I am getting a strange behavior when I reopen my app after it loses focus from the home button. On the simulator the app screen goes black for 5 seconds or more before the application is resumed. On the test device, the application either does the long delay or quits entirely and resets to starting state. I have put NSLog debug comments in the “applicationWillEnterForeground” and “applicationDidBecomeActive” but these only appear after the long delay so I will assume for now that nothing in these functions cause this delay.
I am using the following components in my program:
* a Tab Bar Controller
* 2 Timers, the Map kit
* IP socket streams
* 24 ViewControllers strung together on a storyboard.
* quite a few background images and image buttons
I would happily post code if I know what parts of the program was causing this error, but as it is I am clueless. Has anyone else experienced this type of error? Do any of the components I have listed have a history of causing similar errors?
I was quite far in development when this bug was discovered and I did not test for loss of focus via home button during the incremental development process. Other, smaller projects (which used sockets and timers) did not suffer from the same bug on the same test hardware.
I am using “applicationWillResignActive” to disable the timers, and close the streams. I am using “applicationDidBecomeActive” to restart the timers, and reopen the streams. The delay is occurring before “applicationWillEnterForeground” and “applicationDidBecomeActive” is run. Further more I tried disabling the code that initiates the streams and timers, but this did not have any effect on the bug.
I am using xCode4.4.1, ios6, and am building exclusively for iPads.
It's possible that the debugger is playing tricks with your mind regarding when it shows that you hit a breakpoint and the code execution of applicationWillEnterForeground. I suggest you commit your most recent code to source control and start deleting sections one at a time till you see the behavior go away.
Related
I have an Electron app (running on a Mac) that waits in the background for a key press, before showing a window.
If I leave it in the background overnight and then use it, it will be very slow for the first 10 seconds or so. It seems like updating the DOM and inter-process communication are both slow. The delay isn't coming from my code, and it seems to affect the renderer process primarily. After the initial slowness, it starts working normally.
Is there any reason that an Electron app would do this? Is it getting unloaded from memory somehow?
What's odd is that the initial display of the window happens instantly; it's just after I start to do some inter-process communication that it slows down.
There are a few possible answers to this, but after spending countless hours figuring it out, I thought I'd share the one that worked for me.
I was showing an animated SVG when I put the app in the foreground, and hiding it when I put it in the background. Apparently this was queueing up animation frames even while hidden, and then un-queueing them when it was shown, causing the delay.
It was fixed by upgrading Electron from 8.5.5 to 9.0.0, which I believe upgraded Chromium from 80.0.3987.165 to 83.0.4103.64. Not sure what the exact fix was, but it worked.
I have an iOS Xcode project that previously would load fast, but from time to time, now will hang for five seconds or more during loading. When the app is run on an iPhone, the launch screen displays instantly, but sometimes, not always, and unpredictably, the app just hangs for around 5 seconds or more until the actual interface is displayed. It occurs both on the simulator and device across different iOS versions 7, 8, 9.
Recently, a UIView's class that contains a drawRect function was changed slightly, it has an outlet connection to one of the ViewControllers, but no significant changes made overall. One ViewController has code in the ViewDidLoad, ViewWillAppear, ViewDidAppear functions. All these things I'm investigating if they are impacting the load time.
When I terminate the app, the next time I try running it, it loads super fast without issue. I have no idea what to make of this load behaviour.
Questions
1 - What methods can I use in Xcode to debug an app that loads slowly at irregular and unpredictable times?
2 - What obvious items should I be on the look out in the project that typically cause slow or prolonged load times?
3 - Does Xcode include tools to monitor the processes operating live while loading occurs?
4 - Is it possible to print output for load processes I can review?
Any experienced advice really appreciated. Thanks.
Not sure if you have looked instrumentation. It is the best way to determine this kind of issues with your app.
https://developer.apple.com/library/watchos/documentation/DeveloperTools/Conceptual/InstrumentsUserGuide/index.html
When I terminate the app, the next time I try running it, it loads super fast without issue. I have no idea what to make of this load behavior.
Do you mean exiting the app? Or actually killing it? Cause if it is the former, then the reason is the app was just launched from a suspended state.
I would suggest take a closer look at didFinishLaunchingWithOptions:, and check if you are doing something that takes more time than needed. Run your app with the time profiler instrument, it will tell you where is your bottleneck.
I am in the middle of development of an iOS OpenGL based game. So far I was not very concerned with the app states change and life cycle - background, foreground, suspended, terminated etc. Now I wanted to add support to moving the app into a suspended mode (after pressing home) and then nicely recuperate it after restarting it.
My problem is that after pressing home button, the app always gets terminated (the application delegate always reaches -applicationWillTerminate:)
The documentation mentions that in order to prevent termination it is important to clear as much memory as possible, stop any timers etc. Doing this did not help to prevent termination, so I tried to experimentally copy the app delegate form an Xcode template app, with completely NO initialization of my app objects after launch/activation, no storyboard, nothing special in main.m.
While the template (I used an Xcode game template) is never terminated after pressing home, it ends at -applicationDidEnterBackground:, my app despite of the fact that is uses less memory and starts completely no tasks is always terminated.
What may be the reason. Included but inactive frameworks ? I have no clue.
While attempting to optimize load speed I started placing timers in different places and looking at the performance. The app uses OpenGL and Core Data and has a decent amount of screens and artwork.
But the largest part of the lag seems to be taking place prior to applicationWillEnterForeground (assuming it's not a cold load)
The app shows up and is displayed and the UI is unresponsive for close to 5 seconds. I start a timer and print a time as soon as I can press a button. The time between applicationWillEnterForeground and when I can press the button is 200 milliseconds.
What can be causing my application to be slow to load prior to applicationWillEnterForeground or what can I do evaluate what is happening there? Instruments does not seem to display any information about that part of the launch.
Other testing app I have don't seem the same performance. Is it the bundle size or the amount of memory used by the application? Loading dynamic libraries?
This was related to OpenAL. The app was not closing the OpenAL context and for some reason this caused considerable problems when closing and reloading the app. The app uses CosCos Denshion so I to make sure to call these.
[CDAudioManager end];
[SimpleAudioEngine end];
This is very difficult issue, since it doesn't occur every time.
When an app is just launched, returning from background, it is fine without any freezing.
After some time being in background, when I re-activate it, the whole UI is frozen for while, even the activity indicator is not animating. As time goes on, this freezing gets longer and finally causes the app to be terminated by iOS for not resuming in time.
I would like to learn what are the generic causes of an app to be unresponsive, especially if the app is supporting background running feature and re-activating after a period of being in background.
It looks like I have missed some fundamental techniques that should be respected to avoid freezing problems.
UPDATE: I am suspicious if saving UIImage into Core Data object can be the main reason. At launch, it's not visible, however, as time passes, numerous saveManagedObjectContext are performed while UIImage is still referenced.
Maybe I should have listened to the instruction not to save any image in Core Data?
check for your crash log if you are getting this
Exception Codes: 0x8badf00d
then its most probably your application is taking much time either in launch or while moving in background or terminate, actually app take much time in launch/shut iOS suspend it and our app freeze, there is no such time define in documents but as i experienced it should not be more then 4-5 seconds. check your app delegate applicationDidFinishLaunch or multitasking delegates there is some code which is taking time in completion. For more info lokk at these
http://developer.apple.com/library/ios/#technotes/tn2151/_index.html
http://en.wikipedia.org/wiki/Hexspeak