Question

I’m attempting to make a 24 hour analog clock and currently have a 12 hour clock.

What I wrote:

   currentTime = [NSDate date];
dateComponents = [calendar components:unitFlags fromDate:currentTime];
hour = [dateComponents hour];
minute = [dateComponents minute];
second = [dateComponents second];
hourAngle = (30 * hour + minute / 2);
minAngle = (6 * minute);
secAngle = (6 * second);
secondHand.transform = CGAffineTransformMakeRotation(secAngle * M_PI / 180);
minuteHand.transform = CGAffineTransformMakeRotation(minAngle * M_PI / 180);
hourHand.transform = CGAffineTransformMakeRotation(hourAngle * M_PI / 180);

This works perfectly for a 12 hour clock but I would like to make it 24 so I was advised to divide my angle values by 2 like this:

hourAngle = (30 * hour + minute / 2) /2;
minAngle = (6 * minute) /2;
secAngle = (6 * second) /2; 

However this gives me a top to bottom 180 degree angle which resets after reaching the 180 degrees.

What do I need to change to get a full 360 degree rotation for my clock?

Answer 1

Clearly, the angles for minutes and seconds don’t change. Only the hour angle is halved. Also, be sure that hour reaches all values up to 23.