Qt 数据库的注册和登录功能

widget.h

#ifndef WIDGET_H
#define WIDGET_H
 
#include
#include 
#include 
#include 
#include 
#include 
#include "client.h"
#include 
#include 
#include           //执行sql
#include         //数据库记录的类
 
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
 
class Widget : public QWidget
{
    Q_OBJECT
 
 signals:
    void jump();     //跳转页面的自定义函数     信号
public slots:
    void login_solt();   //登录页面的自定义的槽函数
 
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
 
private slots:
    void on_loginBtn_clicked();
 
    void on_cancleBtn_clicked();
 
    void on_registerBtn_clicked();
 
private:
    Ui::Widget *ui;
    client *s;
 
    //定义一个数据库的类对象
    QSqlDatabase db;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    s =  new client;
    //更改窗口标题
    this->setWindowTitle("光与夜之恋");
    this->setWindowFlag(Qt::FramelessWindowHint);          //去掉窗口头部
    //logo图
    ui->logo->setPixmap(QPixmap(":/qt/a1.webp"));
    ui->logo->setScaledContents(true);
//    //用户名密码图
//    ui->userNamelab->setPixmap(QPixmap(":/qt/q1.webp"));
//    ui->userNamelab->setScaledContents(true);
 
//    ui->pwdlab->setPixmap(QPixmap(":/qt/2.webp"));
//    ui->pwdlab->setScaledContents(true);
 
    //设置账户密码
 
    ui->pwdEdit->setPlaceholderText("密码");
    ui->pwdEdit->setEchoMode(QLineEdit::Password);
 
 
    //将登录按钮连接到自定义的槽函数中
    connect(ui->loginBtn,&QPushButton::clicked,this,&Widget::login_solt);
    //将取消按钮连接到自定义的槽函数中
    connect(ui->cancleBtn,SIGNAL(clicked()),this,SLOT(close()));
    connect(this, &Widget::jump, s, &client::jump_slot);
 
    //数据库的操作
    if(!db.contains("reginst.db"))
    {
        //添加数据库
        db=QSqlDatabase::addDatabase("QSQLITE");
        //设置数据库名字
        db.setDatabaseName("reginst.db");
 
    }
    //打开数据库
    if(!db.open())
    {
        QMessageBox::information(this,"提示","数据库打开失败");
        return ;
    }
    //准备sql语句
    QString sql="create table if not exists zh_info("
                "username varchar(10) primary key,"
                "pwd varchar(10))";
 
    //准备语句执行者
    QSqlQuery querry(db);
    if(!querry.exec(sql))
    {
        QMessageBox::information(this,"失败","数据库创建失败");
        return;
    }
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::login_solt()
{
    QString username=ui->userNameEdit->text();
    QString pwd=ui->pwdEdit->text();
 
}
 
void Widget::on_loginBtn_clicked()
{
    QString username=ui->userNameEdit->text();
    QString pwd=ui->pwdEdit->text();
    //确保每个编辑器中有数据
    if(username.isEmpty()||pwd.isEmpty())
    {
        QMessageBox::information(this,"提示","请将信息填充完整");
        return ;
    }
    //准备sql语句
    QSqlQuery query;
    QString sql = QString("SELECT username, pwd FROM zh_info WHERE username = '%1' AND pwd = '%2'")
            .arg(username).arg(pwd);
    //执行查询
    if (query.exec(sql) && query.next())
    {
        int ret = QMessageBox::information(this, "提示", "登录成功", QMessageBox::Ok);
        if(ret == QMessageBox::Ok)
        {
            emit jump();
            this->hide();
        }
    }
    else
    {
        //登录失败
        QMessageBox::information(this,"失败","用户名或密码错误");
    }
}
 
 
void Widget::on_registerBtn_clicked()
{
    QString username = ui->userNameEdit->text();
    QString pwd = ui->pwdEdit->text();
    //确保每个编辑器中有数据
    if (username.isEmpty() || pwd.isEmpty())
    {
        QMessageBox::information(this, "提示", "请将信息填充完整");
        return;
    }
    //准备sql查询语句
    QSqlQuery query;
    QString sql = QString("select username from zh_info where username = '%1'").arg(username);
    //执行查询
    if (query.exec(sql) && query.next())
    {
        //已存在相同用户名的记录，无法注册
        QMessageBox::information(this, "失败", "该用户名已被注册，请重新选择用户名");
    }
    else
    {
        //注册
        sql = QString("insert into zh_info(username, pwd) VALUES('%1', '%2')").arg(username).arg(pwd);
        if (query.exec(sql))
        {
            QMessageBox::information(this, "成功", "注册成功");
        }
        else
        {
            QMessageBox::information(this, "失败", "注册失败");
        }
    }
}
void Widget::on_cancleBtn_clicked()
{
    ui->pwdEdit->clear();
    ui->userNameEdit->clear();
}

 client.h

#ifndef CLIENT_H
#define CLIENT_H
 
#include 
#include 
#include 
#include 
namespace Ui {
class client;
}
 
class client : public QDockWidget
{
    Q_OBJECT
 
public slots:
    void jump_slot();
public:
    explicit client(QWidget *parent = nullptr);
    ~client();
 
private slots:
    void on_pushButton_2_clicked();
 
private:
    Ui::client *ui;
};
 
#endif // CLIENT_H

client.cpp

#include "client.h"
#include "ui_client.h"
 
client::client(QWidget *parent) :
    QDockWidget(parent),
    ui(new Ui::client)
{
    ui->setupUi(this);
    //更改窗口标题
    this->setWindowTitle("光与夜之恋");
    //logo图
    ui->logo->setPixmap(QPixmap(":/qt/592587c702e7f7674a6c7fa72fe21169.jpg"));
    ui->logo->setScaledContents(true);
 
}
 
client::~client()
{
    delete ui;
}
void client::jump_slot()
{
    this->show();
}
 
void client::on_pushButton_2_clicked()
{
 int ret =QMessageBox::information(this,"提示","该男人已经溜走",QMessageBox::Ok);
 if(ret==QMessageBox::Ok)
 {
     this->close();
 }
}

 main函数

#include "widget.h"
 
#include 
#include "client.h"
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
//    client s;
//    QObject::connect(&w,&Widget::login_solt,&s,&client::jump_slot);
    return a.exec();
}

窗口设计部分

最终效果图：