CheckableComboBox

CheckableComboBox.py

from PyQt5.QtCore import QEvent, Qt
from PyQt5.QtGui import QFontMetrics, QPalette, QStandardItem
from PyQt5.QtWidgets import QComboBox, QStyledItemDelegate, qApp


class CheckableComboBox(QComboBox):
    # Subclass Delegate to increase item height
    class Delegate(QStyledItemDelegate):
        def sizeHint(self, option, index):
            size = super().sizeHint(option, index)
            size.setHeight(20)
            return size

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # Make the combo editable to set a custom text, but readonly
        self.setEditable(True)
        self.lineEdit().setReadOnly(True)
        # Make the lineedit the same color as QPushButton
        palette = qApp.palette()
        palette.setBrush(QPalette.Base, palette.button())
        self.lineEdit().setPalette(palette)

        # Use custom delegate
        self.setItemDelegate(CheckableComboBox.Delegate())

        # Update the text when an item is toggled
        self.model().dataChanged.connect(self.updateText)

        # Hide and show popup when clicking the line edit
        self.lineEdit().installEventFilter(self)
        self.closeOnLineEditClick = False

        # Prevent popup from closing when clicking on an item
        self.view().viewport().installEventFilter(self)

    def resizeEvent(self, event):
        # Recompute text to elide as needed
        self.updateText()
        super().resizeEvent(event)

    def eventFilter(self, object, event):
        if object == self.lineEdit():
            if event.type() == QEvent.MouseButtonRelease:
                if self.closeOnLineEditClick:
                    self.hidePopup()
                else:
                    self.showPopup()
                return True
            return False
        if object == self.view().viewport():
            if event.type() == QEvent.MouseButtonRelease:
                index = self.view().indexAt(event.pos())
                item = self.model().item(index.row())
                if item.text() in ["Select All"]:
                    checked = item.checkState() == Qt.Checked
                    for i in range(self.model().rowCount()):
                        self.model().item(i).setCheckState(Qt.Checked if not checked else Qt.Unchecked)
                else:
                    if item.checkState() == Qt.Checked:
                        item.setCheckState(Qt.Unchecked)
                    else:
                        item.setCheckState(Qt.Checked)
                return True
        return False

    def showPopup(self):
        super().showPopup()
        # When the popup is displayed, a click on the lineedit should close it
        self.closeOnLineEditClick = True

    def hidePopup(self):
        super().hidePopup()
        # Used to prevent immediate reopening when clicking on the lineEdit
        self.startTimer(100)
        # Refresh the display text when closing
        self.updateText()

    def timerEvent(self, event):
        # After timeout, kill timer, and reenable click on line edit
        self.killTimer(event.timerId())
        self.closeOnLineEditClick = False

    def updateText(self):
        texts = []
        for i in range(self.model().rowCount()):
            if self.model().item(i).text()!="Select All":
                if self.model().item(i).checkState() == Qt.Checked:
                    texts.append(self.model().item(i).text())
        text = ", ".join(texts)

        # Compute elided text (with "...")
        metrics = QFontMetrics(self.lineEdit().font())
        elidedText = metrics.elidedText(text, Qt.ElideRight, self.lineEdit().width())
        self.lineEdit().setText(elidedText)

    def addItem(self, text, data=None):
        item = QStandardItem()
        item.setText(text)
        if data is None:
            item.setData(text)
        else:
            item.setData(data)
        item.setFlags(Qt.ItemIsEnabled | Qt.ItemIsUserCheckable)
        item.setData(Qt.Unchecked, Qt.CheckStateRole)
        self.model().appendRow(item)

    def addItems(self, texts, datalist=None):
        for i, text in enumerate(texts):
            try:
                data = datalist[i]
            except (TypeError, IndexError):
                data = None
            self.addItem(text, data)

    def currentData(self):
        # Return the list of selected items data
        res = []
        for i in range(self.model().rowCount()):
            if self.model().item(i).text()!="Select All":
                if self.model().item(i).checkState() == Qt.Checked:
                    res.append(self.model().item(i).data())
        return res

main.py

from CheckableComboBox import CheckableComboBox
from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(400, 600)
        self.horizontalLayout = QtWidgets.QHBoxLayout(Form)
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.frame = CheckableComboBox(Form)
        self.frame.setObjectName("frame")
        comunes = ["Select All",'Ameglia', 'Arcola', 'Bagnone']
        self.frame.addItems(comunes)
        self.frame.activated.connect(self.handleActivated)

        self.horizontalLayout.addWidget(self.frame)
        self.xx = QtWidgets.QPushButton(Form)
        self.horizontalLayout.addWidget(self.xx)
        self.xx.clicked.connect(self.handleActivated)

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))

    def handleActivated(self):
        print(self.frame.currentData())
        
if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    widget = QtWidgets.QWidget()

    widget.show()
    test = Ui_Form()
    test.setupUi(widget)
    sys.exit(app.exec_())