QT之实现简陋聊天

相关知识：QT，数据库，TCP/IP，Socket；

1.登陆界面
包含登陆和注册两种功能，思路如下：

难点：建立服务器和数据库，数据库保存数据，服务器与数据库产生联系
解决：数据库与服务器放在同一个类中，登陆和注册时，客户端与服务端连接，传输数据给服务端，然后通过数据库来处理数据。

大致步骤：创建ui界面 => {connect(登陆按钮,客户端主动连接服务器)，connect(服务器得到新连接，connect(客户端readReady,服务器读取数据))}
=> 客户端写入数据 ->服务器读取数据 => 使用数据库 => 根据数据输出信息/注册账号。

2.实现聊天
如下为基本功能和实现思路：

参考博文：

1. https://blog.csdn.net/weixin_40011728/article/details/77924196
2. https://www.cnblogs.com/yuweifeng/p/9382841.html
3. https://www.cnblogs.com/lifexy/p/10921958.html

上述博文的内容比我的硬核多了…

新发现一个难点：一个服务器连接多个客户端时，要想清楚怎么去确定不同的客户端，之前的错误代码使得一个客户端登陆，结果包括没连接的客户端都登陆了。

效果展示：

数据库展示：

可以说就实现了正常软件基本功能中的一小部分，后续检查发
现注册信息为空没有设置…
如果要优化界面应该不会比做这些功能难，拿QPaint画画，搞些和文件相关的连接应该就可以。
上面两条应该就是体力活了，但是聊天软件本来应该像QQ一样，最起码能加好友，但是我目前没有想好怎么做，这类知识全是第一次接触，可以说大半部分照着参考博文抄来的，查了很多资料去了解各种函数，有时候数据库的操作失败也是莫名其妙的，再继续下去不如系统地学点知识再来做一回。

全部代码如下：
mylogin.h

#ifndef MYLOGIN_H
#define MYLOGIN_H

#include <QWidget>

#include <QTcpServer>
#include <QTcpSocket>

#include <QMessageBox>

#include "myregister.h"
#include "server_sqlite.h"

namespace Ui {
class MyLogin;
}

class MyLogin : public QWidget
{
    Q_OBJECT

public:
    explicit MyLogin(QWidget *parent = nullptr);
    ~MyLogin();
    void clientSend(QString message);

signals:
    void toSignUp();
    void sendContent(QString content);
    void createUi(QString);
    void refreshList(QString);

private slots:
    void signIn();
    void clientRead();
    void updateSign();

private:
    Ui::MyLogin *ui;
    QTcpSocket *clientTcp;
};

#endif // MYLOGIN_H

mylogin.cpp

#include "mylogin.h"
#include "ui_mylogin.h"

MyLogin::MyLogin(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::MyLogin)
{
    ui->setupUi(this);

    connect(ui->pushButton_Login,&QPushButton::clicked,this,&MyLogin::signIn);
    connect(ui->pushButton_Register,&QPushButton::clicked,this,&MyLogin::toSignUp);

}

MyLogin::~MyLogin()
{
    clientTcp->close();
    delete ui;
}

void MyLogin::signIn(){
    clientTcp = new QTcpSocket(this);

    clientTcp->connectToHost("127.0.0.1",8888);

    if(!clientTcp->waitForConnected(20000)){
        QMessageBox::warning(this,"错误","连接超时");
        return;
    }
   // qDebug()<<"连接服务器成功！";

    QString name = ui->lineEdit_Name->text();
    QString password = ui->lineEdit_Password->text();
    if(""==name||""==password){
        QMessageBox::information(this,"提示","请输入完整登陆信息！");
        return;
    }
    QString tmp = name+";"+password;
  //  qDebug()<<"tmp:"<<tmp;
    clientTcp->write(tmp.toUtf8());//将完整信息写入传递给服务器
    connect(clientTcp,&QTcpSocket::readyRead,this,&MyLogin::updateSign);

//    //登陆成功后连接聊天的信号
//    connect(clientTcp,&QTcpSocket::readyRead,[=](){
//       emit
//    });
//    //connect(clientTcp,&QTcpSocket::readyRead,this,&MyLogin::clientRead);

