登录框的按钮操作，并在登录成功后进行界面跳转

app.cpp

#include "app.h"
#include <cstdio>
#include <QDebug>
#include <QLineEdit>
#include <QLabel>
#include <QPainter>
#include <QString>
#include <QMessageBox>
#include <QRegExp>

APP::APP(QWidget *parent) : QWidget(parent)
{

    //================构建窗口setWindowTitle==============================//
    this->setWindowTitle("阿巴阿巴");
    this->setWindowIcon(QIcon("C:/Users/BlackMC/Desktop/icon/wodepeizhenshi.png"));
    this->resize(430,327);
    //this->setStyleSheet("background-color:pink");
    //设定窗口透明度
    this->setWindowOpacity(1.5);
    //================构建画面===========================================//
    bel3 = new QLabel("",this);
    bel3->resize(430,148);
    //bel3->setPixmap(QPixmap("G:/steam/steamapps/workshop/content/431960/2949578938/preview.jpg"));
    bel3->setPixmap(QPixmap("C:/Users/BlackMC/Desktop/icon/p3.jpg"));
    bel3->setScaledContents(true);//图片自适应
    //================构建标签账户(Lable)================================//
    bel1 = new QLabel("账户",this);
    bel1->resize(35,35);
    bel1->setPixmap(QPixmap("C:/Users/BlackMC/Desktop/icon/userName.jpg"));
    bel1->setScaledContents(true);
    bel1->move(120,163);
    //================构建标签密码(Lable)================================//
    bel2 = new QLabel("密码",this);
    bel2->resize(35,35);
    bel2->setPixmap(QPixmap("C:/Users/BlackMC/Desktop/icon/passwd.jpg"));
    bel2->setScaledContents(true);
    bel2->move(118,220);
    //================构建输入框账户(Lable)==============================//
    edit1 = new QLineEdit(this);
    edit1->setStyleSheet("background-color:cyan");
    edit1->setPlaceholderText("QQ密码/手机/邮箱");
    edit1->resize(150,32);
    edit1->move(bel1->x()+55,163);
    //================构建输入框密码(Lable)==============================//
    edit2 = new QLineEdit(this);
    edit2->setStyleSheet("background-color:cyan");
    edit2->resize(150,32);
    edit2->move(bel2->x()+55,220);
    edit2->setPlaceholderText("密码");
    edit2->setEchoMode(QLineEdit :: Password);
    //================构建按钮登录(QPushButton)=========================//
    but1 = new QPushButton("登录",this);
    but1->setStyleSheet("background-color:orange");
    but1->resize(70,30);
    but1->move(195,280);
    but1->setIcon(QIcon("C:/Users/BlackMC/Desktop/icon/login.png"));
    //================构建按钮取消(QPushButton)=========================//
    but2 = new QPushButton("取消",this);
    but2->setStyleSheet("background-color:orange");
    but2->resize(but1->size());
    but2->move(but1->x()+90,280);
    but2->setIcon(QIcon("C:/Users/BlackMC/Desktop/icon/cancel.png"));
    //================构建按钮登录控件==================================//
    connect(but1,&QPushButton::clicked,this,&APP::on_111_clicked);
    //================使用qt4版本的链接，将按钮发射的pressed信号与按钮槽链接=//
    //================构建按钮取消控件==================================//
    connect(but2,SIGNAL(pressed()),but1,SLOT(close()));

}

APP::~APP()
{
}

//按钮登录的槽函数——1
void APP::on_111_clicked()
{
    int result1 = QString::compare("tjq", edit1->text(), Qt::CaseInsensitive);
    int result2 = QString::compare("123456", edit2->text(), Qt::CaseInsensitive);
    if(result1 == 0 && result2 == 0)    //登录成功!
    {
        int ret = QMessageBox::warning(this, QStringLiteral("Good"), QStringLiteral("登录成功!"), QMessageBox::Cancel | QMessageBox::Ok);
        if( ret == QMessageBox::Ok)
        {
            emit jump();
            this->close();
            //connect(but1,&QPushButton::released,this,&APP::on_jumpsecond);
            //connect(QMessageBox::Ok,SIGNAL(QMessageBox::Ok),this,SLOT(&APP::on_jumpsecond));
        }
    }
    else        //登录失败!
    {
        QMessageBox::warning(this, QStringLiteral("Error!"), QStringLiteral("登录失败!"), QMessageBox::Cancel | QMessageBox::Ok);
        edit2->clear();
    }

}
//按钮登录的槽函数——2
/*void APP::on_jumpsecond()

app.h

#include <QDebug>
#include <QLineEdit>
#include <QLabel>
#include <QPainter>
#include <cstdio>
#include <QString>
#include <QMessageBox>
#include <QRegExp>

class APP : public QWidget
{
    Q_OBJECT

signals:
    void my_signal();//信号函数
    void jump();//信号函数
public slots://自定义的槽函数列(只有槽函数才作用与connect的槽函数参数)
    void on_111_clicked();//登录按钮触发-槽函数
    //void on_jumpsecond();//界面跳转触发-槽函数

public:
    APP(QWidget *parent = nullptr);
    ~APP();
private:
    QLabel *bel1;
    QLabel *bel2;
    QLabel *bel3;
    QLineEdit *edit1;
    QLineEdit *edit2;
    QPushButton *but1;
    QPushButton *but2;
};
#endif // APP_H

second.cpp

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

Second::Second(QWidget *parent):QWidget(parent),ui(new Ui::Second)
{
    //================构建窗口setWindowTitle==============================//
    this->setWindowTitle("QQ界面");
    this->setStyleSheet("background-color:pink");
    //this->setWindowIcon(QIcon("C:/Users/BlackMC/Desktop/icon/wodepeizhenshi.png"));
    this->resize(820,327);
    //设定窗口透明度
    this->setWindowOpacity(2.0);
    //===========================================================//



    ui->setupUi(this);
}

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

void Second::jump_second()
{
    this->show();
}

second.h

#ifndef SECOND_H
#define SECOND_H

#include <QWidget>

namespace Ui {
class Second;
}

class Second : public QWidget
{
    Q_OBJECT


public slots:      //槽函数
    void jump_second();

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

private:
    Ui::Second *ui;
};

#endif // SECOND_H

main.cpp

#include "app.h"
#include "second.h"

#include <QApplication>

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

    QObject::connect(&w,&APP::jump,&f,&Second::jump_second);

    return a.exec();
}

Xmain