed(self, index):
 
        # getting which item is pressed
        item = self.model().itemFromIndex(index)
 
        # make it check if unchecked and vice-versa
        if item.checkState() == Qt.Checked:
            item.setCheckState(Qt.Unchecked)
        else:
            item.setCheckState(Qt.Checked)
 
        # calling method
        self.check_items()
 
    # method called by check_items
    def item_checked(self, index):
 
        # getting item at index
        item = self.model().item(index, 0)
 
        # return true if checked else false
        return item.checkState() == Qt.Checked
 
    # calling method
    def check_items(self):
        # blank list
        checkedItems = []
 
        # traversing the items
        for i in range(self.count()):
 
            # if item is checked add it to the list
            if self.item_checked(i):
                checkedItems.append(i)
 
        # call this method
        self.update_labels(checkedItems)
 
    # method to update the label
    def update_labels(self, item_list):
 
        n = ''
        count = 0
 
        # traversing the list
        for i in item_list:
 
            # if count value is 0 don't add comma
            if count == 0:
                n += ' % s' % i
            # else value is greater than 0
            # add comma
            else:
                n += ', % s' % i
 
            # increment count
            count += 1
 
 
        # loop
        for i in range(self.count()):
 
            # getting label
            text_label = self.model().item(i, 0).text()
 
            # default state
            if text_label.find('-') >= 0:
                text_label = text_label.split('-')[0]
 
            # shows the selected items
            item_new_text_label = text_label + ' - selected index: ' + n
 
           # setting text to combo box
            self.setItemText(i, item_new_text_label)
 
    # flush
    sys.stdout.flush()
 
 
class Window(QMainWindow):
    def __init__(self):
        super(QMainWindow, self).__init__()
 
        # creating a widget object
        myQWidget = QWidget()
 
        # vertical box layout
        myBoxLayout = QVBoxLayout()
        myQWidget.setLayout(myBoxLayout)
 
        # central widget
        self.setCentralWidget(myQWidget)
 
        # creating checkable combo box
        self.ComboBox = CheckableComboBox()
 
        # traversing items
        for i in range(3):
            # adding item
            self.ComboBox.addItem("Combobox Item " + str(i))
            item = self.ComboBox.model().item(i, 0)
 
            # setting item unchecked
            item.setCheckState(Qt.Unchecked)
 
        # adding combo box to the layout
        myBoxLayout.addWidget(self.ComboBox)
 
# drivers code
if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    window.resize(480, 320)
    sys.exit(app.exec_())