PyQt5 - 第二个 window 中的按钮在单击时不执行操作

Question

Hello I have 2 python files:

first one is called 'first.py', second is 'second.py':

My program is supposed to guide the user from first window to second window.

The problem is, the first window's button work fine when clicked. But in the second window, the buttons don't work even though they are "connected" to a function.

first.py

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QLineEdit
import sys
from second import Ui_second



              

class Ui_mainwindow(object):
    def setupUi(self, mainwindow):
        mainwindow.setObjectName("mainwindow")
        mainwindow.resize(1039, 717)
        self.centralwidget = QtWidgets.QWidget(mainwindow)
        self.centralwidget.setObjectName("centralwidget")

        

        self.nextbutton1 = QtWidgets.QPushButton(self.centralwidget)


        self.nextbutton1.setGeometry(QtCore.QRect(550, 380, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.nextbutton1.setFont(font)
        self.nextbutton1.setObjectName("nextbutton1")
        self.patientinfo_label = QtWidgets.QLabel(self.centralwidget)
        self.patientinfo_label.setGeometry(QtCore.QRect(360, 230, 191, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.patientinfo_label.setFont(font)
        self.patientinfo_label.setObjectName("patientinfo_label")

        self.lastname_label = QtWidgets.QLabel(self.centralwidget)
        self.lastname_label.setGeometry(QtCore.QRect(360, 270, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.lastname_label.setFont(font)
        self.lastname_label.setObjectName("lastname_label")
        self.lastname_input = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input.setGeometry(QtCore.QRect(460, 278, 150, 20))
        self.lastname_input.setObjectName("lastname_input")
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)

        self.firstname_label = QtWidgets.QLabel(self.centralwidget)
        self.firstname_label.setGeometry(QtCore.QRect(360, 300, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.firstname_label.setFont(font)
        self.firstname_label.setObjectName("firstname_label")
      
        

        self.telephone_label = QtWidgets.QLabel(self.centralwidget)
        self.telephone_label.setGeometry(QtCore.QRect(360, 330, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.telephone_label.setFont(font)
        self.telephone_label.setObjectName("telephone_label")

        self.welcome = QtWidgets.QLabel(self.centralwidget)
        self.welcome.setGeometry(QtCore.QRect(260, 150, 471, 71))
        font = QtGui.QFont()
        font.setPointSize(16)
        font.setBold(True)
        font.setWeight(75)
        self.welcome.setFont(font)
        self.welcome.setObjectName("welcome")
        self.lastname_input_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input_2.setGeometry(QtCore.QRect(460, 308, 150, 20))
        self.lastname_input_2.setObjectName("lastname_input_2")
        self.lastname_input_3 = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input_3.setGeometry(QtCore.QRect(460, 338, 150, 20))
        self.lastname_input_3.setObjectName("lastname_input_3")
        self.nextbutton1_2 = QtWidgets.QPushButton(self.centralwidget)
        self.nextbutton1_2.setGeometry(QtCore.QRect(460, 380, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.nextbutton1_2.setFont(font)
        self.nextbutton1_2.setObjectName("nextbutton1_2")
        mainwindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(mainwindow)
        self.statusbar.setObjectName("statusbar")
        mainwindow.setStatusBar(self.statusbar)

        self.retranslateUi(mainwindow)
        QtCore.QMetaObject.connectSlotsByName(mainwindow)
        mainwindow.setTabOrder(self.lastname_input, self.lastname_input_2)
        mainwindow.setTabOrder(self.lastname_input_2, self.lastname_input_3)
        mainwindow.setTabOrder(self.lastname_input_3, self.nextbutton1)
        mainwindow.setTabOrder(self.nextbutton1, self.nextbutton1_2)

        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input_3.returnPressed.connect(self.clicked)
        self.nextbutton1.clicked.connect(self.clicked1)

    def retranslateUi(self, mainwindow):
        _translate = QtCore.QCoreApplication.translate
        mainwindow.setWindowTitle(_translate("mainwindow", "VeriMed Tech"))
        self.nextbutton1.setText(_translate("mainwindow", "Next"))
        self.patientinfo_label.setText(_translate("mainwindow", "Patient Information"))
        self.lastname_label.setText(_translate("mainwindow", "Last name:"))
        self.firstname_label.setText(_translate("mainwindow", "First name:"))
        self.telephone_label.setText(_translate("mainwindow", "Telephone:"))
        self.welcome.setText(_translate("mainwindow", "Welcome to VeriMed Technologies"))
        self.nextbutton1_2.setText(_translate("mainwindow", "Exit"))


    def clicked1(self):
        print("passed first clicked test")
    
        mainwindow.close()
        ui = Ui_second()
        ui.setupUi(mainwindow)
        mainwindow.show()




