Implementing a "Time Left" Function

Thugzook

Hello everyone.

So, I was able to get a system process delay function working, which gets passed an integer and delays system processes for that many milliseconds that the integer asked for.
I'm trying to work this code into being able to display the time left, in seconds, into a label. So far, nothing has been working.

Any help would be necessary.
CODE

void MainGame2::gameDelay(int msecs)
{
    ///variables
    int timeLeft = msecs; //used in tandem with progress bar

    QTime endTime= QTime::currentTime().addMSecs(msecs);
    while( QTime::currentTime() < endTime )
    {
    ///QCoreApplication handles event loops without UIs
    QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
    }
}//end function delay

koahnig

@Thugzook
It is not completely clear what problem are you see. However, I think you should have a look at the msecsTo funtionality. This is also available for QDateTime and may be easier for bridging days. Also currentDateTime may be of use for you.

Thugzook

I'm not quite sure how to convert to seconds, it what I'm saying.
I'm trying to use a while loop to continue to processEvents until the variable endTime.

Not quite sure how to work this out nor how to effectively work an integer countDown within that loop.

SysTech

I would suggest taking a look at QElapsedTimer. This class allows you to start a "count up" timer.

One of the methods of the class is elapsed() which returns the number of milliseconds since the timer was started.

By knowing how long you want to allow (total time perhaps) and using an elapsed timer with elapsed() the difference between the two will be the remaining time, in milliseconds.

To convert it to a nice human readable form there are lots of ways but you could simply code up (not the prettiest code, downloaded from a stack overflow post):

QString ConvertMStoHumanTime( qint64 ms, bool showDays, bool showMS )
{
  QString Result;
  double interval;
  qint64 intval;

// Days
interval = 24.0 * 60.0 * 60.0 * 1000.0;
intval = (qint64)trunc((double)ms / interval);
if( intval<0 )
  intval = 0;
ms -= (qint64)trunc(intval * interval);
qint32 days = intval;

// Hours
interval = 60.0 * 60.0 * 1000.0;
intval = (qint64)trunc((double)ms / interval);
if( intval<0 )
  intval = 0;
ms -= (qint64)trunc(intval * interval);
qint32 hours = intval;

// Minutes
interval = 60.0 * 1000.0;
intval = (qint64)trunc((double)ms / interval);
if( intval<0 )
  intval = 0;
ms -= (qint64)trunc(intval * interval);
qint32 minutes = intval;

// Seconds
interval = 1000.0;
intval = (qint64)trunc((double)ms / interval);
if( intval<0 )
  intval = 0;
ms -= (qint64)trunc(intval * interval);
qint32 seconds = intval;

// Whatever is left over is milliseconds

char buffer[25];
memset( buffer, 0, 25 );

if( showDays )
{
  if( days<10 )
    sprintf_s( buffer, "%d", days );
  Result.append( QString("%1d ").arg(buffer) );
}

if( hours<10 )
  sprintf_s( buffer, "0%d", hours );
else
  sprintf_s( buffer, "%d", hours );
Result.append( QString("%1:").arg(buffer) );

if( minutes<10 )
  sprintf_s( buffer, "0%d", minutes );
else
  sprintf_s( buffer, "%d", minutes );
Result.append( QString("%1:").arg(buffer) );

if( seconds<10 )
  sprintf_s( buffer, "0%d", seconds );
else
  sprintf_s( buffer, "%d", seconds );
Result.append( QString("%1").arg(buffer) );

if( showMS )
{
  if( ms<10 )
    sprintf_s( buffer, "00%d", ms );
  else if( ms<100 )
    sprintf_s( buffer, "0%d", ms );
  else
    sprintf_s( buffer, "%d", ms );
  Result.append( QString(".%1").arg(buffer) );
}

return Result;
}