Example analysis of QT learning 18 login dialog box

Qt Study 18 Login dialog case analysis

• Login dialog It's... In the application Common parts

• reflection ： How to develop a login dialog that can be reused between different projects ？

• Login dialog box needs analysis

  • Reusable Software components
  • obtain user name and password

• Additional requirements

  • Random verification code

• Design and architecture of login dialog

problem

• How to get user input user name and password ？
  • How to transfer data in two different dialog boxes ？

Through additional Member variables and Member functions , Complete different dialog boxes, see Data transfer

Code display

#ifndef QLOGINDIALOG_H
#define QLOGINDIALOG_H

#include <QDialog>
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>

class QLoginDialog : public QDialog
{
    
    Q_OBJECT
private:
    QLabel UserLabel;
    QLabel PwdLabel;
    QLineEdit UserEdit;
    QLineEdit PwdEdit;
    QPushButton LoginBtn;
    QPushButton CancelBtn;
    QString m_User;
    QString m_Pwd;
private slots:
    void LoginBtn_Clicked();
    void CancelBtn_Clicked();

public:
    QLoginDialog(QWidget *parent = 0);
    ~QLoginDialog();
    QString getUser();
    QString getPwd();
};

#endif // QLOGINDIALOG_H

#include "QLoginDialog.h"
#include <QDebug>

QLoginDialog::QLoginDialog(QWidget *parent) : QDialog(parent, Qt::WindowCloseButtonHint),
    UserLabel(this), PwdLabel(this), UserEdit(this), PwdEdit(this), LoginBtn(this), CancelBtn(this)
{
    
    UserLabel.setText("User ID:");
    UserLabel.move(20, 30);
    UserLabel.resize(60, 25);

    UserEdit.move(85, 30);
    UserEdit.resize(180, 25);

    PwdLabel.setText("Password:");
    PwdLabel.move(20, 65);
    PwdLabel.resize(60, 25);

    PwdEdit.move(85, 65);
    PwdEdit.resize(180, 25);
    PwdEdit.setEchoMode(QLineEdit::Password);

    CancelBtn.setText("Cancel");
    CancelBtn.move(85, 110);
    CancelBtn.resize(85, 30);

    LoginBtn.setText("Login");
    LoginBtn.move(180, 110);
    LoginBtn.resize(85, 30);

    setWindowTitle("Login");
    setFixedSize(285, 170);

    connect(&LoginBtn, SIGNAL(clicked()), this, SLOT(LoginBtn_Clicked()));
    connect(&CancelBtn, SIGNAL(clicked()), this, SLOT(CancelBtn_Clicked()));
}

QLoginDialog::~QLoginDialog()
{
    

}

QString QLoginDialog::getUser()
{
    
    return m_User;
}

QString QLoginDialog::getPwd()
{
    
    return m_Pwd;
}

void QLoginDialog::LoginBtn_Clicked()
{
    
    qDebug() << "LoginBtn_Clicked() begin";
    m_User = UserEdit.text().trimmed();
    m_Pwd = PwdEdit.text();
    done(Accepted);
    qDebug() << "LoginBtn_Clicked() end";
}

void QLoginDialog::CancelBtn_Clicked()
{
    
    qDebug() << "CancelBtn_Clicked() begin";
    done(Rejected);
    qDebug() << "CancelBtn_Clicked() end";
}

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton>

class Widget : public QWidget
{
    
    Q_OBJECT
private:
    QPushButton TestBtn;
private slots:
    void TestBtn_Clicked();

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

};

#endif // WIDGET_H

#include "Widget.h"
#include "QLoginDialog.h"
#include <QDebug>

Widget::Widget(QWidget *parent) :
    QWidget(parent), TestBtn(this)
{
    
    TestBtn.setText("Test Login Dialog");
    setFixedSize(200, 50);
    connect(&TestBtn, SIGNAL(clicked()), this, SLOT(TestBtn_Clicked()));
}

Widget::~Widget()
{
    

}

void Widget::TestBtn_Clicked()
{
    
    QLoginDialog dlg;

    if (dlg.exec() == QDialog::Accepted) {
    
        qDebug() << "Accepted";
        qDebug() << "username:" << dlg.getUser();
        qDebug() << "password:" << dlg.getPwd();
    }
}

#include <QApplication>
#include "Widget.h"

int main(int argc, char *argv[])
{
    
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

Further development

• Check user name and password Is it empty
  • When user name or password An error is prompted when it is empty
• Random verification code
  • When the verification code is input incorrectly, you will be prompted
  • The verification code is refreshed randomly

Summary

• Login dialog as Reusable software components Development
• Between dialog boxes Member variables and Member functions To transfer data
  • Save user data in private member variables
  • Data transfer through public functions