        


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_())

second.py

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QLineEdit
import sys



class Ui_second(object):
    
    def setupUi(self, second):
        second.setObjectName("second")
        second.resize(1039, 717)
        self.centralwidget = QtWidgets.QWidget(second)
        self.centralwidget.setObjectName("centralwidget")
        self.lastname_input = QtWidgets.QLineEdit(self.centralwidget)
        self.imagelabel = QtWidgets.QLabel(self.centralwidget)
        self.imagelabel.setGeometry(QtCore.QRect(130, 250, 201, 141))
        self.imagelabel.setText("")
        self.imagelabel.setPixmap(QtGui.QPixmap("databases/images/cartoon.png"))
        self.imagelabel.setScaledContents(True)
        self.imagelabel.setWordWrap(False)
        self.imagelabel.setObjectName("imagelabel")
        self.lastname_input.setGeometry(QtCore.QRect(460, 275, 200, 30))
        self.lastname_input.setObjectName("lastname_input")
        self.next = QtWidgets.QPushButton(self.centralwidget)
        self.next.setGeometry(QtCore.QRect(570, 430, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.next.setFont(font)
        self.next.setObjectName("next")
        self.patientinfo_label = QtWidgets.QLabel(self.centralwidget)
        self.patientinfo_label.setGeometry(QtCore.QRect(360, 230, 191, 31))
        font = QtGui.QFont()
        font.setPointSize(12)
        font.setBold(True)
        font.setWeight(75)
        self.patientinfo_label.setFont(font)
        self.patientinfo_label.setObjectName("patientinfo_label")
        self.barcode_label = QtWidgets.QLabel(self.centralwidget)
        self.barcode_label.setGeometry(QtCore.QRect(360, 270, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.barcode_label.setFont(font)
        self.barcode_label.setObjectName("barcode_label")
        self.medication_label = QtWidgets.QLabel(self.centralwidget)
        self.medication_label.setGeometry(QtCore.QRect(360, 320, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.medication_label.setFont(font)
        self.medication_label.setObjectName("medication_label")
        font = QtGui.QFont()
        font.setPointSize(11)
        self.welcome = QtWidgets.QLabel(self.centralwidget)
        self.welcome.setGeometry(QtCore.QRect(260, 150, 471, 71))
        font = QtGui.QFont()
        font.setPointSize(16)
        font.setBold(True)
        font.setWeight(75)
        self.welcome.setFont(font)
        self.welcome.setObjectName("welcome")
        self.exit = QtWidgets.QPushButton(self.centralwidget)
        self.exit.setGeometry(QtCore.QRect(480, 430, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.exit.setFont(font)
        self.exit.setObjectName("exit")
        self.medreal_label = QtWidgets.QLabel(self.centralwidget)
        self.medreal_label.setGeometry(QtCore.QRect(460, 323, 200, 30))
        self.medreal_label.setObjectName("medreal_label")
       
        second.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(second)
        self.statusbar.setObjectName("statusbar")
        second.setStatusBar(self.statusbar)

        self.retranslateUi(second)
        QtCore.QMetaObject.connectSlotsByName(second)
        second.setTabOrder(self.lastname_input, self.next)
        second.setTabOrder(self.next, self.exit)

        self.lastname_input.returnPressed.connect(self.clicked2)
        self.next.clicked.connect(self.clicked2)

    def retranslateUi(self, second):
        _translate = QtCore.QCoreApplication.translate
        second.setWindowTitle(_translate("second", "MainWindow"))
        self.next.setText(_translate("second", "Next"))
        self.patientinfo_label.setText(_translate("second", "Medication"))
        self.barcode_label.setText(_translate("second", "Barcode:"))
        self.medication_label.setText(_translate("second", "Medication:"))
        
        self.welcome.setText(_translate("second", "Scan medication"))
        self.exit.setText(_translate("second", "Exit"))
        self.medreal_label.setText(_translate("second",""))
        
    def clicked2(self):        
        print("passed clicked 2test")
        

Answer 1

Do not modify the code generated by Qt Designer but create another class that inherits from the appropriate widget and use the initial class to fill it.

