[FIXED] Change main window active tab from a dialogbox action

Issue

I have two windows in 2 separate classes. The main window and a dialogbox window. The main window contains a Qtabwidget with multiple tabs. The dialogbox has a button.

From the main window, on the click of a button the dialogbox opens. The user performs some action and clicks the save button. On the click of the button I would like the dialogbox to close, and the mainwindow to change from the initial tab to the second tab.

My problem is that I cannot get the tabwidget to change tabs on the dialogbox save button click signal.

Attempt:

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(392, 138)
        self.gridLayout = QtWidgets.QGridLayout(Dialog)
        self.gridLayout.setObjectName("gridLayout")
        self.frame = QtWidgets.QFrame(Dialog)
        self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame.setObjectName("frame")
        self.verticalLayout_2 = QtWidgets.QVBoxLayout(self.frame)
        self.verticalLayout_2.setObjectName("verticalLayout_2")
        self.verticalLayout = QtWidgets.QVBoxLayout()
        self.verticalLayout.setObjectName("verticalLayout")
        self.label = QtWidgets.QLabel(self.frame)
        font = QtGui.QFont()
        font.setPointSize(10)
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.verticalLayout.addWidget(self.label)
        self.lineEdit_vehicleName = QtWidgets.QLineEdit(self.frame)
        self.lineEdit_vehicleName.setObjectName("lineEdit_vehicleName")
        self.verticalLayout.addWidget(self.lineEdit_vehicleName)
        spacerItem = QtWidgets.QSpacerItem(20, 40, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.verticalLayout.addItem(spacerItem)
        self.verticalLayout_2.addLayout(self.verticalLayout)
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        spacerItem1 = QtWidgets.QSpacerItem(40, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem1)
        self.pushButton_save = QtWidgets.QPushButton(self.frame)
        self.pushButton_save.setObjectName("pushButton_save")
        self.horizontalLayout.addWidget(self.pushButton_save)
        self.pushButton_cancel = QtWidgets.QPushButton(self.frame)
        self.pushButton_cancel.setObjectName("pushButton_cancel")
        self.horizontalLayout.addWidget(self.pushButton_cancel)
        self.verticalLayout_2.addLayout(self.horizontalLayout)
        self.gridLayout.addWidget(self.frame, 0, 0, 1, 1)

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

        # Dialog = QtWidgets.QDialog()
        self.pushButton_save.clicked.connect(Dialog.close)
        self.pushButton_save.clicked.connect(Ui_MainWindow.changeTab)

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.label.setText(_translate("Dialog", "Enter Name:"))
        self.pushButton_save.setText(_translate("Dialog", "Save"))
        self.pushButton_cancel.setText(_translate("Dialog", "Cancel"))

class Ui_MainWindow(object):
    def changeTab(self):
        self.tabWidget.setCurrentIndex(1)

    def openDialog(self):
        self.window = QtWidgets.QDialog()
        self.ui = Ui_Dialog()
        self.ui.setupUi(self.window)
        self.window.show()

    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(548, 399)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName("gridLayout")
        self.tabWidget = QtWidgets.QTabWidget(self.centralwidget)
        self.tabWidget.setObjectName("tabWidget")
        self.tab = QtWidgets.QWidget()
        self.tab.setObjectName("tab")
        self.pushButton = QtWidgets.QPushButton(self.tab)
        self.pushButton.setGeometry(QtCore.QRect(240, 160, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.tabWidget.addTab(self.tab, "")
        self.tab_2 = QtWidgets.QWidget()
        self.tab_2.setObjectName("tab_2")
        self.tabWidget.addTab(self.tab_2, "")
        self.gridLayout.addWidget(self.tabWidget, 0, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 548, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.tabWidget.setCurrentIndex(0)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)



        self.pushButton.clicked.connect(self.openDialog)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))
        self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab), _translate("MainWindow", "Tab 1"))
        self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab_2), _translate("MainWindow", "Tab 2"))




