Should Objective-C Custom Timer Class be in Model or Controller - ios

Question

I've created a custom Timer Class with public API allowing access to a property timeLeft, and allowing the calling class to start and pause the timer, as well as a Boolean isTimerPaused.
I need the Timer to be initialized and started, and paused inside of my game loop for various situations. So I've gone ahead with initializing my timer in my game (model) as such:
#define timerDuration 10
self.timer =[[Timer alloc] initWithTimerDurationInSeconds:timerDuration];
Here is a look at my Timer API:
#interface Timer : NSObject
-(id)initWithTimerDurationInSeconds:(NSTimeInterval)duration;
-(void)startTimer;
-(void)pauseTimer;
#property (nonatomic, getter = isTimerPaused)BOOL timerPaused;
#property (nonatomic)NSTimeInterval timeLeft;
#end
and my Timer implementation
#import "Timer.h"
#interface Timer ()
#property (nonatomic)NSTimeInterval timeRemaining;
#property (nonatomic)NSTimeInterval duration;
#property (strong, nonatomic) NSTimer *timer;
#property (strong, nonatomic)NSDate *targetTime;
#end
#implementation Timer
-(id)initWithTimerDurationInSeconds:(NSTimeInterval)duration
{
self = [super init];
if (self)
{
if (duration) _duration = duration;
else NSLog(#"Must Initialize Timer With Duration");
}
return self;
}
-(void)startTimer
{
self.targetTime = [NSDate dateWithTimeIntervalSinceNow:self.duration];
self.timer = [NSTimer scheduledTimerWithTimeInterval:.05 target:self selector:#selector(updateTimerLabel) userInfo:nil repeats:YES];
self.timerPaused = NO;
}
-(void)pauseTimer
{
self.timerPaused = !self.isTimerPaused;
if (self.isTimerPaused)
{
self.timeRemaining = [self.targetTime timeIntervalSinceNow];
[self.timer invalidate];
self.timer = nil;
}
else
{
self.targetTime = [NSDate dateWithTimeIntervalSinceNow:self.timeRemaining];
self.timer = [NSTimer scheduledTimerWithTimeInterval:.05 target:self selector:#selector(updateTimerLabel) userInfo:nil repeats:YES];
}
}
-(void)updateTimeLeft
{
self.timeLeft = [self.targetTime timeIntervalSinceNow];
if (self.timeLeft <=0)
{
[self.timer invalidate];
ago", -timeLeft];
}
}
#end
This all in theory will work great as I can start and stop my timer as needed inside of my game loop, and i can access time left to update my timer UILabel from my Controller.
My issue is this, If the timer were in my controller, I could simply update the label inside of the updateTimeLeft method. With the timer in the model how do I go about refreshing UI Elements continuously. My thought was to have some sort of continuous timer in my controller that would update the UILabel with the timeLeft property from the timer, but that seems inefficient and prone to being slightly inaccurate.
Thanks!

Answer 1

With the timer in the model how do I go about refreshing UI Elements continuously?
Move the timer out of your model. Seriously.
Every graphic representation of MVC you will come across has a nice solid line between the View layer and the Model layer, and there's a reason for that. If the model knows too much about the view, then your application becomes overly data-driven and bloated. The same goes for the opposite. Plug the timer into your controller, and route updates to the model from the controller to prevent any leakage of responsibilities into the wrong parts of your application.