One Button Popup Dialog Box in Main Window, PyQt5

Ah, I just looked at this for a PyQt5 course I am developing. You will need to import the form first.

from dialog import Ui_Dialog as Form

      

        
        
        
      

    

Then create a function that will open the dialog:

def open_dialog(self):
    dialog = QtWidgets.QDialog()
    dialog.ui = Form()
    dialog.ui.setupUi(dialog)
    dialog.exec_()
    dialog.show()

      

        
        
        
      

    

which I will connect to your first button:

self.firstbutton.clicked.connect(self.open_dialog)

      

        
        
        
      

    

In dialog.py you can get rid of these lines:

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Dialog = QtWidgets.QDialog()
    ui = Ui_Dialog()
    ui.setupUi(Dialog)
    Dialog.show()
    sys.exit(app.exec_())

      

        
        
        
      

    

They are only needed if you call the dialog directly. To be a little clearer__name__ != "__main__"

Ok, so in dialog.py, I will create 2 new functions and assign them to buttons.

# 2 sample functions
def return_accept(self):
    print("yes")

def return_cancel(self):
    print("no")

      

        
        
        
      

    

and bind these events to buttons:

# connect the two functions
self.pushButton.clicked.connect(self.return_yes)
self.pushButton_2.clicked.connect(self.return_no)

      

        
        
        
      

    

Completed code

app.py

from PyQt5 import QtCore, QtGui, QtWidgets

from dialog import Ui_Dialog as Form

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(670, 492)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget)
        self.verticalLayout.setObjectName("verticalLayout")
        self.horizontalLayout_2 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_2.setObjectName("horizontalLayout_2")
        self.tableWidget = QtWidgets.QTableWidget(self.centralwidget)
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.setColumnCount(3)
        self.tableWidget.setRowCount(0)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(1, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(2, item)
        self.horizontalLayout_2.addWidget(self.tableWidget)
        self.verticalLayout.addLayout(self.horizontalLayout_2)
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.firstbutton = QtWidgets.QPushButton(self.centralwidget)
        self.firstbutton.setObjectName("firstbutton")
        self.horizontalLayout.addWidget(self.firstbutton)
        self.secondbutton = QtWidgets.QPushButton(self.centralwidget)
        self.secondbutton.setObjectName("secondbutton")
        self.horizontalLayout.addWidget(self.secondbutton)
        self.verticalLayout.addLayout(self.horizontalLayout)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 670, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

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

        self.firstbutton.clicked.connect(self.open_dialog)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        item = self.tableWidget.horizontalHeaderItem(0)
        item.setText(_translate("MainWindow", "First column"))
        item = self.tableWidget.horizontalHeaderItem(1)
        item.setText(_translate("MainWindow", "Second column"))
        item = self.tableWidget.horizontalHeaderItem(2)
        item.setText(_translate("MainWindow", "Third"))
        self.firstbutton.setText(_translate("MainWindow", "Add"))
        self.secondbutton.setText(_translate("MainWindow", "Delete"))

    def open_dialog(self):
        dialog = QtWidgets.QDialog()
        dialog.ui = Form()
        dialog.ui.setupUi(dialog)
        dialog.exec_()
        dialog.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_())

      

        
        
        
      

    

dialog.py

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(358, 126)
        self.verticalLayout = QtWidgets.QVBoxLayout(Dialog)
        self.verticalLayout.setObjectName("verticalLayout")
        self.horizontalLayout_3 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_3.setObjectName("horizontalLayout_3")
        self.dialoglabel = QtWidgets.QLabel(Dialog)
        self.dialoglabel.setObjectName("dialoglabel")
        self.horizontalLayout_3.addWidget(self.dialoglabel)
        self.verticalLayout.addLayout(self.horizontalLayout_3)
        self.horizontalLayout_2 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_2.setObjectName("horizontalLayout_2")
        self.dialoglineedit = QtWidgets.QLineEdit(Dialog)
        self.dialoglineedit.setObjectName("dialoglineedit")
        self.horizontalLayout_2.addWidget(self.dialoglineedit)
        self.verticalLayout.addLayout(self.horizontalLayout_2)
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.pushButton_2 = QtWidgets.QPushButton(Dialog)
        self.pushButton_2.setObjectName("pushButton_2")
        self.horizontalLayout.addWidget(self.pushButton_2)
        self.pushButton = QtWidgets.QPushButton(Dialog)
        self.pushButton.setObjectName("pushButton")
        self.horizontalLayout.addWidget(self.pushButton)
        self.verticalLayout.addLayout(self.horizontalLayout)

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

        # connect the two functions
        self.pushButton.clicked.connect(self.return_yes)
        self.pushButton_2.clicked.connect(self.return_no)

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.dialoglabel.setText(_translate("Dialog", "dialoglabel"))
        self.pushButton_2.setText(_translate("Dialog", "Acept"))
        self.pushButton.setText(_translate("Dialog", "Cancel"))

    # 2 sample functions
    def return_accept(self):
        print("yes")

    def return_cancel(self):
        print("no")