一、继续完善登录框，当登陆成功时，关闭登陆页面，跳转到新的界面中

源码：

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QDebug>           //用于打印输出
#include <QIcon>            //图标头文件
#include <QPushButton>      //按钮类头文件
#include <QLineEdit>        //行编辑器类
#include <QLabel>           //标签文件

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

    //标签类
    QLabel *lab1;
    QLabel *lab2;
    QLabel *lab3;

    //行编辑器类
    QLineEdit *edit1;
    QLineEdit *edit2;

    //按钮类
    QPushButton *btn1;
    QPushButton *btn2;

    //自定义信号
signals:
    void jump();   //跳转信号

public slots:
    void cancel_slot();
    void login_slot();

};
#endif // WIDGET_H

second.h

#ifndef SECOND_H
#define SECOND_H

#include <QWidget>
#include <QDebug>           //用于打印输出
#include <QIcon>            //图标头文件
#include <QPushButton>      //按钮类头文件
#include <QLineEdit>        //行编辑器类
#include <QLabel>           //标签文件


namespace Ui {
class Second;
}

class Second : public QWidget
{
    Q_OBJECT

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

    //标签类
    QLabel *lab1;

public slots:
    void jump_slot();

private:
    Ui::Second *ui;
};

#endif // SECOND_H

widget.cpp

#include "widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    //设置整体大小、标题及图标
    this->setFixedSize(700, 600);
    this->setWindowTitle("IKUN真爱小屋❤");
    this->setWindowIcon(QIcon(":/icon/1.jpeg"));
    this->setWindowOpacity(0.95);              //设置透明度

    //设置Logo标签
    lab1 = new QLabel(this);
    lab1->resize(700,200);
    lab1->setPixmap(QPixmap(":/icon/2.JPG"));
    lab1->setScaledContents(true);         //设置内容自适应

    //设置用户和密码所图标
    lab2 = new QLabel(this);
    lab2->resize(50,50);
    lab2->setPixmap(QPixmap(":/icon/username.png"));
    lab2->setScaledContents(true);
    lab2->move(150,260);

    lab3 = new QLabel(this);
    lab3->resize(50,50);
    lab3->setPixmap(QPixmap(":/icon/passwd.jpg"));
    lab3->setScaledContents(true);
    lab3->move(150,360);

    //设置行编辑器
    edit1 = new QLineEdit(this);
    edit1->resize(190, 40);
    edit1->move(280, 265);
    edit1->setStyleSheet("border : none; "
                         "border-bottom: 2px solid grey;");
    edit1->setPlaceholderText("账号:");

    edit2 = new QLineEdit(this);
    edit2->resize(190, 40);
    edit2->move(280, 365);
    edit2->setStyleSheet("border : none; "
                         "border-bottom: 2px solid grey;");
    edit2->setPlaceholderText("密码:");
    edit2->setEchoMode(QLineEdit::Password);

    //设置按钮 登录
    btn1 = new QPushButton(this);
    btn1->setText("登录");
    btn1->resize(130,40);
    btn1->move(150, 490);
    btn1->setIcon(QIcon(":/icon/login.png"));
    //手动将登录与自定义的槽函数进行连接,该连接是友好的连接qt-5
    connect(btn1, &QPushButton::clicked, this, &Widget::login_slot);

    //设置按钮 取消
    btn2 = new QPushButton(this);
    btn2->setText("取消");
    btn2->resize(130,40);
    btn2->move(440, 490);
    btn2->setIcon(QIcon(":/icon/cancel.png"));
    //手动将取消按钮的clicked信号与自定义的槽函数进行连接-qt4
    connect(btn2, SIGNAL(clicked()), this, SLOT(cancel_slot()));

}

Widget::~Widget()
{
}

//自定义槽函数的实现
void Widget::cancel_slot(){
    this->close();
}

//自定义槽函数的实现
void Widget::login_slot(){
    if(this->edit1->text() == "admin" && this->edit2->text() == "123456"){
        qDebug() << "登陆成功！";
        emit jump();           //发射跳转函数信号
        this->close();
    }else{
        qDebug() << "登陆失败，请重新登录！";
        this->edit2->clear();
    }
}

second.cpp

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

Second::Second(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Second)
{
    ui->setupUi(this);

    //整体设置
    this->setWindowTitle("登录成功提示");
    this->setWindowIcon(QIcon(":/icon/3.jpeg"));

    //设置跳转标签
    lab1 = new QLabel(this);
    lab1->setText("登陆成功！");
    lab1->resize(390,300);
    lab1->setAlignment(Qt::AlignCenter);
}

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

//跳转槽信号
void Second::jump_slot()
{
    this->show();
}

main.cpp

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

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

    Second s;    //实例化第二个界面

    //将第一个界面发射信号与第二个界面的展示槽函数连接
    QObject::connect(&w, &Widget::jump, &s, &Second::jump_slot);

    return a.exec();
}