I'm having an annoying issue with a custom transition using UIViewControllerContextTransitioning when triggering the animation from a tableView
I followed many tutorials out there, to name a few :
- http://www.brightec.co.uk/blog/ios-7-custom-view-controller-transitions-and-rotation-making-it-all-work
- http://objectivetoast.com/2014/03/17/custom-transitions-on-ios/
This is the exact problem I have (but no solution :/ ): Custom transition animation unknown delay between animationControllerForPresentedController and animateTransition
Sometimes it works, sometimes it's just to slow.
I don't know what happens behind the scenes between animationControllerForPresentedController and animateTransition. If you have an idea on how to debug that I'd like to hear it.
Even without seeing your code I'm pretty sure you having a main thread issue. (see http://www.raywenderlich.com/31166/25-ios-app-performance-tips-tricks#mainthread - understand that, both about not blocking the main thread and always doing UI on the main thread.
Related
I have an odd UI bug I am tracking down, where my UI in a particular UIViewController subclass shows up mostly ok and then animates itself to be totally ok.
I have tracked down where the "shift" is occurring, but have not yet completely solved the issue. While attempting to track down and fix the bug, I had a very, very odd thing happen.
I set and hit a breakpoint in -(void)viewDidAppear:(BOOL)animated for the UIViewController in question. When the breakpoint was hit, the UI on the attached phone was wrong. Then, while still on the breakpoint, without me taking any action, the UI performed the "shift" to correct the out-of-position frames.
How is this possible? Shouldn't -(void)viewDidAppear:(BOOL)animated fire on the main/UI thread? If so, how is any adjustment being made to the UI while paused?
There is a method with an asynchronous block as a parameter.
The first time the app runs, this method is called, and there is an animation that covers the entire screen. The method is making a network call that can take a pretty long time, around 7 seconds or so. When the block runs, the callback ends the animation and the app is ready to be interacted with again.
When I run the app in the simulator and tap around, everything runs as it should. When I run the EarlGrey test target, the animation freezes, and the test ultimately fails, because there is an element that can't be found. Behind the animation view (a subclass of UIView), some steps are still successfully carried out, even though the elements are not visible.
Lastly, this only happens on the first run of the app, since the network call in subsequent test runs is much shorter.
I've tried changing configurations to disable animations, and nothing seems to work for me. I can't really paste code, since the app is proprietary.
I'm happy to answer any and all clarifying questions, and very much looking forward to some help!
Disclaimer: This was all #khandpur. I joined the Google Open Source Slack channel, and he helped me debug hard.
The issue was the use of Facebook's Shimmer. I had this line in the setUp method:
[UIApplication sharedApplication].keyWindow.layer.speed = 100;
This was speeding up animations, but causing some conflict with shimmer, not too sure why. I'm going to comment in their repo.
I deleted that line, and while tests are a little slower, they're totally stable now.
Have you considered using kGREYConfigKeyURLBlacklistRegex to black list the URL, i.e prevent EarlGrey from waiting on the request? (assuming that the network wait is unnecessary for ur test). see EarlGrey/Common/GREYConfiguration.h
It seems that the api replaceCurrentItemWithPlayerItem: will stuck the main thread for some seconds, I understand that replacing the item need the information of the new item which might take some time to preload. But questions come up that why replaceCurrentItemWithPlayerItem: with a nil item object would also stuck the main thread?? It happens to me that sometimes it take more than 5 seconds to replace a nil playerItem.
I wonder what can I do to avoid the issue. Thanks for any advices!
I came across a similar blocking UI thread issue when I used UICollectionView to display and preview video in local photo library via ALAssetLibrary.
The scroll on switching videos is not smoothly,so I guess some method block UI thread.Then I use Core Animation of Instruments to analyze what exactly occupy the UI thread.In Time Profiler I found out that replaceCurrentItemWithPlayerItem need about 30ms to execute in main thread,which is more than 16ms (1000/60(fps)) result in choppy scrolling.
