I am almost done programming a fairly large app which does a lot of talking with a backend, has a lot of caff sounds and displays several animations using sprite sheets. Every XIB files is connected with one ViewController and the project uses ARC and is targeted iOS 5.0.
Testing the app using my iPhone 5 and using the Simulator works fine. However while beta testing I noticed several people using an iPhone 4 (specially people running many background apps) experience crashes while using the app. The crashes mostly appears when doing animations.
So.. how do I go from here? I tried using instruments to check allocations and leaks. Almost none leaks are occurring, and to be honest, I have a hard time understanding how I can use the allocations measurement. I made all my IBOutlets _weak and also all my attributes to a big singleton used throughout the app to _weak.
How should I measure? How should I test that memory gets free'd as intended? How do I avoid these crashes related to low memory?
Related
I'm using heap stack analysis techniques, as described widely on SO here
Everything makes sense, except for I'm trying to track down some UIViewController (subclasses) and they never show up in the allocations list (via parsing it or via search). Since most things in the app's lifecycle are going through VCs, and I can track down other objects allocated in them, I assume there's something I'm missing (...perhaps those are grouped under the much more broad malloc calls?)
I'm trying to track down an over-retained VC, so if anyone can provide useful insight, it'd be appreciated. Thanks!
I spent ages on this yesterday using the simulator, with iOS 8 and Xcode 6.3, with no joy. I think it's not symbolicating properly, hence all the mallocs. I think it's an Xcode bug, as it can't even attach to an iOS 7.1 simulator at all. It was working correctly with an iOS 8 device (8.3). Have you tried on a device yourself?
Have filed radar http://openradar.appspot.com/radar?id=4937802231840768
I am writing an app which displays a simple Apple Map across most of the screen. However, when I compare the speed of scrolling, there is a significant slow-down comparative to the native Apple Maps which come with iOS 6.
In my investigation of why, I noticed that the Facebook App (which also uses Apple Maps), the same performance hit is present.
This is most noticeable on iPhone 4 with iOS 6.
Does anyone know of a special view-related performance enhancing step or set of steps which I need to take to increase performance? I would like my maps to move as fluidly as the Apple Maps app.
I was having the same problem, and it looks like it could be due to having Development enabled on the device.
On the Apple Dev Forums I posted to ask about this for my problems (my post) and someone rightly reminded me that a lot of developers have been complaining about sluggish development devices.
So I went to the Organizer and Ignored my device from there, removing it as development enabled. I restarted the device and sure enough my MKMapView was a lot snappier. It was still sluggish at times, but the performance improved significantly.
Try it out for your device and see if you notice a difference.
I're released an iPad game which is developed on the Cocos2d framework. Ive tested the game on a number of devices iPad 3, and iPad 2 and never had any issues.
Now i'm getting a few reports back that its not launching properly on some devices. People are saying they are seeing the default.png images then the app is closing.
Any ideas?
Without crash report this is just a guessing game.
By all means try to reproduce the problem on your side.
Possible problems:
1. If the app takes too long to launch it will be closed by iOS.
2. If it does not have enough memory it will not launch as well.
Try the following:
I. Open many other heavy apps in the background so there is not much memory.
See how it affects your app launch.
II. During launch try to use as many fast taps as possible and fast gestures.
There is possibility that very early taps are not serviced properly or at all
and that can cause the crash.
III. Test on many devices as you can - especially low end.
I found the issue, it was to do with the social framework running on older devices where it isn't available.
I have some strange problems of memory management on iOS 5.1.1, I'm NOT using Automatic Reference Counting in the project. Everything works well on iPad 3 5.1 or other devices with 5.1 or lower, this issue happens to two different project (one game and one app). So I think I have coded the right retain/release stuff.
Generally some Objective-C objects are released before it should be. When access it later, app crash. This happens on an iPad 3 LTE, an iPad 3 Wifi and an iPod Touch 4, all running iOS 5.1.1. It never happened on any device running iOS 5.1 or lower. I haven't found any pattern for this. Sometimes even an UIView which is still one the screen get released, if user touches a button, app crashes.
I understand these kind of issue can be debugged with NSZombies. But when I enable NSZombies, this kind of problem never happened.
It looks like a bug of iOS 5.1.1 to me, I'm wondering if it can be fixed on app side.
I have an existing app that I made some recent changes to and I have been testing those changes. The app works perfectly fine on every iPad I test it on (iOS 4 and iOS 5). After loading several (50+) image-heavy views in my app I get a low memory warning and my viewDidUnload methods get called and they properly nil out all of their controls and my in-memory image cache clears itself out and the app continues just fine.
