qt物软件界面代码一直显示崩溃

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    createLoginWidget();
    createMainWidget();
    createWuyefeeWidget();
    createParkingWidget();
    createRepairWidget();
}

void MainWindow::createLoginWidget()
{
    loginWidget = new QWidget();
    usernameLabel = new QLabel("用户名：");
    usernameLineEdit = new QLineEdit();
    passwordLabel = new QLabel("密码：");
    passwordLineEdit = new QLineEdit();
    passwordLineEdit->setEchoMode(QLineEdit::Password);
    loginButton = new QPushButton("登录");
    QVBoxLayout *loginLayout = new QVBoxLayout();
    loginLayout->addWidget(usernameLabel);
    loginLayout->addWidget(usernameLineEdit);
    loginLayout->addWidget(passwordLabel);
    loginLayout->addWidget(passwordLineEdit);
    loginLayout->addWidget(loginButton);
    loginWidget->setLayout(loginLayout);

    QObject::connect(loginButton, &QPushButton::clicked, [&]() {
        QString username = usernameLineEdit->text();
        QString password = passwordLineEdit->text();
        QSqlQuery query;
        query.prepare("SELECT COUNT(*) FROM users WHERE username = :username AND password = :password");
        query.bindValue(":username", username);
        query.bindValue(":password", password);
        if (query.exec() && query.next() && query.value(0).toInt() > 0) {
            loginWidget->close();
            mainWidget->show();
        } else {
            QMessageBox::warning(nullptr, "错误", "用户名或密码错误");
        }
    });
}

void MainWindow::createMainWidget()
{
    mainWidget = new QWidget();
    tabWidget = new QTabWidget();
    tabWidget->addTab(wuyefeeWidget, "物业缴费");
    tabWidget->addTab(parkingWidget, "停车管理");
    tabWidget->addTab(repairWidget, "维修管理");
    QVBoxLayout *mainLayout = new QVBoxLayout();
    mainLayout->addWidget(tabWidget);
    mainWidget->setLayout(mainLayout);
}

void MainWindow::createWuyefeeWidget()
{
    wuyefeeWidget = new QWidget();
    calendarWidget = new QCalendarWidget()

这个代码一直运行显示崩溃，有没有人可以帮忙看一下哪里出了问题，万分感谢