程式碼示例：

//////////////////////dialog.cpp

Dialog::Dialog(QWidget *parent) :

QDialog(parent),

ui(new Ui::Dialog)

{

ui->setupUi(this);

ui->lineEditPassword->setEchoMode(QLineEdit::Password);

}

Dialog::~Dialog()

{

delete ui;

}

void Dialog::on_pushButtonLogin_clicked()

{

//獲取資料

m_strUser = ui->lineEditUser->text();

m_strPassword = ui->lineEditPassword->text();

//校驗資料

if(m_strUser.isEmpty() || m_strPassword.isEmpty())

{

QMessageBox::information(this, QString(tr("Tips"))

,QString(tr("User name or Password is empty!")));

}

else

{

//正確的使用者名稱和密碼

this->accept();

}

}

void Dialog::on_pushButtonQuit_clicked()

{

this->reject();

}

////////////////////////////////mainwindow.cpp

#include "mainwindow.h"

#include "ui_mainwindow.h"

#include "dialog.h"

MainWindow::MainWindow(QWidget *parent) :

QMainWindow(parent),

ui(new Ui::MainWindow)

{

//

ui->setupUi(this);

//

Dialog* pDlgLogin = new Dialog(NULL);

//以模式對話方塊顯示

int nResult = pDlgLogin->exec();

if(nResult != QDialog::Accepted)

{

//登入錯誤，退出

exit(1);

}

//正常登入

//讀取使用者名稱和密碼

m_strUser = pDlgLogin->m_strUser;

m_Password = pDlgLogin->m_strPassword;

//設定標籤為使用者名稱

ui->labelUserName->setText(m_strUser);

//繫結退出訊號到關閉槽函式

connect(ui->action_Quit, SIGNAL(triggered()), this, SLOT(close()));

//將主視窗移到指定位置

this->move(QPoint(0,0));

//

}

MainWindow::~MainWindow()

{

delete ui;

}