#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

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

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

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

void MainWindow::plainTextEditEventLogClear()
{
    qDebug() << "plainTextEditEventLogClear()";
    ui->plainTextEdit->clear();
}

void MainWindow::on_pushButton_clicked()
{
    logs log;
    log.clear();
}

void MainWindow::on_pushButton_2_clicked()
{
    ui->plainTextEdit->appendPlainText("append text");
}

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QDebug>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    void plainTextEditEventLogClear();

private slots:
    void on_pushButton_clicked();

    void on_pushButton_2_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

#include "logs.h"
#include "mainwindow.h"

logs::logs()
{

}

void logs::clear()
{
    qDebug() << "logs::clear()";
    MainWindow mw;
    mw.plainTextEditEventLogClear();
}

#ifndef LOGS_H
#define LOGS_H


class logs
{
public:
    logs();
    void clear();
};

#endif // LOGS_H

void MainWindow::plainTextEditEventLogClear()
{
    qDebug() << "plainTextEditEventLogClear()";
    ui->plainTextEdit->clear();
}

void logs::clear()
{
    qDebug() << "logs::clear()";
    MainWindow mw;
    mw.plainTextEditEventLogClear();
}

#include "mainwindow.h"
#include <QApplication>

MainWindow *w = NULL;

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    w = new MainWindow;
    w->show();

    return a.exec();
}