#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include<QPushButton>
#include<QLineEdit>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

private slots:
    void doTHE();
private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H






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

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

    connect(btn,SIGNAL(clicked()),this,SLOT(doTHE()));
}

void MainWindow::doTHE(){
    ui->lineEdit->setText("hello mt");
}

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