QT用户登录注册，数据库实现

登录窗口头文件

#ifndef LOGINUI_H
#define LOGINUI_H#include <QWidget>
#include <QLineEdit>
#include <QPushButton>
#include <QLabel>
#include <QMessageBox>#include <QSqlDatabase> //数据库管理类
#include <QSqlQuery>    //执行sql语句的类
#include <QSqlRecord>   //数据库记录类#include <QKeyEvent>#include "client.h"class LoginUI : public QWidget
{Q_OBJECTprivate://标签类组件QLabel* Background_Lab;QLabel* Titile_Lab;QLabel* Username_Lab;QLabel* Password_Lab;//按钮类组件QPushButton* Close_Btn;QPushButton* Hide_Btn;QPushButton* Login_Btn;QPushButton* Register_Btn;//行编辑器类组件QLineEdit* Username_Edit;QLineEdit* Password_Edit;//声明数据库对象QSqlDatabase db;//UI绘制函数bool DrawLoginUI();//构造函数LoginUI();bool construct();private slots://槽函数void On_CloseBtn_Clicked();void On_Loginbtn_Slots();void On_Registerbtn_Slots();public://实例化对象static LoginUI* NewInstance();void show();~LoginUI();signals:void jump();};
#endif //LOGINUI_H

登录窗口函数实现

#include "LoginUI.h"
#include <QDebug>bool LoginUI::DrawLoginUI()
{bool ret = true;//背景色设置Background_Lab = new QLabel(this);if( Background_Lab != nullptr){Background_Lab->resize(538, 160);Background_Lab->setStyleSheet("background-color:rgb(115,70,240)");}else{ret = false;}//窗口标识Titile_Lab = new QLabel(this);if( Titile_Lab != nullptr ){Titile_Lab->resize(90, 50);Titile_Lab->setPixmap(QPixmap(":/QT_Icon/QQ_Icon.png"));Titile_Lab->setScaledContents(true);}else{ret = false;}//关闭按键Close_Btn = new QPushButton(this);if( Close_Btn != nullptr ){Close_Btn->resize(20, 20);Close_Btn->setIcon(QIcon(":/QT_Icon/close02.png"));Close_Btn->move(508, 10);connect(this->Close_Btn, &QPushButton::clicked, this, &LoginUI::On_CloseBtn_Clicked);}else{ret = false;}//隐藏按键Hide_Btn = new QPushButton(this);if( Hide_Btn != nullptr ){Hide_Btn->resize(20, 20);Hide_Btn->setIcon(QIcon(":/QT_Icon/hide02.png"));Hide_Btn->move(468, 10);connect(this->Hide_Btn, &QPushButton::clicked, this, &LoginUI::hide);}else{ret = false;}//用户名输入栏Username_Edit = new QLineEdit(this);if( Username_Edit != nullptr ){Username_Edit->resize(260, 40);Username_Edit->move(159, 173);Username_Edit->setMaxLength(16);Username_Edit->setPlaceholderText("QQ账号/手机号/邮箱");}else{ret = false;}//密码输入栏Password_Edit = new QLineEdit(this);if( Password_Edit != nullptr ){Password_Edit->resize(260, 40);Password_Edit->move(Username_Edit->x(), Username_Edit->y()+60);Password_Edit->setEchoMode(QLineEdit::Password);Password_Edit->setMaxLength(16);}else{ret = false;}//用户名输入栏标签Username_Lab = new QLabel(this);if( Username_Lab != nullptr ){Username_Lab->resize(30, 30);Username_Lab->move(Username_Edit->x()-40, Username_Edit->y()+5);Username_Lab->setPixmap(QPixmap(":/QT_Icon/windos_icon1.png"));Username_Lab->setScaledContents(true);}else{ret = false;}//密码输入栏标签Password_Lab = new QLabel(this);if( Password_Lab != nullptr ){Password_Lab->resize(30, 30);Password_Lab->move(Password_Edit->x()-40, Password_Edit->y()+5);Password_Lab->setPixmap(QPixmap(":/QT_Icon/password.png"));Password_Lab->setScaledContents(true);}else{ret = false;}//登录按键Login_Btn = new QPushButton("登录",this);if( Login_Btn != nullptr ){Login_Btn->resize(130, 