QT中显示类的时候程序总是崩溃

[maochengjie]

用QT写了一个类，用来显示一些数据库的信息，但是，没当实例化这个类的时候，程序就会崩溃，搞了一天都没搞出来原因，求高手帮助。
下面是源代码，
owneddialog.h

#ifndef OWNEDDIALOG_H
#define OWNEDDIALOG_H

#include <QtGui/QDialog>
#include <QList>
#include "userbooks.h"
#include "book.h"

class QSqlTableModel;

namespace Ui {
    class OwnedDialog;
}

class OwnedDialog : public QDialog {
    Q_OBJECT
    Q_DISABLE_COPY(OwnedDialog)
public:
    explicit OwnedDialog( UserBooks *books, UserBooks *adminBooks, QWidget *parent = 0);
    virtual ~OwnedDialog();

protected:
    virtual void changeEvent(QEvent *e);
    virtual void showEvent( QShowEvent* );

private:
    Ui::OwnedDialog *m_ui;
    QSqlTableModel *model;      //
    UserBooks *books;           //当前用户所借的书
    UserBooks *adminBooks;      //图书馆中所有的书，由管理员掌控
    QList<Book> *bookList;

private slots:
    void on_returnButton_clicked();     //点击还书按钮
    void setBookDetail(QString bookName);      //当选择另一个书名时，改变编辑框的值
    void on_closeButton_clicked();              //按下关闭按钮

private:
    bool updateData();                  //当还了书后更新显示

};

#endif // OWNEDDIALOG_H
[/code]

owneddialog.cpp

#include <QSqlTableModel>
#include <QSqlQuery>
#include <QMessageBox>
#include <QList>
#include "owneddialog.h"
#include "book.h"
#include "ui_owneddialog.h"

OwnedDialog::OwnedDialog( UserBooks *books, UserBooks *adminBooks, QWidget *parent) :
    QDialog(parent),
    m_ui(new Ui::OwnedDialog)
{
    m_ui->setupUi(this);
     this->setModal( true );
    this->books = books;
    this->adminBooks = adminBooks;
    model = new QSqlTableModel;
    bookList = books->getBookList();


    connect(m_ui->booknameComboBox, SIGNAL(currentIndexChanged(QString)), this, SLOT(setBookDetail(QString)));
    connect( qApp, SIGNAL(lastWindowClosed()), books, SLOT(write()));   //退出程序保存数据
    //如果当前用户不是管理员，程序退出时保存管理员的书籍信息
    if( books->getUser()->getName() != "admin")
        connect(qApp, SIGNAL(lastWindowClosed()), adminBooks, SLOT(write()));
}

OwnedDialog::~OwnedDialog()
{
    delete m_ui;
}

void OwnedDialog::changeEvent(QEvent *e)
{
    switch (e->type()) {
    case QEvent::LanguageChange:
        m_ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

void OwnedDialog::showEvent( QShowEvent *event )
{

        updateData();


}


//点击还书按钮，还掉选中书籍
void OwnedDialog::on_returnButton_clicked()
{
    QString bookName = m_ui->booknameComboBox->currentText();
    Book toReturn = books->getBook( bookName );


    //在数据库中删除选中书籍
    QSqlQuery delBook;
    QString sql = QString("delete from %1 where name = '%2'").arg( books->getUser()->getName()).arg( bookName);
    if( delBook.exec( sql ) && books->remove( toReturn ) )
    {
        QMessageBox::information( this, tr("Book Returned"), tr("Return the book seccussfully!!") );

    }
    else
    {
        QMessageBox::information( this, tr("Book Return Failed"), tr("Sorry but Fail to Return the book !!") );
    }
}

void OwnedDialog::setBookDetail( QString bookName)
{
    Book temp = books->getBook( bookName );
    m_ui->authorLineEdit->setText( temp.getAuthor() );
    m_ui->copyLineEdit->setText( tr("%1").arg( temp.getCopy()) );
    m_ui->pressLineEdit->setText( temp.getPress() );
}

void OwnedDialog::on_closeButton_clicked()
{
    close();
}


bool OwnedDialog::updateData()
{

   
       model->setTable( tr("%1").arg(books->getUser()->getName()) );
        model->select();
     model->removeColumn(0); // don't show the ID
     model->setHeaderData(0, Qt::Horizontal, tr("Name"));
     model->setHeaderData(1, Qt::Horizontal, tr("Author"));
     model->setHeaderData(2, Qt::Horizontal, tr("Copy"));
     model->setHeaderData(3, Qt::Horizontal, tr("Press"));

