登录窗口头文件

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QToolBar>
#include <QMenuBar>
#include <QPushButton>
#include <QStatusBar>
#include <QLabel>
#include <QDockWidget>//浮动窗口类
#include <QTextEdit>
#include <QIcon>
#include <QMovie>
#include <QString>
#include <cstring>
#include <QDebug>
#include <QMessageBox>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
signals:
    void jump();

public slots:
    void login_slot();

private slots:
    void on_cancel_btn_clicked();

private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

 登录窗口主文件

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    //窗口名
    this->setWindowTitle("QQ");
    this->setWindowIcon(QIcon(":/01login/icon/kun.webp"));
    this->setFixedSize(480,400);
    QMovie *kk=new QMovie(":/01login/icon/dance.gif");
    ui->logo_label->setMovie(kk);
    kk->start();
    ui->logo_label->setScaledContents(true);
    //账号密码图标
    ui->host_label->setPixmap(QPixmap(":/01login/icon/zhanghu.png"));
    ui->host_label->setScaledContents(true);
    ui->passwd_label->setPixmap(QPixmap(":/01login/icon/passwd.jpg"));
    ui->passwd_label->setScaledContents(true);
    //账号密码文本
    ui->host_edit->setPlaceholderText("账号");
    ui->passwd_edit->setPlaceholderText("密码");
    //连接登录跳转信号和槽函数
    connect(ui->login_btn,&QPushButton::clicked,this,&MainWindow::login_slot);
}
void MainWindow::login_slot()
{
    QString usrname = ui->host_edit->text();
    QString pwd = ui->passwd_edit->text();
    if(usrname=="admin"&&pwd=="123456")//若账号密码正确
    {
        qDebug()<< "login success";
        //消息对话框
        QMessageBox msg(
                     QMessageBox::Information,
                    "通知",
                    "登陆成功",
                    QMessageBox::Ok,
                    this);
        int ret = msg.exec();
        if(ret==QMessageBox::Ok)
        {
                   this -> close();
        }
        //跳转到新页面
        emit jump();
    }
    else//若密码错误
    {
        qDebug()<< "login defeat";
        //基于属性弹出消息对话框
        QMessageBox msg(
                     QMessageBox::Critical,
                    "登录失败",
                    "账号和密码不匹配，是否重新登录",
                    QMessageBox::Yes|QMessageBox::No,
                    this);
        int ret = msg.exec();
        if(ret==QMessageBox::Yes)//若yes则清空密码
        {
              ui -> passwd_edit->clear();
        }
        else//若no则直接关闭登录界面
        {
            this->close();
        }

    }
}
MainWindow::~MainWindow()
{
    delete ui;

}


void MainWindow::on_cancel_btn_clicked()//取消
{
    //基于静态成员函数消息对话框的弹出
    int ret = QMessageBox::question(
                this,
                "再次确认",
                "您是否确定要退出登录",
                QMessageBox::Yes|QMessageBox::No);
    if(ret==QMessageBox::Yes)//若yes则关闭登录界面
    {
          this->close();
    }
    else//若no则关闭对话框继续执行登录界面
    {
    }
}

跳转页面头文件
 

#ifndef SECOND_H
#define SECOND_H

#include <QWidget>

namespace Ui {
class second;
}

class second : public QWidget
{
    Q_OBJECT

public:
    explicit second(QWidget *parent = nullptr);
    ~second();

public slots:
    void jumpslot();
    void sureslot();

private:
    Ui::second *ui;
};

#endif // SECOND_H

跳转页面主文件

#include "second.h"
#include "ui_second.h"

second::second(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::second)
{
    ui->setupUi(this);
    connect(ui->sure_btn,&QPushButton::clicked,this,&second::sureslot);
}

second::~second()
{
    delete ui;
}

void second::jumpslot()
{
    this->show();
}
void second::sureslot()
{
    this->close();
}

主文件

#include "mainwindow.h"
#include "second.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    second s;
    QObject::connect(&w,&MainWindow::jump,&s,&second::jumpslot);

    return a.exec();
}