However, on an iPhone 4 and iPhone4s (iOS 5.0.1 and iOS 5.1) I run into a problem where my application runs out of memory without ever receiving a low memory warning. After loading several different views, eventually a new view will come up and be mostly blank and on the console I see memory allocation messages and the whole phone becomes un-responsive and sometimes kills my app.
The particular view that this happens on is different every time, so it's not related to any one view, just the accumulation of memory over time. I have also confirmed that I don't have any memory leaks either.
This existing question is similar:
IOS app killed for Low Memory but no Memory Warning received
and that answer suggests that this could happen if I'm stuck in a loop, but I'm pretty sure that my code isn't stuck in any loops. I'm just clicking through from one view to another in a UINavigationController and several images load in each view. Also, the other question was specifically happening on an iPad where I'm not seeing this issue on an iPad, only iPhones.
BTW, I've tried registering for the low memory notification through NotificationCenter and have an applicationDidReceiveMemoryWarning method in my app delegate and have breakpoints at both and neither get called. Also, no low memory message shows up in the debugger console either.
Any ideas on what might be happening?
Added on 3/26/2012:
Interestingly enough, when I tested my app on the new iPad, it has this same problem that I'm seeing on the iPhone 4 and 4s where the low memory notification is not being received. So I'm wondering if I'm seeing the same problem as this other thread:
The New iPad: Low Memory Warnings Not Appearing?
but that the developer on that thread is testing an iPad-only app and therefore not testing and finding this same problem on any iPhones.
I have done some extensive testing and have a list of devices where I properly received the low memory warning and devices where I don't ever receive it. So far I only see the problem on iOS5 or greater, however on iPad1s with iOS 5.0 and 5.1 I don't see the issue, so it's not just a problem on all devices on iOS 5.
Here is that list:
Proper Low Memory Warning
iPad1 4.2.1
iPad1 5.0
iPad1 5.1
iPad2 4.3.3
iPhone3G 4.2.1
iPod 3G 4.3.3
iPhone4 4.3.3
No Low Memory Warning
iPhone4 5.1
iPhone4s 5.0.1
iPad3 5.1
I've been banging my head on similar problems for the past week. I'm doing something different but with images so somewhat related.
You don't say where all those images are located - hopefully you write them to the file system, then load them into views using [UIImage imageWithContentsOfFile] (or if using CGImageRefs, then use a CGImageSourceCreateWithURL). What you want to avoid is having the images in memory (no swapping in iOS!).
in my case I had some mmap memory to hold the images, I had even unmapped the memory (which syncs it to the file system), but since syncing takes so long, I was being "charged" for that unsynced memory. What I did was essentially call fcntl(fd, F_FULLSYNC) on each of these files to force the system to flush each block before I continued.
I'm working on an app with tons of big images, on an iPad 3.
If I set iOS 5.0 as the Deployment Target, applicationDidReceiveMemoryWarning does not get called if the app consumes too much memory, and the app crashes.
However, applicationDidReceiveMemoryWarning does get called if I set iOS 5.1 as the Deployment Target. The OS thus flushes the cache containing the images that were previously loaded and the app doesn't crash.
The main problem is that I use UIImage imageNamed: to load my images, if your images are big use UIImage imageWithContentsOfFile instead so that they don't get cached (which is an issue if the size of the #2x is very big).
Note that if I display many images very quickly, applicationDidReceiveMemoryWarning doesn't get called in time in iOS 5.1, and I crash!
Can you try running in Instruments for the "Time Profiler" tool? It'll tell you if you're CPU bound in a different thread (though unless you create them yourself I'll be surprised if that's the case). Also good to run the "Allocations" instrument if that doesn't reveal smoking guns.
I have found exactly the behaviour on an iPad 3 running iOS 5.1. applicationDidReceiveMemoryWarning does not get called, nor NSNotifications for UIApplicationDidReceiveMemoryWarningNotification. I also tested the exact same code on some other devices, so you can add these to your list:
Proper low memory warning
iPad 2 5.0.1
iPad 2 4.3.5
iPhone 3GS 5.0.1
No low memory warning
iPad 3 5.1
The pattern could be: iOS devices with 512 MB or 1 GB memory running 5.0.1 - 5.1.
I'm not doing any heavy UIImage handling in this app. It seems that the behaviour from the OS has changed - either it is deliberately killing apps more aggressively (e.g. trying to be smarter about killing apps that look as though they have too onerous memory usage), or the low memory notifications are just broken.