UITableView Scroll issue with 100% cpu usage static

Question

NicolaCastellani OP

Created Sep ’17

Replies 3

Boosts 0

Views 1.8k

Participants 2

Hi to all!

I'm new on Apple Developer Program so I'm sorry for any bad-practise on this Forum.

I'm testing our applications on iOS 11 beta 8 (Xcode beta 6) and I'm getting stuck with an Hard issue on UITableView.

The scenario is:

# We have a 500+ rows on a UITableView with 8 columns.

# When we scroll there is no issue, when the table stop scrolling the cpu usage jump up to 100%.

# If we have scrolled a small number of rows the cpu usage drop down after one second.

# If we scroll at half table the cpu usage jumps to 100% and never go down.

It seems to be a problem with CoreFoundation while animating the scroll, here there is the instruments record:

https://www.dropbox.com/sh/mk13pf15b08imof/AADc-XJJjmrp6ZKZGqD68Mola?dl=0

As you can see from those screenshots there are 2 core processes wich are looping and put cpu at highest usage:

1.99 s 62.4% 0 s __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__

1.19 s 37.3% 0 s __CFRunLoopDoTimers

I don't know why this happens in iOS 11, on iOS 10.3.3 there wasn't this issue, the only differences on the main swift file are some @objc tags and the new swift 4 compiler.

Let me know if you need more informations, Cheers!

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Answer 1

anils OP

Sep ’17

Have you tried on latest beta.

0

Answer 2

NicolaCastellani OP

Sep ’17

Hi Anils, thanks for you reply.

Yes I've tried but the problem persist.

Cheers.

0

Answer 3

NicolaCastellani OP

Oct ’17

Ok so I've partially solved this issue (wich is still present on iOS 11.1 beta 2 XCode 9.1 beta 2).

The problem was related to the UITextView, for some reason when you assign something wich is nil or empty or is not a String value to the UITextView.text property after scrolling the Table the iOS system start an infinite loop.

I think this problem is related to the dequeReusableCell function, I've solved the issue just adding a check like this:

if(myTextView.text != ""){
     myViewContainer.addSubView(myTextView);
}

This isn't a good solution to this bug, but now my tableview doesn't crash my entire application.
I swear than the future iOS releases will solve this issue.

0