试图用信号将QTcpServer连接到GUI

我在服务器和客户端之间创建了一个连接，该连接在控制台中工作得很好，但我无法将我的QTcpServer类与信号和插槽连接到GUI。下面是我的代码:

ServerTCP.cpp

ServerTcp :: ServerTcp (QWidget *parent)
{
    listen(QHostAddress::Any,4000);
    QObject:: connect(this, SIGNAL(newConnection()),
    this, SLOT(connectionRequest()));
}
void ServerTcp :: connectionRequest()
 {
    emit IHM_connection(); 
    clientConnection = nextPendingConnection();
    QObject:: connect(clientConnection, SIGNAL(readyRead()),
    this, SLOT(read()));
}
void ServerTcp::read()
{
    QString ligne;
    while(clientConnection->canReadLine())    
    {
        ligne = clientConnection->readLine(); 
        emit IHM_text(ligne);           
    }
    QTextStream text(clientConnection);      

}

ManinWindow.cpp

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QObject::connect(&server,SIGNAL(IHM_connetion()),this,SLOT(connectionRequested()));
    QObject::connect(&server,SIGNAL(read(QString)),this,SLOT(print_text(QString)));
}

void MainWindow::on_quitButton_clicked()
{
    qApp->quit();
}
void MainWindow::print_text(QString text){
     ui->log->append("message : " + text);
}
void MainWindow::connectionRequested(){
    ui->log->append("connection OK!");
}
MainWindow::~MainWindow()
{
    delete ui;
}