     //在表格中显示该用户所借阅的书籍
     m_ui->tableView->clearSpans();
     m_ui->tableView->setModel( model );
     m_ui->tableView->setEditTriggers( QAbstractItemView::NoEditTriggers );

     //在退还书籍中显示信息
     bookList = books->getBookList();
     m_ui->booknameComboBox->clear();
     for(int i = 0; i < bookList->size(); i++ )
     {
         Book temp = bookList->at( i );
         m_ui->booknameComboBox->addItem( temp.getName() );
     }


     return true;
}

我个人觉得应该是C++语法的问题，应该是构造函数有问题，因为即使我不显示这个窗口，只是实例化一个对象，程序在退出时也会崩溃！！

[猫已经找不回了]

写个析构函数，里面delete你在
OwnedDialog::OwnedDialog( UserBooks *books, UserBooks *adminBooks, QWidget *parent) :
QDialog(parent),
m_ui(new Ui::OwnedDialog)
{
m_ui->setupUi(this);
this->setModal( true );
this->books = books;
this->adminBooks = adminBooks;
model = new QSqlTableModel;
bookList = books->getBookList();


connect(m_ui->booknameComboBox, SIGNAL(currentIndexChanged(QString)), this, SLOT(setBookDetail(QString)));
connect( qApp, SIGNAL(lastWindowClosed()), books, SLOT(write())); //退出程序保存数据
//如果当前用户不是管理员，程序退出时保存管理员的书籍信息
if( books->getUser()->getName() != "admin")
connect(qApp, SIGNAL(lastWindowClosed()), adminBooks, SLOT(write()));
}

构造函数里new的东西看下。

[hityct1]

是在这出现异常？设置下断点，在哪崩溃的。

OwnedDialog::~OwnedDialog()
{
    delete m_ui;
}

[maochengjie]

非常感谢！！
但是我觉得好像还没有到析构函数那里程序就出问题了，因为在窗口关闭后，还有可能再次打开，所以，即使没有到调用析构函数那一步，程序也会崩溃，基本上时，只要实例化一个对象，程序关闭时就会崩溃；还有一种情况就是，还没有到程序关闭，只是打开了一次该窗口，关闭后，想再次打开显示该窗口时，程序就直接崩溃了。我也觉得可能是哪个指针有问题。
实在是郁闷。

[maochengjie]

[Quote=引用 2 楼 hityct1 的回复:]
是在这出现异常？设置下断点，在哪崩溃的。

C/C++ code
OwnedDialog::~OwnedDialog()
{
delete m_ui;
}
[/Quote]

谢谢参与!!
我认为在构造函数里面崩溃的，因为，根本就不用显示该窗口，只实例化一个对象，程序关闭时也会崩溃。
所以，应该和析构函数没关系。

[maochengjie]

[Quote=引用 1 楼 hairetz 的回复:]
写个析构函数，里面delete你在
OwnedDialog::OwnedDialog( UserBooks *books, UserBooks *adminBooks, QWidget *parent) :
QDialog(parent),
m_ui(new Ui::OwnedDialog)
{
m_ui->setupUi(this);
this->setModal( true );
this->books = books;
this->adminBooks = adminBooks;
model = new QSqlTableModel;
bookList = books->getBookList();


connect(m_ui->book…
[/Quote]

非常感谢！！
但是我觉得好像还没有到析构函数那里程序就出问题了，因为在窗口关闭后，还有可能再次打开，所以，即使没有到调用析构函数那一步，程序也会崩溃，基本上时，只要实例化一个对象，程序关闭时就会崩溃；还有一种情况就是，还没有到程序关闭，只是打开了一次该窗口，关闭后，想再次打开显示该窗口时，程序就直接崩溃了。我也觉得可能是哪个指针有问题。
实在是郁闷。

[HelloDan]

这样的问题一般是delete时出错

[xiaocha]

一大堆代码, 又不全,
请楼主设置断点, 单步跟踪, 确定在那一行出问题,
才好帮你解决问题, 你也好自己解决问题
让我们瞎猜只是浪费大家的时间

[xurunhua_nwpu]

好，顶上去！