how to prevent an NSTimer to be delayed or interrupted by user interface actions in iOS 5

Question

How can I prevent a NSTimer from being delayed by the user scrolling a table?

I found the answer:

I had a timer that repeated about 8 or 9 times with intervals of 0.4 to 0.8 seconds. I don't need much precision, but if the user scrolls a table the timer would stop working until the table finished scrolling (this could be a few seconds wait!). I thought I needed background threads, but timers on background threads were somewhat complicated to implement.

The answer to my problem was very very simple and easy. I just need to add a line after invoking the timer:

//////////// start the timer

self.playingTimer = [NSTimer scheduledTimerWithTimeInterval:tempo target:self selector:@selector(playSoundFromArray:) userInfo:nil repeats:YES];

//////////// the magic line:

[[NSRunLoop currentRunLoop] addTimer:self.playingTimer forMode:UITrackingRunLoopMode];

Now I can scroll the table as much as I want and my timers work OK!!!

Now I need to study a little more NSRunLoop...

You should really post in question form, then answer your own question. — Patrick Perini, May 11 '12 at 21:25
Yup. Remove the first paragraph, then include the first two sentences of the second in the question. Remainder goes in the answer. I'd upvote both. — Steven Fisher, May 11 '12 at 21:29
Thanks for the suggestion. It's my first port here. I'm not allowed to answer my own questions in about 8 hours... — alvira, May 11 '12 at 21:50
Why haven't you answered your own question yet? It's been much more then 8 hours. — pasawaya, Jun 23 '12 at 03:08

score 1 · Answer 1 · answered Aug 15 '12 at 07:21

1

You should add your timer for NSDefaultRunLoopMode mode. UITrackingRunLoopMode is used by tracking UI actions(in your case scrolling).

answered Aug 15 '12 at 07:21

cekisakurek

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how to prevent an NSTimer to be delayed or interrupted by user interface actions in iOS 5

1 Answers1