小部件未显示在滚动区域中

Question

我使用pyqt设计器创建了两个.ui文件：一个是主窗口，另一个是Widget。每当我尝试将小部件添加到主窗口中的滚动区域时，它都不会显示在屏幕上，而且我也不知道为什么。

很抱歉，如果这是一个愚蠢的问题，我仍在学习pyqt5和pyqt设计器。任何帮助将不胜感激，谢谢。

代码：

namespace Assets.Areas.Clinical.Models
{
    public class ClinicalPAT
    {
        [Key]
        public int ClinicalPATID { get; set; }
        public int ClinicalAssetID { get; set; }
        public DateTime? WarrantyEndDate { get; set; }
        [DataType(DataType.Date)]
        [DisplayFormat(DataFormatString = "{0:ddd/MMMM/yyyy}", ApplyFormatInEditMode = true)]
        public DateTime? InspectionDate { get; set; }
        public int? InspectionOutcomeID { get; set; }
        [StringLength(100, MinimumLength = 2)]
        public string InspectionDocumnets { get; set; }
        [DataType(DataType.Date)]
        [DisplayFormat(DataFormatString = "{0:ddd/MMMM/yyyy}", ApplyFormatInEditMode = true)]
        public DateTime? InspectionDueDate { get; set; }

        public virtual InspectionOutcome InspectionOutcomeResult { get; set; }
    }
}

Ui_Reddit：

   class Window(QMainWindow):
        def __init__(self):
            super(Window,self).__init__()
            self.ui=Ui_Reddit()
            self.ui.setupUi(self)
            self.setStyle(QStyleFactory.create('Cleanlooks'))
            #self.setGeometry(300, 300, 600, 600)
            self.setWindowTitle("Reddit")
            self.show()
            self.mainWindow()

        def mainWindow(self):
            #to handle all the api calls using praw
            self.x = RedditApi()
            self.printSubmissions()

        def printSubmissions(self):
            #Gets the list of all submission titles to be displayed
            #TO DO: Get and add other things like points and comments

            self.submissions = self.x.showSubmissions()

            for submission in self.submissions:

                card = QWidget()
                card_ui = Ui_Card()
                card_ui.setupUi(card)
                card_ui.title.setText(submission)
                self.ui.verticalLayout_2.addWidget(card)

Ui_Card：

class Ui_Reddit(object):
    def setupUi(self, Reddit):
        Reddit.setObjectName("Reddit")
        Reddit.resize(800, 600)
        Reddit.setTabShape(QtWidgets.QTabWidget.Rounded)
        self.centralwidget = QtWidgets.QWidget(Reddit)
        self.centralwidget.setObjectName("centralwidget")
        self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea.setGeometry(QtCore.QRect(10, 60, 781, 531))
        self.scrollArea.setWidgetResizable(True)
        self.scrollArea.setObjectName("scrollArea")
        self.scrollAreaWidgetContents = QtWidgets.QWidget()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 779, 
        529))

     self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
        self.verticalLayoutWidget_2 = 
        QtWidgets.QWidget(self.scrollAreaWidgetContents)
        self.verticalLayoutWidget_2.setGeometry(QtCore.QRect(-1, -1, 811, 
        551))
        self.verticalLayoutWidget_2.setObjectName("verticalLayoutWidget_2")
        self.verticalLayout_2 = 
        QtWidgets.QVBoxLayout(self.verticalLayoutWidget_2)
        self.verticalLayout_2.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout_2.setObjectName("verticalLayout_2")
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.horizontalLayoutWidget = QtWidgets.QWidget(self.centralwidget)
        self.horizontalLayoutWidget.setGeometry(QtCore.QRect(0, 0, 801, 51))
        self.horizontalLayoutWidget.setObjectName("horizontalLayoutWidget")
        self.horizontalLayout = 
        QtWidgets.QHBoxLayout(self.horizontalLayoutWidget)
        self.horizontalLayout.setContentsMargins(0, 0, 0, 0)
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.label = QtWidgets.QLabel(self.horizontalLayoutWidget)
        self.label.setIndent(5)
        self.label.setObjectName("label")
        self.horizontalLayout.addWidget(self.label)
        self.comboBox = QtWidgets.QComboBox(self.horizontalLayoutWidget)
        self.comboBox.setObjectName("comboBox")
        self.horizontalLayout.addWidget(self.comboBox)
        spacerItem = QtWidgets.QSpacerItem(40, 20, 
        QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem)
        self.search_bar = QtWidgets.QLineEdit(self.horizontalLayoutWidget)
        self.search_bar.setText("")
        self.search_bar.setObjectName("search_bar")
        self.horizontalLayout.addWidget(self.search_bar)
        self.pushButton = QtWidgets.QPushButton(self.horizontalLayoutWidget)
        self.pushButton.setFlat(False)
        self.pushButton.setObjectName("pushButton")
        self.horizontalLayout.addWidget(self.pushButton)
        spacerItem1 = QtWidgets.QSpacerItem(40, 20, 
        QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem1)
        Reddit.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(Reddit)
        self.statusbar.setObjectName("statusbar")
        Reddit.setStatusBar(self.statusbar)

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

    def retranslateUi(self, Reddit):
        _translate = QtCore.QCoreApplication.translate
        Reddit.setWindowTitle(_translate("Reddit", "MainWindow"))
        self.label.setText(_translate("Reddit", "TextLabel"))
        self.search_bar.setPlaceholderText(_translate("Reddit", "Search"))
        self.pushButton.setText(_translate("Reddit", "PushButton"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Reddit = QtWidgets.QMainWindow()
    ui = Ui_Reddit()
    ui.setupUi(Reddit)
    Reddit.show()
    sys.exit(app.exec_())