}

void MyLogin::clientSend(QString message){
    //qDebug()<<"clientSend:"<<message;
    clientTcp->write(message.toUtf8());
}

void MyLogin::clientRead(){
    QTcpSocket *client = qobject_cast<QTcpSocket *>(sender());
    QString content = client->readAll();
    QStringList analysis = content.split("|");
    if("refreshFriendList"==analysis.at(0)){
        emit refreshList(analysis.at(1));
        return;
    }
   //qDebug()<<"emit:"<<content;
    emit sendContent(content);
}

void MyLogin::updateSign(){
    disconnect(clientTcp,&QTcpSocket::readyRead,this,&MyLogin::updateSign);
    connect(clientTcp,&QTcpSocket::readyRead,this,&MyLogin::clientRead);
    QString tmp = clientTcp->readAll();
    QStringList analysis = tmp.split("|");
    emit createUi(analysis.at(1));
}

myregister.h

#ifndef MYREGISTER_H
#define MYREGISTER_H

#include <QWidget>

#include <QTcpSocket>
#include <QTcpServer>

#include <QMessageBox>
#include <QDebug>



namespace Ui {
class MyRegister;
}

class MyRegister : public QWidget
{
    Q_OBJECT

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

private slots:
    void signUp();

private:
    Ui::MyRegister *ui;

    QTcpSocket *myReg;
};

#endif // MYREGISTER_H

myregister.cpp

#include "myregister.h"
#include "ui_myregister.h"

MyRegister::MyRegister(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::MyRegister)
{
    ui->setupUi(this);

    connect(ui->pushButton_Sure,&QPushButton::clicked,this,&MyRegister::signUp);
}

MyRegister::~MyRegister()
{
    myReg->close();
    delete ui;
}

void MyRegister::signUp(){
    myReg = new QTcpSocket;
    myReg->connectToHost("127.0.0.1",8888);
    if(!myReg->waitForConnected(20000)){
        QMessageBox::warning(this,"错误","连接超时");
        return;
    }
    qDebug()<<"连接服务器成功！";

    QString name = ui->lineEdit_Name->text();
    QString pas1 = ui->lineEdit_Password->text();
    QString pas2 = ui->lineEdit_PasswordAgain->text();

    if(pas1 != pas2){
       QMessageBox::warning(this,"警告","两次输入密码不一致！");
       return;
    }

    QString temp = name+";"+pas1+";0";
    myReg->write(temp.toUtf8());
}

server_sqlite.h //服务器&数据库

#ifndef SERVER_SQLITE_H
#define SERVER_SQLITE_H

#include <QSqlDatabase>
#include <QSqlRecord>
#include <QSqlQuery>
#include <QSqlError>

#include <QTcpServer>
#include <QTcpSocket>

#include <QMessageBox>

#include <QApplication>
#include <QObject>

#include <QDebug>

class Server_Sqlite:public QObject
{
    Q_OBJECT

public:
    Server_Sqlite();
    ~Server_Sqlite();
    void dataInit();
    void getChartRecord();

    QList<QTcpSocket *>onlineClients;//在线用户表
    QList<QString>onlineName;//在线用户昵称

private slots:
    void newClient();
    void serverRead();
    void serverDisconnect();
    void sendMessage();

private:
    QSqlDatabase db;

    QTcpServer *myServer;


};

#endif // SERVER_SQLITE_H

server_sqlite.cpp

#include "server_sqlite.h"

Server_Sqlite::Server_Sqlite()
{
     myServer = new QTcpServer;

     //监听,端口号:8888
     bool isOk = myServer->listen(QHostAddress::Any,8888);

     //监听失败
     if(false == isOk){
         QMessageBox::warning(NULL,"监听","8888监听失败！");
         return;
     }else{
         qDebug()<<"监听成功！";
     }

     //当有客户端连接时候,触发信号：newConnection()
     connect(myServer,&QTcpServer::newConnection,this,&Server_Sqlite::newClient);
}

Server_Sqlite::~Server_Sqlite(){
    db.close();
    myServer->close();
}

void Server_Sqlite::dataInit(){
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(QApplication::applicationDirPath()+"/scooters.dat");     //在本目录下生成
    db.open();