I suggest you to carefully read the official guidelines about using Designer , and remember to never edit the output of pyuic https://www.riverbankcomputing.com/static/Docs/PyQt5/designer.html

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QLineEdit

#from second import Ui_second
class Ui_second(object):
    def setupUi(self, second):
        second.setObjectName("second")
        second.resize(1039, 717)
        self.centralwidget = QtWidgets.QWidget(second)
        self.centralwidget.setObjectName("centralwidget")
        self.lastname_input = QtWidgets.QLineEdit(self.centralwidget)
        self.imagelabel = QtWidgets.QLabel(self.centralwidget)
        self.imagelabel.setGeometry(QtCore.QRect(130, 250, 201, 141))
        self.imagelabel.setText("")
        self.imagelabel.setPixmap(QtGui.QPixmap("databases/images/cartoon.png"))
        self.imagelabel.setScaledContents(True)
        self.imagelabel.setWordWrap(False)
        self.imagelabel.setObjectName("imagelabel")
        self.lastname_input.setGeometry(QtCore.QRect(460, 275, 200, 30))
        self.lastname_input.setObjectName("lastname_input")
        self.next = QtWidgets.QPushButton(self.centralwidget)
        self.next.setGeometry(QtCore.QRect(570, 430, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.next.setFont(font)
        self.next.setObjectName("next")
        self.patientinfo_label = QtWidgets.QLabel(self.centralwidget)
        self.patientinfo_label.setGeometry(QtCore.QRect(360, 230, 191, 31))
        font = QtGui.QFont()
        font.setPointSize(12)
        font.setBold(True)
        font.setWeight(75)
        self.patientinfo_label.setFont(font)
        self.patientinfo_label.setObjectName("patientinfo_label")
        self.barcode_label = QtWidgets.QLabel(self.centralwidget)
        self.barcode_label.setGeometry(QtCore.QRect(360, 270, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.barcode_label.setFont(font)
        self.barcode_label.setObjectName("barcode_label")
        self.medication_label = QtWidgets.QLabel(self.centralwidget)
        self.medication_label.setGeometry(QtCore.QRect(360, 320, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.medication_label.setFont(font)
        self.medication_label.setObjectName("medication_label")
        font = QtGui.QFont()
        font.setPointSize(11)
        self.welcome = QtWidgets.QLabel(self.centralwidget)
        self.welcome.setGeometry(QtCore.QRect(260, 150, 471, 71))
        font = QtGui.QFont()
        font.setPointSize(16)
        font.setBold(True)
        font.setWeight(75)
        self.welcome.setFont(font)
        self.welcome.setObjectName("welcome")
        self.exit = QtWidgets.QPushButton(self.centralwidget)
        self.exit.setGeometry(QtCore.QRect(480, 430, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.exit.setFont(font)
        self.exit.setObjectName("exit")
        self.medreal_label = QtWidgets.QLabel(self.centralwidget)
        self.medreal_label.setGeometry(QtCore.QRect(460, 323, 200, 30))
        self.medreal_label.setObjectName("medreal_label")
       
        second.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(second)
        self.statusbar.setObjectName("statusbar")
        second.setStatusBar(self.statusbar)

        self.retranslateUi(second)
        QtCore.QMetaObject.connectSlotsByName(second)
        second.setTabOrder(self.lastname_input, self.next)
        second.setTabOrder(self.next, self.exit)

#        self.lastname_input.returnPressed.connect(self.clicked2)
#        self.next.clicked.connect(self.clicked2)

    def retranslateUi(self, second):
        _translate = QtCore.QCoreApplication.translate
        second.setWindowTitle(_translate("second", "MainWindow"))
        self.next.setText(_translate("second", "Next"))
        self.patientinfo_label.setText(_translate("second", "Medication"))
        self.barcode_label.setText(_translate("second", "Barcode:"))
        self.medication_label.setText(_translate("second", "Medication:"))
        
        self.welcome.setText(_translate("second", "Scan medication"))
        self.exit.setText(_translate("second", "Exit"))
        self.medreal_label.setText(_translate("second",""))
        
#    def clicked2(self):        
#        print("passed clicked 2test")
              

class Ui_mainwindow(object):
    def setupUi(self, mainwindow):
        mainwindow.setObjectName("mainwindow")
        mainwindow.resize(1039, 717)
        self.centralwidget = QtWidgets.QWidget(mainwindow)
        self.centralwidget.setObjectName("centralwidget")
        self.nextbutton1 = QtWidgets.QPushButton(self.centralwidget)
        self.nextbutton1.setGeometry(QtCore.QRect(550, 380, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.nextbutton1.setFont(font)
        self.nextbutton1.setObjectName("nextbutton1")
        self.patientinfo_label = QtWidgets.QLabel(self.centralwidget)
        self.patientinfo_label.setGeometry(QtCore.QRect(360, 230, 191, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.patientinfo_label.setFont(font)
        self.patientinfo_label.setObjectName("patientinfo_label")
        self.lastname_label = QtWidgets.QLabel(self.centralwidget)
        self.lastname_label.setGeometry(QtCore.QRect(360, 270, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.lastname_label.setFont(font)
        self.lastname_label.setObjectName("lastname_label")
        self.lastname_input = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input.setGeometry(QtCore.QRect(460, 278, 150, 20))
        self.lastname_input.setObjectName("lastname_input")
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)

