手动实现登录框：

widget.cpp: 

#include "widget.h"
#include <QMovie>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    //设置尺寸
    this->resize(800,600);  //设置宽高
    //设置固定尺寸
    this->setFixedSize(800,600);

    //窗口标题操作
    qDebug()<<this->windowTitle();  //获取窗口标题
    this->setWindowTitle("iKun论坛");

    //设置窗口图标
    this->setWindowIcon(QIcon("D:\\Icon\\kun.png"));



    //QLabel
    QLabel *lab1 = new QLabel(this);    //指定父组件
    lab1->resize(800,325);      //重新设置尺寸
    lab1->setAlignment(Qt::AlignCenter);    //垂直和水平全都剧中

    //使用QMovie加载gif图片
    QMovie *gifMovie = new QMovie("D:\\Icon\\kunkun.gif");
    lab1->setMovie(gifMovie);
    lab1->setScaledContents(true);  //自适应大小
    gifMovie->start();  //开始播放gif

    QLabel *lab2 = new QLabel(this);    //指定父组件
    lab2->resize(80,50);
    lab2->move(200,350);
    lab2->setPixmap(QPixmap("D:\\Icon\\zhongfen.png"));
    lab2->setScaledContents(true);  //图片自适应大小

    QLabel *lab3 = new QLabel(this);
    lab3->resize(80,50);
    lab3->move(200,420);
    lab3->setPixmap(QPixmap("D:\\Icon\\tieshankao.png"));
    lab3->setScaledContents(true);  //图片自适应大小

    QLabel *lab4 = new QLabel(this);
    lab4->resize(175,250);  //重新设置尺寸
    lab4->move(0,340);       //移动位置
    QMovie *gifMovie2 = new QMovie("D:\\Icon\\kunkun2.gif");
    lab4->setMovie(gifMovie2);
    lab4->setScaledContents(true);  //自适应大小
    gifMovie2->start();  //开始播放gif


    //QLineEdit
    QLineEdit *edit1 = new QLineEdit(this); //有参构造，构造时给定父组件
    edit1->resize(300,50);
    edit1->move(300,350);   //移动
    edit1->setPlaceholderText("黑子名");   //设置占位符

    QLineEdit *edit2 = new QLineEdit(this);
    edit2->resize(edit1->size());   //设置和edit1的大小相同
    edit2->move(300,420);   //移动
    edit2->setEchoMode(QLineEdit::Password);    //设置密文模式
    edit2->setPlaceholderText("鸡脚");   //设置占位符


    //QPushButton
    QPushButton *btn1 = new QPushButton(this);
    btn1->setText("你干嘛哎哟~");    //设置按钮上文本内容
    btn1->resize(140,50);    //设置组件的大小
    btn1->move(470,500);    //移动组件
    btn1->setIcon(QIcon("D:\\Icon\\kun2.png"));
    QSize iconSize(50,50);   //设置图标大小
    btn1->setIconSize(iconSize);

    QPushButton *btn2 = new QPushButton(this);
    btn2->setText("食不食油饼");
    btn2->resize(btn1->size());     //设置和btn1一样的大小
    btn2->move(650,500);
    btn2->setIcon(QIcon("D:\\Icon\\kun3.png"));
    btn2->setIconSize(iconSize);
}


Widget::~Widget()
{
}

main.cpp:

#include "widget.h"

#include <QApplication>

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

widget.h:

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QDebug>              //信息调试类，用于打印输出的
#include<QIcon>          //图标头文件
#include<QPushButton>     //按钮类头文件
#include<QLineEdit>       //行编辑器类
#include<QLabel>              //标签类

class Widget : public QWidget
{
    Q_OBJECT

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



};
#endif // WIDGET_H

first.pro:

QT       += core gui
QT += multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# 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

SOURCES += \
    main.cpp \
    widget.cpp

HEADERS += \
    widget.h

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