如何在pyqt 5 gui中添加滚动条？

Question

I have created a gui with controller file to switch between windows. The files includes several parameters which will be set by previous windows, hence, the size can be quite big. Therefore, I need to create a scrollbar to be able to reach the last elements, but wonder how I can implement this in my code.

from controller.py

import sys
from PyQt5 import QtCore, QtWidgets

from firstwindow import Login
class Controller:

    def __init__(self):
        pass

    def show_login(self):
        self.login = Login()
        self.login.switch_window.connect(self.show_main)
        self.login.show()

    def show_main(self):
        self.MAP                   = self.login.MAP
        #Parameters from file
        self.NUM                    = self.login.spinBoxNUM.value()
        self.login.close()


def main():
    app = QtWidgets.QApplication(sys.argv)
    controller = Controller()
    controller.show_login()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

and from the Login class file: firstwindow.py

import sys
from PyQt5 import QtCore, QtWidgets, QtGui

class Login(QtWidgets.QWidget):

    switch_window = QtCore.pyqtSignal()

    def __init__(self):
        QtWidgets.QWidget.__init__(self)
        self.setupUi(self)
        self.setWindowTitle('First')

    def setupUi(self, FirstWindow):
        FirstWindow.setObjectName("First")
        FirstWindow.setEnabled(True)
        FirstWindow.resize(675,776)

        FirstWindow.setFocusPolicy(QtCore.Qt.TabFocus)

        layout = QtWidgets.QGridLayout()
        #Lots of elements + buttons: example:
        self.spinBoxNUM = QtWidgets.QSpinBox()
        layout.addWidget(self.spinBoxNUM,1,2)
        self.spinBoxLEVELS  = QtWidgets.QSpinBox()
        self.spinBoxLEVELS.setValue(2)
        self.spinBoxLEVELS.setMaximum(156)
        layout.addWidget(self.spinBoxLEVELS,11,2)

        #CONTINUE AND QUIT BUTTON
        self.QuitButton      = QtWidgets.QPushButton("Quit")
        self.QContinueButton = QtWidgets.QPushButton("Continue")
        #actions
        self.QuitButton.clicked.connect(FirstWindow.close)
        self.QContinueButton.clicked.connect(self.login)
        layout.addWidget(self.QuitButton,15,1)
        layout.addWidget(self.QContinueButton,15,2)

        self.setLayout(layout)
     def login(self):
        self.MAP    = [[1 for x in range(4)]for y in range(self.LEVELS)]
        self.switch_window.emit()

Answer 1

Try it:

import sys
from PyQt5 import QtCore, QtGui, QtWidgets

#from firstwindow import Login
class Login(QtWidgets.QWidget): 

    switch_window = QtCore.pyqtSignal()

    def __init__(self):
        QtWidgets.QWidget.__init__(self)
        self.setupUi(self)
        self.setWindowTitle('First')

    def setupUi(self, FirstWindow):
        FirstWindow.setObjectName("First")
        FirstWindow.setEnabled(True)
        FirstWindow.resize(675, 776)

        FirstWindow.setFocusPolicy(QtCore.Qt.TabFocus)


        #Lots of elements + buttons: example:
        self.spinBoxNUM = QtWidgets.QSpinBox()
        self.spinBoxLEVELS  = QtWidgets.QSpinBox()
        self.spinBoxLEVELS.setValue(2)
        self.spinBoxLEVELS.setMaximum(156)

        #CONTINUE AND QUIT BUTTON
        self.QuitButton      = QtWidgets.QPushButton("Quit")
        self.QContinueButton = QtWidgets.QPushButton("Continue")
        #actions
        self.QuitButton.clicked.connect(FirstWindow.close)
        self.QContinueButton.clicked.connect(self.login)


        layout = QtWidgets.QGridLayout()
        layout.addWidget(self.spinBoxNUM,      1, 2)
        layout.addWidget(self.spinBoxLEVELS,  11, 2)
        layout.addWidget(self.QuitButton,     15, 1)
        layout.addWidget(self.QContinueButton,15, 2)

        self.setLayout(layout)

    def login(self):
        self.MAP    = [[1 for x in range(4)]for y in range(7)]     # ??? (self.LEVELS)]
        self.switch_window.emit()

    def sizeHint(self):                                            # <--- sizeHint
        return QtCore.QSize(700, 500)



#class Controller:
class Controller(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.show_login()

    def show_login(self):
        self.login = Login()

        self.scrollArea = QtWidgets.QScrollArea()                   # +++
        self.scrollArea.setWidget(self.login)                       # +++

        self.login.switch_window.connect(self.show_main)

        self.scrollArea.show()                                      # +++
        self.scrollArea.resize(700, 500)                            # +++
#        self.login.show()

    def show_main(self):
        self.MAP                   = self.login.MAP
        #Parameters from file
        self.NUM                    = self.login.spinBoxNUM.value()

#        self.login.close()
        self.scrollArea.hide()                                       # +++
        self.show()                                                  # +++


def main():
    app = QtWidgets.QApplication(sys.argv)
    controller = Controller()
    controller.setWindowTitle("Controller")
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()