    QSqlQuery query;
//  query.exec("DROP TABLE clients");     //先清空一下表
//  query.exec("DROP TABLE chartRecord");
    if(!query.exec("CREATE TABLE clients ("
                       "name VARCHAR(40) NOT NULL, "
                       "password VARCHAR(40) NOT NULL,"
                       "score INTEGER NOT NULL)")){
        qDebug()<<"clients已被创建或出错！";
    }
                    //创建一个clients表

    query.exec("CREATE TABLE chartRecord ("
               "message VARCHAR(200) NOT NULL)");
}

void Server_Sqlite::newClient(){
    QTcpSocket *clientPort;
    clientPort = myServer->nextPendingConnection();
    //与对应的客户端产生连接
    connect(clientPort,&QTcpSocket::readyRead,this,&Server_Sqlite::serverRead);
    connect(clientPort,&QTcpSocket::disconnected,this,&Server_Sqlite::serverDisconnect);
    onlineClients.push_back(clientPort);
}

void Server_Sqlite::serverRead(){
    QTcpSocket *clientPort =qobject_cast<QTcpSocket *>(sender());

    bool flag = false;
    QList<QTcpSocket *>::iterator it;
    for(it = onlineClients.begin();it != onlineClients.end();it++){
        if((*it) == clientPort){
            flag = true; break;
        }
    }
    if(!flag)return;

    disconnect(clientPort,&QTcpSocket::readyRead,this,&Server_Sqlite::serverRead);
    //获取数据,查询数据库
    QString str = clientPort->readAll();
    qDebug()<<"读入数据"<<str;
    QStringList analysis = str.split(";");//str:name;password
    QString tmp = QString("select * from clients where name = '%1'").arg(analysis.at(0));
    qDebug()<<tmp;
    qDebug()<<"length="<<analysis.length();
    QSqlQuery query;
    query.exec(tmp);
    if(!query.next()){//在数据库中没找到该用户名
        qDebug()<<"没找到！";
        if(analysis.length() == 3){
            query.prepare("INSERT INTO clients (name,password,score) "
                          "VALUES(:name, :password, :score)");
            QString myName = analysis.at(0);
            QString myPassword = analysis.at(1);
            qDebug()<<myName<<myPassword;
            query.prepare("INSERT INTO clients (name, password, score) "
                          "VALUES (:name, :password, :score)");
                            //为每一列标题添加绑定值
                query.bindValue(":name", myName);
                query.bindValue(":password", myPassword);
                query.bindValue(":score", 0 );
                query.exec();               //加入库中
            QMessageBox::information(NULL,"提示","注册成功！");
            return;
        }
        QMessageBox::information(NULL,"提示","该用户尚未注册！");
        return;
    }else{//找到该用户名
        qDebug()<<"找到了！";
        if(analysis.length() == 3){
            QMessageBox::warning(NULL,"警告","该用户名已被注册！");
            return;
        }
        if(analysis.at(1) != query.value(1)){//0:name 1:password 2:score
            qDebug()<<query.value(1).toString();
            QMessageBox::warning(NULL,"提示","密码输入错误！");
            return;
        }else{
              int newScore =query.value(2).toInt()+1;
              tmp = QString("update clients set score = %1 where name = '%2'").arg(newScore).arg(analysis.at(0));
              query.exec(tmp);
        }
    }
   // qDebug()<<"来新客人了";
    onlineName.push_back(analysis.at(0));
    tmp.clear();
    QList<QString>::iterator it2;
    for(it2 = onlineName.begin(); it2 != onlineName.end(); ++it2){
        tmp+=";"+(*it2);
    }
    for(it = onlineClients.begin();it != onlineClients.end();it++){
        (*it)->write("refreshFriendList|"+tmp.toUtf8());
    }
    connect(clientPort,&QTcpSocket::readyRead,this,&Server_Sqlite::sendMessage);
}

void Server_Sqlite::sendMessage(){
        //哪一个QTcpSocketc对象可读就会发出readyRead()信号，通过信号的发出者找到相应的对象
        QTcpSocket *client = qobject_cast<QTcpSocket *>(sender());
        QString str = client->readAll();
        //群发
        QList<QTcpSocket *>::iterator it;
        for(it = onlineClients.begin();it != onlineClients.end();it++){
            qDebug()<<"群发："<<str;
            (*it)->write(str.toUtf8());
        }
        QSqlQuery query;
        QString tmp = QString("insert into chartRecord (message) values ('%1')").arg(str);
        query.exec(tmp);
}

void Server_Sqlite::serverDisconnect(){//断开连接删去该用户
    QTcpSocket *client = qobject_cast<QTcpSocket *>(sender());
    onlineClients.removeOne(client);
    qDebug()<<"断开连接";
}

widgt.h//聊天窗口

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

#include <QObject>

//主窗口用户列表使用
#include <QTextBrowser>
#include <QLabel>

#include "server_sqlite.h"
#include "mylogin.h"
#include "myregister.h"

