#include <QLCDNumber>
 
class NumClock : public QLCDNumber
{
 Q_OBJECT
public:
 explicit NumClock(QWidget *parent = nullptr);
 void mousePressEvent(QMouseEvent *event);
 void mouseMoveEvent(QMouseEvent *event);
 
signals:
 
public slots:
 void updateTime();
 
private:
 QTimer * timer;
 QPoint mouseOfPonit; // 鼠標坐標跟窗口左上角坐標的偏移值
 bool showColon;    //是否顯示：
};

#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); // 設置精度為較高精度，差距在毫秒內
 timer->start(1000);
 connect(timer, SIGNAL(timeout()), this, SLOT(updateTime()),Qt::QueuedConnection);
 
 setWindowFlag(Qt::FramelessWindowHint); //沒有面板邊框標題欄的窗體
 setWindowOpacity(0.5); //設置窗口的透明度
 
 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);
}