QT 信号与槽

?.h文件

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

public slots:
    void buttonLable();

private:
    Ui::Widget *ui;
};
#endif // WIDGET_H

.cpp文件

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>

int i = 1;
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    connect(ui->pushButton, SIGNAL( clicked()) ,  this, SLOT(buttonLable()));
     connect(ui->pushButton_2, SIGNAL( clicked()) ,  this, SLOT(buttonLable()));
}

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

void Widget::buttonLable()
{
    qDebug()<<"void buttonLable()";

    QString str = QString("此按键点击了 %1 次").arg(i++);
    this->ui->label->setText(str);
}

现象