PyQt5 QtableWidget update row on cell click (mac)

Question

I recently switched to mac and my pyqt5 application isnt running like it should. I have a table set up with checkboxes in the rows. On a pc, when you click on a checkbox it first updates the row, then hits the checkbox. on mac it just hits the checkbox without triggering a row change. I'm cant even figure out what row i'm on to make any changes.

here is basic code that would work on a pc, but always outputs "0, 3" on a mac:

    for i in range(4):
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(i, item)
        item.setText(_translate("MainWindow", str(i)))

        self.tableWidget.setCellWidget(i, 0, QtWidgets.QCheckBox())
        self.tableWidget.cellWidget(i, 0).clicked.connect(lambda: print(self.tableWidget.currentRow(), i))

Here is the full file if you would like to test this yourself:

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate

        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.tableWidget = QtWidgets.QTableWidget(self.centralwidget)
        self.tableWidget.setGeometry(QtCore.QRect(195, 101, 371, 321))
        self.tableWidget.setObjectName("tableWidget")

        MainWindow.setCentralWidget(self.centralwidget)

        self.tableWidget.setColumnCount(1)
        self.tableWidget.setRowCount(4)

        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, item)
        item = self.tableWidget.horizontalHeaderItem(0)
        item.setText(_translate("MainWindow", "Value"))

        for i in range(4):
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setVerticalHeaderItem(i, item)
            item.setText(_translate("MainWindow", str(i)))

            self.tableWidget.setCellWidget(i, 0, QtWidgets.QCheckBox())
            self.tableWidget.cellWidget(i, 0).clicked.connect(lambda: print(self.tableWidget.currentRow(), i))


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

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


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

Not overly sure if this will be the solution, but be careful about connecting signals in a loop, as you may end up with the wrong variables being used (eg. i might always be 3).

Instead of creating the lambda like this:

lambda: print(self.tableWidget.currentRow(), i)

Try manually setting the i parameter:

lambda checked, i=i: print(self.tableWidget.currentRow(), i)

As pointed out by musicamante, clicked signals emit a checked variable, which will need to be ignored otherwise it will overwrite the value you've set for i.

As an alternative way of doing things, this is a potentially cleaner solution, but without testing I'm not sure if manually defining the slot as int will bypass the checked argument or not.

def setupUI(self):
    ...
    self.tableWidget.cellWidget(i, 0).clicked.connect(partial(self.someMethod, i))

@QtCore.Slot(int)
def someMethod(self, i):
    print(self.tableWidget.currentRow(), i)