【qt】自定义信号

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

在这里插入图片描述
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

自定义信号

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_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic: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));}