Qt 1. 按键QPushButton和文本框QTextEdit

//ex2.cpp
#include "ex2.h"
#include "ui_ex2.h"

int static cnt = 0;

Ex2::Ex2(QWidget *parent)
    : QDialog(parent)
    , ui(new Ui::Ex2)
{
    ui->setupUi(this);
}

Ex2::~Ex2()
{
    delete ui;
}


void Ex2::on_pushButtonMy1_clicked()
{
    cnt ++;
    QString str = QString::number(cnt,10);
    ui->textEditMy1->setText(str);
}

void Ex2::on_pushButtonMy2_clicked()
{
    if(cnt > 0) cnt --;
    QString str = QString::number(cnt,10);
    ui->textEditMy1->setText(str);
}

//main.cpp
#include "ex2.h"
#include <QtSerialPort/QtSerialPort>
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Ex2 w;
    w.show();
    return a.exec();
}