我们在上篇中，服务器收到的消息是由线程类去处理的，消息在线程类中，传不到widget中的ui中去，如果我们要在界面显示客户端的消息，必须通过自定义信号.

1.构建信号

当线程收到信息，就会被填充在ba中，然后sendtowidget函数在接收到ba参数的时候就会发出信号给widget,为什么会发送信号给widget,我们可以在widget中写一个connect联系起来，如下图

2.演示

3.代码实现

qtthread.h

#ifndef QTTHREAD_H
#define QTTHREAD_H

#include <QObject>
#include<QThread>
#include<QTcpSocket>
#include<QDebug>

class qtthread : public QObject
{
    Q_OBJECT
public:
    explicit qtthread(QTcpSocket*s,QObject *parent = nullptr);
    void run();
    void serverrecv();

signals:
    void sendtowidget(QByteArray t);
private:
     QTcpSocket* s;

};

#endif // QTTHREAD_H

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QTcpSocket>
#include<QTcpServer>
#include<qtthread.h>
//#include<QThread>
#define PORT 8080
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 deal();
   // void serverrecv();
    void threaddeal(QByteArray st);

private:
    Ui::Widget *ui;
    QTcpServer *server;
};
#endif // WIDGET_H

qtthread.cpp

#include "qtthread.h"

qtthread::qtthread(QTcpSocket *socket, QObject *parent) : QObject(parent)
{
   s=socket;
}
void qtthread :: run()
{

     connect(s,&QTcpSocket::readyRead,this,&qtthread::serverrecv);

}
void qtthread ::serverrecv()
{

   // qDebug()<<s->readAll();
    QByteArray ba=s->readAll();
    emit sendtowidget(ba);


}

widget.cpp

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    server=new QTcpServer;
    server->listen(QHostAddress::AnyIPv4,PORT);
    connect(server,&QTcpServer::newConnection,this,&Widget::deal);
}

Widget::~Widget()
{
    delete ui;
}
void Widget::deal()
{

    QTcpSocket* socket=server->nextPendingConnection();
    ui->clientip->setText(socket->peerAddress().toString());
    ui->clientport->setText(QString::number(socket->peerPort()));

   // connect(socket,&QTcpSocket::readyRead,this,&Widget::serverrecv);

     qtthread *st=new qtthread(socket);
     st->run();

     connect(st,&qtthread::sendtowidget,this,&Widget::threaddeal);



}
//void Widget::serverrecv()
//{

//    QTcpSocket* socket=(QTcpSocket*)sender();
//   // socket->readAll();//QBytearray
//    ui->recvinfo->setText(QString(socket->readAll()));

//}
void Widget::threaddeal(QByteArray st)
{
    ui->recvinfo->setText(QString(st));




}