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_())

Solution

PyQt recommends not modifying the code generated by Qt Designer, instead it creates a class that inherits from the appropriate widget. On the other hand, the save and cancel buttons must be connected to the accept and reject methods, respectively. To get the information you can use exec_() that will return a value associated to the button that you have pressed, and if it is the save button then you must change the currentIndex of QTabWidget

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(392, 138)
        self.gridLayout = QtWidgets.QGridLayout(Dialog)
        self.gridLayout.setObjectName("gridLayout")
        self.frame = QtWidgets.QFrame(Dialog)
        self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame.setObjectName("frame")
        self.verticalLayout_2 = QtWidgets.QVBoxLayout(self.frame)
        self.verticalLayout_2.setObjectName("verticalLayout_2")
        self.verticalLayout = QtWidgets.QVBoxLayout()
        self.verticalLayout.setObjectName("verticalLayout")
        self.label = QtWidgets.QLabel(self.frame)
        font = QtGui.QFont()
        font.setPointSize(10)
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.verticalLayout.addWidget(self.label)
        self.lineEdit_vehicleName = QtWidgets.QLineEdit(self.frame)
        self.lineEdit_vehicleName.setObjectName("lineEdit_vehicleName")
        self.verticalLayout.addWidget(self.lineEdit_vehicleName)
        spacerItem = QtWidgets.QSpacerItem(20, 40, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.verticalLayout.addItem(spacerItem)
        self.verticalLayout_2.addLayout(self.verticalLayout)
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        spacerItem1 = QtWidgets.QSpacerItem(40, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem1)
        self.pushButton_save = QtWidgets.QPushButton(self.frame)
        self.pushButton_save.setObjectName("pushButton_save")
        self.horizontalLayout.addWidget(self.pushButton_save)
        self.pushButton_cancel = QtWidgets.QPushButton(self.frame)
        self.pushButton_cancel.setObjectName("pushButton_cancel")
        self.horizontalLayout.addWidget(self.pushButton_cancel)
        self.verticalLayout_2.addLayout(self.horizontalLayout)
        self.gridLayout.addWidget(self.frame, 0, 0, 1, 1)

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

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.label.setText(_translate("Dialog", "Enter Name:"))
        self.pushButton_save.setText(_translate("Dialog", "Save"))
        self.pushButton_cancel.setText(_translate("Dialog", "Cancel"))

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(548, 399)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName("gridLayout")
        self.tabWidget = QtWidgets.QTabWidget(self.centralwidget)
        self.tabWidget.setObjectName("tabWidget")
        self.tab = QtWidgets.QWidget()
        self.tab.setObjectName("tab")
        self.pushButton = QtWidgets.QPushButton(self.tab)
        self.pushButton.setGeometry(QtCore.QRect(240, 160, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.tabWidget.addTab(self.tab, "")
        self.tab_2 = QtWidgets.QWidget()
        self.tab_2.setObjectName("tab_2")
        self.tabWidget.addTab(self.tab_2, "")
        self.gridLayout.addWidget(self.tabWidget, 0, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 548, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.tabWidget.setCurrentIndex(0)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))
        self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab), _translate("MainWindow", "Tab 1"))
        self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab_2), _translate("MainWindow", "Tab 2"))


class MainWindow(Ui_MainWindow, QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)
        self.pushButton.clicked.connect(self.openDialog)

    @QtCore.pyqtSlot()
    def openDialog(self):
        self.dialog = Dialog()
        if  self.dialog.exec_() == QtWidgets.QDialog.Accepted:
            self.tabWidget.setCurrentIndex(1)


class Dialog(Ui_Dialog, QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__(parent)
        self.setupUi(self)
        self.pushButton_save.clicked.connect(self.accept)
        self.pushButton_cancel.clicked.connect(self.reject)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

_{For more information read https://www.riverbankcomputing.com/static/Docs/PyQt5/designer.html}

Answered By - eyllanesc