How to access the remaining time of a non repeating NSTimer

Question

I'm trying to access the remaining time of an NSTimer X. I want to update the title of a button every second to reflect remaining mm:ss until zero. I couldn't find anything here.

For example: [btY setTitle:[What to insert here?] forState:UIControlStateSelected];

Or would you rather solve this in a different way?

Answer 1

You can use fireDate

NSTimer *timer = [NSTimer timerWithInterval:1.0 target:self selector:@selector(updateButton) userInfo:nil repeats:YES];


- (void)updateButton:(NSTimer*)timer
{
    float timeRemaining = timer.fireDate.timeIntervalSinceNow;
    // Format timeRemaining into your preferred string form and 
    // update the button text
}

Answer 2

This is generally not how you would solve this.

Create a repeating NSTimer set to the resolution at which you want to update the button instead.

So for instance, if you want your button to change every second until zero, create a NSTimer like so:

NSTimer *timer = [NSTimer timerWithInterval:1.0 target:self selector:@selector(updateButton) userInfo:nil repeats:YES];

Then implement updateButton; basically have a counter for remaining seconds, and every time updateButton gets called, decrease the counter by one, and update the title of the button.