不收费的网站有哪些我想投资谁有项目

在上一篇多文档窗口设计(MDI)的基础上增加了一个登录界面（splash）.

该模块可以扩展为常规的软件登录界面。

界面展示如下

如果用户名和密码输入正确，则调到MDI界面，如果用户名和密码一共输入三次以上，则程序强制退出。

保存用户名的作用是，将本次输入正确的用户名和密码保存到注册表(注意注册表里不能直接放铭文密码)，下次启动该软件会自动填写用户名。

注册表中保存的数据如下，密码是经过MD5加密过后的。

界面设置如下

编辑框密码隐形显示需要设置

程序结果如下：

主程序main

#include "mainwindow.h"#include <QApplication>
#include"tlogindialog.h"
int main(int argc, char *argv[])
{QApplication a(argc, argv);TLoginDialog *dlgLogin=new TLoginDialog();dlgLogin->resize(640,480);if(dlgLogin->exec()==QDialog::Accepted){MainWindow w;w.show();return a.exec();}elsereturn 0;}

tlogindialog.h和tlogindialog.cpp如下

#ifndef TLOGINDIALOG_H
#define TLOGINDIALOG_H#include <QDialog>namespace Ui {
class TLoginDialog;
}class TLoginDialog : public QDialog
{Q_OBJECTpublic:explicit TLoginDialog(QWidget *parent = nullptr);~TLoginDialog();private:Ui::TLoginDialog *ui;bool m_moving=false;QPoint m_lastPos;QString m_user="user";QString m_pwd="12345";int m_tryCount=0;const int M_MAXCOUT=3;void readSettings();void writeSettings();QString encrypt(const QString &str);// QWidget interface
protected:virtual void mousePressEvent(QMouseEvent *event) override;virtual void mouseReleaseEvent(QMouseEvent *event) override;virtual void mouseMoveEvent(QMouseEvent *event) override;
private slots:void on_btnOk_clicked();
};#endif // TLOGINDIALOG_H
/************************************************.cpp***************************/
#include "tlogindialog.h"
#include "ui_tlogindialog.h"
#include<QMouseEvent>
#include<QCryptographicHash>
#include<QSettings>
#include<QMessageBox>
TLoginDialog::TLoginDialog(QWidget *parent): QDialog(parent), ui(new Ui::TLoginDialog)
{ui->setupUi(this);setAttribute(Qt::WA_DeleteOnClose);setWindowFlag(Qt::SplashScreen);QApplication::setOrganizationName("Sun Company");QApplication::setApplicationName("MDI_SPLASH");readSettings();}TLoginDialog::~TLoginDialog()
{delete ui;
}void TLoginDialog::readSettings()
{QSettings settings;bool saved=settings.value("saved",false).toBool();m_user=settings.value("UserName","user").toString();QString defaultPSWD=encrypt("12345");m_pwd=settings.value("PSWD",defaultPSWD).toString();if(saved){ui->EditUser->setText(m_user);}ui->checkBox->setChecked(saved);
}void TLoginDialog::writeSettings()
{QSettings settings;settings.setValue("UserName",m_user);settings.setValue("PSWD",m_pwd);settings.setValue("saved",ui->checkBox->isChecked());}QString TLoginDialog::encrypt(const QString &str)
{QByteArray btArray=str.toLocal8Bit();QCryptographicHash hash(QCryptographicHash::Md5);hash.addData(btArray);QByteArray resultArray=hash.result();QString md5=resultArray.toHex();return md5;
}
void TLoginDialog::mousePressEvent(QMouseEvent *event)
{if(event->button()==Qt::LeftButton){m_moving=true;m_lastPos=event->globalPosition().toPoint()-this->pos();}return QDialog::mousePressEvent(event);
}void TLoginDialog::mouseReleaseEvent(QMouseEvent *event)
{m_moving=false;event->accept();
}void TLoginDialog::mouseMoveEvent(QMouseEvent *event)
{QPoint eventPos=event->globalPosition().toPoint();if(m_moving&&(event->buttons()&Qt::LeftButton)&& (eventPos-m_lastPos-pos()).manhattanLength()>QApplication::startDragDistance()){move(eventPos-m_lastPos);m_lastPos=eventPos-this->pos();}return QDialog::mouseMoveEvent(event);
}void TLoginDialog::on_btnOk_clicked()
{QString user=ui->EditUser->text().trimmed();QString pwd=ui->EditPwd->text().trimmed();QString encrptPSWD=encrypt(pwd);if((m_user==user)&&(encrptPSWD==m_pwd)){writeSettings();this->accept();}else{m_tryCount++;if(m_tryCount>M_MAXCOUT){QMessageBox::critical(this,"错误","输入错误次数太多,强行退出");this->reject();}elseQMessageBox::warning(this,"错误提示","用户名或者密码错误");}
}