40);Login_Btn->setStyleSheet("background-color:rgb(8,189,253);");Login_Btn->move(Password_Lab->x(), Password_Lab->y()+60);connect(this->Login_Btn, &QPushButton::clicked, this, &LoginUI::On_Loginbtn_Slots);}else{ret = false;}//注册按键Register_Btn = new QPushButton("注册",this);if( Register_Btn != nullptr ){Register_Btn->resize(130, 40);Register_Btn->setStyleSheet("background-color:rgb(8,189,253);");Register_Btn->move(Login_Btn->x()+170, Login_Btn->y());connect(this->Register_Btn, &QPushButton::clicked, this, &LoginUI::On_Registerbtn_Slots);}else{ret = false;}return ret;
}LoginUI::LoginUI(): QWidget(nullptr, Qt::WindowCloseButtonHint)
{
}void LoginUI::show()
{setWindowFlag(Qt::FramelessWindowHint);setFixedSize(538, 373);QWidget::show();
}LoginUI::~LoginUI()
{
}//构造函数
bool LoginUI::construct()
{//UI界面绘制bool ret = true;ret = DrawLoginUI();//数据库创建//判断自己的数据库对象中，是否包含要处理的数据库，没有则添加一个数据库if( !db.contains("UserMsg.db")){//添加一个数据库，调用该类中的静态成员函数addDatabase()db = QSqlDatabase::addDatabase("QSQLITE");//使用sqlite3数据库//设置数据库名字db.setDatabaseName("UserMsg.db");}//此时数据库已经创建完成//打开数据库if( !db.open() ){QMessageBox::information(this, "提示", "数据库打开失败");ret = false;}//使用sql语句进行创建表的操作//准备sql语句QString Create_Table_Sql = "create table if not exists user_msg(""user_name varchar(16) primary key,""password varchar(16))";//准备语句执行者QSqlQuery querry;//执行sql语句if( !querry.exec(Create_Table_Sql) ){QMessageBox::information(this, "提示", "创建表失败");ret = false;}return ret;}//关闭按键槽函数
void LoginUI::On_CloseBtn_Clicked()
{QMessageBox box(QMessageBox::Question, "关闭", "您确定要退出？", QMessageBox::Yes | QMessageBox::No, this);box.setDefaultButton(QMessageBox::No);int ret = box.exec();if(ret == QMessageBox::Yes){this->close();}else if(ret == QMessageBox::No){}
}//登录按键槽函数
void LoginUI::On_Loginbtn_Slots()
{//获取ui界面的用户信息QString name = Username_Edit->text();QString password = Password_Edit->text();if( name.isEmpty() ){QMessageBox::information(this, "提示", "请输入用户名");return;}else if( password.isEmpty() ){QMessageBox::information(this, "提示", "请输入密码");return;}//准备sql查询语句QString sql = QString("select * from user_msg where user_name = '%1' and password = '%2'").arg(name).arg(password);//准备语句执行者QSqlQuery querry;querry.exec(sql);//    qDebug() <<querry.exec(sql);//    qDebug() << querry.value(0);
//    qDebug() << querry.value(1);//执行sql语句if( !querry.next() ){QMessageBox::information(this, "提示", "账号密码错误");return;}else{QMessageBox::information(this, "提示", "登陆成功");emit jump();this->close();}}//注册事件槽函数
void LoginUI::On_Registerbtn_Slots()
{//获取ui界面的用户信息QString name = Username_Edit->text();QString password = Password_Edit->text();//确保用户信息输入完整if( name.isEmpty() || password.isEmpty() ){QMessageBox::information(this, "提示", "请将信息填写完整");return;}//准备sql语句QString sql = QString("insert into user_msg(user_name, password) ""values('%1', '%2')").arg(name).arg(password);//准备语句执行者QSqlQuery querry;if( !querry.exec(sql) ){QMessageBox::information(this, "提示", "注册失败");return;}else{QMessageBox::information(this, "提示", "注册成功");}
}//创建一个新对象
LoginUI *LoginUI::NewInstance()
{LoginUI* ret = new LoginUI;if( !ret->construct() || ret == nullptr ){delete ret;ret = nullptr;}return ret;
}