測試QTimer定時器精準度的小程序

可以在dialog上添加三個label查看時間和異常次數，也可以在打印輸出欄看每次timer超時事件誤差適度少（都是ms級別的）

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QDateTime>

namespace Ui {
class Dialog;
}

class QTimer;

class Dialog : public QDialog
{
    Q_OBJECT

public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
public slots:
    void slotOneSec();

private:
    Ui::Dialog *ui;
    QDateTime m_time;
    QTimer *m_oneSecTimer;
    int num;
};

#endif // DIALOG_H

#include "dialog.h"
#include "ui_dialog.h"
#include <QTimer>
#include <QDebug>

Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
    num = 0;
    m_oneSecTimer = new QTimer();
    connect(m_oneSecTimer, SIGNAL(timeout()), this, SLOT(slotOneSec()));

    m_time = QDateTime::currentDateTime();
    m_oneSecTimer->start(1000);

    ui->myTime->setText(m_time.toString("hh:mm:ss"));
    ui->computerTime->setText(QDateTime::currentDateTime().toString("hh:mm:ss"));
}

Dialog::~Dialog()
{
    delete m_oneSecTimer;
    delete ui;
}

void Dialog::slotOneSec()
{
    m_time = m_time.addSecs(1);
    ui->myTime->setText(m_time.toString("hh:mm:ss"));
    ui->computerTime->setText(QDateTime::currentDateTime().toString("hh:mm:ss"));
    //如果兩次定時間隔大於10秒，次數就會+1
    qDebug()<<"===="<<abs(m_time.toMSecsSinceEpoch() - QDateTime::currentDateTime().toMSecsSinceEpoch());
    if(abs(m_time.toMSecsSinceEpoch() - QDateTime::currentDateTime().toMSecsSinceEpoch()) > 10000)
    {
        num++;
    }
    ui->exception->setText(QString::number(num));
    //校準事件
    m_time = QDateTime::currentDateTime();
}

效果圖