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

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

private slots:
    void mainCreadUi(QString name);
    void refreshChart(QString content);
    void refreshList(QString names);

private:
    Ui::Widget *ui;
    QTextBrowser *xin;
    QLabel *record;

    Server_Sqlite *serSql;
    MyLogin *log;
    MyRegister *reg;
};
#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);

//    serSql = new Server_Sqlite;
//    serSql->dataInit();

    this->setWindowTitle("群聊窗口");

    log = new MyLogin;

    connect(log,SIGNAL(createUi(QString)),this,SLOT(mainCreadUi(QString)));
    connect(log,&MyLogin::toSignUp,[=](){
        reg = new MyRegister;
        reg->show();
    });

    //发送消息写入聊天框
    connect(ui->pushButton_Send,&QPushButton::clicked,[=](){
       QString fasoner = ui->label_Name->text();
       QString message = ui->textEdit_Send->toPlainText();
       qDebug()<<fasoner<<message;
       log->clientSend(fasoner+":\n"+message);
    });
    connect(log,&MyLogin::sendContent,this,&Widget::refreshChart);
    //查看历史记录
    record = new QLabel(this);
    record->setText("消息记录：");
    record->move(565,40);
    xin = new QTextBrowser(this);
    xin->move(565,60);
    xin->setFixedSize(325,330);

    connect(ui->pushButton_ChartRecord,&QPushButton::clicked,[=](){
        if(ui->pushButton_ChartRecord->text()!="关闭记录"){
        this->setFixedSize(900,405);
        record->show();
        xin->show();
        ui->pushButton_ChartRecord->setText("关闭记录");
        qDebug()<<"数据库数据：";
            QSqlQuery query;
            query.exec("select * from chartRecord");
            while(query.next()){
                QString message = query.value(0).toString();
                xin->append(message);
        }
        }else{
            ui->pushButton_ChartRecord->setText("历史记录");
            record->close();
            xin->close();
            this->setFixedSize(565,405);
        }
    });

    //更新在线列表
    connect(log,SIGNAL(refreshList(QString)),this,SLOT(refreshList(QString)));

    log->show();
}

Widget::~Widget()
{
    qDebug()<<"数据库数据：";
        QSqlQuery query;
        query.exec("select * from chartRecord");
        while(query.next()){
            QString message = query.value(0).toString();
            qDebug()<<message;
    }
    delete ui;
}

void Widget::mainCreadUi(QString names){
    ui->textEdit_Friends->setReadOnly(true);
    QStringList analysis = names.split(";");
    ui->label_Name->setText(analysis.back());
    for(int i=0;i<analysis.length();i++){
        QString tmp = QString("select * from clients where name = '%1'").arg(analysis.at(i));
        int score;
        QSqlQuery query;
        query.exec(tmp);
        while(query.next()){
            score = query.value(2).toInt();//name;passowrd;score
            tmp.sprintf("%-15s%-5d",analysis.at(i).toStdString().data(),score);
            ui->textEdit_Friends->append(QString(tmp));
        }
    }
    QString name = analysis.back();
    this->show();
    log->close();
}

void Widget::refreshChart(QString content){
    ui->textEdit_Send->clear();
    ui->textBrowser_Chart->append(content);
}

void Widget::refreshList(QString names){
    ui->textEdit_Friends->clear();
    QStringList analysis = names.split(";");
    for(int i=0;i<analysis.length();i++){
        QString tmp = QString("select * from clients where name = '%1'").arg(analysis.at(i));
        int score;
        QSqlQuery query;
        query.exec(tmp);
        while(query.next()){
            score = query.value(2).toInt();//name;passowrd;score
            tmp.sprintf("%-15s%-5d",analysis.at(i).toStdString().data(),score);
            ui->textEdit_Friends->append(QString(tmp));
        }
    }
}

最后是main.cpp

#include "widget.h"
#include "server_sqlite.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Server_Sqlite tmp;
    tmp.dataInit();
    Widget w,w2,w3;
  //w.show();
    return a.exec();
}