CODEWITHSUNDEEP
pythonpyqtpyqt5qt-signalsqt-slot
aoh
aoh

Reputation: 1160

Optional Signal Arguments

I have a function which has default keyword arguments. I'm having trouble implementing this as I keep getting an error that if my signal has two arguments then I need to pass both arguments. Is there any way around this?

class Controller(QWidget):
    trigger = pyqtSignal(str, str)
    def __init__(self):
        self.trigger.connect(self.myfunc)

    @pyqtSlot(str, str)
    def function(argument, optional_argument=''):
         do something

c = Controller()
c.trigger.emit('Hello', 'World') # This works
c.trigger.emit('Hello')  # This fails and says I need 2 arguments

Upvotes: 6

Views: 3574

Answers (1)

eyllanesc
eyllanesc

Reputation: 243955

You must make the connection pointing to signature in the connection besides overloading the types that the signal supports:

import sys
from PyQt5 import QtCore


class Controller(QtCore.QObject):
    trigger = QtCore.pyqtSignal([str], [str, str])

    def __init__(self):
        super(Controller, self).__init__()
        self.trigger[str].connect(self.function)
        self.trigger[str, str].connect(self.function)

    @QtCore.pyqtSlot(str)
    @QtCore.pyqtSlot(str, str)
    def function(self, argument,  optional_argument=''):
        print(argument, optional_argument)


def main():
    app = QtCore.QCoreApplication(sys.argv)
    c = Controller()
    c.trigger[str].emit('Hello')
    c.trigger[str, str].emit('Hello', 'World')
    QtCore.QTimer.singleShot(100, QtCore.QCoreApplication.quit)
    sys.exit(app.exec_())


if __name__ == "__main__":
     main()

Upvotes: 15

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