Question

I would like to make a sequence of activities (A and B) using 2 timers.
I get some problems with timer invalidate…
Is this the correct way to proceed?
Thank you!!!

timerAStart = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(startActivityA) userInfo:nil repeats:NO];
timerAStop = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(StopA) userInfo:nil repeats:NO];
timerBStart = [NSTimer scheduledTimerWithTimeInterval:3 target:self selector:@selector(startActivityB) userInfo:nil repeats:NO];
timerBStop = [NSTimer scheduledTimerWithTimeInterval:4 target:self selector:@selector(StopB) userInfo:nil repeats:NO];
- (void) StopA {
[timerAStart invalidate];
timerAStart=nil;
}
- (void) StopB {
[timerBStart invalidate];
timerBStart=nil;
}

Answer 1

You don’t need to invalidate since your timer is non-repeating. If you look at the documentation you’ll see that non-repeating timers self-invalidate.