1> 继续完善登录框，当登录成功时，关闭登录界面，跳转到新的界面中

widget.h

#include "widget.h"
//#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    //, ui(new Ui::Widget)
{
    //ui->setupUi(this);
    this->setFixedSize(800,650);   //设置固定尺寸
    qDebug()<<this->windowTitle();   //获取窗口标题
    this->setWindowTitle("英雄去超越");
    this->setWindowOpacity(0.9);

    //5.设置窗口图标
    this->setWindowIcon(QIcon(":/icon/yxlm.png"));

    //设置大图
    lab1 = new QLabel(this);
    lab1->resize(800,380);
    lab1->setPixmap(QPixmap(":/icon/logo.png"));
    lab1->setScaledContents(true);

    //使用无参构造函数,构造出一个按钮
    btn1 = new QPushButton;
    btn1->setParent(this);  //将当前界面设置成父组件
    btn1->setText("登录");  //设置按钮上的文本内容
    btn1->resize(80,40);        //重新设置组件的大小
    btn1->move(500,550);         //移动组件
    btn1->setStyleSheet("background-color:cyan;");//设置样式表
    btn1->setIcon(QIcon(":/icon/2.png"));

    btn2 = new QPushButton(this);
    btn2->setText("取消");  //设置按钮上的文本内容
    btn2->resize(80,40);        //重新设置组件的大小
    btn2->move(600,550);         //移动组件
    btn2->setStyleSheet("background-color:skyblue;");//设置样式表
    btn2->setIcon(QIcon(":/icon/1.png"));

    edit1 = new QLineEdit;
    edit1->setParent(this);
    edit1->resize(300,40);
    edit1-> move(250,450);
    edit1->setEchoMode((QLineEdit::Password));
    edit1->setPlaceholderText("密码");

    edit2 = new QLineEdit(this);
    edit2->resize(300,40);
    edit2-> move(250,400);
    edit2->setPlaceholderText("账号");

    lab2 = new QLabel;
    lab2->setParent(this);
    lab2->setText("账号");
    lab2->resize(50,50);
    lab2->move(200,400);

    lab3 = new QLabel(this);
    lab3->setText("密码");
    lab3->resize(50,50);
    lab3->move(200,450);

    connect(btn1,SIGNAL(clicked()),this,SLOT(btn1_slot()));

    //qt5
    connect(btn2,&QPushButton::clicked,this,&Widget::btn2_slot);


    //将自定义的信号与槽函数进行连接
    connect(this,&Widget::my_signal,[&](){
        qDebug()<<"我已经成功连接取消按钮";
        btn2->resize(btn2->width()+1,btn2->height()+1);
    });

    //将同一个信号连接到同一个槽
    //connect(this,&Widget::my_signal,this,&Widget::close);

}

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

void Widget::my_slot()
{
    this->close();
}

void Widget::btn1_slot()
{
    QString userName = edit2->text();
    QString pwd =  edit1->text();

    if(userName == "admin" && pwd == "123456" )
    {
        qDebug()<<"登录成功";
        this->close();
        emit jump();
        this->close();
    }else
    {
        qDebug()<<"登录失败，请重新登录";
        edit1->clear();
    }
}

void Widget::btn2_slot()
{
    static int num = 0;
    qDebug()<<++num;

    //发射自定义的信号
    emit my_signal();
}

2> 新建一个工程文件，将默认提供的代码加上注释信息

工程管理文件.pro

QT       += core gui
#表示引入qt所需的类库，如核心库、图形化界面库

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
#如果超过4.0版本，系统会自动加上widgets库

CONFIG += c++11
#该版本的qt支持c++11后的语法

# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

#管理源文件
SOURCES += \
    main.cpp \
    widget.cpp

#管理头文件
HEADERS += \
    widget.h

#管理ui文件
FORMS += \
    widget.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

3> 思维导图