I've gotten some strange behavior lately. All animation suddenly stops working sometimes.
Sometimes everything runs smooth, and other times this happens. Pushing and popping views just snaps into place, UITableView cellrow animation doesn't work.
The app uses a lot of background threads so maybe there is something in there?
I can't really post code since I don't know where the problem is.
Has anyone had the same problem?
Could that be you attempting to update UI/animate in different background threads?
Try?
dispatch_async(dispatch_get_main_queue(), ^{
// code to update ui or start animation
});
Related
I have looked at multiple stackoverflow posts and googled about it for hours, but can't figure out why transition is so choppy. I am not doing too much work on my main thread, and I am just using some functions to calculate numbers to display in the tableview, which I tried putting on a separate thread, but that didn't help either!
It's choppy when I run it on the simulator and my phone too.
https://recordit.co/S5I772t5t6
Please help!!
Check if the pushed view controller has clear background color, or a background color with alpha < 1. In my experience this might cause the push animation to look odd.
I am running an app on the simulator and the launch screen is shown for much longer than normal, and then oddly fades into the app with what seems to be an opacity animation. I commented out all functions up until the viewDidLoad in the initial view controller and this didn't help. I placed log statements at points that might be slowing down or delaying but all the logs are logged out immediately and then this delay goes on for a few seconds and the fade happens. I tried using time profiler in instruments but the read-outs from completely mysterious to me.
Is this familiar to any one or are there other steps I can take to resolve this?
Sounds like you accidentally turned on Slow Animations in the simulator. Just turn it off again (Debug > Slow Animations, Command-T).
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.
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()
})