        self.firstname_label = QtWidgets.QLabel(self.centralwidget)
        self.firstname_label.setGeometry(QtCore.QRect(360, 300, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.firstname_label.setFont(font)
        self.firstname_label.setObjectName("firstname_label")
        self.telephone_label = QtWidgets.QLabel(self.centralwidget)
        self.telephone_label.setGeometry(QtCore.QRect(360, 330, 100, 31))
        font = QtGui.QFont()
        font.setPointSize(11)
        self.telephone_label.setFont(font)
        self.telephone_label.setObjectName("telephone_label")

        self.welcome = QtWidgets.QLabel(self.centralwidget)
        self.welcome.setGeometry(QtCore.QRect(260, 150, 471, 71))
        font = QtGui.QFont()
        font.setPointSize(16)
        font.setBold(True)
        font.setWeight(75)
        self.welcome.setFont(font)
        self.welcome.setObjectName("welcome")
        self.lastname_input_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input_2.setGeometry(QtCore.QRect(460, 308, 150, 20))
        self.lastname_input_2.setObjectName("lastname_input_2")
        self.lastname_input_3 = QtWidgets.QLineEdit(self.centralwidget)
        self.lastname_input_3.setGeometry(QtCore.QRect(460, 338, 150, 20))
        self.lastname_input_3.setObjectName("lastname_input_3")
        self.nextbutton1_2 = QtWidgets.QPushButton(self.centralwidget)
        self.nextbutton1_2.setGeometry(QtCore.QRect(460, 380, 80, 20))
        font = QtGui.QFont()
        font.setPointSize(9)
        self.nextbutton1_2.setFont(font)
        self.nextbutton1_2.setObjectName("nextbutton1_2")
        mainwindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(mainwindow)
        self.statusbar.setObjectName("statusbar")
        mainwindow.setStatusBar(self.statusbar)

        self.retranslateUi(mainwindow)
        QtCore.QMetaObject.connectSlotsByName(mainwindow)
        mainwindow.setTabOrder(self.lastname_input, self.lastname_input_2)
        mainwindow.setTabOrder(self.lastname_input_2, self.lastname_input_3)
        mainwindow.setTabOrder(self.lastname_input_3, self.nextbutton1)
        mainwindow.setTabOrder(self.nextbutton1, self.nextbutton1_2)

        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input.returnPressed.connect(self.clicked)
        #self.lastname_input_3.returnPressed.connect(self.clicked)
#        self.nextbutton1.clicked.connect(self.clicked1)

    def retranslateUi(self, mainwindow):
        _translate = QtCore.QCoreApplication.translate
        mainwindow.setWindowTitle(_translate("mainwindow", "VeriMed Tech"))
        self.nextbutton1.setText(_translate("mainwindow", "Next"))
        self.patientinfo_label.setText(_translate("mainwindow", "Patient Information"))
        self.lastname_label.setText(_translate("mainwindow", "Last name:"))
        self.firstname_label.setText(_translate("mainwindow", "First name:"))
        self.telephone_label.setText(_translate("mainwindow", "Telephone:"))
        self.welcome.setText(_translate("mainwindow", "Welcome to VeriMed Technologies"))
        self.nextbutton1_2.setText(_translate("mainwindow", "Exit"))


#    def clicked1(self):
#        print("passed first clicked test")
#        mainwindow.close()
#        ui = Ui_second()
#        ui.setupUi(mainwindow)
#        mainwindow.show()


class SecondWindow(QtWidgets.QMainWindow, Ui_second):        
    def __init__(self, parent=None):
        super(SecondWindow, self).__init__(parent)
        
        self.setupUi(self)
        self.parent = parent
        
        self.lastname_input.returnPressed.connect(self.clicked2)
        self.next.clicked.connect(self.clicked2) 

    def clicked2(self):        
        print("passed clicked 2test")
        
        # ...
        
        self.parent.show()
        self.hide()
        

class FirstWindow(QtWidgets.QMainWindow, Ui_mainwindow):        
    def __init__(self):
        super(FirstWindow, self).__init__()
        
        self.setupUi(self)
        
        self.nextbutton1.clicked.connect(self.clicked1)  

    def clicked1(self):
        print("passed first clicked test")
    
        self.secondWindow = SecondWindow(self)
        self.secondWindow.show()
        self.hide()
        

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
#    mainwindow = QtWidgets.QMainWindow()
#    ui = Ui_mainwindow()
#    ui.setupUi(mainwindow)
#    mainwindow.show()

    w = FirstWindow()
    w.show()
    sys.exit(app.exec_())