Nsryjdtyk

Preface: I am working on a flashcard app in PyQt5 and I am trying to have an "Enter" button do an action that compares 2 strings by calling a function(one of which from the textEdit box, the other from a list of strings that I have pre coded.) Secondly, I want it to show the comparison as "Right or wrong" by calling the checkanswer() function, but when I press the button and try to get it to call a different function, it will repeat the same behavior from checkanswer().. even though I am trying to call nextcard() [in the print("correct") case]

Which brings me to my question: Can each QPushButton do only one action? I want it to inform the user (or force them to enter the correct answer) before moving on to the next word. Essentially I want one button to call the checkanswer() function as well as the nextword() method at different times.

Here is the code for my main window.. If you need any more information let me know and I will add it here.

class MainWindow(QtWidgets.QMainWindow):



    textvalue = ""

    cardnum = 0                                                     # intialize card number from 0

    def __init__(self):

        super().__init__()

        self.ui = Ui_MainWindow()

        self.ui.setupUi(self)

        self.ui.pushButtonEnter.clicked.connect(self.checkanswer)

        self.show()



    def checkanswer(self):

        textvalue = self.ui.lineEditAnswer.text()

        print("You entered: " + textvalue + " $? " + deck[self.cardnum].deflist[0])

        if textvalue == deck[self.cardnum].deflist[0]:

            print("Correct!")

            self.ui.lineEditAnswer.clear()

            textvalue = ""

            self.ui.labelVocab.setText("Correct!n " + deck[self.cardnum].deflist[0])

            self.ui.pushButtonEnter.setText("Continue")

            self.ui.pushButtonEnter.clicked.connect(self.nextword)

        else:

            print("Incorrect!")

            print(self.cardnum)

            self.ui.lineEditAnswer.clear()

            self.ui.labelVocab.setText("Oops! Correct answer is: " + deck[self.cardnum].deflist[0])



    def nextword(self):

        self.cardnum += 1

        self.ui.lineEditAnswer.clear()

        self.ui.pushButtonEnter.setText("Enter")

        self.ui.labelVocab.setText(deck[self.cardnum].vocab)

        self.ui.pushButtonEnter.clicked.connect(self.checkanswer)



    if __name__ == "__main__":

        deck = parser.parser()

        app = QApplication(sys.argv)

        win = MainWindow()

        win.show()

        win.ui.labelVocab.setText(deck[MainWindow.cardnum].vocab)



        sys.exit(app.exec_())

First of all, there is a nice introduction in the Qt doc.:

Signals & Slots

which I warmly recommend to read.

Somewhere in the middle, you find the following paragraph:

By default, for every connection you make, a signal is emitted; two signals are emitted for duplicate connections. You can break all of these connections with a single disconnect() call. If you pass the Qt::UniqueConnection type, the connection will only be made if it is not a duplicate. If there is already a duplicate (exact same signal to the exact same slot on the same objects), the connection will fail and connect will return false.

I must admit, I was not aware about the single disconnect(). Usually, I store the connection for a signal handler which is returned by connect() when I intend to disconnect it later. Furthermore, Qt allows also to disconnect a handler by the same arguments which were given in connect() but I never have used this.

Here my little Python sample for fiddling:

#!/usr/bin/python3



import sys

from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton



app = QApplication(sys.argv)

qBtn1 = QPushButton("Click me")

qBtn1.show()



def onBtn1Clicked():

  print("onBtn1Clicked")

  qBtn1.clicked.disconnect()

  qBtn1.setText("Click me again")

  qBtn1.clicked.connect(onBtn1ClickedAgain)



def onBtn1ClickedAgain():

  print("onBtn1ClickedAgain")

  qBtn1.clicked.disconnect()

  qBtn1.setText("Click me")

  qBtn1.clicked.connect(onBtn1Clicked)



qBtn1.clicked.connect(onBtn1Clicked)

sys.exit(app.exec_())

The signal handlers onBtn1Clicked() and onBtn1ClickedAgain() connect each other mutual exclusive.

Tested in cygwin64 on Windows 10:

$ /usr/bin/python3 --version

Python 3.6.4



$ ./testQPushButton.py

onBtn1Clicked

onBtn1ClickedAgain

onBtn1Clicked

onBtn1ClickedAgain

Concerning the multiple calls of a signal handler, I recommend the following: comment the line qBtn1.clicked.disconnect() in both handlers and see what happens (on console).

As Scheff as pointed out in the comments, you can call the pushButton.disconnect() method and then connect clicked to another action.
This is how I fixed my code:


self.ui.pushButtonEnter.disconnect()
self.ui.pushButtonEnter.clicked.connect(self.checkanswer)