Gesture response slows with use

Question

I am using UIGestureRecognizer to detect taps or swipes and change page in my app.

After some use (perhaps 50 odd page loads) the app starts to respond noticeably slower to gestures. You can tap and wait a full second for the gesture to be recognised.

I have checked my code and it is not the page turning that is slowing down, as that still works by other means (bluetooth keyboard). Also the response of buttons and menus does not slow down.

Does anyone know what might be causing this? It eventually causes the app to become unusable.

score 3 · Accepted Answer · answered Jan 09 '12 at 12:37

3

There could be quite a few things. The first thing I would do is run instruments against the app and look for leaks. A slow down like this could be caused by objects being created and not released. Also note that the leaks instrument does not pick up everything. I've often picked up on objects leaking by looking at the allocations and checking that the correct number of instances are alive.

answered Jan 09 '12 at 12:37

drekka

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Turns out I was adding multiple gesture recognisers, but this is still great advice to anyone whose app is slowing down. – colincameron Jan 09 '12 at 12:43
Had a feeling it would be something like that:-) – drekka Jan 09 '12 at 22:34
Thank you so much! I was way off with this, thought it was related to UICollectionView and CPU usage and searching for touch lag found nothing, had to be very specific to get here :) Thanks !! – keisar Apr 01 '14 at 06:34

score 3 · Answer 2 · answered Jan 09 '12 at 12:40

3

Problem solved! It turns out I was adding new gesture recognisers each time a page was loaded without removing the previous ones.

answered Jan 09 '12 at 12:40

colincameron

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score 1 · Answer 3 · edited May 23 '17 at 10:29

I was having this slow segue problem, only when swiping for the segue. I came to this thread and saw the post from @colincameron saying that he was stacking gesture recognizers with each load.

So I went and found this SO thread, where @robmayoff shows how to remove all gesture recognizers from a view. You could add this removal code to your prepareForSegue, viewDidDisappear, etc

Swift

subview.gestureRecognizers?.forEach(subview.removeGestureRecognizer)

That code solved my slow segue problem.

Gesture response slows with use

3 Answers3