mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

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

    tmp = new Class_2;



    connect(tmp, SIGNAL(send_name(QString str)), this, SLOT(name(QString str)));

    //connect(link, &Link::clicked,  mainWindow, &MainWindow::doSmth);
    //connect(tmp, &tmp::send_name(QString str), this, &MainWindow::name(QString str));
    //connect(SECOND_CLASS, &SECOND_CLASS_NAME::textIsChanged, this, &FIRST_CLASS_NAME::textIsChangedSlot);
    connect(tmp, &tmp::send_name, this, MainWindow::name);
}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_pushButton_clicked()
{
    tmp->show();
}

void MainWindow::name(QString str)
{
    user_name = str;
    ui->statusbar->showMessage(user_name);
}

void MainWindow::on_pushButton_2_clicked()
{
    ui->statusbar->showMessage(user_name);
}