To solve the problem,first I tried that put replaceCurrentItemWithPlayerItem in to background thread using GCD,but It not work.I'm not sure if it is because the Cocoa itself need update UI when call replaceCurrentItemWithPlayerItem,which means the UI thread is still block.Finally I made it work by putting replaceCurrentItemWithPlayerItem at the scrolling end (the delegate func scrollViewDidEndDecelerating(scrollView: UIScrollView)).Now the scrolling is smoothly,yep!
Therefore,my advice is obvious : Using Instruments to analyse what exactly occupy the UI thread
I have a strange issue both on mobile device and in simulator.
After a while spent in the application, animations on UIView are disabled (like if animated was set to NO), notably on :
pushViewController in a UINavigationController (also true for popTo)
displaying a UIActionSheet
switching between views with IIDeckViewController
This is quite strange as all transition are usually animated, and in a non predictable way, they all become non-animated
Everything was working well a few days agos, and as far as I can remind, I did not make any changes that should lead to such a behavior.
Any ideas ?
Thanks
Cheers
We recently had some trouble like this, the culprit was initiating some animations from a non-main thread (perhaps you are initiating a transition). This caused some trouble with animations transactions getting rolled back and this broke animations until the transaction was rolled back. There were some entries on the console pointing to CA transactions. Setting CA_DEBUG_TRANSACTIONS=1 on the environment quickly revealed the stack of where the the transactions were started.
The fix was to not do anything that would create transactions from a non-main thread.
My app runs fine in iOS6, but in an unspecified upcoming version of iOS that I cannot name for NDA reasons, all UIViewController transition animations stop working. New views just pop into place instantly. I am not sure if this unspecified future version of iOS is the cause, as I've seen this happen occasionally in iOS6.
Sometimes animations start working for a while and then stop shortly after, making me think it's some sort of memory warning issue, but my app is using a fairly reasonable ~125MB of RAM at most times. Can anyone offer any advice or things to investigate?
The described behavior has always existed: if you do work on background threads and then call and UIKit methods then more often than not the update will be delayed in a weird way.
Because of this you should always dispatch_async onto the main queue to update the UI.
Those bugs are very hard to catch since they do not always occur predictably.
To catch them I built a method that swizzles some UIKit methods to check if they are called on the main thread. This allows you to stop on a symbolic breakpoint, whenever you have forgotten to dispatch back onto main queue.
https://github.com/Cocoanetics/DTFoundation/blob/develop/Core/Source/iOS/Debug/UIView%2BDTDebug.m
A good workaround from the Apple dev forums on this issue:
Do this:
[UIView setAnimationsEnabled:YES]
And animations start working again. I suspect that this is either a straight up iOS7 bug, or somewhere in my code an animation or UIViewController launch is happening on a background thread, causing animations to stop. Probably unrelated to the unspecified future version of iOS.
This issue appears to be caused by doing UIKit stuff in background threads. I have a pre-render cache full of NSOperations that renders complex UIViews to UIImages to cache the output. This seemed to work fine in iOS6, but probably does cross the line somewhat. I'll need to replace this functionality with something that renders images and text to a graphics buffer rather than using UIViews and UILabels at all.
All you have to do is catch hold of main queue while updating UI on receiving response from an API.Ios uses main queue by default for updating UI but it is not 100 percent efficient.Hence you have to make sure that the UI gets updated on main thread only and the way to do that is as below:
DispatchQueue.main.async{
//UI related code eg:
self.label.text = "abc"
self.button.setTitle("xyz",.normal)
self.tableView.reloadData()
}
If you are not catching hold of main thread animations may or may not work.
But if you are using main thread animations will definetely work.
Correct Code while updating UI on api response:
Alamofire.getApiCall(paramaters: parameters, completion:{
response in
// UI related code.
DispatchQueue.main.async{
self.label.text = "abc"
self.button.setTitle("xyz",.normal)
self.tableView.reloadData()
}
})
Incorrect Code which may cause animations to stop and lead to weird crashes:
Alamofire.getApiCall(paramaters: parameters, completion:{
response in
// UI related code.
self.label.text = "abc"
self.button.setTitle("xyz",.normal)
self.tableView.reloadData()
})