QTimer与QTime实现电子时钟

#include <QLCDNumber> class NumClock : public QLCDNumber{  Q_OBJECTpublic:  explicit NumClock(QWidget *parent = nullptr);  void mousePressEvent(QMouseEvent *event);  void mouseMoveEvent(QMouseEvent *event); signals: public slots:  void updateTime(); private:  QTimer * timer;  QPoint mouseOfPonit; // 鼠标坐标跟窗口左上角坐标的偏移值  bool showColon;       //是否显示：};

#include "numclock.h"#include <QTimer>#include <QTime>#include <QMouseEvent>#include <QDebug> NumClock::NumClock(QWidget *parent) : QLCDNumber(parent){  timer = new QTimer(this);  timer->setTimerType(Qt::PreciseTimer); // 设置精度为较高精度，差距在毫秒内  timer->start(1000);  connect(timer, SIGNAL(timeout()), this, SLOT(updateTime()),Qt::QueuedConnection);   setWindowFlag(Qt::FramelessWindowHint); //没有面板边框标题栏的窗体  setWindowOpacity(0.5); //设置窗口的透明度   showColon = true;   this->setDigitCount(8);  resize(150, 100);   updateTime();    setAttribute(Qt::WA_DeleteOnClose);} void NumClock::mousePressEvent(QMouseEvent *event){  if(event->button() == Qt::LeftButton){    mouseOfPonit = event->globalPos() - this->pos();    event->accept();  }else{    close();  }} void NumClock::mouseMoveEvent(QMouseEvent *event){  if(event->buttons() & Qt::LeftButton){    move(event->globalPos() - mouseOfPonit);    event->accept();  }} void NumClock::updateTime(){  QString timeStr = QTime::currentTime().toString("hh:mm:ss");  if(showColon){    timeStr = timeStr.replace(QString(":"), QString(" "));    qDebug() << timeStr;    showColon = false;  }else{    timeStr = timeStr.replace(QString(" "), QString(":"));    showColon = true;    qDebug() << timeStr;  }  display(timeStr);}