How to create an NSTimer

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Timers are good if you want to delay executing a method, or if you need to call a method repeatedly. To set a one-off timer without setting a property you can use this:

// calls the updateLabel method in 5 seconds
[NSTimer scheduledTimerWithTimeInterval:5.0 target:self selector:@selector(updateLabel) userInfo:nil repeats:NO];

However, you won’t be able to stop it without a reference. This is fine for one-off timers, but you need one if you want to stop a repeating timer.

To start a repeating timer self.myTimer:

// calls the updateLabel method every 0.1 seconds
self.myTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateLabel) userInfo:nil repeats:YES];

And to stop if:

// stop the timer
[self.myTimer invalidate];

Here’s a working example on GitHub: https://github.com/versluis/TimerFun



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